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TemperaTure managemenTSOLuTIOnS
Heat tRaCe DeSIGN GUIDe
Copyright © 2002-2007, 2009-2012, 2015, Chromalox, Inc. All rights reserved. Chromalox and the Chromalox logo are trademarks of Chromalox, Inc.
103 Gamma Drive Pittsburgh, PA 15238 USA
Phone: (412) 967-3800 Fax: (412) 967-5148 Toll-Free 1-800-443-2640
www.chromalox.com
PJ130-8
Table2
InsulationAdjustm
entFactors
Insulation
Factor
Pip
e Insulation Typ
eP
ipe Insulatio
n Type
Insulation
Factor
Glass fiber (A
STM
C547)
1.00
Calcium
silicate (AS
TM C
533)
1.48
Cellular glass (A
STM
C552)
1.48
Rigid cellular urethane (A
STM
C591)
0.64
Foamed elastom
er (AS
TM C
534) 1.16
Mineral fib
er blanket (A
STM
C553)
1.16
Expanded
perlite (A
STM
C610)
1.90
1.Basic
HeatLoss:Afterdeterm
iningthe
differencebetw
eenthe
ambientand
desiredpipe
maintenance
temperature,T
m ,useTable
1to
figurethe
basicheatloss
forthepipe
sizeand
insulationthickness.
2.Insulation
Adjustment:
UsingTable
2,findthe
typeofinsulation
beingused
andits
insulationfactor.
Heat Trace Design Guide
APipe
HeatLossCalculations
• Heat Trace System Design
• Materials & Components
• Specification Tables
3.Calculate
QF :
Multiply
thebasic
heatlossfigure
fromTable
1by
theadjustm
entfactorfromTable
2to
calculatethe
estimated
heatloss,QF ,in
watts
perfootofpipelength.
4.CorrectforIndoorLocation/W
indSpeed:
Iflocationis
indoors,multiply
QF by
0.9.Table
1is
basedon
10%safety
factorand20
mph
wind
speed;add5%
margin
foreach5
mph
over20m
phw
indspeed.
Table1
PipeHeatLoss
QP in
W/ftBased
onTem
peratureDifferentialand
InsulationThickness
Nominal
PipeSize,
in.(ID)
Temperature
DifferenceBetw
eenPipe
andAm
bient
DegºF40ºF
50ºF60ºF
70ºF80ºF
90ºF100ºF
120ºF140ºF
160ºF180ºF
200ºF220ºF
240ºF260ºF
1"Insulation
Thickness1/ 2"
W/ft
1.41.8
2.12.5
2.83.2
3.54.2
5.15.9
6.67.7
8.59.2
10.03/ 4"
W/ft
1.62.0
2.42.8
3.23.6
4.04.8
5.96.7
7.68.8
9.710.6
11.4
1"W
/ft1.8
2.32.8
3.23.7
4.14.6
5.56.8
7.78.7
10.111.1
12.113.2
11/ 2"
W/ft
2.43.1
3.74.3
4.95.5
6.17.3
9.010.2
11.513.4
14.816.1
17.4
2"W
/ft2.8
3.54.1
4.85.5
6.26.9
8.310.1
11.613.0
15.216.7
18.219.7
21/ 2"
W/ft
3.24.0
4.85.6
6.47.2
8.09.6
11.813.4
15.117.6
19.421.1
22.9
3"W
/ft3.7
4.75.6
6.57.4
8.49.3
11.213.7
15.617.6
20.522.5
24.626.6
4"W
/ft4.6
5.86.9
8.19.2
10.411.5
13.816.9
19.321.7
25.327.8
30.432.9
6"W
/ft6.4
8.09.6
11.212.8
14.416.0
19.223.5
26.930.2
35.238.7
42.245.8
8"W
/ft8.1
10.112.1
14.116.2
18.220.2
24.229.7
33.938.2
44.448.9
53.357.8
10"W
/ft9.9
12.414.8
17.319.8
22.224.7
29.636.3
41.546.7
54.359.8
65.270.6
12"W
/ft11.6
14.517.4
20.323.2
26.129.0
34.842.6
48.754.8
63.870.2
76.682.9
14"W
/ft12.6
15.819.0
22.125.3
28.431.6
37.946.5
53.159.7
69.576.5
83.490.4
16"W
/ft14.3
17.921.5
25.128.7
32.335.9
43.052.7
60.267.8
78.986.8
94.6102.5
18"W
/ft16.0
20.124.1
28.132.1
36.140.1
48.158.9
67.475.8
88.297.0
105.9114.7
20"W
/ft17.7
22.226.6
31.035.4
39.944.3
53.265.1
74.483.7
97.5107.2
117.0126.7
22"W
/ft19.4
24.329.1
34.038.8
43.748.5
58.271.3
81.591.7
106.7117.4
128.0138.7
24"W
/ft21.1
26.431.6
36.942.2
47.452.7
63.277.5
88.599.6
115.9127.5
139.1150.7
1.5"Insulation
Thickness1/ 2"
W/ft
1.11.4
1.72.0
2.22.5
2.83.5
4.14.7
5.56.2
6.87.4
8.03/ 4"
W/ft
1.21.6
1.92.2
2.52.8
3.13.9
4.65.2
6.16.8
7.58.2
8.9
1"W
/ft1.4
1.82.2
2.52.9
3.23.6
4.55.3
6.07.1
7.98.7
9.510.3
11/ 2"
W/ft
1.82.3
2.83.2
3.74.1
4.65.8
6.87.7
9.110.1
11.112.1
13.2
2"W
/ft2.1
2.63.1
3.64.2
4.75.2
6.67.6
8.710.3
11.412.6
13.714.9
21/ 2"
W/ft
2.43.0
3.54.1
4.75.3
5.97.4
8.79.9
11.713.0
14.315.6
16.9
3"W
/ft2.7
3.44.1
4.85.4
6.16.8
8.610.0
11.413.5
15.016.5
18.019.4
4"W
/ft3.3
4.25.0
5.86.6
7.58.3
10.512.2
13.916.4
18.320.1
21.923.7
6"W
/ft4.5
5.76.8
7.99.0
10.211.3
14.216.6
19.022.4
24.927.3
29.832.3
8"W
/ft5.6
7.18.5
9.911.3
12.714.1
17.820.7
23.727.9
31.034.1
37.240.3
10"W
/ft6.8
8.010.3
12.013.7
15.417.1
21.525.1
28.733.9
37.641.4
45.148.9
12"W
/ft8.0
10.012.0
14.016.0
18.020.0
25.229.4
33.639.6
44.048.4
52.857.2
14"W
/ft8.7
10.913.0
15.217.4
19.521.7
27.331.9
36.543.0
47.752.5
57.362.1
16"W
/ft9.8
12.314.8
17.219.7
22.124.6
31.036.2
41.348.7
54.159.5
64.970.4
18"W
/ft11.0
13.716.4
19.221.9
24.727.4
34.540.3
46.054.3
60.366.3
72.378.4
20"W
/ft12.1
15.118.1
21.124.2
27.230.2
38.144.4
50.759.8
66.473.1
79.786.4
22"W
/ft13.2
16.519.8
23.126.4
29.733.0
41.648.5
55.465.3
72.679.9
87.194.4
24"W
/ft14.3
17.921.5
25.128.6
32.235.8
45.152.6
60.170.9
78.886.6
94.5102.4
2"Insulation
Thickness1/ 2"
W/ft
1.01.2
1.41.7
1.92.2
2.43.0
3.54.0
4.85.3
5.86.3
7.23/ 4"
W/ft
1.11.4
1.61.9
2.22.4
2.73.4
4.04.5
5.35.9
6.57.1
8.1
1"W
/ft1.2
1.51.8
2.12.4
2.73.0
3.84.4
5.05.9
6.67.3
7.99.0
11/ 2"
W/ft
1.51.9
2.32.7
3.03.4
3.84.8
5.66.4
7.58.4
9.210.0
11.4
2"W
/ft1.7
2.22.6
3.03.4
3.94.3
5.46.3
7.28.5
9.510.4
11.412.9
21/ 2"
W/ft
1.92.4
2.93.4
3.84.3
4.86.0
7.18.1
9.510.6
11.612.7
14.4
3"W
/ft2.2
2.83.3
3.94.4
5.05.5
6.98.1
9.210.9
12.113.3
14.516.4
4"W
/ft2.6
3.34.0
4.65.3
5.96.6
8.39.7
11.113.1
14.516.0
17.419.7
6"W
/ft3.6
4.55.3
6.27.1
8.08.9
11.213.1
15.017.6
19.621.5
23.526.6
8"W
/ft4.4
5.66.7
7.88.9
10.011.1
14.016.3
18.622.0
24.426.9
29.333.2
10"W
/ft5.3
6.78.0
9.310.6
12.013.3
16.819.6
22.326.3
29.332.2
35.139.8
12"W
/ft6.2
7.89.3
10.912.4
14.015.5
19.522.8
26.030.7
34.137.5
40.946.3
14"W
/ft6.7
8.410.1
11.813.4
15.116.8
21.224.7
28.233.3
37.040.7
44.450.2
16"W
/ft7.6
9.511.3
13.215.1
17.018.9
23.827.8
31.837.4
41.645.7
49.956.5
18"W
/ft8.4
10.512.6
14.716.8
18.921.0
26.530.9
35.341.6
46.250.8
55.462.8
20"W
/ft9.2
11.613.9
16.218.5
20.823.1
29.134.0
38.845.7
50.855.9
61.069.1
22"W
/ft10.1
12.615.2
17.720.2
22.725.3
31.837.1
42.450.0
55.661.1
66.775.5
24"W
/ft11.0
13.716.4
19.221.9
24.727.4
34.540.3
46.054.3
60.366.3
72.381.9
609.6m
mW
/m36.1
44.953.8
63.071.9
3"(76.2
mm
)InsulationThickness
1/ 2"W
/ft0.8
1.01.2
1.41.6
1.82.0
2.52.9
3.44.0
4.44.8
5.56.0
3/ 4"W
/ft0.9
1.11.3
1.51.8
2.02.2
2.83.2
3.74.4
4.85.3
6.16.67
1"W
/ft1.0
1.31.5
1.82.0
2.32.5
3.23.7
4.25.0
5.56.1
6.97.5
11/ 2"
W/ft
1.21.5
1.82.1
2.42.7
3.03.8
4.45.0
5.96.6
7.38.3
9.0
2"W
/ft1.3
1.72.0
2.32.6
3.03.3
4.24.9
5.56.5
7.38.0
9.19.9
21/ 2"
W/ft
1.51.9
2.22.6
3.03.3
3.74.7
5.46.2
7.38.1
9.010.2
11.1
3"W
/ft1.7
2.12.5
2.93.4
3.84.2
5.36.2
7.18.3
9.210.2
11.612.6
4"W
/ft2.0
2.53.0
3.54.0
4.55.0
6.37.4
8.49.9
11.012.1
13.815.0
6"W
/ft2.6
3.33.9
4.65.2
5.96.5
8.29.6
10.912.9
14.315.7
17.919.4
8"W
/ft3.2
4.04.8
5.66.4
7.28.0
10.111.8
13.415.8
17.619.4
22.123.9
10"W
/ft3.8
4.85.7
6.77.6
8.69.5
12.014.0
16.018.8
20.923.0
26.228.4
12"W
/ft4.4
5.56.5
7.68.7
9.810.9
13.716.0
18.321.6
24.026.4
30.132.6
14"W
/ft4.7
5.97.1
8.39.4
10.611.8
14.917.3
19.823.4
26.028.6
32.635.3
16"W
/ft5.3
6.78.0
9.310.6
12.013.3
16.819.6
22.326.3
29.332.2
36.739.8
18”W
/ft5.9
7.48.8
10.311.8
13.214.7
18.521.6
24.729.1
32.335.6
40.644.0
20"W
/ft6.4
8.19.7
11.312.9
14.516.1
20.323.7
27.031.9
35.439.0
44.448.1
22"W
/ft7.0
8.810.5
12.314.0
15.817.5
22.125.7
29.434.7
38.542.4
48.352.3
24"W
/ft7.6
9.511.3
13.215.1
17.018.9
23.827.8
31.837.4
41.645.7
52.256.5
Nominal
PipeSize,
in.(ID)
Temperature
DifferenceBetw
eenPipe
andAm
bient
DegºF40ºF
50ºF60ºF
70ºF80ºF
90ºF100ºF
120ºF140ºF
160ºF180ºF
200ºF220ºF
240ºF260ºF
3”Insulation
Thickness
Installation Tips• Do not twist buss wires together at end
of circuit
• Insulate all conductive parts
• Seal all electrical connections against moisture
• Seal ends of exposed cable during installation
• Do not expose cables to temperatures abovetheir maximum ratings
• Install cable with aluminum tape for useon plastic pipes
• Locate ambient temperature sensors in coldestexpected area
• Locate pipe temperature sensors at lowestexpected line temperature
• Use sufficient cable to trace additional heat sinks
• Install cable so that valves can be removedwithout removing cable
Important SafeguardsMechanical Inspection
• Inspect all insulation and weatherproofing
• Inspect all junction box, connection box andsensor connections
• Verify all circuits have been properlygrounded
• Verify all circuits are connected in properpanel locations
• Verify proper circuit breakers are in place(always use 30mA trip GFI-type breakers)
• Verify all circuit lengths are within manufacturer’sspecified limits
• Verify all proper safety warnings are in place
• Verify all end seal, splice/tee locations are markedon lagging
Electrical Tests
• Insulation Resistance (Megger)– Before tracing pipes– After installing terminations– Before insulating pipes– After insulating pipes– Before energizing system
• Circuit Voltage
• Initial Current– Note ambient temp and pipe temp
• Stabilized Current (15 minutes of operation)– Note ambient temp and pipe temp
• Always use ground fault circuit breakers(30mA trip level)
Tools Needed• Wire Cutters/Strippers
• Megger
• Phillips Head Screwdriver
• Standard Screwdriver
• Voltmeter
• Utility Knife
• Hammer
SRL Cable• 150ºF / 65oC Maximum Maintenance
• 185ºF / 85oC Maximum Exposure
• 3-10 W/ft / 10-33 W/m
• 16 AWG with Optional TPE orFluoropolymer Jacket
SRM Cable• 302ºF / 150oC Maximum Maintenance
• 420ºF / 215oC Maximum Exposure
• 5-20 W/ft / 16-66 W/m
• 16 AWG with Optional Fluoropolymer Jacket
103 Gamma DrivePittsburgh, PA 15238USA
Chromalox®
PRECISION HEAT AND CONTROL
Copyright © 2002-2007, 2009-2012, Chromalox, Inc. All rights reserved.
Phone: (412) 967-3800Fax: (412) 967-5148Toll-Free: 1-800-443-2640
www.chromalox.com
PJ130-6
HEAT TRACE THERMAL DESIGN
SRP Cable• 225°F / 110°C Maintenance Temperature
• 275°F / 135°C Maximum Exposure Temperature
• 5-15 W/ft / 16-49 W/m
• 16 AWG with Optional Fluoropolymer Jacket
Chromalox
CableSelection
1.SelectHeating
CableFam
ily:Based
onthe
maxim
umm
aintenancetem
peraturerating,m
aximum
exposuretem
peraturerating,and
areaclassification,selectthe
heatingcable
family
fromTable
3.(SeeChrom
aloxHeatTrace
CableProductInform
ationSheets
forcableconstruction
options,voltageratings,
andw
attageoutputs
available.)
2.SelectTherm
alOutputRating:
(a)ForMetalPipes
–Use
Figures1,2
or4(b)ForPlastic
Pipes–
UseFigure
3by
findingthe
intersectionofthe
calculatedheatloss,Q
F ,andpipe
maintenance
temperature,T
m .Selectthecable
with
atherm
aloutputthatequalsorexceeds
QF atT
m .
Pip
eTem
perature
(ºF)M
aintenanceTem
perature
010
2030
5060
7080
90100
110120
130140
150
Thermal Output (W/ft)
14131211109876543210
4.88
SRL10&
HSRL10
SRL8&
HSRL8
SRL5&
HSRL5
SRL3&
HSRL3
CableOutput
versusTem
perature
40
Figure1
SRL&
HSRL–
ThermalOutput
Ratingson
InsulatedM
etalPipeFigure
2SRM
/E&
HSRM–
ThermalOutput
Ratingson
InsulatedM
etalPipeFigure
3SRL
&HSRL
–Therm
alOutputRatingson
PlasticPipe
with
Aluminum
Tape
B3.
Determine
TotalCableLength:
Inaddition
topipe
length,in-linecom
ponentssuch
asvalves,flanges,
andpipe
supportsrequire
additionalheattracingto
maintain
Tm .
SeeTable
4.Calculatethe
totalcable
lengthrequired
bycom
biningthe
pipelength
with
theadditionallengths
neededforallthe
othercomponents.
Table3
HeatingCable
Families
NOTE:Itis
theresponsibility
ofthefacility
managerorengineerto
determine
theclassification
ofanarea
where
heattracew
illbeinstalled.The
factorycan
helpdeterm
inea
suitablecable
basedon
theinform
ationprovided.
Table4
AdditionalCableLengths
Requiredfor
In-LineCom
ponentsBased
onPipe
IPS(Ir on
PipeSize)
1/ 2 in.1.00
1.001.00
1.001.00
1.001.00
0.30
3/ 4 in.1.50
1.001.00
1.001.50
1.001.00
0.30
1in.
2.001.00
1.001.00
1.501.00
1.000.30
11/ 2 in.
2.501.50
1.501.50
2.002.00
2.000.30
2in.
2.502.00
2.002.00
2.002.00
2.000.30
21/ 2 in.
2.502.00
2.002.00
2.002.00
2.000.30
3in.
3.002.50
2.502.50
2.002.00
2.000.50
4in.
4.003.00
3.003.00
2.502.50
2.500.50
6in.
5.003.50
3.503.50
2.502.50
2.500.80
8in.
7.004.00
4.004.00
2.502.50
2.500.80
10in.
8.004.50
4.504.50
3.003.00
3.000.80
12in.
9.005.00
5.005.00
3.003.00
3.000.80
14in.
10.005.50
5.505.50
3.003.00
3.001.00
16in.
11.006.00
6.006.00
3.503.50
3.501.00
18in.
12.007.00
7.007.00
3.503.50
3.501.00
20in.
13.007.50
7.507.50
3.503.50
3.501.00
22in.
13.007.50
7.507.50
3.503.50
3.501.00
24in.
15.008.00
8.008.00
4.004.00
4.001.00
PipingSize
GateValve
GlobeValve
BallValveButterfly
ValveHanger
SupportShoe
SupportSleeperSupport
FlangePair
ft
010
2030
5060
7080
90100
110120
130140
15040
Pip
eTem
perature
(ºF)
SRL10&
HSRL10
Thermal Output (W/ft)
9876543210
SRL8&
HSRL8SRL5&
HSRL5
SRL3&
HSRL3
CableOutput
versusTem
perature
Figure4
SRP–
ThermalOutputRatings
onInsulated
MetalPipe
Pip
eTem
perature
(ºF)
Heat Output (W/ft)
2120191817161514131211109876543210
15W
/ft
10W
/ft
5W
/ft
CableOutput
versusTem
perature
010
2030
4050
6070
8090
100110
120130
140150
160170
180190
200210
220230
HeatingCable
Family
AreaClassification
PipeM
aterial
Maxim
umM
aintenanceTem
perature
Maxim
umExposure
Temperature
(PowerOff)
Approvals
U.S.Other
SRL(Self-RegulatingLow
Temperature)
Ordinary
Plastic/Metal
150ºF/65ºC
185ºF/85ºC
UL,CSA,FMGOST,Cenelec,CE,ATEX
ClassI,Div.2,Gr.B,C,D
CSA,FM,(Gr.A,CSA
Only)GOST,Cenelec,CE,ATEX
ClassII,Div.2,Gr.E,F,G
CSA,FM,(Gr.E,CSA
Only)GOST,Cenelec,CE
ClassIII,Div.2
FMOnly
GOST,Cenelec,CE,ATEX
SRM/E
(Self-RegulatingM
ediumTem
perature)
Ordinary
MetalOnly
302ºF/150ºC
420ºF/215ºC
UL,CSA,FMGOST,Cenelec,CE,ATEX
ClassIDiv.2,Gr.A,B,C,D
CSA,FM,(Gr.A,CSA
Only)GOST,Cenelec,CE,ATEX
ClassII,Div.2,Gr.F,G
CSAOnly
GOST,Cenelec,CE,ATEX
SRP(Self-RegulatingM
ediumTem
perature)
Ordinary
MetalOnly
225ºF/110ºC
275ºF/135ºC
UL,CSA,FMPending
GOST,Cenelec,CE,ATEX
Pending
ClassI,Div.2,Gr.B,C,D
ClassII,Div.2,Gr.
F,G
ClassIII
HSRL(H-Self-RegulatingLow
Temperature)
ClassI,Div.1,Gr.B,C,D
Plastic/Metal
150ºF/65ºC
185ºF/85ºC
CSA,FM
ClassII,Div.1,Gr.E,F,G
CSA,FM
ClassIII,Div.1
CSA,FM
HSRM(H-Self-RegulatingM
ediumTem
perature)
ClassI,Div.1,Gr.B,C,D
MetalOnly
302ºF/150ºC
420ºF/215ºC
CSA,FM
ClassII,Div.1,Gr.E,F,G
CSA,FM
ClassIII,Div.1
CSA,FM
CWM
(ConstantWattage)
OrdinaryM
etalOnlyConsultFactory
392ºF/200ºC
UL,CSA
HazardousArea,ConsultFactory
MI(M
ineralInsulated)
Ordinary
MetalOnly
ConsultFactory1,100ºF
/595ºC
CSA,FM
ClassI,Div.2,Gr.B,C,D
CSA,FM
ClassII,Div.2,Gr.E,F,G
CSA,FM
ClassIII
CSA,FM
050
100150
200250
300
Pip
eTem
perature
(ºF)
SRM/E20
&HSRM
20Power Output (W/ft)
24201612840
SRM/E15
&HSRM
15
SRM/E10
&HSRM
10
SRM/E8
&HSRM
8
SRM/E5
&HSRM
5
SRM/E3
&HSRM
3
CableOutput
versusTem
perature
Table2
InsulationAdjustm
entFactors
Insulation
Factor
Pip
e Insulation Typ
eP
ipe Insulatio
n Type
Insulation
Factor
Glass fiber (A
STM
C547)
1.00
Calcium
silicate (AS
TM C
533)
1.48
Cellular glass (A
STM
C552)
1.48
Rigid cellular urethane (A
STM
C591)
0.64
Foamed elastom
er (AS
TM C
534) 1.16
Mineral fib
er blanket (A
STM
C553)
1.16
Expanded
perlite (A
STM
C610)
1.90
1.Basic
HeatLoss:Afterdeterm
iningthe
differencebetw
eenthe
ambientand
desiredpipe
maintenance
temperature,T
m ,useTable
1to
figurethe
basicheatloss
forthepipe
sizeand
insulationthickness.
2.Insulation
Adjustment:
UsingTable
2,findthe
typeofinsulation
beingused
andits
insulationfactor.
Heat Trace Design Guide
APipe
HeatLossCalculations
• Heat Trace System Design
• Materials & Components
• Specification Tables
3.Calculate
QF :
Multiply
thebasic
heatlossfigure
fromTable
1by
theadjustm
entfactorfromTable
2to
calculatethe
estimated
heatloss,QF ,in
watts
perfootofpipelength.
4.CorrectforIndoorLocation/W
indSpeed:
Iflocationis
indoors,multiply
QF by
0.9.Table
1is
basedon
10%safety
factorand20
mph
wind
speed;add5%
margin
foreach5
mph
over20m
phw
indspeed.
Table1
PipeHeatLoss
QP in
W/ftBased
onTem
peratureDifferentialand
InsulationThickness
Nominal
PipeSize,
in.(ID)
Temperature
DifferenceBetw
eenPipe
andAm
bient
DegºF40ºF
50ºF60ºF
70ºF80ºF
90ºF100ºF
120ºF140ºF
160ºF180ºF
200ºF220ºF
240ºF260ºF
1"Insulation
Thickness1/ 2"
W/ft
1.41.8
2.12.5
2.83.2
3.54.2
5.15.9
6.67.7
8.59.2
10.03/ 4"
W/ft
1.62.0
2.42.8
3.23.6
4.04.8
5.96.7
7.68.8
9.710.6
11.4
1"W
/ft1.8
2.32.8
3.23.7
4.14.6
5.56.8
7.78.7
10.111.1
12.113.2
11/ 2"
W/ft
2.43.1
3.74.3
4.95.5
6.17.3
9.010.2
11.513.4
14.816.1
17.4
2"W
/ft2.8
3.54.1
4.85.5
6.26.9
8.310.1
11.613.0
15.216.7
18.219.7
21/ 2"
W/ft
3.24.0
4.85.6
6.47.2
8.09.6
11.813.4
15.117.6
19.421.1
22.9
3"W
/ft3.7
4.75.6
6.57.4
8.49.3
11.213.7
15.617.6
20.522.5
24.626.6
4"W
/ft4.6
5.86.9
8.19.2
10.411.5
13.816.9
19.321.7
25.327.8
30.432.9
6"W
/ft6.4
8.09.6
11.212.8
14.416.0
19.223.5
26.930.2
35.238.7
42.245.8
8"W
/ft8.1
10.112.1
14.116.2
18.220.2
24.229.7
33.938.2
44.448.9
53.357.8
10"W
/ft9.9
12.414.8
17.319.8
22.224.7
29.636.3
41.546.7
54.359.8
65.270.6
12"W
/ft11.6
14.517.4
20.323.2
26.129.0
34.842.6
48.754.8
63.870.2
76.682.9
14"W
/ft12.6
15.819.0
22.125.3
28.431.6
37.946.5
53.159.7
69.576.5
83.490.4
16"W
/ft14.3
17.921.5
25.128.7
32.335.9
43.052.7
60.267.8
78.986.8
94.6102.5
18"W
/ft16.0
20.124.1
28.132.1
36.140.1
48.158.9
67.475.8
88.297.0
105.9114.7
20"W
/ft17.7
22.226.6
31.035.4
39.944.3
53.265.1
74.483.7
97.5107.2
117.0126.7
22"W
/ft19.4
24.329.1
34.038.8
43.748.5
58.271.3
81.591.7
106.7117.4
128.0138.7
24"W
/ft21.1
26.431.6
36.942.2
47.452.7
63.277.5
88.599.6
115.9127.5
139.1150.7
1.5"Insulation
Thickness1/ 2"
W/ft
1.11.4
1.72.0
2.22.5
2.83.5
4.14.7
5.56.2
6.87.4
8.03/ 4"
W/ft
1.21.6
1.92.2
2.52.8
3.13.9
4.65.2
6.16.8
7.58.2
8.9
1"W
/ft1.4
1.82.2
2.52.9
3.23.6
4.55.3
6.07.1
7.98.7
9.510.3
11/ 2"
W/ft
1.82.3
2.83.2
3.74.1
4.65.8
6.87.7
9.110.1
11.112.1
13.2
2"W
/ft2.1
2.63.1
3.64.2
4.75.2
6.67.6
8.710.3
11.412.6
13.714.9
21/ 2"
W/ft
2.43.0
3.54.1
4.75.3
5.97.4
8.79.9
11.713.0
14.315.6
16.9
3"W
/ft2.7
3.44.1
4.85.4
6.16.8
8.610.0
11.413.5
15.016.5
18.019.4
4"W
/ft3.3
4.25.0
5.86.6
7.58.3
10.512.2
13.916.4
18.320.1
21.923.7
6"W
/ft4.5
5.76.8
7.99.0
10.211.3
14.216.6
19.022.4
24.927.3
29.832.3
8"W
/ft5.6
7.18.5
9.911.3
12.714.1
17.820.7
23.727.9
31.034.1
37.240.3
10"W
/ft6.8
8.010.3
12.013.7
15.417.1
21.525.1
28.733.9
37.641.4
45.148.9
12"W
/ft8.0
10.012.0
14.016.0
18.020.0
25.229.4
33.639.6
44.048.4
52.857.2
14"W
/ft8.7
10.913.0
15.217.4
19.521.7
27.331.9
36.543.0
47.752.5
57.362.1
16"W
/ft9.8
12.314.8
17.219.7
22.124.6
31.036.2
41.348.7
54.159.5
64.970.4
18"W
/ft11.0
13.716.4
19.221.9
24.727.4
34.540.3
46.054.3
60.366.3
72.378.4
20"W
/ft12.1
15.118.1
21.124.2
27.230.2
38.144.4
50.759.8
66.473.1
79.786.4
22"W
/ft13.2
16.519.8
23.126.4
29.733.0
41.648.5
55.465.3
72.679.9
87.194.4
24"W
/ft14.3
17.921.5
25.128.6
32.235.8
45.152.6
60.170.9
78.886.6
94.5102.4
2"Insulation
Thickness1/ 2"
W/ft
1.01.2
1.41.7
1.92.2
2.43.0
3.54.0
4.85.3
5.86.3
7.23/ 4"
W/ft
1.11.4
1.61.9
2.22.4
2.73.4
4.04.5
5.35.9
6.57.1
8.1
1"W
/ft1.2
1.51.8
2.12.4
2.73.0
3.84.4
5.05.9
6.67.3
7.99.0
11/ 2"
W/ft
1.51.9
2.32.7
3.03.4
3.84.8
5.66.4
7.58.4
9.210.0
11.4
2"W
/ft1.7
2.22.6
3.03.4
3.94.3
5.46.3
7.28.5
9.510.4
11.412.9
21/ 2"
W/ft
1.92.4
2.93.4
3.84.3
4.86.0
7.18.1
9.510.6
11.612.7
14.4
3"W
/ft2.2
2.83.3
3.94.4
5.05.5
6.98.1
9.210.9
12.113.3
14.516.4
4"W
/ft2.6
3.34.0
4.65.3
5.96.6
8.39.7
11.113.1
14.516.0
17.419.7
6"W
/ft3.6
4.55.3
6.27.1
8.08.9
11.213.1
15.017.6
19.621.5
23.526.6
8"W
/ft4.4
5.66.7
7.88.9
10.011.1
14.016.3
18.622.0
24.426.9
29.333.2
10"W
/ft5.3
6.78.0
9.310.6
12.013.3
16.819.6
22.326.3
29.332.2
35.139.8
12"W
/ft6.2
7.89.3
10.912.4
14.015.5
19.522.8
26.030.7
34.137.5
40.946.3
14"W
/ft6.7
8.410.1
11.813.4
15.116.8
21.224.7
28.233.3
37.040.7
44.450.2
16"W
/ft7.6
9.511.3
13.215.1
17.018.9
23.827.8
31.837.4
41.645.7
49.956.5
18"W
/ft8.4
10.512.6
14.716.8
18.921.0
26.530.9
35.341.6
46.250.8
55.462.8
20"W
/ft9.2
11.613.9
16.218.5
20.823.1
29.134.0
38.845.7
50.855.9
61.069.1
22"W
/ft10.1
12.615.2
17.720.2
22.725.3
31.837.1
42.450.0
55.661.1
66.775.5
24"W
/ft11.0
13.716.4
19.221.9
24.727.4
34.540.3
46.054.3
60.366.3
72.381.9
609.6m
mW
/m36.1
44.953.8
63.071.9
3"(76.2
mm
)InsulationThickness
1/ 2"W
/ft0.8
1.01.2
1.41.6
1.82.0
2.52.9
3.44.0
4.44.8
5.56.0
3/ 4"W
/ft0.9
1.11.3
1.51.8
2.02.2
2.83.2
3.74.4
4.85.3
6.16.67
1"W
/ft1.0
1.31.5
1.82.0
2.32.5
3.23.7
4.25.0
5.56.1
6.97.5
11/ 2"
W/ft
1.21.5
1.82.1
2.42.7
3.03.8
4.45.0
5.96.6
7.38.3
9.0
2"W
/ft1.3
1.72.0
2.32.6
3.03.3
4.24.9
5.56.5
7.38.0
9.19.9
21/ 2"
W/ft
1.51.9
2.22.6
3.03.3
3.74.7
5.46.2
7.38.1
9.010.2
11.1
3"W
/ft1.7
2.12.5
2.93.4
3.84.2
5.36.2
7.18.3
9.210.2
11.612.6
4"W
/ft2.0
2.53.0
3.54.0
4.55.0
6.37.4
8.49.9
11.012.1
13.815.0
6"W
/ft2.6
3.33.9
4.65.2
5.96.5
8.29.6
10.912.9
14.315.7
17.919.4
8"W
/ft3.2
4.04.8
5.66.4
7.28.0
10.111.8
13.415.8
17.619.4
22.123.9
10"W
/ft3.8
4.85.7
6.77.6
8.69.5
12.014.0
16.018.8
20.923.0
26.228.4
12"W
/ft4.4
5.56.5
7.68.7
9.810.9
13.716.0
18.321.6
24.026.4
30.132.6
14"W
/ft4.7
5.97.1
8.39.4
10.611.8
14.917.3
19.823.4
26.028.6
32.635.3
16"W
/ft5.3
6.78.0
9.310.6
12.013.3
16.819.6
22.326.3
29.332.2
36.739.8
18”W
/ft5.9
7.48.8
10.311.8
13.214.7
18.521.6
24.729.1
32.335.6
40.644.0
20"W
/ft6.4
8.19.7
11.312.9
14.516.1
20.323.7
27.031.9
35.439.0
44.448.1
22"W
/ft7.0
8.810.5
12.314.0
15.817.5
22.125.7
29.434.7
38.542.4
48.352.3
24"W
/ft7.6
9.511.3
13.215.1
17.018.9
23.827.8
31.837.4
41.645.7
52.256.5
Nominal
PipeSize,
in.(ID)
Temperature
DifferenceBetw
eenPipe
andAm
bient
DegºF40ºF
50ºF60ºF
70ºF80ºF
90ºF100ºF
120ºF140ºF
160ºF180ºF
200ºF220ºF
240ºF260ºF
3”Insulation
Thickness
Installation Tips• Do not twist buss wires together at end
of circuit
• Insulate all conductive parts
• Seal all electrical connections against moisture
• Seal ends of exposed cable during installation
• Do not expose cables to temperatures abovetheir maximum ratings
• Install cable with aluminum tape for useon plastic pipes
• Locate ambient temperature sensors in coldestexpected area
• Locate pipe temperature sensors at lowestexpected line temperature
• Use sufficient cable to trace additional heat sinks
• Install cable so that valves can be removedwithout removing cable
Important SafeguardsMechanical Inspection
• Inspect all insulation and weatherproofing
• Inspect all junction box, connection box andsensor connections
• Verify all circuits have been properlygrounded
• Verify all circuits are connected in properpanel locations
• Verify proper circuit breakers are in place(always use 30mA trip GFI-type breakers)
• Verify all circuit lengths are within manufacturer’sspecified limits
• Verify all proper safety warnings are in place
• Verify all end seal, splice/tee locations are markedon lagging
Electrical Tests
• Insulation Resistance (Megger)– Before tracing pipes– After installing terminations– Before insulating pipes– After insulating pipes– Before energizing system
• Circuit Voltage
• Initial Current– Note ambient temp and pipe temp
• Stabilized Current (15 minutes of operation)– Note ambient temp and pipe temp
• Always use ground fault circuit breakers(30mA trip level)
Tools Needed• Wire Cutters/Strippers
• Megger
• Phillips Head Screwdriver
• Standard Screwdriver
• Voltmeter
• Utility Knife
• Hammer
SRL Cable• 150ºF / 65oC Maximum Maintenance
• 185ºF / 85oC Maximum Exposure
• 3-10 W/ft / 10-33 W/m
• 16 AWG with Optional TPE orFluoropolymer Jacket
SRM Cable• 302ºF / 150oC Maximum Maintenance
• 420ºF / 215oC Maximum Exposure
• 5-20 W/ft / 16-66 W/m
• 16 AWG with Optional Fluoropolymer Jacket
103 Gamma DrivePittsburgh, PA 15238USA
Chromalox®
PRECISION HEAT AND CONTROL
Copyright © 2002-2007, 2009-2012, Chromalox, Inc. All rights reserved.
Phone: (412) 967-3800Fax: (412) 967-5148Toll-Free: 1-800-443-2640
www.chromalox.com
PJ130-6
HEAT TRACE THERMAL DESIGN
SRP Cable• 225°F / 110°C Maintenance Temperature
• 275°F / 135°C Maximum Exposure Temperature
• 5-15 W/ft / 16-49 W/m
• 16 AWG with Optional Fluoropolymer Jacket
Chromalox
CableSelection
1.SelectHeating
CableFam
ily:Based
onthe
maxim
umm
aintenancetem
peraturerating,m
aximum
exposuretem
peraturerating,and
areaclassification,selectthe
heatingcable
family
fromTable
3.(SeeChrom
aloxHeatTrace
CableProductInform
ationSheets
forcableconstruction
options,voltageratings,
andw
attageoutputs
available.)
2.SelectTherm
alOutputRating:
(a)ForMetalPipes
–Use
Figures1,2
or4(b)ForPlastic
Pipes–
UseFigure
3by
findingthe
intersectionofthe
calculatedheatloss,Q
F ,andpipe
maintenance
temperature,T
m .Selectthecable
with
atherm
aloutputthatequalsorexceeds
QF atT
m .
Pip
eTem
perature
(ºF)M
aintenanceTem
perature
010
2030
5060
7080
90100
110120
130140
150
Thermal Output (W/ft)
14131211109876543210
4.88
SRL10&
HSRL10
SRL8&
HSRL8
SRL5&
HSRL5
SRL3&
HSRL3
CableOutput
versusTem
perature
40
Figure1
SRL&
HSRL–
ThermalOutput
Ratingson
InsulatedM
etalPipeFigure
2SRM
/E&
HSRM–
ThermalOutput
Ratingson
InsulatedM
etalPipeFigure
3SRL
&HSRL
–Therm
alOutputRatingson
PlasticPipe
with
Aluminum
Tape
B3.
Determine
TotalCableLength:
Inaddition
topipe
length,in-linecom
ponentssuch
asvalves,flanges,
andpipe
supportsrequire
additionalheattracingto
maintain
Tm .
SeeTable
4.Calculatethe
totalcable
lengthrequired
bycom
biningthe
pipelength
with
theadditionallengths
neededforallthe
othercomponents.
Table3
HeatingCable
Families
NOTE:Itis
theresponsibility
ofthefacility
managerorengineerto
determine
theclassification
ofanarea
where
heattracew
illbeinstalled.The
factorycan
helpdeterm
inea
suitablecable
basedon
theinform
ationprovided.
Table4
AdditionalCableLengths
Requiredfor
In-LineCom
ponentsBased
onPipe
IPS(Ir on
PipeSize)
1/ 2 in.1.00
1.001.00
1.001.00
1.001.00
0.30
3/ 4 in.1.50
1.001.00
1.001.50
1.001.00
0.30
1in.
2.001.00
1.001.00
1.501.00
1.000.30
11/ 2 in.
2.501.50
1.501.50
2.002.00
2.000.30
2in.
2.502.00
2.002.00
2.002.00
2.000.30
21/ 2 in.
2.502.00
2.002.00
2.002.00
2.000.30
3in.
3.002.50
2.502.50
2.002.00
2.000.50
4in.
4.003.00
3.003.00
2.502.50
2.500.50
6in.
5.003.50
3.503.50
2.502.50
2.500.80
8in.
7.004.00
4.004.00
2.502.50
2.500.80
10in.
8.004.50
4.504.50
3.003.00
3.000.80
12in.
9.005.00
5.005.00
3.003.00
3.000.80
14in.
10.005.50
5.505.50
3.003.00
3.001.00
16in.
11.006.00
6.006.00
3.503.50
3.501.00
18in.
12.007.00
7.007.00
3.503.50
3.501.00
20in.
13.007.50
7.507.50
3.503.50
3.501.00
22in.
13.007.50
7.507.50
3.503.50
3.501.00
24in.
15.008.00
8.008.00
4.004.00
4.001.00
PipingSize
GateValve
GlobeValve
BallValveButterfly
ValveHanger
SupportShoe
SupportSleeperSupport
FlangePair
ft
010
2030
5060
7080
90100
110120
130140
15040
Pip
eTem
perature
(ºF)
SRL10&
HSRL10
Thermal Output (W/ft)
9876543210
SRL8&
HSRL8SRL5&
HSRL5
SRL3&
HSRL3
CableOutput
versusTem
perature
Figure4
SRP–
ThermalOutputRatings
onInsulated
MetalPipe
Pip
eTem
perature
(ºF)
Heat Output (W/ft)
2120191817161514131211109876543210
15W
/ft
10W
/ft
5W
/ft
CableOutput
versusTem
perature
010
2030
4050
6070
8090
100110
120130
140150
160170
180190
200210
220230
HeatingCable
Family
AreaClassification
PipeM
aterial
Maxim
umM
aintenanceTem
perature
Maxim
umExposure
Temperature
(PowerOff)
Approvals
U.S.Other
SRL(Self-RegulatingLow
Temperature)
Ordinary
Plastic/Metal
150ºF/65ºC
185ºF/85ºC
UL,CSA,FMGOST,Cenelec,CE,ATEX
ClassI,Div.2,Gr.B,C,D
CSA,FM,(Gr.A,CSA
Only)GOST,Cenelec,CE,ATEX
ClassII,Div.2,Gr.E,F,G
CSA,FM,(Gr.E,CSA
Only)GOST,Cenelec,CE
ClassIII,Div.2
FMOnly
GOST,Cenelec,CE,ATEX
SRM/E
(Self-RegulatingM
ediumTem
perature)
Ordinary
MetalOnly
302ºF/150ºC
420ºF/215ºC
UL,CSA,FMGOST,Cenelec,CE,ATEX
ClassIDiv.2,Gr.A,B,C,D
CSA,FM,(Gr.A,CSA
Only)GOST,Cenelec,CE,ATEX
ClassII,Div.2,Gr.F,G
CSAOnly
GOST,Cenelec,CE,ATEX
SRP(Self-RegulatingM
ediumTem
perature)
Ordinary
MetalOnly
225ºF/110ºC
275ºF/135ºC
UL,CSA,FMPending
GOST,Cenelec,CE,ATEX
Pending
ClassI,Div.2,Gr.B,C,D
ClassII,Div.2,Gr.
F,G
ClassIII
HSRL(H-Self-RegulatingLow
Temperature)
ClassI,Div.1,Gr.B,C,D
Plastic/Metal
150ºF/65ºC
185ºF/85ºC
CSA,FM
ClassII,Div.1,Gr.E,F,G
CSA,FM
ClassIII,Div.1
CSA,FM
HSRM(H-Self-RegulatingM
ediumTem
perature)
ClassI,Div.1,Gr.B,C,D
MetalOnly
302ºF/150ºC
420ºF/215ºC
CSA,FM
ClassII,Div.1,Gr.E,F,G
CSA,FM
ClassIII,Div.1
CSA,FM
CWM
(ConstantWattage)
OrdinaryM
etalOnlyConsultFactory
392ºF/200ºC
UL,CSA
HazardousArea,ConsultFactory
MI(M
ineralInsulated)
Ordinary
MetalOnly
ConsultFactory1,100ºF
/595ºC
CSA,FM
ClassI,Div.2,Gr.B,C,D
CSA,FM
ClassII,Div.2,Gr.E,F,G
CSA,FM
ClassIII
CSA,FM
050
100150
200250
300
Pip
eTem
perature
(ºF)
SRM/E20
&HSRM
20Power Output (W/ft)
24201612840
SRM/E15
&HSRM
15
SRM/E10
&HSRM
10
SRM/E8
&HSRM
8
SRM/E5
&HSRM
5
SRM/E3
&HSRM
3
CableOutput
versusTem
perature
Table2
InsulationAdjustm
entFactors
Insulation
Factor
Pip
e Insulation Typ
eP
ipe Insulatio
n Type
Insulation
Factor
Glass fiber (A
STM
C547)
1.00
Calcium
silicate (AS
TM C
533)
1.48
Cellular glass (A
STM
C552)
1.48
Rigid cellular urethane (A
STM
C591)
0.64
Foamed elastom
er (AS
TM C
534) 1.16
Mineral fib
er blanket (A
STM
C553)
1.16
Expanded
perlite (A
STM
C610)
1.90
1.Basic
HeatLoss:Afterdeterm
iningthe
differencebetw
eenthe
ambientand
desiredpipe
maintenance
temperature,T
m ,useTable
1to
figurethe
basicheatloss
forthepipe
sizeand
insulationthickness.
2.Insulation
Adjustment:
UsingTable
2,findthe
typeofinsulation
beingused
andits
insulationfactor.
Heat Trace Design Guide
APipe
HeatLossCalculations
• Heat Trace System Design
• Materials & Components
• Specification Tables
3.Calculate
QF :
Multiply
thebasic
heatlossfigure
fromTable
1by
theadjustm
entfactorfromTable
2to
calculatethe
estimated
heatloss,QF ,in
watts
perfootofpipelength.
4.CorrectforIndoorLocation/W
indSpeed:
Iflocationis
indoors,multiply
QF by
0.9.Table
1is
basedon
10%safety
factorand20
mph
wind
speed;add5%
margin
foreach5
mph
over20m
phw
indspeed.
Table1
PipeHeatLoss
QP in
W/ftBased
onTem
peratureDifferentialand
InsulationThickness
Nominal
PipeSize,
in.(ID)
Temperature
DifferenceBetw
eenPipe
andAm
bient
DegºF40ºF
50ºF60ºF
70ºF80ºF
90ºF100ºF
120ºF140ºF
160ºF180ºF
200ºF220ºF
240ºF260ºF
1"Insulation
Thickness1/ 2"
W/ft
1.41.8
2.12.5
2.83.2
3.54.2
5.15.9
6.67.7
8.59.2
10.03/ 4"
W/ft
1.62.0
2.42.8
3.23.6
4.04.8
5.96.7
7.68.8
9.710.6
11.4
1"W
/ft1.8
2.32.8
3.23.7
4.14.6
5.56.8
7.78.7
10.111.1
12.113.2
11/ 2"
W/ft
2.43.1
3.74.3
4.95.5
6.17.3
9.010.2
11.513.4
14.816.1
17.4
2"W
/ft2.8
3.54.1
4.85.5
6.26.9
8.310.1
11.613.0
15.216.7
18.219.7
21/ 2"
W/ft
3.24.0
4.85.6
6.47.2
8.09.6
11.813.4
15.117.6
19.421.1
22.9
3"W
/ft3.7
4.75.6
6.57.4
8.49.3
11.213.7
15.617.6
20.522.5
24.626.6
4"W
/ft4.6
5.86.9
8.19.2
10.411.5
13.816.9
19.321.7
25.327.8
30.432.9
6"W
/ft6.4
8.09.6
11.212.8
14.416.0
19.223.5
26.930.2
35.238.7
42.245.8
8"W
/ft8.1
10.112.1
14.116.2
18.220.2
24.229.7
33.938.2
44.448.9
53.357.8
10"W
/ft9.9
12.414.8
17.319.8
22.224.7
29.636.3
41.546.7
54.359.8
65.270.6
12"W
/ft11.6
14.517.4
20.323.2
26.129.0
34.842.6
48.754.8
63.870.2
76.682.9
14"W
/ft12.6
15.819.0
22.125.3
28.431.6
37.946.5
53.159.7
69.576.5
83.490.4
16"W
/ft14.3
17.921.5
25.128.7
32.335.9
43.052.7
60.267.8
78.986.8
94.6102.5
18"W
/ft16.0
20.124.1
28.132.1
36.140.1
48.158.9
67.475.8
88.297.0
105.9114.7
20"W
/ft17.7
22.226.6
31.035.4
39.944.3
53.265.1
74.483.7
97.5107.2
117.0126.7
22"W
/ft19.4
24.329.1
34.038.8
43.748.5
58.271.3
81.591.7
106.7117.4
128.0138.7
24"W
/ft21.1
26.431.6
36.942.2
47.452.7
63.277.5
88.599.6
115.9127.5
139.1150.7
1.5"Insulation
Thickness1/ 2"
W/ft
1.11.4
1.72.0
2.22.5
2.83.5
4.14.7
5.56.2
6.87.4
8.03/ 4"
W/ft
1.21.6
1.92.2
2.52.8
3.13.9
4.65.2
6.16.8
7.58.2
8.9
1"W
/ft1.4
1.82.2
2.52.9
3.23.6
4.55.3
6.07.1
7.98.7
9.510.3
11/ 2"
W/ft
1.82.3
2.83.2
3.74.1
4.65.8
6.87.7
9.110.1
11.112.1
13.2
2"W
/ft2.1
2.63.1
3.64.2
4.75.2
6.67.6
8.710.3
11.412.6
13.714.9
21/ 2"
W/ft
2.43.0
3.54.1
4.75.3
5.97.4
8.79.9
11.713.0
14.315.6
16.9
3"W
/ft2.7
3.44.1
4.85.4
6.16.8
8.610.0
11.413.5
15.016.5
18.019.4
4"W
/ft3.3
4.25.0
5.86.6
7.58.3
10.512.2
13.916.4
18.320.1
21.923.7
6"W
/ft4.5
5.76.8
7.99.0
10.211.3
14.216.6
19.022.4
24.927.3
29.832.3
8"W
/ft5.6
7.18.5
9.911.3
12.714.1
17.820.7
23.727.9
31.034.1
37.240.3
10"W
/ft6.8
8.010.3
12.013.7
15.417.1
21.525.1
28.733.9
37.641.4
45.148.9
12"W
/ft8.0
10.012.0
14.016.0
18.020.0
25.229.4
33.639.6
44.048.4
52.857.2
14"W
/ft8.7
10.913.0
15.217.4
19.521.7
27.331.9
36.543.0
47.752.5
57.362.1
16"W
/ft9.8
12.314.8
17.219.7
22.124.6
31.036.2
41.348.7
54.159.5
64.970.4
18"W
/ft11.0
13.716.4
19.221.9
24.727.4
34.540.3
46.054.3
60.366.3
72.378.4
20"W
/ft12.1
15.118.1
21.124.2
27.230.2
38.144.4
50.759.8
66.473.1
79.786.4
22"W
/ft13.2
16.519.8
23.126.4
29.733.0
41.648.5
55.465.3
72.679.9
87.194.4
24"W
/ft14.3
17.921.5
25.128.6
32.235.8
45.152.6
60.170.9
78.886.6
94.5102.4
2"Insulation
Thickness1/ 2"
W/ft
1.01.2
1.41.7
1.92.2
2.43.0
3.54.0
4.85.3
5.86.3
7.23/ 4"
W/ft
1.11.4
1.61.9
2.22.4
2.73.4
4.04.5
5.35.9
6.57.1
8.1
1"W
/ft1.2
1.51.8
2.12.4
2.73.0
3.84.4
5.05.9
6.67.3
7.99.0
11/ 2"
W/ft
1.51.9
2.32.7
3.03.4
3.84.8
5.66.4
7.58.4
9.210.0
11.4
2"W
/ft1.7
2.22.6
3.03.4
3.94.3
5.46.3
7.28.5
9.510.4
11.412.9
21/ 2"
W/ft
1.92.4
2.93.4
3.84.3
4.86.0
7.18.1
9.510.6
11.612.7
14.4
3"W
/ft2.2
2.83.3
3.94.4
5.05.5
6.98.1
9.210.9
12.113.3
14.516.4
4"W
/ft2.6
3.34.0
4.65.3
5.96.6
8.39.7
11.113.1
14.516.0
17.419.7
6"W
/ft3.6
4.55.3
6.27.1
8.08.9
11.213.1
15.017.6
19.621.5
23.526.6
8"W
/ft4.4
5.66.7
7.88.9
10.011.1
14.016.3
18.622.0
24.426.9
29.333.2
10"W
/ft5.3
6.78.0
9.310.6
12.013.3
16.819.6
22.326.3
29.332.2
35.139.8
12"W
/ft6.2
7.89.3
10.912.4
14.015.5
19.522.8
26.030.7
34.137.5
40.946.3
14"W
/ft6.7
8.410.1
11.813.4
15.116.8
21.224.7
28.233.3
37.040.7
44.450.2
16"W
/ft7.6
9.511.3
13.215.1
17.018.9
23.827.8
31.837.4
41.645.7
49.956.5
18"W
/ft8.4
10.512.6
14.716.8
18.921.0
26.530.9
35.341.6
46.250.8
55.462.8
20"W
/ft9.2
11.613.9
16.218.5
20.823.1
29.134.0
38.845.7
50.855.9
61.069.1
22"W
/ft10.1
12.615.2
17.720.2
22.725.3
31.837.1
42.450.0
55.661.1
66.775.5
24"W
/ft11.0
13.716.4
19.221.9
24.727.4
34.540.3
46.054.3
60.366.3
72.381.9
609.6m
mW
/m36.1
44.953.8
63.071.9
3"(76.2
mm
)InsulationThickness
1/ 2"W
/ft0.8
1.01.2
1.41.6
1.82.0
2.52.9
3.44.0
4.44.8
5.56.0
3/ 4"W
/ft0.9
1.11.3
1.51.8
2.02.2
2.83.2
3.74.4
4.85.3
6.16.67
1"W
/ft1.0
1.31.5
1.82.0
2.32.5
3.23.7
4.25.0
5.56.1
6.97.5
11/ 2"
W/ft
1.21.5
1.82.1
2.42.7
3.03.8
4.45.0
5.96.6
7.38.3
9.0
2"W
/ft1.3
1.72.0
2.32.6
3.03.3
4.24.9
5.56.5
7.38.0
9.19.9
21/ 2"
W/ft
1.51.9
2.22.6
3.03.3
3.74.7
5.46.2
7.38.1
9.010.2
11.1
3"W
/ft1.7
2.12.5
2.93.4
3.84.2
5.36.2
7.18.3
9.210.2
11.612.6
4"W
/ft2.0
2.53.0
3.54.0
4.55.0
6.37.4
8.49.9
11.012.1
13.815.0
6"W
/ft2.6
3.33.9
4.65.2
5.96.5
8.29.6
10.912.9
14.315.7
17.919.4
8"W
/ft3.2
4.04.8
5.66.4
7.28.0
10.111.8
13.415.8
17.619.4
22.123.9
10"W
/ft3.8
4.85.7
6.77.6
8.69.5
12.014.0
16.018.8
20.923.0
26.228.4
12"W
/ft4.4
5.56.5
7.68.7
9.810.9
13.716.0
18.321.6
24.026.4
30.132.6
14"W
/ft4.7
5.97.1
8.39.4
10.611.8
14.917.3
19.823.4
26.028.6
32.635.3
16"W
/ft5.3
6.78.0
9.310.6
12.013.3
16.819.6
22.326.3
29.332.2
36.739.8
18”W
/ft5.9
7.48.8
10.311.8
13.214.7
18.521.6
24.729.1
32.335.6
40.644.0
20"W
/ft6.4
8.19.7
11.312.9
14.516.1
20.323.7
27.031.9
35.439.0
44.448.1
22"W
/ft7.0
8.810.5
12.314.0
15.817.5
22.125.7
29.434.7
38.542.4
48.352.3
24"W
/ft7.6
9.511.3
13.215.1
17.018.9
23.827.8
31.837.4
41.645.7
52.256.5
Nominal
PipeSize,
in.(ID)
Temperature
DifferenceBetw
eenPipe
andAm
bient
DegºF40ºF
50ºF60ºF
70ºF80ºF
90ºF100ºF
120ºF140ºF
160ºF180ºF
200ºF220ºF
240ºF260ºF
3”Insulation
Thickness
Installation Tips• Do not twist buss wires together at end
of circuit
• Insulate all conductive parts
• Seal all electrical connections against moisture
• Seal ends of exposed cable during installation
• Do not expose cables to temperatures abovetheir maximum ratings
• Install cable with aluminum tape for useon plastic pipes
• Locate ambient temperature sensors in coldestexpected area
• Locate pipe temperature sensors at lowestexpected line temperature
• Use sufficient cable to trace additional heat sinks
• Install cable so that valves can be removedwithout removing cable
Important SafeguardsMechanical Inspection
• Inspect all insulation and weatherproofing
• Inspect all junction box, connection box andsensor connections
• Verify all circuits have been properlygrounded
• Verify all circuits are connected in properpanel locations
• Verify proper circuit breakers are in place(always use 30mA trip GFI-type breakers)
• Verify all circuit lengths are within manufacturer’sspecified limits
• Verify all proper safety warnings are in place
• Verify all end seal, splice/tee locations are markedon lagging
Electrical Tests
• Insulation Resistance (Megger)– Before tracing pipes– After installing terminations– Before insulating pipes– After insulating pipes– Before energizing system
• Circuit Voltage
• Initial Current– Note ambient temp and pipe temp
• Stabilized Current (15 minutes of operation)– Note ambient temp and pipe temp
• Always use ground fault circuit breakers(30mA trip level)
Tools Needed• Wire Cutters/Strippers
• Megger
• Phillips Head Screwdriver
• Standard Screwdriver
• Voltmeter
• Utility Knife
• Hammer
SRL Cable• 150ºF / 65oC Maximum Maintenance
• 185ºF / 85oC Maximum Exposure
• 3-10 W/ft / 10-33 W/m
• 16 AWG with Optional TPE orFluoropolymer Jacket
SRM Cable• 302ºF / 150oC Maximum Maintenance
• 420ºF / 215oC Maximum Exposure
• 5-20 W/ft / 16-66 W/m
• 16 AWG with Optional Fluoropolymer Jacket
103 Gamma DrivePittsburgh, PA 15238USA
Chromalox®
PRECISION HEAT AND CONTROL
Copyright © 2002-2007, 2009-2012, Chromalox, Inc. All rights reserved.
Phone: (412) 967-3800Fax: (412) 967-5148Toll-Free: 1-800-443-2640
www.chromalox.com
PJ130-6
HEAT TRACE THERMAL DESIGN
SRP Cable• 225°F / 110°C Maintenance Temperature
• 275°F / 135°C Maximum Exposure Temperature
• 5-15 W/ft / 16-49 W/m
• 16 AWG with Optional Fluoropolymer Jacket
Chromalox
CableSelection
1.SelectHeating
CableFam
ily:Based
onthe
maxim
umm
aintenancetem
peraturerating,m
aximum
exposuretem
peraturerating,and
areaclassification,selectthe
heatingcable
family
fromTable
3.(SeeChrom
aloxHeatTrace
CableProductInform
ationSheets
forcableconstruction
options,voltageratings,
andw
attageoutputs
available.)
2.SelectTherm
alOutputRating:
(a)ForMetalPipes
–Use
Figures1,2
or4(b)ForPlastic
Pipes–
UseFigure
3by
findingthe
intersectionofthe
calculatedheatloss,Q
F ,andpipe
maintenance
temperature,T
m .Selectthecable
with
atherm
aloutputthatequalsorexceeds
QF atT
m .
Pip
eTem
perature
(ºF)M
aintenanceTem
perature
010
2030
5060
7080
90100
110120
130140
150
Thermal Output (W/ft)
14131211109876543210
4.88
SRL10&
HSRL10
SRL8&
HSRL8
SRL5&
HSRL5
SRL3&
HSRL3
CableOutput
versusTem
perature
40
Figure1
SRL&
HSRL–
ThermalOutput
Ratingson
InsulatedM
etalPipeFigure
2SRM
/E&
HSRM–
ThermalOutput
Ratingson
InsulatedM
etalPipeFigure
3SRL
&HSRL
–Therm
alOutputRatingson
PlasticPipe
with
Aluminum
Tape
B3.
Determine
TotalCableLength:
Inaddition
topipe
length,in-linecom
ponentssuch
asvalves,flanges,
andpipe
supportsrequire
additionalheattracingto
maintain
Tm .
SeeTable
4.Calculatethe
totalcable
lengthrequired
bycom
biningthe
pipelength
with
theadditionallengths
neededforallthe
othercomponents.
Table3
HeatingCable
Families
NOTE:Itis
theresponsibility
ofthefacility
managerorengineerto
determine
theclassification
ofanarea
where
heattracew
illbeinstalled.The
factorycan
helpdeterm
inea
suitablecable
basedon
theinform
ationprovided.
Table4
AdditionalCableLengths
Requiredfor
In-LineCom
ponentsBased
onPipe
IPS(Ir on
PipeSize)
1/ 2 in.1.00
1.001.00
1.001.00
1.001.00
0.30
3/ 4 in.1.50
1.001.00
1.001.50
1.001.00
0.30
1in.
2.001.00
1.001.00
1.501.00
1.000.30
11/ 2 in.
2.501.50
1.501.50
2.002.00
2.000.30
2in.
2.502.00
2.002.00
2.002.00
2.000.30
21/ 2 in.
2.502.00
2.002.00
2.002.00
2.000.30
3in.
3.002.50
2.502.50
2.002.00
2.000.50
4in.
4.003.00
3.003.00
2.502.50
2.500.50
6in.
5.003.50
3.503.50
2.502.50
2.500.80
8in.
7.004.00
4.004.00
2.502.50
2.500.80
10in.
8.004.50
4.504.50
3.003.00
3.000.80
12in.
9.005.00
5.005.00
3.003.00
3.000.80
14in.
10.005.50
5.505.50
3.003.00
3.001.00
16in.
11.006.00
6.006.00
3.503.50
3.501.00
18in.
12.007.00
7.007.00
3.503.50
3.501.00
20in.
13.007.50
7.507.50
3.503.50
3.501.00
22in.
13.007.50
7.507.50
3.503.50
3.501.00
24in.
15.008.00
8.008.00
4.004.00
4.001.00
PipingSize
GateValve
GlobeValve
BallValveButterfly
ValveHanger
SupportShoe
SupportSleeperSupport
FlangePair
ft
010
2030
5060
7080
90100
110120
130140
15040
Pip
eTem
perature
(ºF)
SRL10&
HSRL10
Thermal Output (W/ft)
9876543210
SRL8&
HSRL8SRL5&
HSRL5
SRL3&
HSRL3
CableOutput
versusTem
perature
Figure4
SRP–
ThermalOutputRatings
onInsulated
MetalPipe
Pip
eTem
perature
(ºF)
Heat Output (W/ft)
2120191817161514131211109876543210
15W
/ft
10W
/ft
5W
/ft
CableOutput
versusTem
perature
010
2030
4050
6070
8090
100110
120130
140150
160170
180190
200210
220230
HeatingCable
Family
AreaClassification
PipeM
aterial
Maxim
umM
aintenanceTem
perature
Maxim
umExposure
Temperature
(PowerOff)
Approvals
U.S.Other
SRL(Self-RegulatingLow
Temperature)
Ordinary
Plastic/Metal
150ºF/65ºC
185ºF/85ºC
UL,CSA,FMGOST,Cenelec,CE,ATEX
ClassI,Div.2,Gr.B,C,D
CSA,FM,(Gr.A,CSA
Only)GOST,Cenelec,CE,ATEX
ClassII,Div.2,Gr.E,F,G
CSA,FM,(Gr.E,CSA
Only)GOST,Cenelec,CE
ClassIII,Div.2
FMOnly
GOST,Cenelec,CE,ATEX
SRM/E
(Self-RegulatingM
ediumTem
perature)
Ordinary
MetalOnly
302ºF/150ºC
420ºF/215ºC
UL,CSA,FMGOST,Cenelec,CE,ATEX
ClassIDiv.2,Gr.A,B,C,D
CSA,FM,(Gr.A,CSA
Only)GOST,Cenelec,CE,ATEX
ClassII,Div.2,Gr.F,G
CSAOnly
GOST,Cenelec,CE,ATEX
SRP(Self-RegulatingM
ediumTem
perature)
Ordinary
MetalOnly
225ºF/110ºC
275ºF/135ºC
UL,CSA,FMPending
GOST,Cenelec,CE,ATEX
Pending
ClassI,Div.2,Gr.B,C,D
ClassII,Div.2,Gr.
F,G
ClassIII
HSRL(H-Self-RegulatingLow
Temperature)
ClassI,Div.1,Gr.B,C,D
Plastic/Metal
150ºF/65ºC
185ºF/85ºC
CSA,FM
ClassII,Div.1,Gr.E,F,G
CSA,FM
ClassIII,Div.1
CSA,FM
HSRM(H-Self-RegulatingM
ediumTem
perature)
ClassI,Div.1,Gr.B,C,D
MetalOnly
302ºF/150ºC
420ºF/215ºC
CSA,FM
ClassII,Div.1,Gr.E,F,G
CSA,FM
ClassIII,Div.1
CSA,FM
CWM
(ConstantWattage)
OrdinaryM
etalOnlyConsultFactory
392ºF/200ºC
UL,CSA
HazardousArea,ConsultFactory
MI(M
ineralInsulated)
Ordinary
MetalOnly
ConsultFactory1,100ºF
/595ºC
CSA,FM
ClassI,Div.2,Gr.B,C,D
CSA,FM
ClassII,Div.2,Gr.E,F,G
CSA,FM
ClassIII
CSA,FM
050
100150
200250
300
Pip
eTem
perature
(ºF)
SRM/E20
&HSRM
20Power Output (W/ft)
24201612840
SRM/E15
&HSRM
15
SRM/E10
&HSRM
10
SRM/E8
&HSRM
8
SRM/E5
&HSRM
5
SRM/E3
&HSRM
3
CableOutput
versusTem
perature
Table2
InsulationAdjustm
entFactors
Insulation
Factor
Pip
e Insulation Typ
eP
ipe Insulatio
n Type
Insulation
Factor
Glass fiber (A
STM
C547)
1.00
Calcium
silicate (AS
TM C
533)
1.48
Cellular glass (A
STM
C552)
1.48
Rigid cellular urethane (A
STM
C591)
0.64
Foamed elastom
er (AS
TM C
534) 1.16
Mineral fib
er blanket (A
STM
C553)
1.16
Expanded
perlite (A
STM
C610)
1.90
1.Basic
HeatLoss:Afterdeterm
iningthe
differencebetw
eenthe
ambientand
desiredpipe
maintenance
temperature,T
m ,useTable
1to
figurethe
basicheatloss
forthepipe
sizeand
insulationthickness.
2.Insulation
Adjustment:
UsingTable
2,findthe
typeofinsulation
beingused
andits
insulationfactor.
Heat Trace Design Guide
APipe
HeatLossCalculations
• Heat Trace System Design
• Materials & Components
• Specification Tables
3.Calculate
QF :
Multiply
thebasic
heatlossfigure
fromTable
1by
theadjustm
entfactorfromTable
2to
calculatethe
estimated
heatloss,QF ,in
watts
perfootofpipelength.
4.CorrectforIndoorLocation/W
indSpeed:
Iflocationis
indoors,multiply
QF by
0.9.Table
1is
basedon
10%safety
factorand20
mph
wind
speed;add5%
margin
foreach5
mph
over20m
phw
indspeed.
Table1
PipeHeatLoss
QP in
W/ftBased
onTem
peratureDifferentialand
InsulationThickness
Nominal
PipeSize,
in.(ID)
Temperature
DifferenceBetw
eenPipe
andAm
bient
DegºF40ºF
50ºF60ºF
70ºF80ºF
90ºF100ºF
120ºF140ºF
160ºF180ºF
200ºF220ºF
240ºF260ºF
1"Insulation
Thickness1/ 2"
W/ft
1.41.8
2.12.5
2.83.2
3.54.2
5.15.9
6.67.7
8.59.2
10.03/ 4"
W/ft
1.62.0
2.42.8
3.23.6
4.04.8
5.96.7
7.68.8
9.710.6
11.4
1"W
/ft1.8
2.32.8
3.23.7
4.14.6
5.56.8
7.78.7
10.111.1
12.113.2
11/ 2"
W/ft
2.43.1
3.74.3
4.95.5
6.17.3
9.010.2
11.513.4
14.816.1
17.4
2"W
/ft2.8
3.54.1
4.85.5
6.26.9
8.310.1
11.613.0
15.216.7
18.219.7
21/ 2"
W/ft
3.24.0
4.85.6
6.47.2
8.09.6
11.813.4
15.117.6
19.421.1
22.9
3"W
/ft3.7
4.75.6
6.57.4
8.49.3
11.213.7
15.617.6
20.522.5
24.626.6
4"W
/ft4.6
5.86.9
8.19.2
10.411.5
13.816.9
19.321.7
25.327.8
30.432.9
6"W
/ft6.4
8.09.6
11.212.8
14.416.0
19.223.5
26.930.2
35.238.7
42.245.8
8"W
/ft8.1
10.112.1
14.116.2
18.220.2
24.229.7
33.938.2
44.448.9
53.357.8
10"W
/ft9.9
12.414.8
17.319.8
22.224.7
29.636.3
41.546.7
54.359.8
65.270.6
12"W
/ft11.6
14.517.4
20.323.2
26.129.0
34.842.6
48.754.8
63.870.2
76.682.9
14"W
/ft12.6
15.819.0
22.125.3
28.431.6
37.946.5
53.159.7
69.576.5
83.490.4
16"W
/ft14.3
17.921.5
25.128.7
32.335.9
43.052.7
60.267.8
78.986.8
94.6102.5
18"W
/ft16.0
20.124.1
28.132.1
36.140.1
48.158.9
67.475.8
88.297.0
105.9114.7
20"W
/ft17.7
22.226.6
31.035.4
39.944.3
53.265.1
74.483.7
97.5107.2
117.0126.7
22"W
/ft19.4
24.329.1
34.038.8
43.748.5
58.271.3
81.591.7
106.7117.4
128.0138.7
24"W
/ft21.1
26.431.6
36.942.2
47.452.7
63.277.5
88.599.6
115.9127.5
139.1150.7
1.5"Insulation
Thickness1/ 2"
W/ft
1.11.4
1.72.0
2.22.5
2.83.5
4.14.7
5.56.2
6.87.4
8.03/ 4"
W/ft
1.21.6
1.92.2
2.52.8
3.13.9
4.65.2
6.16.8
7.58.2
8.9
1"W
/ft1.4
1.82.2
2.52.9
3.23.6
4.55.3
6.07.1
7.98.7
9.510.3
11/ 2"
W/ft
1.82.3
2.83.2
3.74.1
4.65.8
6.87.7
9.110.1
11.112.1
13.2
2"W
/ft2.1
2.63.1
3.64.2
4.75.2
6.67.6
8.710.3
11.412.6
13.714.9
21/ 2"
W/ft
2.43.0
3.54.1
4.75.3
5.97.4
8.79.9
11.713.0
14.315.6
16.9
3"W
/ft2.7
3.44.1
4.85.4
6.16.8
8.610.0
11.413.5
15.016.5
18.019.4
4"W
/ft3.3
4.25.0
5.86.6
7.58.3
10.512.2
13.916.4
18.320.1
21.923.7
6"W
/ft4.5
5.76.8
7.99.0
10.211.3
14.216.6
19.022.4
24.927.3
29.832.3
8"W
/ft5.6
7.18.5
9.911.3
12.714.1
17.820.7
23.727.9
31.034.1
37.240.3
10"W
/ft6.8
8.010.3
12.013.7
15.417.1
21.525.1
28.733.9
37.641.4
45.148.9
12"W
/ft8.0
10.012.0
14.016.0
18.020.0
25.229.4
33.639.6
44.048.4
52.857.2
14"W
/ft8.7
10.913.0
15.217.4
19.521.7
27.331.9
36.543.0
47.752.5
57.362.1
16"W
/ft9.8
12.314.8
17.219.7
22.124.6
31.036.2
41.348.7
54.159.5
64.970.4
18"W
/ft11.0
13.716.4
19.221.9
24.727.4
34.540.3
46.054.3
60.366.3
72.378.4
20"W
/ft12.1
15.118.1
21.124.2
27.230.2
38.144.4
50.759.8
66.473.1
79.786.4
22"W
/ft13.2
16.519.8
23.126.4
29.733.0
41.648.5
55.465.3
72.679.9
87.194.4
24"W
/ft14.3
17.921.5
25.128.6
32.235.8
45.152.6
60.170.9
78.886.6
94.5102.4
2"Insulation
Thickness1/ 2"
W/ft
1.01.2
1.41.7
1.92.2
2.43.0
3.54.0
4.85.3
5.86.3
7.23/ 4"
W/ft
1.11.4
1.61.9
2.22.4
2.73.4
4.04.5
5.35.9
6.57.1
8.1
1"W
/ft1.2
1.51.8
2.12.4
2.73.0
3.84.4
5.05.9
6.67.3
7.99.0
11/ 2"
W/ft
1.51.9
2.32.7
3.03.4
3.84.8
5.66.4
7.58.4
9.210.0
11.4
2"W
/ft1.7
2.22.6
3.03.4
3.94.3
5.46.3
7.28.5
9.510.4
11.412.9
21/ 2"
W/ft
1.92.4
2.93.4
3.84.3
4.86.0
7.18.1
9.510.6
11.612.7
14.4
3"W
/ft2.2
2.83.3
3.94.4
5.05.5
6.98.1
9.210.9
12.113.3
14.516.4
4"W
/ft2.6
3.34.0
4.65.3
5.96.6
8.39.7
11.113.1
14.516.0
17.419.7
6"W
/ft3.6
4.55.3
6.27.1
8.08.9
11.213.1
15.017.6
19.621.5
23.526.6
8"W
/ft4.4
5.66.7
7.88.9
10.011.1
14.016.3
18.622.0
24.426.9
29.333.2
10"W
/ft5.3
6.78.0
9.310.6
12.013.3
16.819.6
22.326.3
29.332.2
35.139.8
12"W
/ft6.2
7.89.3
10.912.4
14.015.5
19.522.8
26.030.7
34.137.5
40.946.3
14"W
/ft6.7
8.410.1
11.813.4
15.116.8
21.224.7
28.233.3
37.040.7
44.450.2
16"W
/ft7.6
9.511.3
13.215.1
17.018.9
23.827.8
31.837.4
41.645.7
49.956.5
18"W
/ft8.4
10.512.6
14.716.8
18.921.0
26.530.9
35.341.6
46.250.8
55.462.8
20"W
/ft9.2
11.613.9
16.218.5
20.823.1
29.134.0
38.845.7
50.855.9
61.069.1
22"W
/ft10.1
12.615.2
17.720.2
22.725.3
31.837.1
42.450.0
55.661.1
66.775.5
24"W
/ft11.0
13.716.4
19.221.9
24.727.4
34.540.3
46.054.3
60.366.3
72.381.9
609.6m
mW
/m36.1
44.953.8
63.071.9
3"(76.2
mm
)InsulationThickness
1/ 2"W
/ft0.8
1.01.2
1.41.6
1.82.0
2.52.9
3.44.0
4.44.8
5.56.0
3/ 4"W
/ft0.9
1.11.3
1.51.8
2.02.2
2.83.2
3.74.4
4.85.3
6.16.67
1"W
/ft1.0
1.31.5
1.82.0
2.32.5
3.23.7
4.25.0
5.56.1
6.97.5
11/ 2"
W/ft
1.21.5
1.82.1
2.42.7
3.03.8
4.45.0
5.96.6
7.38.3
9.0
2"W
/ft1.3
1.72.0
2.32.6
3.03.3
4.24.9
5.56.5
7.38.0
9.19.9
21/ 2"
W/ft
1.51.9
2.22.6
3.03.3
3.74.7
5.46.2
7.38.1
9.010.2
11.1
3"W
/ft1.7
2.12.5
2.93.4
3.84.2
5.36.2
7.18.3
9.210.2
11.612.6
4"W
/ft2.0
2.53.0
3.54.0
4.55.0
6.37.4
8.49.9
11.012.1
13.815.0
6"W
/ft2.6
3.33.9
4.65.2
5.96.5
8.29.6
10.912.9
14.315.7
17.919.4
8"W
/ft3.2
4.04.8
5.66.4
7.28.0
10.111.8
13.415.8
17.619.4
22.123.9
10"W
/ft3.8
4.85.7
6.77.6
8.69.5
12.014.0
16.018.8
20.923.0
26.228.4
12"W
/ft4.4
5.56.5
7.68.7
9.810.9
13.716.0
18.321.6
24.026.4
30.132.6
14"W
/ft4.7
5.97.1
8.39.4
10.611.8
14.917.3
19.823.4
26.028.6
32.635.3
16"W
/ft5.3
6.78.0
9.310.6
12.013.3
16.819.6
22.326.3
29.332.2
36.739.8
18”W
/ft5.9
7.48.8
10.311.8
13.214.7
18.521.6
24.729.1
32.335.6
40.644.0
20"W
/ft6.4
8.19.7
11.312.9
14.516.1
20.323.7
27.031.9
35.439.0
44.448.1
22"W
/ft7.0
8.810.5
12.314.0
15.817.5
22.125.7
29.434.7
38.542.4
48.352.3
24"W
/ft7.6
9.511.3
13.215.1
17.018.9
23.827.8
31.837.4
41.645.7
52.256.5
Nominal
PipeSize,
in.(ID)
Temperature
DifferenceBetw
eenPipe
andAm
bient
DegºF40ºF
50ºF60ºF
70ºF80ºF
90ºF100ºF
120ºF140ºF
160ºF180ºF
200ºF220ºF
240ºF260ºF
3”Insulation
Thickness
Installation Tips• Do not twist buss wires together at end
of circuit
• Insulate all conductive parts
• Seal all electrical connections against moisture
• Seal ends of exposed cable during installation
• Do not expose cables to temperatures abovetheir maximum ratings
• Install cable with aluminum tape for useon plastic pipes
• Locate ambient temperature sensors in coldestexpected area
• Locate pipe temperature sensors at lowestexpected line temperature
• Use sufficient cable to trace additional heat sinks
• Install cable so that valves can be removedwithout removing cable
Important SafeguardsMechanical Inspection
• Inspect all insulation and weatherproofing
• Inspect all junction box, connection box andsensor connections
• Verify all circuits have been properlygrounded
• Verify all circuits are connected in properpanel locations
• Verify proper circuit breakers are in place(always use 30mA trip GFI-type breakers)
• Verify all circuit lengths are within manufacturer’sspecified limits
• Verify all proper safety warnings are in place
• Verify all end seal, splice/tee locations are markedon lagging
Electrical Tests
• Insulation Resistance (Megger)– Before tracing pipes– After installing terminations– Before insulating pipes– After insulating pipes– Before energizing system
• Circuit Voltage
• Initial Current– Note ambient temp and pipe temp
• Stabilized Current (15 minutes of operation)– Note ambient temp and pipe temp
• Always use ground fault circuit breakers(30mA trip level)
Tools Needed• Wire Cutters/Strippers
• Megger
• Phillips Head Screwdriver
• Standard Screwdriver
• Voltmeter
• Utility Knife
• Hammer
SRL Cable• 150ºF / 65oC Maximum Maintenance
• 185ºF / 85oC Maximum Exposure
• 3-10 W/ft / 10-33 W/m
• 16 AWG with Optional TPE orFluoropolymer Jacket
SRM Cable• 302ºF / 150oC Maximum Maintenance
• 420ºF / 215oC Maximum Exposure
• 5-20 W/ft / 16-66 W/m
• 16 AWG with Optional Fluoropolymer Jacket
103 Gamma DrivePittsburgh, PA 15238USA
Chromalox®
PRECISION HEAT AND CONTROL
Copyright © 2002-2007, 2009-2012, Chromalox, Inc. All rights reserved.
Phone: (412) 967-3800Fax: (412) 967-5148Toll-Free: 1-800-443-2640
www.chromalox.com
PJ130-6
HEAT TRACE THERMAL DESIGN
SRP Cable• 225°F / 110°C Maintenance Temperature
• 275°F / 135°C Maximum Exposure Temperature
• 5-15 W/ft / 16-49 W/m
• 16 AWG with Optional Fluoropolymer Jacket
Chromalox
CableSelection
1.SelectHeating
CableFam
ily:Based
onthe
maxim
umm
aintenancetem
peraturerating,m
aximum
exposuretem
peraturerating,and
areaclassification,selectthe
heatingcable
family
fromTable
3.(SeeChrom
aloxHeatTrace
CableProductInform
ationSheets
forcableconstruction
options,voltageratings,
andw
attageoutputs
available.)
2.SelectTherm
alOutputRating:
(a)ForMetalPipes
–Use
Figures1,2
or4(b)ForPlastic
Pipes–
UseFigure
3by
findingthe
intersectionofthe
calculatedheatloss,Q
F ,andpipe
maintenance
temperature,T
m .Selectthecable
with
atherm
aloutputthatequalsorexceeds
QF atT
m .
Pip
eTem
perature
(ºF)M
aintenanceTem
perature
010
2030
5060
7080
90100
110120
130140
150
Thermal Output (W/ft)
14131211109876543210
4.88
SRL10&
HSRL10
SRL8&
HSRL8
SRL5&
HSRL5
SRL3&
HSRL3
CableOutput
versusTem
perature
40
Figure1
SRL&
HSRL–
ThermalOutput
Ratingson
InsulatedM
etalPipeFigure
2SRM
/E&
HSRM–
ThermalOutput
Ratingson
InsulatedM
etalPipeFigure
3SRL
&HSRL
–Therm
alOutputRatingson
PlasticPipe
with
Aluminum
Tape
B3.
Determine
TotalCableLength:
Inaddition
topipe
length,in-linecom
ponentssuch
asvalves,flanges,
andpipe
supportsrequire
additionalheattracingto
maintain
Tm .
SeeTable
4.Calculatethe
totalcable
lengthrequired
bycom
biningthe
pipelength
with
theadditionallengths
neededforallthe
othercomponents.
Table3
HeatingCable
Families
NOTE:Itis
theresponsibility
ofthefacility
managerorengineerto
determine
theclassification
ofanarea
where
heattracew
illbeinstalled.The
factorycan
helpdeterm
inea
suitablecable
basedon
theinform
ationprovided.
Table4
AdditionalCableLengths
Requiredfor
In-LineCom
ponentsBased
onPipe
IPS(Ir on
PipeSize)
1/ 2 in.1.00
1.001.00
1.001.00
1.001.00
0.30
3/ 4 in.1.50
1.001.00
1.001.50
1.001.00
0.30
1in.
2.001.00
1.001.00
1.501.00
1.000.30
11/ 2 in.
2.501.50
1.501.50
2.002.00
2.000.30
2in.
2.502.00
2.002.00
2.002.00
2.000.30
21/ 2 in.
2.502.00
2.002.00
2.002.00
2.000.30
3in.
3.002.50
2.502.50
2.002.00
2.000.50
4in.
4.003.00
3.003.00
2.502.50
2.500.50
6in.
5.003.50
3.503.50
2.502.50
2.500.80
8in.
7.004.00
4.004.00
2.502.50
2.500.80
10in.
8.004.50
4.504.50
3.003.00
3.000.80
12in.
9.005.00
5.005.00
3.003.00
3.000.80
14in.
10.005.50
5.505.50
3.003.00
3.001.00
16in.
11.006.00
6.006.00
3.503.50
3.501.00
18in.
12.007.00
7.007.00
3.503.50
3.501.00
20in.
13.007.50
7.507.50
3.503.50
3.501.00
22in.
13.007.50
7.507.50
3.503.50
3.501.00
24in.
15.008.00
8.008.00
4.004.00
4.001.00
PipingSize
GateValve
GlobeValve
BallValveButterfly
ValveHanger
SupportShoe
SupportSleeperSupport
FlangePair
ft
010
2030
5060
7080
90100
110120
130140
15040
Pip
eTem
perature
(ºF)
SRL10&
HSRL10
Thermal Output (W/ft)
9876543210
SRL8&
HSRL8SRL5&
HSRL5
SRL3&
HSRL3
CableOutput
versusTem
perature
Figure4
SRP–
ThermalOutputRatings
onInsulated
MetalPipe
Pip
eTem
perature
(ºF)
Heat Output (W/ft)
2120191817161514131211109876543210
15W
/ft
10W
/ft
5W
/ft
CableOutput
versusTem
perature
010
2030
4050
6070
8090
100110
120130
140150
160170
180190
200210
220230
HeatingCable
Family
AreaClassification
PipeM
aterial
Maxim
umM
aintenanceTem
perature
Maxim
umExposure
Temperature
(PowerOff)
Approvals
U.S.Other
SRL(Self-RegulatingLow
Temperature)
Ordinary
Plastic/Metal
150ºF/65ºC
185ºF/85ºC
UL,CSA,FMGOST,Cenelec,CE,ATEX
ClassI,Div.2,Gr.B,C,D
CSA,FM,(Gr.A,CSA
Only)GOST,Cenelec,CE,ATEX
ClassII,Div.2,Gr.E,F,G
CSA,FM,(Gr.E,CSA
Only)GOST,Cenelec,CE
ClassIII,Div.2
FMOnly
GOST,Cenelec,CE,ATEX
SRM/E
(Self-RegulatingM
ediumTem
perature)
Ordinary
MetalOnly
302ºF/150ºC
420ºF/215ºC
UL,CSA,FMGOST,Cenelec,CE,ATEX
ClassIDiv.2,Gr.A,B,C,D
CSA,FM,(Gr.A,CSA
Only)GOST,Cenelec,CE,ATEX
ClassII,Div.2,Gr.F,G
CSAOnly
GOST,Cenelec,CE,ATEX
SRP(Self-RegulatingM
ediumTem
perature)
Ordinary
MetalOnly
225ºF/110ºC
275ºF/135ºC
UL,CSA,FMPending
GOST,Cenelec,CE,ATEX
Pending
ClassI,Div.2,Gr.B,C,D
ClassII,Div.2,Gr.
F,G
ClassIII
HSRL(H-Self-RegulatingLow
Temperature)
ClassI,Div.1,Gr.B,C,D
Plastic/Metal
150ºF/65ºC
185ºF/85ºC
CSA,FM
ClassII,Div.1,Gr.E,F,G
CSA,FM
ClassIII,Div.1
CSA,FM
HSRM(H-Self-RegulatingM
ediumTem
perature)
ClassI,Div.1,Gr.B,C,D
MetalOnly
302ºF/150ºC
420ºF/215ºC
CSA,FM
ClassII,Div.1,Gr.E,F,G
CSA,FM
ClassIII,Div.1
CSA,FM
CWM
(ConstantWattage)
OrdinaryM
etalOnlyConsultFactory
392ºF/200ºC
UL,CSA
HazardousArea,ConsultFactory
MI(M
ineralInsulated)
Ordinary
MetalOnly
ConsultFactory1,100ºF
/595ºC
CSA,FM
ClassI,Div.2,Gr.B,C,D
CSA,FM
ClassII,Div.2,Gr.E,F,G
CSA,FM
ClassIII
CSA,FM
050
100150
200250
300
Pip
eTem
perature
(ºF)
SRM/E20
&HSRM
20
Power Output (W/ft)
24201612840
SRM/E15
&HSRM
15
SRM/E10
&HSRM
10
SRM/E8
&HSRM
8
SRM/E5
&HSRM
5
SRM/E3
&HSRM
3
CableOutput
versusTem
perature
1.2.
a3.4.
pIpe HeaT LO
SS CaLCu
LaTIOn
S
Basic Heat Loss: After determining the difference betw
een the ambient and desired pipe m
aintenance
temperature, T
m , use Table 1 to figure the basic heat loss for the pipe size and insulation thickness.
Calculate QF : M
ultiply the basic heat loss figure from Table 1 by the adjustm
ent factor from Table 2 to
calculate the estimated heat loss, Q
F , in watts per foot of pipe length.
Correct for Indoor Location/ Wind Speed: If location is indoors, m
ultiply QF by 0.9. Table 1 is based on
10% safety factor and 20 m
ph wind speed; add 5%
margin for each 5 m
ph over 20 mph w
ind speed.Insulation Adjustm
ent: Using Table 2, find the type of insulation being used and its insulation factor.
Insulation Adjustment Factors
B3.
1.2.
CHr
Om
aLOx Ca
BLe SeLeCTIO
n
Select Heating Cable Family: Based on the m
aximum
maintenance tem
perature rating, maxim
um
exposure temperature rating, and area classification, select the heating cable fam
ily from Table 3. (See
Chromalox Heat Trace Cable Product Inform
ation Sheets for cable construction options, voltage ratings, and w
attage outputs available.)
Determine Total Cable Length: In addition to pipe length, in-line com
ponents such as valves, flanges, and pipe supports require additional heat tracing to m
aintain Tm. See Table 4. Calculate the total
cable length required by combining the pipe length w
ith the additional lengths needed for all the other com
ponents.
Select Thermal Output Rating:
(a) For Metal Pipes – Use Figures 1, 2 or 4
(b) For Plastic Pipes – Use Figure 3 by finding the intersection of the calculated heat loss, QF , and pipe
maintenance tem
perature, Tm . Select the cable w
ith a thermal output that equals or exceeds Q
F at Tm .
Table 4Additional Cable Lengths Required for In-Line Com
ponentsBased on Pipe IPS (Iron Pipe Size)
Table 3
Table 1
Table 2
Heating Cable Families
Pipe Heat Loss QP in W
/ft Based on Temperature Differential and Insulation Thickness
Installation Tips • Do not twist buss wires together at end of circuit
• Insulate all conductive parts
• Seal all electrical connections against moisture
• Seal ends of exposed cable during installation
• Do not expose cables to temperatures above their maximum ratings
• Install cable with aluminum tape for use on plastic pipes
• Locate ambient temperature sensors in coldest expected area
• Locate pipe temperature sensors at lowest expected line temperature
• Use sufficient cable to trace additional heat sinks
• Install cable so that valves can be removed without removing cable
Important Safeguards Mechanical Inspection • Inspect all insulation and weatherproofing
• Inspect all junction box, connection box, and sensor connections
• Verify all circuits have been properly grounded
• Verify all circuits are connected in proper panel locations
• Verify proper circuit breakers are in place (always use 30 mA trip GFI-type breakers)
• Verify all circuit lengths are within manufacturer’s specified limits
• Verify all proper safety warnings are in place
• Verify all end seal, splice/tee locations are marked on lagging
Electrical Tests
• Insulation Resistance (Megger) ✓ Before tracing pipes ✓ After installing terminations ✓ Before insulating pipes ✓ After insulating pipes ✓ Before energizing system
• Circuit Voltage
• Initial Current ✓ Note ambient temp and pipe temp
• Stabilized Current (15 minutes of operation) ✓ Note ambient temp and pipe temp
• Always use ground fault circuit breakers (30 mA trip level)
Tools Needed • Wire Cutters/Strippers
• Megger
• Phillips Head Screwdriver
• Standard Screwdriver
• Voltmeter
• Utility Knife
• Hammer
SrL Cable • 150ºF / 65ºC Maximum Maintenance
• 185ºF / 85ºC Maximum Exposure
• 3 to 10 W/ft / 10 to 33 W/m
• 16 AWG with Optional TPE or Fluoropolymer Jacket
Srp Cable • 225°F / 110°C Maintenance Temperature
• 275°F / 135°C Maximum Exposure Temperature
• 5 to 15 W/ft / 16 to 49 W/m
• 16 AWG with Optional Fluoropolymer Jacket
Srm Cable • 302ºF / 150ºC Maximum Maintenance
• 420ºF / 215ºC Maximum Exposure
• 5 to 20 W/ft / 16 to 66 W/m
• 16 AWG with Optional Fluoropolymer Jacket
Figure 1Figure 2
Figure 3Figure 4
SRL & HSRL – Therm
al Output Ratings on Insulated M
etal PipeSRM
/E & HSRM
– Thermal Output
Ratings on Insulated Metal Pipe
SRL & HSRL – Thermal Output Ratings
on Plastic Pipe with Alum
inum Tape
SRP – Thermal Output Ratings
on Insulated Metal Pipe
Pip
e Temp
erature (ºF)
Heat Output (W/ft)
2120191817161514131211109876543210
15 W/ft
10 W/ft
5 W/ft
Cable OutputversusTem
perature
0 10
20 30
40 50
60 70
80 90
100 110
120 130
140 150
160 170
180 190
200 210 220 230
010
2030
5060
7080
90100
110120
130140
15040
Pip
e Temp
erature (ºF)
SRL10 & HSRL10
Thermal Output (W/ft)
9876543210
SRL8 & HSRL8SRL5 & HSRL5
SRL3 & HSRL3
Cable OutputversusTem
perature
050
100150
200250
300
Pip
e Temp
erature (ºF)
SRM/E20 &
HSRM20
Power Output (W/ft)24201612840
SRM/E15 &
HSRM15
SRM/E10 &
HSRM10
SRM/E8 & HSRM
8
SRM/E5 & HSRM
5
SRM/E3 & HSRM
3
Cable OutputversusTem
perature
Pip
e Temp
erature (ºF)M
aintenance Temperature
010
2030
5060
7080
90100
110120
130140
150
Thermal Output (W/ft)
14131211109876543210
4.88
SRL10 & HSRL10
SRL8 & HSRL8
SRL5 & HSRL5
SRL3 & HSRL3
Cable OutputversusTem
perature
40
Tem
per
aTu
re
man
agem
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TIO
nS
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t tR
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Table 2 Insulation Adjustment Factors
Insulation Factor
Pipe Insulation TypePipe Insulation TypeInsulation Factor
Glass fiber (ASTM C547) 1.00
Calcium silicate (ASTM C533) 1.48
Cellular glass (ASTM C552) 1.48
Rigid cellular urethane (ASTM C591) 0.64
Foamed elastomer (ASTM C534) 1.16
Mineral fiber blanket (ASTM C553) 1.16
Expanded perlite (ASTM C610) 1.90
1. Basic Heat Loss: After determining the difference between the ambient and desired pipe maintenance
temperature, Tm, use Table 1 to figure the basic heat loss for the pipe size and insulation thickness.
2. Insulation Adjustment: Using Table 2, find the type of insulation being used and its insulation factor.
Hea
tTr
ace
Des
ign
Gui
de
A Pipe Heat Loss Calculations
•He
atTr
ace
Syst
emDe
sign
•M
ater
ials
&Co
mpo
nent
s
•Sp
ecifi
catio
nTa
bles
3. Calculate QF: Multiply the basic heat loss figure from Table 1 by the adjustment factor from Table 2 to
calculate the estimated heat loss, QF, in watts per foot of pipe length.
4. Correct for Indoor Location/ Wind Speed: If location is indoors, multiply QF by 0.9. Table 1 is based on
10% safety factor and 20 mph wind speed; add 5% margin for each 5 mph over 20 mph wind speed.
Table 1 Pipe Heat Loss QP in W/ft Based on Temperature Differential and Insulation Thickness
NominalPipe Size,
in. (ID)
Temperature Difference Between Pipe and Ambient
DegºF 40ºF 50ºF 60ºF 70ºF 80ºF 90ºF 100ºF 120ºF 140ºF 160ºF 180ºF 200ºF 220ºF 240ºF 260ºF
1" Insulation Thickness1/2" W/ft 1.4 1.8 2.1 2.5 2.8 3.2 3.5 4.2 5.1 5.9 6.6 7.7 8.5 9.2 10.03/4" W/ft 1.6 2.0 2.4 2.8 3.2 3.6 4.0 4.8 5.9 6.7 7.6 8.8 9.7 10.6 11.4
1" W/ft 1.8 2.3 2.8 3.2 3.7 4.1 4.6 5.5 6.8 7.7 8.7 10.1 11.1 12.1 13.2
11/2" W/ft 2.4 3.1 3.7 4.3 4.9 5.5 6.1 7.3 9.0 10.2 11.5 13.4 14.8 16.1 17.4
2" W/ft 2.8 3.5 4.1 4.8 5.5 6.2 6.9 8.3 10.1 11.6 13.0 15.2 16.7 18.2 19.7
21/2" W/ft 3.2 4.0 4.8 5.6 6.4 7.2 8.0 9.6 11.8 13.4 15.1 17.6 19.4 21.1 22.9
3" W/ft 3.7 4.7 5.6 6.5 7.4 8.4 9.3 11.2 13.7 15.6 17.6 20.5 22.5 24.6 26.6
4" W/ft 4.6 5.8 6.9 8.1 9.2 10.4 11.5 13.8 16.9 19.3 21.7 25.3 27.8 30.4 32.9
6" W/ft 6.4 8.0 9.6 11.2 12.8 14.4 16.0 19.2 23.5 26.9 30.2 35.2 38.7 42.2 45.8
8" W/ft 8.1 10.1 12.1 14.1 16.2 18.2 20.2 24.2 29.7 33.9 38.2 44.4 48.9 53.3 57.8
10" W/ft 9.9 12.4 14.8 17.3 19.8 22.2 24.7 29.6 36.3 41.5 46.7 54.3 59.8 65.2 70.6
12" W/ft 11.6 14.5 17.4 20.3 23.2 26.1 29.0 34.8 42.6 48.7 54.8 63.8 70.2 76.6 82.9
14" W/ft 12.6 15.8 19.0 22.1 25.3 28.4 31.6 37.9 46.5 53.1 59.7 69.5 76.5 83.4 90.4
16" W/ft 14.3 17.9 21.5 25.1 28.7 32.3 35.9 43.0 52.7 60.2 67.8 78.9 86.8 94.6 102.5
18" W/ft 16.0 20.1 24.1 28.1 32.1 36.1 40.1 48.1 58.9 67.4 75.8 88.2 97.0 105.9 114.7
20" W/ft 17.7 22.2 26.6 31.0 35.4 39.9 44.3 53.2 65.1 74.4 83.7 97.5 107.2 117.0 126.7
22" W/ft 19.4 24.3 29.1 34.0 38.8 43.7 48.5 58.2 71.3 81.5 91.7 106.7 117.4 128.0 138.7
24" W/ft 21.1 26.4 31.6 36.9 42.2 47.4 52.7 63.2 77.5 88.5 99.6 115.9 127.5 139.1 150.7
1.5" Insulation Thickness1/2" W/ft 1.1 1.4 1.7 2.0 2.2 2.5 2.8 3.5 4.1 4.7 5.5 6.2 6.8 7.4 8.03/4" W/ft 1.2 1.6 1.9 2.2 2.5 2.8 3.1 3.9 4.6 5.2 6.1 6.8 7.5 8.2 8.9
1" W/ft 1.4 1.8 2.2 2.5 2.9 3.2 3.6 4.5 5.3 6.0 7.1 7.9 8.7 9.5 10.3
11/2" W/ft 1.8 2.3 2.8 3.2 3.7 4.1 4.6 5.8 6.8 7.7 9.1 10.1 11.1 12.1 13.2
2" W/ft 2.1 2.6 3.1 3.6 4.2 4.7 5.2 6.6 7.6 8.7 10.3 11.4 12.6 13.7 14.9
21/2" W/ft 2.4 3.0 3.5 4.1 4.7 5.3 5.9 7.4 8.7 9.9 11.7 13.0 14.3 15.6 16.9
3" W/ft 2.7 3.4 4.1 4.8 5.4 6.1 6.8 8.6 10.0 11.4 13.5 15.0 16.5 18.0 19.4
4" W/ft 3.3 4.2 5.0 5.8 6.6 7.5 8.3 10.5 12.2 13.9 16.4 18.3 20.1 21.9 23.7
6" W/ft 4.5 5.7 6.8 7.9 9.0 10.2 11.3 14.2 16.6 19.0 22.4 24.9 27.3 29.8 32.3
8" W/ft 5.6 7.1 8.5 9.9 11.3 12.7 14.1 17.8 20.7 23.7 27.9 31.0 34.1 37.2 40.3
10" W/ft 6.8 8.0 10.3 12.0 13.7 15.4 17.1 21.5 25.1 28.7 33.9 37.6 41.4 45.1 48.9
12" W/ft 8.0 10.0 12.0 14.0 16.0 18.0 20.0 25.2 29.4 33.6 39.6 44.0 48.4 52.8 57.2
14" W/ft 8.7 10.9 13.0 15.2 17.4 19.5 21.7 27.3 31.9 36.5 43.0 47.7 52.5 57.3 62.1
16" W/ft 9.8 12.3 14.8 17.2 19.7 22.1 24.6 31.0 36.2 41.3 48.7 54.1 59.5 64.9 70.4
18" W/ft 11.0 13.7 16.4 19.2 21.9 24.7 27.4 34.5 40.3 46.0 54.3 60.3 66.3 72.3 78.4
20" W/ft 12.1 15.1 18.1 21.1 24.2 27.2 30.2 38.1 44.4 50.7 59.8 66.4 73.1 79.7 86.4
22" W/ft 13.2 16.5 19.8 23.1 26.4 29.7 33.0 41.6 48.5 55.4 65.3 72.6 79.9 87.1 94.4
24" W/ft 14.3 17.9 21.5 25.1 28.6 32.2 35.8 45.1 52.6 60.1 70.9 78.8 86.6 94.5 102.4
2" Insulation Thickness1/2" W/ft 1.0 1.2 1.4 1.7 1.9 2.2 2.4 3.0 3.5 4.0 4.8 5.3 5.8 6.3 7.23/4" W/ft 1.1 1.4 1.6 1.9 2.2 2.4 2.7 3.4 4.0 4.5 5.3 5.9 6.5 7.1 8.1
1" W/ft 1.2 1.5 1.8 2.1 2.4 2.7 3.0 3.8 4.4 5.0 5.9 6.6 7.3 7.9 9.0
11/2" W/ft 1.5 1.9 2.3 2.7 3.0 3.4 3.8 4.8 5.6 6.4 7.5 8.4 9.2 10.0 11.4
2" W/ft 1.7 2.2 2.6 3.0 3.4 3.9 4.3 5.4 6.3 7.2 8.5 9.5 10.4 11.4 12.9
21/2" W/ft 1.9 2.4 2.9 3.4 3.8 4.3 4.8 6.0 7.1 8.1 9.5 10.6 11.6 12.7 14.4
3" W/ft 2.2 2.8 3.3 3.9 4.4 5.0 5.5 6.9 8.1 9.2 10.9 12.1 13.3 14.5 16.4
4" W/ft 2.6 3.3 4.0 4.6 5.3 5.9 6.6 8.3 9.7 11.1 13.1 14.5 16.0 17.4 19.7
6" W/ft 3.6 4.5 5.3 6.2 7.1 8.0 8.9 11.2 13.1 15.0 17.6 19.6 21.5 23.5 26.6
8" W/ft 4.4 5.6 6.7 7.8 8.9 10.0 11.1 14.0 16.3 18.6 22.0 24.4 26.9 29.3 33.2
10" W/ft 5.3 6.7 8.0 9.3 10.6 12.0 13.3 16.8 19.6 22.3 26.3 29.3 32.2 35.1 39.8
12" W/ft 6.2 7.8 9.3 10.9 12.4 14.0 15.5 19.5 22.8 26.0 30.7 34.1 37.5 40.9 46.3
14" W/ft 6.7 8.4 10.1 11.8 13.4 15.1 16.8 21.2 24.7 28.2 33.3 37.0 40.7 44.4 50.2
16" W/ft 7.6 9.5 11.3 13.2 15.1 17.0 18.9 23.8 27.8 31.8 37.4 41.6 45.7 49.9 56.5
18" W/ft 8.4 10.5 12.6 14.7 16.8 18.9 21.0 26.5 30.9 35.3 41.6 46.2 50.8 55.4 62.8
20" W/ft 9.2 11.6 13.9 16.2 18.5 20.8 23.1 29.1 34.0 38.8 45.7 50.8 55.9 61.0 69.1
22" W/ft 10.1 12.6 15.2 17.7 20.2 22.7 25.3 31.8 37.1 42.4 50.0 55.6 61.1 66.7 75.5
24" W/ft 11.0 13.7 16.4 19.2 21.9 24.7 27.4 34.5 40.3 46.0 54.3 60.3 66.3 72.3 81.9
609.6 mm W/m 36.1 44.9 53.8 63.0 71.9 3" (76.2 mm) Insulation Thickness1/2" W/ft 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.5 2.9 3.4 4.0 4.4 4.8 5.5 6.03/4" W/ft 0.9 1.1 1.3 1.5 1.8 2.0 2.2 2.8 3.2 3.7 4.4 4.8 5.3 6.1 6.67
1" W/ft 1.0 1.3 1.5 1.8 2.0 2.3 2.5 3.2 3.7 4.2 5.0 5.5 6.1 6.9 7.5
11/2" W/ft 1.2 1.5 1.8 2.1 2.4 2.7 3.0 3.8 4.4 5.0 5.9 6.6 7.3 8.3 9.0
2" W/ft 1.3 1.7 2.0 2.3 2.6 3.0 3.3 4.2 4.9 5.5 6.5 7.3 8.0 9.1 9.9
21/2" W/ft 1.5 1.9 2.2 2.6 3.0 3.3 3.7 4.7 5.4 6.2 7.3 8.1 9.0 10.2 11.1
3" W/ft 1.7 2.1 2.5 2.9 3.4 3.8 4.2 5.3 6.2 7.1 8.3 9.2 10.2 11.6 12.6
4" W/ft 2.0 2.5 3.0 3.5 4.0 4.5 5.0 6.3 7.4 8.4 9.9 11.0 12.1 13.8 15.0
6" W/ft 2.6 3.3 3.9 4.6 5.2 5.9 6.5 8.2 9.6 10.9 12.9 14.3 15.7 17.9 19.4
8" W/ft 3.2 4.0 4.8 5.6 6.4 7.2 8.0 10.1 11.8 13.4 15.8 17.6 19.4 22.1 23.9
10" W/ft 3.8 4.8 5.7 6.7 7.6 8.6 9.5 12.0 14.0 16.0 18.8 20.9 23.0 26.2 28.4
12" W/ft 4.4 5.5 6.5 7.6 8.7 9.8 10.9 13.7 16.0 18.3 21.6 24.0 26.4 30.1 32.6
14" W/ft 4.7 5.9 7.1 8.3 9.4 10.6 11.8 14.9 17.3 19.8 23.4 26.0 28.6 32.6 35.3
16" W/ft 5.3 6.7 8.0 9.3 10.6 12.0 13.3 16.8 19.6 22.3 26.3 29.3 32.2 36.7 39.8
18” W/ft 5.9 7.4 8.8 10.3 11.8 13.2 14.7 18.5 21.6 24.7 29.1 32.3 35.6 40.6 44.0
20" W/ft 6.4 8.1 9.7 11.3 12.9 14.5 16.1 20.3 23.7 27.0 31.9 35.4 39.0 44.4 48.1
22" W/ft 7.0 8.8 10.5 12.3 14.0 15.8 17.5 22.1 25.7 29.4 34.7 38.5 42.4 48.3 52.3
24" W/ft 7.6 9.5 11.3 13.2 15.1 17.0 18.9 23.8 27.8 31.8 37.4 41.6 45.7 52.2 56.5
NominalPipe Size,
in. (ID)
Temperature Difference Between Pipe and Ambient
DegºF 40ºF 50ºF 60ºF 70ºF 80ºF 90ºF 100ºF 120ºF 140ºF 160ºF 180ºF 200ºF 220ºF 240ºF 260ºF
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Chromalox Cable Selection
1. Select Heating Cable Family: Based on the maximum maintenance temperature rating, maximumexposure temperature rating, and area classification, select the heating cable family from Table 3. (SeeChromalox Heat Trace Cable Product Information Sheets for cable construction options, voltage ratings,and wattage outputs available.)
2. Select Thermal Output Rating:
(a) For Metal Pipes – Use Figures 1, 2 or 4(b) For Plastic Pipes – Use Figure 3 by finding the intersection of the calculated heat loss, QF, and pipe
maintenance temperature, Tm. Select the cable with a thermal output that equals or exceeds QF at Tm.
Pipe Temperature (ºF)Maintenance Temperature
0 10 20 30 50 60 70 80 90 100 110 120 130 140 150
Ther
mal
Out
put
(W/f
t)
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
4.88
SRL10 & HSRL10
SRL8 & HSRL8
SRL5 & HSRL5
SRL3 & HSRL3
Cable OutputversusTemperature
40
Figure 1 SRL & HSRL – Thermal OutputRatings on Insulated Metal Pipe Figure 2 SRM/E & HSRM – Thermal Output
Ratings on Insulated Metal Pipe Figure 3 SRL & HSRL – Thermal Output Ratingson Plastic Pipe with Aluminum Tape
B3. Determine Total Cable Length: In addition to pipe length, in-line components such as valves, flanges,
and pipe supports require additional heat tracing to maintain Tm. See Table 4. Calculate the totalcable length required by combining the pipe length with the additional lengths needed for all theother components.
Table 3 Heating Cable Families
NOTE: It is the responsibility of the facility manager or engineer to determine the classification of an area where heat trace will be installed. The factory can help determine a suitablecable based on the information provided.
Table 4Additional Cable Lengths Required for In-Line ComponentsBased on Pipe IPS (Iron Pipe Size)
1/2 in. 1.00 1.00 1.00 1.00 1.00 1.00 1.00 0.30
3/4 in. 1.50 1.00 1.00 1.00 1.50 1.00 1.00 0.30
1 in. 2.00 1.00 1.00 1.00 1.50 1.00 1.00 0.30
11/2 in. 2.50 1.50 1.50 1.50 2.00 2.00 2.00 0.30
2 in. 2.50 2.00 2.00 2.00 2.00 2.00 2.00 0.30
21/2 in. 2.50 2.00 2.00 2.00 2.00 2.00 2.00 0.30
3 in. 3.00 2.50 2.50 2.50 2.00 2.00 2.00 0.50
4 in. 4.00 3.00 3.00 3.00 2.50 2.50 2.50 0.50
6 in. 5.00 3.50 3.50 3.50 2.50 2.50 2.50 0.80
8 in. 7.00 4.00 4.00 4.00 2.50 2.50 2.50 0.80
10 in. 8.00 4.50 4.50 4.50 3.00 3.00 3.00 0.80
12 in. 9.00 5.00 5.00 5.00 3.00 3.00 3.00 0.80
14 in. 10.00 5.50 5.50 5.50 3.00 3.00 3.00 1.00
16 in. 11.00 6.00 6.00 6.00 3.50 3.50 3.50 1.00
18 in. 12.00 7.00 7.00 7.00 3.50 3.50 3.50 1.00
20 in. 13.00 7.50 7.50 7.50 3.50 3.50 3.50 1.00
22 in. 13.00 7.50 7.50 7.50 3.50 3.50 3.50 1.00
24 in. 15.00 8.00 8.00 8.00 4.00 4.00 4.00 1.00
Piping Size Gate Valve Globe Valve Ball Valve Butterfly Valve Hanger SupportShoe Support Sleeper Support Flange Pair
ft
0 10 20 30 50 60 70 80 90 100 110 120 130 140 15040
Pipe Temperature (ºF)
SRL10 & HSRL10
Ther
mal
Out
put
(W/f
t)
9
8
7
6
5
4
3
2
1
0
SRL8 &HSRL8
SRL5 & HSRL5
SRL3 & HSRL3
Cable OutputversusTemperature
Figure 4 SRP – Thermal Output Ratingson Insulated Metal Pipe
Pipe Temperature (ºF)
Hea
tO
utp
ut(W
/ft)
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
15 W/ft
10 W/ft
5 W/ft
Cable OutputversusTemperature
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230
Heating CableFamily
AreaClassification
PipeMaterial
MaximumMaintenanceTemperature
Maximum ExposureTemperature(Power Off)
Approvals
U.S. Other
SRL(Self-RegulatingLow Temperature)
Ordinary
Plastic/Metal 150ºF / 65ºC 185ºF / 85ºC
UL, CSA, FM GOST, Cenelec,CE, ATEX
Class I, Div.2, Gr. B, C, D CSA, FM, (Gr. A, CSA Only) GOST, Cenelec,CE, ATEX
Class II, Div.2, Gr. E, F, G CSA, FM, (Gr. E, CSA Only) GOST, Cenelec,CE
Class III, Div.2 FM Only GOST, Cenelec,CE, ATEX
SRM/E(Self-RegulatingMediumTemperature)
Ordinary
Metal Only 302ºF / 150ºC 420ºF / 215ºC
UL, CSA, FM GOST, Cenelec,CE, ATEX
Class I Div.2, Gr. A, B, C, D CSA, FM, (Gr. A, CSA Only) GOST, Cenelec,CE, ATEX
Class II, Div.2, Gr. F, G CSA Only GOST, Cenelec,CE, ATEX
SRP(Self-RegulatingMediumTemperature)
Ordinary
Metal Only 225ºF / 110ºC 275ºF / 135ºC UL, CSA, FMPending
GOST, Cenelec, CE,ATEX Pending
Class I, Div.2, Gr. B, C, D
Class II, Div.2, Gr. F, G
Class III
HSRL(H-Self-RegulatingLow Temperature)
Class I, Div.1, Gr. B, C, D
Plastic/Metal 150ºF / 65ºC 185ºF / 85ºC
CSA, FM
Class II, Div.1, Gr. E, F, G CSA, FM
Class III, Div.1 CSA, FM
HSRM(H-Self-RegulatingMediumTemperature)
Class I, Div.1, Gr. B, C, D
Metal Only 302ºF / 150ºC 420ºF / 215ºC
CSA, FM
Class II, Div.1, Gr. E, F, G CSA, FM
Class III, Div.1 CSA, FM
CWM(Constant Wattage)
OrdinaryMetal Only Consult Factory 392ºF / 200ºC
UL, CSA
Hazardous Area, Consult Factory
MI (MineralInsulated)
Ordinary
Metal Only Consult Factory 1,100ºF / 595ºC
CSA, FM
Class I, Div.2, Gr. B, C, D CSA, FM
Class II, Div.2, Gr. E, F, G CSA, FM
Class III CSA, FM
0 50 100 150 200 250 300
Pipe Temperature (ºF)
SRM/E20 &HSRM20
Pow
erO
utp
ut(W
/ft)
24
20
16
12
8
4
0
SRM/E15 &HSRM15
SRM/E10 &HSRM10
SRM/E8 & HSRM8
SRM/E5 & HSRM5
SRM/E3 & HSRM3
Cable OutputversusTemperature
Table 2 Insulation Adjustment Factors
Insulation Factor
Pipe Insulation TypePipe Insulation TypeInsulation Factor
Glass fiber (ASTM C547) 1.00
Calcium silicate (ASTM C533) 1.48
Cellular glass (ASTM C552) 1.48
Rigid cellular urethane (ASTM C591) 0.64
Foamed elastomer (ASTM C534) 1.16
Mineral fiber blanket (ASTM C553) 1.16
Expanded perlite (ASTM C610) 1.90
1. Basic Heat Loss: After determining the difference between the ambient and desired pipe maintenance
temperature, Tm, use Table 1 to figure the basic heat loss for the pipe size and insulation thickness.
2. Insulation Adjustment: Using Table 2, find the type of insulation being used and its insulation factor.
Hea
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ater
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3. Calculate QF: Multiply the basic heat loss figure from Table 1 by the adjustment factor from Table 2 to
calculate the estimated heat loss, QF, in watts per foot of pipe length.
4. Correct for Indoor Location/ Wind Speed: If location is indoors, multiply QF by 0.9. Table 1 is based on
10% safety factor and 20 mph wind speed; add 5% margin for each 5 mph over 20 mph wind speed.
Table 1 Pipe Heat Loss QP in W/ft Based on Temperature Differential and Insulation Thickness
NominalPipe Size,
in. (ID)
Temperature Difference Between Pipe and Ambient
DegºF 40ºF 50ºF 60ºF 70ºF 80ºF 90ºF 100ºF 120ºF 140ºF 160ºF 180ºF 200ºF 220ºF 240ºF 260ºF
1" Insulation Thickness1/2" W/ft 1.4 1.8 2.1 2.5 2.8 3.2 3.5 4.2 5.1 5.9 6.6 7.7 8.5 9.2 10.03/4" W/ft 1.6 2.0 2.4 2.8 3.2 3.6 4.0 4.8 5.9 6.7 7.6 8.8 9.7 10.6 11.4
1" W/ft 1.8 2.3 2.8 3.2 3.7 4.1 4.6 5.5 6.8 7.7 8.7 10.1 11.1 12.1 13.2
11/2" W/ft 2.4 3.1 3.7 4.3 4.9 5.5 6.1 7.3 9.0 10.2 11.5 13.4 14.8 16.1 17.4
2" W/ft 2.8 3.5 4.1 4.8 5.5 6.2 6.9 8.3 10.1 11.6 13.0 15.2 16.7 18.2 19.7
21/2" W/ft 3.2 4.0 4.8 5.6 6.4 7.2 8.0 9.6 11.8 13.4 15.1 17.6 19.4 21.1 22.9
3" W/ft 3.7 4.7 5.6 6.5 7.4 8.4 9.3 11.2 13.7 15.6 17.6 20.5 22.5 24.6 26.6
4" W/ft 4.6 5.8 6.9 8.1 9.2 10.4 11.5 13.8 16.9 19.3 21.7 25.3 27.8 30.4 32.9
6" W/ft 6.4 8.0 9.6 11.2 12.8 14.4 16.0 19.2 23.5 26.9 30.2 35.2 38.7 42.2 45.8
8" W/ft 8.1 10.1 12.1 14.1 16.2 18.2 20.2 24.2 29.7 33.9 38.2 44.4 48.9 53.3 57.8
10" W/ft 9.9 12.4 14.8 17.3 19.8 22.2 24.7 29.6 36.3 41.5 46.7 54.3 59.8 65.2 70.6
12" W/ft 11.6 14.5 17.4 20.3 23.2 26.1 29.0 34.8 42.6 48.7 54.8 63.8 70.2 76.6 82.9
14" W/ft 12.6 15.8 19.0 22.1 25.3 28.4 31.6 37.9 46.5 53.1 59.7 69.5 76.5 83.4 90.4
16" W/ft 14.3 17.9 21.5 25.1 28.7 32.3 35.9 43.0 52.7 60.2 67.8 78.9 86.8 94.6 102.5
18" W/ft 16.0 20.1 24.1 28.1 32.1 36.1 40.1 48.1 58.9 67.4 75.8 88.2 97.0 105.9 114.7
20" W/ft 17.7 22.2 26.6 31.0 35.4 39.9 44.3 53.2 65.1 74.4 83.7 97.5 107.2 117.0 126.7
22" W/ft 19.4 24.3 29.1 34.0 38.8 43.7 48.5 58.2 71.3 81.5 91.7 106.7 117.4 128.0 138.7
24" W/ft 21.1 26.4 31.6 36.9 42.2 47.4 52.7 63.2 77.5 88.5 99.6 115.9 127.5 139.1 150.7
1.5" Insulation Thickness1/2" W/ft 1.1 1.4 1.7 2.0 2.2 2.5 2.8 3.5 4.1 4.7 5.5 6.2 6.8 7.4 8.03/4" W/ft 1.2 1.6 1.9 2.2 2.5 2.8 3.1 3.9 4.6 5.2 6.1 6.8 7.5 8.2 8.9
1" W/ft 1.4 1.8 2.2 2.5 2.9 3.2 3.6 4.5 5.3 6.0 7.1 7.9 8.7 9.5 10.3
11/2" W/ft 1.8 2.3 2.8 3.2 3.7 4.1 4.6 5.8 6.8 7.7 9.1 10.1 11.1 12.1 13.2
2" W/ft 2.1 2.6 3.1 3.6 4.2 4.7 5.2 6.6 7.6 8.7 10.3 11.4 12.6 13.7 14.9
21/2" W/ft 2.4 3.0 3.5 4.1 4.7 5.3 5.9 7.4 8.7 9.9 11.7 13.0 14.3 15.6 16.9
3" W/ft 2.7 3.4 4.1 4.8 5.4 6.1 6.8 8.6 10.0 11.4 13.5 15.0 16.5 18.0 19.4
4" W/ft 3.3 4.2 5.0 5.8 6.6 7.5 8.3 10.5 12.2 13.9 16.4 18.3 20.1 21.9 23.7
6" W/ft 4.5 5.7 6.8 7.9 9.0 10.2 11.3 14.2 16.6 19.0 22.4 24.9 27.3 29.8 32.3
8" W/ft 5.6 7.1 8.5 9.9 11.3 12.7 14.1 17.8 20.7 23.7 27.9 31.0 34.1 37.2 40.3
10" W/ft 6.8 8.0 10.3 12.0 13.7 15.4 17.1 21.5 25.1 28.7 33.9 37.6 41.4 45.1 48.9
12" W/ft 8.0 10.0 12.0 14.0 16.0 18.0 20.0 25.2 29.4 33.6 39.6 44.0 48.4 52.8 57.2
14" W/ft 8.7 10.9 13.0 15.2 17.4 19.5 21.7 27.3 31.9 36.5 43.0 47.7 52.5 57.3 62.1
16" W/ft 9.8 12.3 14.8 17.2 19.7 22.1 24.6 31.0 36.2 41.3 48.7 54.1 59.5 64.9 70.4
18" W/ft 11.0 13.7 16.4 19.2 21.9 24.7 27.4 34.5 40.3 46.0 54.3 60.3 66.3 72.3 78.4
20" W/ft 12.1 15.1 18.1 21.1 24.2 27.2 30.2 38.1 44.4 50.7 59.8 66.4 73.1 79.7 86.4
22" W/ft 13.2 16.5 19.8 23.1 26.4 29.7 33.0 41.6 48.5 55.4 65.3 72.6 79.9 87.1 94.4
24" W/ft 14.3 17.9 21.5 25.1 28.6 32.2 35.8 45.1 52.6 60.1 70.9 78.8 86.6 94.5 102.4
2" Insulation Thickness1/2" W/ft 1.0 1.2 1.4 1.7 1.9 2.2 2.4 3.0 3.5 4.0 4.8 5.3 5.8 6.3 7.23/4" W/ft 1.1 1.4 1.6 1.9 2.2 2.4 2.7 3.4 4.0 4.5 5.3 5.9 6.5 7.1 8.1
1" W/ft 1.2 1.5 1.8 2.1 2.4 2.7 3.0 3.8 4.4 5.0 5.9 6.6 7.3 7.9 9.0
11/2" W/ft 1.5 1.9 2.3 2.7 3.0 3.4 3.8 4.8 5.6 6.4 7.5 8.4 9.2 10.0 11.4
2" W/ft 1.7 2.2 2.6 3.0 3.4 3.9 4.3 5.4 6.3 7.2 8.5 9.5 10.4 11.4 12.9
21/2" W/ft 1.9 2.4 2.9 3.4 3.8 4.3 4.8 6.0 7.1 8.1 9.5 10.6 11.6 12.7 14.4
3" W/ft 2.2 2.8 3.3 3.9 4.4 5.0 5.5 6.9 8.1 9.2 10.9 12.1 13.3 14.5 16.4
4" W/ft 2.6 3.3 4.0 4.6 5.3 5.9 6.6 8.3 9.7 11.1 13.1 14.5 16.0 17.4 19.7
6" W/ft 3.6 4.5 5.3 6.2 7.1 8.0 8.9 11.2 13.1 15.0 17.6 19.6 21.5 23.5 26.6
8" W/ft 4.4 5.6 6.7 7.8 8.9 10.0 11.1 14.0 16.3 18.6 22.0 24.4 26.9 29.3 33.2
10" W/ft 5.3 6.7 8.0 9.3 10.6 12.0 13.3 16.8 19.6 22.3 26.3 29.3 32.2 35.1 39.8
12" W/ft 6.2 7.8 9.3 10.9 12.4 14.0 15.5 19.5 22.8 26.0 30.7 34.1 37.5 40.9 46.3
14" W/ft 6.7 8.4 10.1 11.8 13.4 15.1 16.8 21.2 24.7 28.2 33.3 37.0 40.7 44.4 50.2
16" W/ft 7.6 9.5 11.3 13.2 15.1 17.0 18.9 23.8 27.8 31.8 37.4 41.6 45.7 49.9 56.5
18" W/ft 8.4 10.5 12.6 14.7 16.8 18.9 21.0 26.5 30.9 35.3 41.6 46.2 50.8 55.4 62.8
20" W/ft 9.2 11.6 13.9 16.2 18.5 20.8 23.1 29.1 34.0 38.8 45.7 50.8 55.9 61.0 69.1
22" W/ft 10.1 12.6 15.2 17.7 20.2 22.7 25.3 31.8 37.1 42.4 50.0 55.6 61.1 66.7 75.5
24" W/ft 11.0 13.7 16.4 19.2 21.9 24.7 27.4 34.5 40.3 46.0 54.3 60.3 66.3 72.3 81.9
609.6 mm W/m 36.1 44.9 53.8 63.0 71.9 3" (76.2 mm) Insulation Thickness1/2" W/ft 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.5 2.9 3.4 4.0 4.4 4.8 5.5 6.03/4" W/ft 0.9 1.1 1.3 1.5 1.8 2.0 2.2 2.8 3.2 3.7 4.4 4.8 5.3 6.1 6.67
1" W/ft 1.0 1.3 1.5 1.8 2.0 2.3 2.5 3.2 3.7 4.2 5.0 5.5 6.1 6.9 7.5
11/2" W/ft 1.2 1.5 1.8 2.1 2.4 2.7 3.0 3.8 4.4 5.0 5.9 6.6 7.3 8.3 9.0
2" W/ft 1.3 1.7 2.0 2.3 2.6 3.0 3.3 4.2 4.9 5.5 6.5 7.3 8.0 9.1 9.9
21/2" W/ft 1.5 1.9 2.2 2.6 3.0 3.3 3.7 4.7 5.4 6.2 7.3 8.1 9.0 10.2 11.1
3" W/ft 1.7 2.1 2.5 2.9 3.4 3.8 4.2 5.3 6.2 7.1 8.3 9.2 10.2 11.6 12.6
4" W/ft 2.0 2.5 3.0 3.5 4.0 4.5 5.0 6.3 7.4 8.4 9.9 11.0 12.1 13.8 15.0
6" W/ft 2.6 3.3 3.9 4.6 5.2 5.9 6.5 8.2 9.6 10.9 12.9 14.3 15.7 17.9 19.4
8" W/ft 3.2 4.0 4.8 5.6 6.4 7.2 8.0 10.1 11.8 13.4 15.8 17.6 19.4 22.1 23.9
10" W/ft 3.8 4.8 5.7 6.7 7.6 8.6 9.5 12.0 14.0 16.0 18.8 20.9 23.0 26.2 28.4
12" W/ft 4.4 5.5 6.5 7.6 8.7 9.8 10.9 13.7 16.0 18.3 21.6 24.0 26.4 30.1 32.6
14" W/ft 4.7 5.9 7.1 8.3 9.4 10.6 11.8 14.9 17.3 19.8 23.4 26.0 28.6 32.6 35.3
16" W/ft 5.3 6.7 8.0 9.3 10.6 12.0 13.3 16.8 19.6 22.3 26.3 29.3 32.2 36.7 39.8
18” W/ft 5.9 7.4 8.8 10.3 11.8 13.2 14.7 18.5 21.6 24.7 29.1 32.3 35.6 40.6 44.0
20" W/ft 6.4 8.1 9.7 11.3 12.9 14.5 16.1 20.3 23.7 27.0 31.9 35.4 39.0 44.4 48.1
22" W/ft 7.0 8.8 10.5 12.3 14.0 15.8 17.5 22.1 25.7 29.4 34.7 38.5 42.4 48.3 52.3
24" W/ft 7.6 9.5 11.3 13.2 15.1 17.0 18.9 23.8 27.8 31.8 37.4 41.6 45.7 52.2 56.5
NominalPipe Size,
in. (ID)
Temperature Difference Between Pipe and Ambient
DegºF 40ºF 50ºF 60ºF 70ºF 80ºF 90ºF 100ºF 120ºF 140ºF 160ºF 180ºF 200ºF 220ºF 240ºF 260ºF
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Chromalox Cable Selection
1. Select Heating Cable Family: Based on the maximum maintenance temperature rating, maximumexposure temperature rating, and area classification, select the heating cable family from Table 3. (SeeChromalox Heat Trace Cable Product Information Sheets for cable construction options, voltage ratings,and wattage outputs available.)
2. Select Thermal Output Rating:
(a) For Metal Pipes – Use Figures 1, 2 or 4(b) For Plastic Pipes – Use Figure 3 by finding the intersection of the calculated heat loss, QF, and pipe
maintenance temperature, Tm. Select the cable with a thermal output that equals or exceeds QF at Tm.
Pipe Temperature (ºF)Maintenance Temperature
0 10 20 30 50 60 70 80 90 100 110 120 130 140 150
Ther
mal
Out
put
(W/f
t)
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
4.88
SRL10 & HSRL10
SRL8 & HSRL8
SRL5 & HSRL5
SRL3 & HSRL3
Cable OutputversusTemperature
40
Figure 1 SRL & HSRL – Thermal OutputRatings on Insulated Metal Pipe Figure 2 SRM/E & HSRM – Thermal Output
Ratings on Insulated Metal Pipe Figure 3 SRL & HSRL – Thermal Output Ratingson Plastic Pipe with Aluminum Tape
B3. Determine Total Cable Length: In addition to pipe length, in-line components such as valves, flanges,
and pipe supports require additional heat tracing to maintain Tm. See Table 4. Calculate the totalcable length required by combining the pipe length with the additional lengths needed for all theother components.
Table 3 Heating Cable Families
NOTE: It is the responsibility of the facility manager or engineer to determine the classification of an area where heat trace will be installed. The factory can help determine a suitablecable based on the information provided.
Table 4Additional Cable Lengths Required for In-Line ComponentsBased on Pipe IPS (Iron Pipe Size)
1/2 in. 1.00 1.00 1.00 1.00 1.00 1.00 1.00 0.30
3/4 in. 1.50 1.00 1.00 1.00 1.50 1.00 1.00 0.30
1 in. 2.00 1.00 1.00 1.00 1.50 1.00 1.00 0.30
11/2 in. 2.50 1.50 1.50 1.50 2.00 2.00 2.00 0.30
2 in. 2.50 2.00 2.00 2.00 2.00 2.00 2.00 0.30
21/2 in. 2.50 2.00 2.00 2.00 2.00 2.00 2.00 0.30
3 in. 3.00 2.50 2.50 2.50 2.00 2.00 2.00 0.50
4 in. 4.00 3.00 3.00 3.00 2.50 2.50 2.50 0.50
6 in. 5.00 3.50 3.50 3.50 2.50 2.50 2.50 0.80
8 in. 7.00 4.00 4.00 4.00 2.50 2.50 2.50 0.80
10 in. 8.00 4.50 4.50 4.50 3.00 3.00 3.00 0.80
12 in. 9.00 5.00 5.00 5.00 3.00 3.00 3.00 0.80
14 in. 10.00 5.50 5.50 5.50 3.00 3.00 3.00 1.00
16 in. 11.00 6.00 6.00 6.00 3.50 3.50 3.50 1.00
18 in. 12.00 7.00 7.00 7.00 3.50 3.50 3.50 1.00
20 in. 13.00 7.50 7.50 7.50 3.50 3.50 3.50 1.00
22 in. 13.00 7.50 7.50 7.50 3.50 3.50 3.50 1.00
24 in. 15.00 8.00 8.00 8.00 4.00 4.00 4.00 1.00
Piping Size Gate Valve Globe Valve Ball Valve Butterfly Valve Hanger SupportShoe Support Sleeper Support Flange Pair
ft
0 10 20 30 50 60 70 80 90 100 110 120 130 140 15040
Pipe Temperature (ºF)
SRL10 & HSRL10
Ther
mal
Out
put
(W/f
t)
9
8
7
6
5
4
3
2
1
0
SRL8 &HSRL8
SRL5 & HSRL5
SRL3 & HSRL3
Cable OutputversusTemperature
Figure 4 SRP – Thermal Output Ratingson Insulated Metal Pipe
Pipe Temperature (ºF)
Hea
tO
utp
ut(W
/ft)
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
15 W/ft
10 W/ft
5 W/ft
Cable OutputversusTemperature
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230
Heating CableFamily
AreaClassification
PipeMaterial
MaximumMaintenanceTemperature
Maximum ExposureTemperature(Power Off)
Approvals
U.S. Other
SRL(Self-RegulatingLow Temperature)
Ordinary
Plastic/Metal 150ºF / 65ºC 185ºF / 85ºC
UL, CSA, FM GOST, Cenelec,CE, ATEX
Class I, Div.2, Gr. B, C, D CSA, FM, (Gr. A, CSA Only) GOST, Cenelec,CE, ATEX
Class II, Div.2, Gr. E, F, G CSA, FM, (Gr. E, CSA Only) GOST, Cenelec,CE
Class III, Div.2 FM Only GOST, Cenelec,CE, ATEX
SRM/E(Self-RegulatingMediumTemperature)
Ordinary
Metal Only 302ºF / 150ºC 420ºF / 215ºC
UL, CSA, FM GOST, Cenelec,CE, ATEX
Class I Div.2, Gr. A, B, C, D CSA, FM, (Gr. A, CSA Only) GOST, Cenelec,CE, ATEX
Class II, Div.2, Gr. F, G CSA Only GOST, Cenelec,CE, ATEX
SRP(Self-RegulatingMediumTemperature)
Ordinary
Metal Only 225ºF / 110ºC 275ºF / 135ºC UL, CSA, FMPending
GOST, Cenelec, CE,ATEX Pending
Class I, Div.2, Gr. B, C, D
Class II, Div.2, Gr. F, G
Class III
HSRL(H-Self-RegulatingLow Temperature)
Class I, Div.1, Gr. B, C, D
Plastic/Metal 150ºF / 65ºC 185ºF / 85ºC
CSA, FM
Class II, Div.1, Gr. E, F, G CSA, FM
Class III, Div.1 CSA, FM
HSRM(H-Self-RegulatingMediumTemperature)
Class I, Div.1, Gr. B, C, D
Metal Only 302ºF / 150ºC 420ºF / 215ºC
CSA, FM
Class II, Div.1, Gr. E, F, G CSA, FM
Class III, Div.1 CSA, FM
CWM(Constant Wattage)
OrdinaryMetal Only Consult Factory 392ºF / 200ºC
UL, CSA
Hazardous Area, Consult Factory
MI (MineralInsulated)
Ordinary
Metal Only Consult Factory 1,100ºF / 595ºC
CSA, FM
Class I, Div.2, Gr. B, C, D CSA, FM
Class II, Div.2, Gr. E, F, G CSA, FM
Class III CSA, FM
0 50 100 150 200 250 300
Pipe Temperature (ºF)
SRM/E20 &HSRM20
Pow
erO
utp
ut(W
/ft)
24
20
16
12
8
4
0
SRM/E15 &HSRM15
SRM/E10 &HSRM10
SRM/E8 & HSRM8
SRM/E5 & HSRM5
SRM/E3 & HSRM3
Cable OutputversusTemperature
Table 2 Insulation Adjustment Factors
Insulation Factor
Pipe Insulation TypePipe Insulation TypeInsulation Factor
Glass fiber (ASTM C547) 1.00
Calcium silicate (ASTM C533) 1.48
Cellular glass (ASTM C552) 1.48
Rigid cellular urethane (ASTM C591) 0.64
Foamed elastomer (ASTM C534) 1.16
Mineral fiber blanket (ASTM C553) 1.16
Expanded perlite (ASTM C610) 1.90
1. Basic Heat Loss: After determining the difference between the ambient and desired pipe maintenance
temperature, Tm, use Table 1 to figure the basic heat loss for the pipe size and insulation thickness.
2. Insulation Adjustment: Using Table 2, find the type of insulation being used and its insulation factor.
Hea
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ater
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3. Calculate QF: Multiply the basic heat loss figure from Table 1 by the adjustment factor from Table 2 to
calculate the estimated heat loss, QF, in watts per foot of pipe length.
4. Correct for Indoor Location/ Wind Speed: If location is indoors, multiply QF by 0.9. Table 1 is based on
10% safety factor and 20 mph wind speed; add 5% margin for each 5 mph over 20 mph wind speed.
Table 1 Pipe Heat Loss QP in W/ft Based on Temperature Differential and Insulation Thickness
NominalPipe Size,
in. (ID)
Temperature Difference Between Pipe and Ambient
DegºF 40ºF 50ºF 60ºF 70ºF 80ºF 90ºF 100ºF 120ºF 140ºF 160ºF 180ºF 200ºF 220ºF 240ºF 260ºF
1" Insulation Thickness1/2" W/ft 1.4 1.8 2.1 2.5 2.8 3.2 3.5 4.2 5.1 5.9 6.6 7.7 8.5 9.2 10.03/4" W/ft 1.6 2.0 2.4 2.8 3.2 3.6 4.0 4.8 5.9 6.7 7.6 8.8 9.7 10.6 11.4
1" W/ft 1.8 2.3 2.8 3.2 3.7 4.1 4.6 5.5 6.8 7.7 8.7 10.1 11.1 12.1 13.2
11/2" W/ft 2.4 3.1 3.7 4.3 4.9 5.5 6.1 7.3 9.0 10.2 11.5 13.4 14.8 16.1 17.4
2" W/ft 2.8 3.5 4.1 4.8 5.5 6.2 6.9 8.3 10.1 11.6 13.0 15.2 16.7 18.2 19.7
21/2" W/ft 3.2 4.0 4.8 5.6 6.4 7.2 8.0 9.6 11.8 13.4 15.1 17.6 19.4 21.1 22.9
3" W/ft 3.7 4.7 5.6 6.5 7.4 8.4 9.3 11.2 13.7 15.6 17.6 20.5 22.5 24.6 26.6
4" W/ft 4.6 5.8 6.9 8.1 9.2 10.4 11.5 13.8 16.9 19.3 21.7 25.3 27.8 30.4 32.9
6" W/ft 6.4 8.0 9.6 11.2 12.8 14.4 16.0 19.2 23.5 26.9 30.2 35.2 38.7 42.2 45.8
8" W/ft 8.1 10.1 12.1 14.1 16.2 18.2 20.2 24.2 29.7 33.9 38.2 44.4 48.9 53.3 57.8
10" W/ft 9.9 12.4 14.8 17.3 19.8 22.2 24.7 29.6 36.3 41.5 46.7 54.3 59.8 65.2 70.6
12" W/ft 11.6 14.5 17.4 20.3 23.2 26.1 29.0 34.8 42.6 48.7 54.8 63.8 70.2 76.6 82.9
14" W/ft 12.6 15.8 19.0 22.1 25.3 28.4 31.6 37.9 46.5 53.1 59.7 69.5 76.5 83.4 90.4
16" W/ft 14.3 17.9 21.5 25.1 28.7 32.3 35.9 43.0 52.7 60.2 67.8 78.9 86.8 94.6 102.5
18" W/ft 16.0 20.1 24.1 28.1 32.1 36.1 40.1 48.1 58.9 67.4 75.8 88.2 97.0 105.9 114.7
20" W/ft 17.7 22.2 26.6 31.0 35.4 39.9 44.3 53.2 65.1 74.4 83.7 97.5 107.2 117.0 126.7
22" W/ft 19.4 24.3 29.1 34.0 38.8 43.7 48.5 58.2 71.3 81.5 91.7 106.7 117.4 128.0 138.7
24" W/ft 21.1 26.4 31.6 36.9 42.2 47.4 52.7 63.2 77.5 88.5 99.6 115.9 127.5 139.1 150.7
1.5" Insulation Thickness1/2" W/ft 1.1 1.4 1.7 2.0 2.2 2.5 2.8 3.5 4.1 4.7 5.5 6.2 6.8 7.4 8.03/4" W/ft 1.2 1.6 1.9 2.2 2.5 2.8 3.1 3.9 4.6 5.2 6.1 6.8 7.5 8.2 8.9
1" W/ft 1.4 1.8 2.2 2.5 2.9 3.2 3.6 4.5 5.3 6.0 7.1 7.9 8.7 9.5 10.3
11/2" W/ft 1.8 2.3 2.8 3.2 3.7 4.1 4.6 5.8 6.8 7.7 9.1 10.1 11.1 12.1 13.2
2" W/ft 2.1 2.6 3.1 3.6 4.2 4.7 5.2 6.6 7.6 8.7 10.3 11.4 12.6 13.7 14.9
21/2" W/ft 2.4 3.0 3.5 4.1 4.7 5.3 5.9 7.4 8.7 9.9 11.7 13.0 14.3 15.6 16.9
3" W/ft 2.7 3.4 4.1 4.8 5.4 6.1 6.8 8.6 10.0 11.4 13.5 15.0 16.5 18.0 19.4
4" W/ft 3.3 4.2 5.0 5.8 6.6 7.5 8.3 10.5 12.2 13.9 16.4 18.3 20.1 21.9 23.7
6" W/ft 4.5 5.7 6.8 7.9 9.0 10.2 11.3 14.2 16.6 19.0 22.4 24.9 27.3 29.8 32.3
8" W/ft 5.6 7.1 8.5 9.9 11.3 12.7 14.1 17.8 20.7 23.7 27.9 31.0 34.1 37.2 40.3
10" W/ft 6.8 8.0 10.3 12.0 13.7 15.4 17.1 21.5 25.1 28.7 33.9 37.6 41.4 45.1 48.9
12" W/ft 8.0 10.0 12.0 14.0 16.0 18.0 20.0 25.2 29.4 33.6 39.6 44.0 48.4 52.8 57.2
14" W/ft 8.7 10.9 13.0 15.2 17.4 19.5 21.7 27.3 31.9 36.5 43.0 47.7 52.5 57.3 62.1
16" W/ft 9.8 12.3 14.8 17.2 19.7 22.1 24.6 31.0 36.2 41.3 48.7 54.1 59.5 64.9 70.4
18" W/ft 11.0 13.7 16.4 19.2 21.9 24.7 27.4 34.5 40.3 46.0 54.3 60.3 66.3 72.3 78.4
20" W/ft 12.1 15.1 18.1 21.1 24.2 27.2 30.2 38.1 44.4 50.7 59.8 66.4 73.1 79.7 86.4
22" W/ft 13.2 16.5 19.8 23.1 26.4 29.7 33.0 41.6 48.5 55.4 65.3 72.6 79.9 87.1 94.4
24" W/ft 14.3 17.9 21.5 25.1 28.6 32.2 35.8 45.1 52.6 60.1 70.9 78.8 86.6 94.5 102.4
2" Insulation Thickness1/2" W/ft 1.0 1.2 1.4 1.7 1.9 2.2 2.4 3.0 3.5 4.0 4.8 5.3 5.8 6.3 7.23/4" W/ft 1.1 1.4 1.6 1.9 2.2 2.4 2.7 3.4 4.0 4.5 5.3 5.9 6.5 7.1 8.1
1" W/ft 1.2 1.5 1.8 2.1 2.4 2.7 3.0 3.8 4.4 5.0 5.9 6.6 7.3 7.9 9.0
11/2" W/ft 1.5 1.9 2.3 2.7 3.0 3.4 3.8 4.8 5.6 6.4 7.5 8.4 9.2 10.0 11.4
2" W/ft 1.7 2.2 2.6 3.0 3.4 3.9 4.3 5.4 6.3 7.2 8.5 9.5 10.4 11.4 12.9
21/2" W/ft 1.9 2.4 2.9 3.4 3.8 4.3 4.8 6.0 7.1 8.1 9.5 10.6 11.6 12.7 14.4
3" W/ft 2.2 2.8 3.3 3.9 4.4 5.0 5.5 6.9 8.1 9.2 10.9 12.1 13.3 14.5 16.4
4" W/ft 2.6 3.3 4.0 4.6 5.3 5.9 6.6 8.3 9.7 11.1 13.1 14.5 16.0 17.4 19.7
6" W/ft 3.6 4.5 5.3 6.2 7.1 8.0 8.9 11.2 13.1 15.0 17.6 19.6 21.5 23.5 26.6
8" W/ft 4.4 5.6 6.7 7.8 8.9 10.0 11.1 14.0 16.3 18.6 22.0 24.4 26.9 29.3 33.2
10" W/ft 5.3 6.7 8.0 9.3 10.6 12.0 13.3 16.8 19.6 22.3 26.3 29.3 32.2 35.1 39.8
12" W/ft 6.2 7.8 9.3 10.9 12.4 14.0 15.5 19.5 22.8 26.0 30.7 34.1 37.5 40.9 46.3
14" W/ft 6.7 8.4 10.1 11.8 13.4 15.1 16.8 21.2 24.7 28.2 33.3 37.0 40.7 44.4 50.2
16" W/ft 7.6 9.5 11.3 13.2 15.1 17.0 18.9 23.8 27.8 31.8 37.4 41.6 45.7 49.9 56.5
18" W/ft 8.4 10.5 12.6 14.7 16.8 18.9 21.0 26.5 30.9 35.3 41.6 46.2 50.8 55.4 62.8
20" W/ft 9.2 11.6 13.9 16.2 18.5 20.8 23.1 29.1 34.0 38.8 45.7 50.8 55.9 61.0 69.1
22" W/ft 10.1 12.6 15.2 17.7 20.2 22.7 25.3 31.8 37.1 42.4 50.0 55.6 61.1 66.7 75.5
24" W/ft 11.0 13.7 16.4 19.2 21.9 24.7 27.4 34.5 40.3 46.0 54.3 60.3 66.3 72.3 81.9
609.6 mm W/m 36.1 44.9 53.8 63.0 71.9 3" (76.2 mm) Insulation Thickness1/2" W/ft 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.5 2.9 3.4 4.0 4.4 4.8 5.5 6.03/4" W/ft 0.9 1.1 1.3 1.5 1.8 2.0 2.2 2.8 3.2 3.7 4.4 4.8 5.3 6.1 6.67
1" W/ft 1.0 1.3 1.5 1.8 2.0 2.3 2.5 3.2 3.7 4.2 5.0 5.5 6.1 6.9 7.5
11/2" W/ft 1.2 1.5 1.8 2.1 2.4 2.7 3.0 3.8 4.4 5.0 5.9 6.6 7.3 8.3 9.0
2" W/ft 1.3 1.7 2.0 2.3 2.6 3.0 3.3 4.2 4.9 5.5 6.5 7.3 8.0 9.1 9.9
21/2" W/ft 1.5 1.9 2.2 2.6 3.0 3.3 3.7 4.7 5.4 6.2 7.3 8.1 9.0 10.2 11.1
3" W/ft 1.7 2.1 2.5 2.9 3.4 3.8 4.2 5.3 6.2 7.1 8.3 9.2 10.2 11.6 12.6
4" W/ft 2.0 2.5 3.0 3.5 4.0 4.5 5.0 6.3 7.4 8.4 9.9 11.0 12.1 13.8 15.0
6" W/ft 2.6 3.3 3.9 4.6 5.2 5.9 6.5 8.2 9.6 10.9 12.9 14.3 15.7 17.9 19.4
8" W/ft 3.2 4.0 4.8 5.6 6.4 7.2 8.0 10.1 11.8 13.4 15.8 17.6 19.4 22.1 23.9
10" W/ft 3.8 4.8 5.7 6.7 7.6 8.6 9.5 12.0 14.0 16.0 18.8 20.9 23.0 26.2 28.4
12" W/ft 4.4 5.5 6.5 7.6 8.7 9.8 10.9 13.7 16.0 18.3 21.6 24.0 26.4 30.1 32.6
14" W/ft 4.7 5.9 7.1 8.3 9.4 10.6 11.8 14.9 17.3 19.8 23.4 26.0 28.6 32.6 35.3
16" W/ft 5.3 6.7 8.0 9.3 10.6 12.0 13.3 16.8 19.6 22.3 26.3 29.3 32.2 36.7 39.8
18” W/ft 5.9 7.4 8.8 10.3 11.8 13.2 14.7 18.5 21.6 24.7 29.1 32.3 35.6 40.6 44.0
20" W/ft 6.4 8.1 9.7 11.3 12.9 14.5 16.1 20.3 23.7 27.0 31.9 35.4 39.0 44.4 48.1
22" W/ft 7.0 8.8 10.5 12.3 14.0 15.8 17.5 22.1 25.7 29.4 34.7 38.5 42.4 48.3 52.3
24" W/ft 7.6 9.5 11.3 13.2 15.1 17.0 18.9 23.8 27.8 31.8 37.4 41.6 45.7 52.2 56.5
NominalPipe Size,
in. (ID)
Temperature Difference Between Pipe and Ambient
DegºF 40ºF 50ºF 60ºF 70ºF 80ºF 90ºF 100ºF 120ºF 140ºF 160ºF 180ºF 200ºF 220ºF 240ºF 260ºF
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Chromalox Cable Selection
1. Select Heating Cable Family: Based on the maximum maintenance temperature rating, maximumexposure temperature rating, and area classification, select the heating cable family from Table 3. (SeeChromalox Heat Trace Cable Product Information Sheets for cable construction options, voltage ratings,and wattage outputs available.)
2. Select Thermal Output Rating:
(a) For Metal Pipes – Use Figures 1, 2 or 4(b) For Plastic Pipes – Use Figure 3 by finding the intersection of the calculated heat loss, QF, and pipe
maintenance temperature, Tm. Select the cable with a thermal output that equals or exceeds QF at Tm.
Pipe Temperature (ºF)Maintenance Temperature
0 10 20 30 50 60 70 80 90 100 110 120 130 140 150
Ther
mal
Out
put
(W/f
t)
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
4.88
SRL10 & HSRL10
SRL8 & HSRL8
SRL5 & HSRL5
SRL3 & HSRL3
Cable OutputversusTemperature
40
Figure 1 SRL & HSRL – Thermal OutputRatings on Insulated Metal Pipe Figure 2 SRM/E & HSRM – Thermal Output
Ratings on Insulated Metal Pipe Figure 3 SRL & HSRL – Thermal Output Ratingson Plastic Pipe with Aluminum Tape
B3. Determine Total Cable Length: In addition to pipe length, in-line components such as valves, flanges,
and pipe supports require additional heat tracing to maintain Tm. See Table 4. Calculate the totalcable length required by combining the pipe length with the additional lengths needed for all theother components.
Table 3 Heating Cable Families
NOTE: It is the responsibility of the facility manager or engineer to determine the classification of an area where heat trace will be installed. The factory can help determine a suitablecable based on the information provided.
Table 4Additional Cable Lengths Required for In-Line ComponentsBased on Pipe IPS (Iron Pipe Size)
1/2 in. 1.00 1.00 1.00 1.00 1.00 1.00 1.00 0.30
3/4 in. 1.50 1.00 1.00 1.00 1.50 1.00 1.00 0.30
1 in. 2.00 1.00 1.00 1.00 1.50 1.00 1.00 0.30
11/2 in. 2.50 1.50 1.50 1.50 2.00 2.00 2.00 0.30
2 in. 2.50 2.00 2.00 2.00 2.00 2.00 2.00 0.30
21/2 in. 2.50 2.00 2.00 2.00 2.00 2.00 2.00 0.30
3 in. 3.00 2.50 2.50 2.50 2.00 2.00 2.00 0.50
4 in. 4.00 3.00 3.00 3.00 2.50 2.50 2.50 0.50
6 in. 5.00 3.50 3.50 3.50 2.50 2.50 2.50 0.80
8 in. 7.00 4.00 4.00 4.00 2.50 2.50 2.50 0.80
10 in. 8.00 4.50 4.50 4.50 3.00 3.00 3.00 0.80
12 in. 9.00 5.00 5.00 5.00 3.00 3.00 3.00 0.80
14 in. 10.00 5.50 5.50 5.50 3.00 3.00 3.00 1.00
16 in. 11.00 6.00 6.00 6.00 3.50 3.50 3.50 1.00
18 in. 12.00 7.00 7.00 7.00 3.50 3.50 3.50 1.00
20 in. 13.00 7.50 7.50 7.50 3.50 3.50 3.50 1.00
22 in. 13.00 7.50 7.50 7.50 3.50 3.50 3.50 1.00
24 in. 15.00 8.00 8.00 8.00 4.00 4.00 4.00 1.00
Piping Size Gate Valve Globe Valve Ball Valve Butterfly Valve Hanger SupportShoe Support Sleeper Support Flange Pair
ft
0 10 20 30 50 60 70 80 90 100 110 120 130 140 15040
Pipe Temperature (ºF)
SRL10 & HSRL10
Ther
mal
Out
put
(W/f
t)
9
8
7
6
5
4
3
2
1
0
SRL8 &HSRL8
SRL5 & HSRL5
SRL3 & HSRL3
Cable OutputversusTemperature
Figure 4 SRP – Thermal Output Ratingson Insulated Metal Pipe
Pipe Temperature (ºF)
Hea
tO
utp
ut(W
/ft)
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
15 W/ft
10 W/ft
5 W/ft
Cable OutputversusTemperature
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230
Heating CableFamily
AreaClassification
PipeMaterial
MaximumMaintenanceTemperature
Maximum ExposureTemperature(Power Off)
Approvals
U.S. Other
SRL(Self-RegulatingLow Temperature)
Ordinary
Plastic/Metal 150ºF / 65ºC 185ºF / 85ºC
UL, CSA, FM GOST, Cenelec,CE, ATEX
Class I, Div.2, Gr. B, C, D CSA, FM, (Gr. A, CSA Only) GOST, Cenelec,CE, ATEX
Class II, Div.2, Gr. E, F, G CSA, FM, (Gr. E, CSA Only) GOST, Cenelec,CE
Class III, Div.2 FM Only GOST, Cenelec,CE, ATEX
SRM/E(Self-RegulatingMediumTemperature)
Ordinary
Metal Only 302ºF / 150ºC 420ºF / 215ºC
UL, CSA, FM GOST, Cenelec,CE, ATEX
Class I Div.2, Gr. A, B, C, D CSA, FM, (Gr. A, CSA Only) GOST, Cenelec,CE, ATEX
Class II, Div.2, Gr. F, G CSA Only GOST, Cenelec,CE, ATEX
SRP(Self-RegulatingMediumTemperature)
Ordinary
Metal Only 225ºF / 110ºC 275ºF / 135ºC UL, CSA, FMPending
GOST, Cenelec, CE,ATEX Pending
Class I, Div.2, Gr. B, C, D
Class II, Div.2, Gr. F, G
Class III
HSRL(H-Self-RegulatingLow Temperature)
Class I, Div.1, Gr. B, C, D
Plastic/Metal 150ºF / 65ºC 185ºF / 85ºC
CSA, FM
Class II, Div.1, Gr. E, F, G CSA, FM
Class III, Div.1 CSA, FM
HSRM(H-Self-RegulatingMediumTemperature)
Class I, Div.1, Gr. B, C, D
Metal Only 302ºF / 150ºC 420ºF / 215ºC
CSA, FM
Class II, Div.1, Gr. E, F, G CSA, FM
Class III, Div.1 CSA, FM
CWM(Constant Wattage)
OrdinaryMetal Only Consult Factory 392ºF / 200ºC
UL, CSA
Hazardous Area, Consult Factory
MI (MineralInsulated)
Ordinary
Metal Only Consult Factory 1,100ºF / 595ºC
CSA, FM
Class I, Div.2, Gr. B, C, D CSA, FM
Class II, Div.2, Gr. E, F, G CSA, FM
Class III CSA, FM
0 50 100 150 200 250 300
Pipe Temperature (ºF)
SRM/E20 &HSRM20
Pow
erO
utp
ut(W
/ft)
24
20
16
12
8
4
0
SRM/E15 &HSRM15
SRM/E10 &HSRM10
SRM/E8 & HSRM8
SRM/E5 & HSRM5
SRM/E3 & HSRM3
Cable OutputversusTemperature
Table 2 Insulation Adjustment Factors
Insulation Factor
Pipe Insulation TypePipe Insulation TypeInsulation Factor
Glass fiber (ASTM C547) 1.00
Calcium silicate (ASTM C533) 1.48
Cellular glass (ASTM C552) 1.48
Rigid cellular urethane (ASTM C591) 0.64
Foamed elastomer (ASTM C534) 1.16
Mineral fiber blanket (ASTM C553) 1.16
Expanded perlite (ASTM C610) 1.90
1. Basic Heat Loss: After determining the difference between the ambient and desired pipe maintenance
temperature, Tm, use Table 1 to figure the basic heat loss for the pipe size and insulation thickness.
2. Insulation Adjustment: Using Table 2, find the type of insulation being used and its insulation factor.
Hea
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ater
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3. Calculate QF: Multiply the basic heat loss figure from Table 1 by the adjustment factor from Table 2 to
calculate the estimated heat loss, QF, in watts per foot of pipe length.
4. Correct for Indoor Location/ Wind Speed: If location is indoors, multiply QF by 0.9. Table 1 is based on
10% safety factor and 20 mph wind speed; add 5% margin for each 5 mph over 20 mph wind speed.
Table 1 Pipe Heat Loss QP in W/ft Based on Temperature Differential and Insulation Thickness
NominalPipe Size,
in. (ID)
Temperature Difference Between Pipe and Ambient
DegºF 40ºF 50ºF 60ºF 70ºF 80ºF 90ºF 100ºF 120ºF 140ºF 160ºF 180ºF 200ºF 220ºF 240ºF 260ºF
1" Insulation Thickness1/2" W/ft 1.4 1.8 2.1 2.5 2.8 3.2 3.5 4.2 5.1 5.9 6.6 7.7 8.5 9.2 10.03/4" W/ft 1.6 2.0 2.4 2.8 3.2 3.6 4.0 4.8 5.9 6.7 7.6 8.8 9.7 10.6 11.4
1" W/ft 1.8 2.3 2.8 3.2 3.7 4.1 4.6 5.5 6.8 7.7 8.7 10.1 11.1 12.1 13.2
11/2" W/ft 2.4 3.1 3.7 4.3 4.9 5.5 6.1 7.3 9.0 10.2 11.5 13.4 14.8 16.1 17.4
2" W/ft 2.8 3.5 4.1 4.8 5.5 6.2 6.9 8.3 10.1 11.6 13.0 15.2 16.7 18.2 19.7
21/2" W/ft 3.2 4.0 4.8 5.6 6.4 7.2 8.0 9.6 11.8 13.4 15.1 17.6 19.4 21.1 22.9
3" W/ft 3.7 4.7 5.6 6.5 7.4 8.4 9.3 11.2 13.7 15.6 17.6 20.5 22.5 24.6 26.6
4" W/ft 4.6 5.8 6.9 8.1 9.2 10.4 11.5 13.8 16.9 19.3 21.7 25.3 27.8 30.4 32.9
6" W/ft 6.4 8.0 9.6 11.2 12.8 14.4 16.0 19.2 23.5 26.9 30.2 35.2 38.7 42.2 45.8
8" W/ft 8.1 10.1 12.1 14.1 16.2 18.2 20.2 24.2 29.7 33.9 38.2 44.4 48.9 53.3 57.8
10" W/ft 9.9 12.4 14.8 17.3 19.8 22.2 24.7 29.6 36.3 41.5 46.7 54.3 59.8 65.2 70.6
12" W/ft 11.6 14.5 17.4 20.3 23.2 26.1 29.0 34.8 42.6 48.7 54.8 63.8 70.2 76.6 82.9
14" W/ft 12.6 15.8 19.0 22.1 25.3 28.4 31.6 37.9 46.5 53.1 59.7 69.5 76.5 83.4 90.4
16" W/ft 14.3 17.9 21.5 25.1 28.7 32.3 35.9 43.0 52.7 60.2 67.8 78.9 86.8 94.6 102.5
18" W/ft 16.0 20.1 24.1 28.1 32.1 36.1 40.1 48.1 58.9 67.4 75.8 88.2 97.0 105.9 114.7
20" W/ft 17.7 22.2 26.6 31.0 35.4 39.9 44.3 53.2 65.1 74.4 83.7 97.5 107.2 117.0 126.7
22" W/ft 19.4 24.3 29.1 34.0 38.8 43.7 48.5 58.2 71.3 81.5 91.7 106.7 117.4 128.0 138.7
24" W/ft 21.1 26.4 31.6 36.9 42.2 47.4 52.7 63.2 77.5 88.5 99.6 115.9 127.5 139.1 150.7
1.5" Insulation Thickness1/2" W/ft 1.1 1.4 1.7 2.0 2.2 2.5 2.8 3.5 4.1 4.7 5.5 6.2 6.8 7.4 8.03/4" W/ft 1.2 1.6 1.9 2.2 2.5 2.8 3.1 3.9 4.6 5.2 6.1 6.8 7.5 8.2 8.9
1" W/ft 1.4 1.8 2.2 2.5 2.9 3.2 3.6 4.5 5.3 6.0 7.1 7.9 8.7 9.5 10.3
11/2" W/ft 1.8 2.3 2.8 3.2 3.7 4.1 4.6 5.8 6.8 7.7 9.1 10.1 11.1 12.1 13.2
2" W/ft 2.1 2.6 3.1 3.6 4.2 4.7 5.2 6.6 7.6 8.7 10.3 11.4 12.6 13.7 14.9
21/2" W/ft 2.4 3.0 3.5 4.1 4.7 5.3 5.9 7.4 8.7 9.9 11.7 13.0 14.3 15.6 16.9
3" W/ft 2.7 3.4 4.1 4.8 5.4 6.1 6.8 8.6 10.0 11.4 13.5 15.0 16.5 18.0 19.4
4" W/ft 3.3 4.2 5.0 5.8 6.6 7.5 8.3 10.5 12.2 13.9 16.4 18.3 20.1 21.9 23.7
6" W/ft 4.5 5.7 6.8 7.9 9.0 10.2 11.3 14.2 16.6 19.0 22.4 24.9 27.3 29.8 32.3
8" W/ft 5.6 7.1 8.5 9.9 11.3 12.7 14.1 17.8 20.7 23.7 27.9 31.0 34.1 37.2 40.3
10" W/ft 6.8 8.0 10.3 12.0 13.7 15.4 17.1 21.5 25.1 28.7 33.9 37.6 41.4 45.1 48.9
12" W/ft 8.0 10.0 12.0 14.0 16.0 18.0 20.0 25.2 29.4 33.6 39.6 44.0 48.4 52.8 57.2
14" W/ft 8.7 10.9 13.0 15.2 17.4 19.5 21.7 27.3 31.9 36.5 43.0 47.7 52.5 57.3 62.1
16" W/ft 9.8 12.3 14.8 17.2 19.7 22.1 24.6 31.0 36.2 41.3 48.7 54.1 59.5 64.9 70.4
18" W/ft 11.0 13.7 16.4 19.2 21.9 24.7 27.4 34.5 40.3 46.0 54.3 60.3 66.3 72.3 78.4
20" W/ft 12.1 15.1 18.1 21.1 24.2 27.2 30.2 38.1 44.4 50.7 59.8 66.4 73.1 79.7 86.4
22" W/ft 13.2 16.5 19.8 23.1 26.4 29.7 33.0 41.6 48.5 55.4 65.3 72.6 79.9 87.1 94.4
24" W/ft 14.3 17.9 21.5 25.1 28.6 32.2 35.8 45.1 52.6 60.1 70.9 78.8 86.6 94.5 102.4
2" Insulation Thickness1/2" W/ft 1.0 1.2 1.4 1.7 1.9 2.2 2.4 3.0 3.5 4.0 4.8 5.3 5.8 6.3 7.23/4" W/ft 1.1 1.4 1.6 1.9 2.2 2.4 2.7 3.4 4.0 4.5 5.3 5.9 6.5 7.1 8.1
1" W/ft 1.2 1.5 1.8 2.1 2.4 2.7 3.0 3.8 4.4 5.0 5.9 6.6 7.3 7.9 9.0
11/2" W/ft 1.5 1.9 2.3 2.7 3.0 3.4 3.8 4.8 5.6 6.4 7.5 8.4 9.2 10.0 11.4
2" W/ft 1.7 2.2 2.6 3.0 3.4 3.9 4.3 5.4 6.3 7.2 8.5 9.5 10.4 11.4 12.9
21/2" W/ft 1.9 2.4 2.9 3.4 3.8 4.3 4.8 6.0 7.1 8.1 9.5 10.6 11.6 12.7 14.4
3" W/ft 2.2 2.8 3.3 3.9 4.4 5.0 5.5 6.9 8.1 9.2 10.9 12.1 13.3 14.5 16.4
4" W/ft 2.6 3.3 4.0 4.6 5.3 5.9 6.6 8.3 9.7 11.1 13.1 14.5 16.0 17.4 19.7
6" W/ft 3.6 4.5 5.3 6.2 7.1 8.0 8.9 11.2 13.1 15.0 17.6 19.6 21.5 23.5 26.6
8" W/ft 4.4 5.6 6.7 7.8 8.9 10.0 11.1 14.0 16.3 18.6 22.0 24.4 26.9 29.3 33.2
10" W/ft 5.3 6.7 8.0 9.3 10.6 12.0 13.3 16.8 19.6 22.3 26.3 29.3 32.2 35.1 39.8
12" W/ft 6.2 7.8 9.3 10.9 12.4 14.0 15.5 19.5 22.8 26.0 30.7 34.1 37.5 40.9 46.3
14" W/ft 6.7 8.4 10.1 11.8 13.4 15.1 16.8 21.2 24.7 28.2 33.3 37.0 40.7 44.4 50.2
16" W/ft 7.6 9.5 11.3 13.2 15.1 17.0 18.9 23.8 27.8 31.8 37.4 41.6 45.7 49.9 56.5
18" W/ft 8.4 10.5 12.6 14.7 16.8 18.9 21.0 26.5 30.9 35.3 41.6 46.2 50.8 55.4 62.8
20" W/ft 9.2 11.6 13.9 16.2 18.5 20.8 23.1 29.1 34.0 38.8 45.7 50.8 55.9 61.0 69.1
22" W/ft 10.1 12.6 15.2 17.7 20.2 22.7 25.3 31.8 37.1 42.4 50.0 55.6 61.1 66.7 75.5
24" W/ft 11.0 13.7 16.4 19.2 21.9 24.7 27.4 34.5 40.3 46.0 54.3 60.3 66.3 72.3 81.9
609.6 mm W/m 36.1 44.9 53.8 63.0 71.9 3" (76.2 mm) Insulation Thickness1/2" W/ft 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.5 2.9 3.4 4.0 4.4 4.8 5.5 6.03/4" W/ft 0.9 1.1 1.3 1.5 1.8 2.0 2.2 2.8 3.2 3.7 4.4 4.8 5.3 6.1 6.67
1" W/ft 1.0 1.3 1.5 1.8 2.0 2.3 2.5 3.2 3.7 4.2 5.0 5.5 6.1 6.9 7.5
11/2" W/ft 1.2 1.5 1.8 2.1 2.4 2.7 3.0 3.8 4.4 5.0 5.9 6.6 7.3 8.3 9.0
2" W/ft 1.3 1.7 2.0 2.3 2.6 3.0 3.3 4.2 4.9 5.5 6.5 7.3 8.0 9.1 9.9
21/2" W/ft 1.5 1.9 2.2 2.6 3.0 3.3 3.7 4.7 5.4 6.2 7.3 8.1 9.0 10.2 11.1
3" W/ft 1.7 2.1 2.5 2.9 3.4 3.8 4.2 5.3 6.2 7.1 8.3 9.2 10.2 11.6 12.6
4" W/ft 2.0 2.5 3.0 3.5 4.0 4.5 5.0 6.3 7.4 8.4 9.9 11.0 12.1 13.8 15.0
6" W/ft 2.6 3.3 3.9 4.6 5.2 5.9 6.5 8.2 9.6 10.9 12.9 14.3 15.7 17.9 19.4
8" W/ft 3.2 4.0 4.8 5.6 6.4 7.2 8.0 10.1 11.8 13.4 15.8 17.6 19.4 22.1 23.9
10" W/ft 3.8 4.8 5.7 6.7 7.6 8.6 9.5 12.0 14.0 16.0 18.8 20.9 23.0 26.2 28.4
12" W/ft 4.4 5.5 6.5 7.6 8.7 9.8 10.9 13.7 16.0 18.3 21.6 24.0 26.4 30.1 32.6
14" W/ft 4.7 5.9 7.1 8.3 9.4 10.6 11.8 14.9 17.3 19.8 23.4 26.0 28.6 32.6 35.3
16" W/ft 5.3 6.7 8.0 9.3 10.6 12.0 13.3 16.8 19.6 22.3 26.3 29.3 32.2 36.7 39.8
18” W/ft 5.9 7.4 8.8 10.3 11.8 13.2 14.7 18.5 21.6 24.7 29.1 32.3 35.6 40.6 44.0
20" W/ft 6.4 8.1 9.7 11.3 12.9 14.5 16.1 20.3 23.7 27.0 31.9 35.4 39.0 44.4 48.1
22" W/ft 7.0 8.8 10.5 12.3 14.0 15.8 17.5 22.1 25.7 29.4 34.7 38.5 42.4 48.3 52.3
24" W/ft 7.6 9.5 11.3 13.2 15.1 17.0 18.9 23.8 27.8 31.8 37.4 41.6 45.7 52.2 56.5
NominalPipe Size,
in. (ID)
Temperature Difference Between Pipe and Ambient
DegºF 40ºF 50ºF 60ºF 70ºF 80ºF 90ºF 100ºF 120ºF 140ºF 160ºF 180ºF 200ºF 220ºF 240ºF 260ºF
3” Insulation Thickness
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Chromalox Cable Selection
1. Select Heating Cable Family: Based on the maximum maintenance temperature rating, maximumexposure temperature rating, and area classification, select the heating cable family from Table 3. (SeeChromalox Heat Trace Cable Product Information Sheets for cable construction options, voltage ratings,and wattage outputs available.)
2. Select Thermal Output Rating:
(a) For Metal Pipes – Use Figures 1, 2 or 4(b) For Plastic Pipes – Use Figure 3 by finding the intersection of the calculated heat loss, QF, and pipe
maintenance temperature, Tm. Select the cable with a thermal output that equals or exceeds QF at Tm.
Pipe Temperature (ºF)Maintenance Temperature
0 10 20 30 50 60 70 80 90 100 110 120 130 140 150
Ther
mal
Out
put
(W/f
t)
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
4.88
SRL10 & HSRL10
SRL8 & HSRL8
SRL5 & HSRL5
SRL3 & HSRL3
Cable OutputversusTemperature
40
Figure 1 SRL & HSRL – Thermal OutputRatings on Insulated Metal Pipe Figure 2 SRM/E & HSRM – Thermal Output
Ratings on Insulated Metal Pipe Figure 3 SRL & HSRL – Thermal Output Ratingson Plastic Pipe with Aluminum Tape
B3. Determine Total Cable Length: In addition to pipe length, in-line components such as valves, flanges,
and pipe supports require additional heat tracing to maintain Tm. See Table 4. Calculate the totalcable length required by combining the pipe length with the additional lengths needed for all theother components.
Table 3 Heating Cable Families
NOTE: It is the responsibility of the facility manager or engineer to determine the classification of an area where heat trace will be installed. The factory can help determine a suitablecable based on the information provided.
Table 4Additional Cable Lengths Required for In-Line ComponentsBased on Pipe IPS (Iron Pipe Size)
1/2 in. 1.00 1.00 1.00 1.00 1.00 1.00 1.00 0.30
3/4 in. 1.50 1.00 1.00 1.00 1.50 1.00 1.00 0.30
1 in. 2.00 1.00 1.00 1.00 1.50 1.00 1.00 0.30
11/2 in. 2.50 1.50 1.50 1.50 2.00 2.00 2.00 0.30
2 in. 2.50 2.00 2.00 2.00 2.00 2.00 2.00 0.30
21/2 in. 2.50 2.00 2.00 2.00 2.00 2.00 2.00 0.30
3 in. 3.00 2.50 2.50 2.50 2.00 2.00 2.00 0.50
4 in. 4.00 3.00 3.00 3.00 2.50 2.50 2.50 0.50
6 in. 5.00 3.50 3.50 3.50 2.50 2.50 2.50 0.80
8 in. 7.00 4.00 4.00 4.00 2.50 2.50 2.50 0.80
10 in. 8.00 4.50 4.50 4.50 3.00 3.00 3.00 0.80
12 in. 9.00 5.00 5.00 5.00 3.00 3.00 3.00 0.80
14 in. 10.00 5.50 5.50 5.50 3.00 3.00 3.00 1.00
16 in. 11.00 6.00 6.00 6.00 3.50 3.50 3.50 1.00
18 in. 12.00 7.00 7.00 7.00 3.50 3.50 3.50 1.00
20 in. 13.00 7.50 7.50 7.50 3.50 3.50 3.50 1.00
22 in. 13.00 7.50 7.50 7.50 3.50 3.50 3.50 1.00
24 in. 15.00 8.00 8.00 8.00 4.00 4.00 4.00 1.00
Piping Size Gate Valve Globe Valve Ball Valve Butterfly Valve Hanger SupportShoe Support Sleeper Support Flange Pair
ft
0 10 20 30 50 60 70 80 90 100 110 120 130 140 15040
Pipe Temperature (ºF)
SRL10 & HSRL10
Ther
mal
Out
put
(W/f
t)
9
8
7
6
5
4
3
2
1
0
SRL8 &HSRL8
SRL5 & HSRL5
SRL3 & HSRL3
Cable OutputversusTemperature
Figure 4 SRP – Thermal Output Ratingson Insulated Metal Pipe
Pipe Temperature (ºF)
Hea
tO
utp
ut(W
/ft)
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
15 W/ft
10 W/ft
5 W/ft
Cable OutputversusTemperature
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230
Heating CableFamily
AreaClassification
PipeMaterial
MaximumMaintenanceTemperature
Maximum ExposureTemperature(Power Off)
Approvals
U.S. Other
SRL(Self-RegulatingLow Temperature)
Ordinary
Plastic/Metal 150ºF / 65ºC 185ºF / 85ºC
UL, CSA, FM GOST, Cenelec,CE, ATEX
Class I, Div.2, Gr. B, C, D CSA, FM, (Gr. A, CSA Only) GOST, Cenelec,CE, ATEX
Class II, Div.2, Gr. E, F, G CSA, FM, (Gr. E, CSA Only) GOST, Cenelec,CE
Class III, Div.2 FM Only GOST, Cenelec,CE, ATEX
SRM/E(Self-RegulatingMediumTemperature)
Ordinary
Metal Only 302ºF / 150ºC 420ºF / 215ºC
UL, CSA, FM GOST, Cenelec,CE, ATEX
Class I Div.2, Gr. A, B, C, D CSA, FM, (Gr. A, CSA Only) GOST, Cenelec,CE, ATEX
Class II, Div.2, Gr. F, G CSA Only GOST, Cenelec,CE, ATEX
SRP(Self-RegulatingMediumTemperature)
Ordinary
Metal Only 225ºF / 110ºC 275ºF / 135ºC UL, CSA, FMPending
GOST, Cenelec, CE,ATEX Pending
Class I, Div.2, Gr. B, C, D
Class II, Div.2, Gr. F, G
Class III
HSRL(H-Self-RegulatingLow Temperature)
Class I, Div.1, Gr. B, C, D
Plastic/Metal 150ºF / 65ºC 185ºF / 85ºC
CSA, FM
Class II, Div.1, Gr. E, F, G CSA, FM
Class III, Div.1 CSA, FM
HSRM(H-Self-RegulatingMediumTemperature)
Class I, Div.1, Gr. B, C, D
Metal Only 302ºF / 150ºC 420ºF / 215ºC
CSA, FM
Class II, Div.1, Gr. E, F, G CSA, FM
Class III, Div.1 CSA, FM
CWM(Constant Wattage)
OrdinaryMetal Only Consult Factory 392ºF / 200ºC
UL, CSA
Hazardous Area, Consult Factory
MI (MineralInsulated)
Ordinary
Metal Only Consult Factory 1,100ºF / 595ºC
CSA, FM
Class I, Div.2, Gr. B, C, D CSA, FM
Class II, Div.2, Gr. E, F, G CSA, FM
Class III CSA, FM
0 50 100 150 200 250 300
Pipe Temperature (ºF)
SRM/E20 &HSRM20
Pow
erO
utp
ut(W
/ft)
24
20
16
12
8
4
0
SRM/E15 &HSRM15
SRM/E10 &HSRM10
SRM/E8 & HSRM8
SRM/E5 & HSRM5
SRM/E3 & HSRM3
Cable OutputversusTemperature
1.
2.
a3.
4.
pIpe HeaT LOSS CaLCuLaTIOnS
Basic Heat Loss: After determining the difference between the ambient and desired pipe maintenance
temperature, Tm, use Table 1 to figure the basic heat loss for the pipe size and insulation thickness.
Calculate QF: Multiply the basic heat loss figure from Table 1 by the adjustment factor from Table 2 to calculate the estimated heat loss, QF, in watts per foot of pipe length.
Correct for Indoor Location/ Wind Speed: If location is indoors, multiply QF by 0.9. Table 1 is based on 10% safety factor and 20 mph wind speed; add 5% margin for each 5 mph over 20 mph wind speed.
Insulation Adjustment: Using Table 2, find the type of insulation being used and its insulation factor.
Insulation Adjustment Factors
B3.1.
2.
CHrOmaLOx CaBLe SeLeCTIOn
Select Heating Cable Family: Based on the maximum maintenance temperature rating, maximum exposure temperature rating, and area classification, select the heating cable family from Table 3. (See Chromalox Heat Trace Cable Product Information Sheets for cable construction options, voltage ratings, and wattage outputs available.)
Determine Total Cable Length: In addition to pipe length, in-line components such as valves, flanges, and pipe supports require additional heat tracing to maintain Tm. See Table 4. Calculate the total cable length required by combining the pipe length with the additional lengths needed for all the other components.
Select Thermal Output Rating:
(a) For Metal Pipes – Use Figures 1, 2 or 4 (b) For Plastic Pipes – Use Figure 3 by finding the intersection of the calculated heat loss, QF, and pipe maintenance temperature, Tm. Select the cable with a thermal output that equals or exceeds QF at Tm.
Table 4Additional Cable Lengths Required for In-Line ComponentsBased on Pipe IPS (Iron Pipe Size)Table 3
Table 1
Table 2
Heating Cable Families
Pipe Heat Loss QP in W/ft Based on Temperature Differential and Insulation Thickness
Inst
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ose
cabl
es to
tem
pera
ture
s ab
ove
thei
r max
imum
ratin
gs
• In
stal
l cab
le w
ith a
lum
inum
tape
for u
se o
n pl
astic
pip
es
• Lo
cate
am
bien
t tem
pera
ture
sen
sors
in c
olde
st e
xpec
ted
area
• Lo
cate
pip
e te
mpe
ratu
re s
enso
rs a
t low
est e
xpec
ted
line
te
mpe
ratu
re
• Us
e su
ffici
ent c
able
to tr
ace
addi
tiona
l hea
t sin
ks
• In
stal
l cab
le s
o th
at v
alve
s ca
n be
rem
oved
with
out r
emov
ing
cabl
e
Impo
rtan
t Saf
egua
rds
Mec
hani
cal I
nspe
ctio
n •
Insp
ect a
ll in
sula
tion
and
wea
ther
proo
fing
• In
spec
t all
junc
tion
box,
con
nect
ion
box,
and
sen
sor c
onne
ctio
ns
• Ve
rify
all c
ircui
ts h
ave
been
pro
perly
gro
unde
d
• Ve
rify
all c
ircui
ts a
re c
onne
cted
in p
rope
r pan
el lo
catio
ns
• Ve
rify
prop
er c
ircui
t bre
aker
s ar
e in
pla
ce (a
lway
s us
e 30
mA
trip
GFI-t
ype
brea
kers
)
• Ve
rify
all c
ircui
t len
gths
are
with
in m
anuf
actu
rer’s
spe
cifie
d lim
its
• Ve
rify
all p
rope
r saf
ety
war
ning
s ar
e in
pla
ce
• Ve
rify
all e
nd s
eal,
splic
e/te
e lo
catio
ns a
re m
arke
d on
lagg
ing
Elec
tric
al T
ests
• In
sula
tion
Resi
stan
ce (M
egge
r) ✓
Bef
ore
traci
ng p
ipes
✓ A
fter i
nsta
lling
term
inat
ions
✓ B
efor
e in
sula
ting
pipe
s
✓ A
fter i
nsul
atin
g pi
pes
✓
Bef
ore
ener
gizin
g sy
stem
• Ci
rcui
t Vol
tage
• In
itial
Cur
rent
✓ N
ote
ambi
ent t
emp
and
pipe
tem
p
• St
abiliz
ed C
urre
nt (1
5 m
inut
es o
f ope
ratio
n)
✓
Not
e am
bien
t tem
p an
d pi
pe te
mp
• Al
way
s us
e gr
ound
faul
t circ
uit b
reak
ers
(30
mA
trip
leve
l)
Tool
s N
eede
d •
Wire
Cut
ters
/Stri
pper
s
• M
egge
r
• Ph
illip
s He
ad S
crew
driv
er
• St
anda
rd S
crew
driv
er
• Vo
ltmet
er
• Ut
ility
Kni
fe
• Ha
mm
er
SrL
Cab
le
• 15
0ºF
/ 65º
C M
axim
um M
aint
enan
ce
• 18
5ºF
/ 85º
C M
axim
um E
xpos
ure
• 3
to 1
0 W
/ft /
10 to
33
W/m
• 16
AW
G w
ith O
ptio
nal T
PE o
r Flu
orop
olym
er J
acke
t
Srp
Cab
le
• 22
5°F
/ 110
°C M
aint
enan
ce T
empe
ratu
re
• 27
5°F
/ 135
°C M
axim
um E
xpos
ure
Tem
pera
ture
• 5
to 1
5 W
/ft /
16 to
49
W/m
• 16
AW
G w
ith O
ptio
nal F
luor
opol
ymer
Jac
ket
Srm
Cab
le
• 30
2ºF
/ 150
ºC M
axim
um M
aint
enan
ce
• 42
0ºF
/ 215
ºC M
axim
um E
xpos
ure
• 5
to 2
0 W
/ft /
16 to
66
W/m
• 16
AW
G w
ith O
ptio
nal F
luor
opol
ymer
Jac
ket
Figure 1 Figure 2 Figure 3 Figure 4SRL & HSRL – Thermal Output Ratings on Insulated Metal Pipe
SRM/E & HSRM – Thermal Output Ratings on Insulated Metal Pipe
SRL & HSRL – Thermal Output Ratings on Plastic Pipe with Aluminum Tape
SRP – Thermal Output Ratings on Insulated Metal Pipe
Pipe Temperature (ºF)
Hea
t O
utp
ut (W
/ft)
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
15 W/ft
10 W/ft
5 W/ft
Cable OutputversusTemperature
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230
0 10 20 30 50 60 70 80 90 100 110 120 130 140 15040
Pipe Temperature (ºF)
SRL10 & HSRL10
Ther
mal
Out
put
(W/f
t)
9
8
7
6
5
4
3
2
1
0
SRL8 & HSRL8
SRL5 & HSRL5
SRL3 & HSRL3
Cable OutputversusTemperature
0 50 100 150 200 250 300
Pipe Temperature (ºF)
SRM/E20 & HSRM20
Pow
er O
utp
ut (W
/ft)
24
20
16
12
8
4
0
SRM/E15 & HSRM15
SRM/E10 & HSRM10
SRM/E8 & HSRM8
SRM/E5 & HSRM5
SRM/E3 & HSRM3
Cable OutputversusTemperature
Pipe Temperature (ºF)Maintenance Temperature
0 10 20 30 50 60 70 80 90 100 110 120 130 140 150
Ther
mal
Out
put
(W/f
t)
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
4.88
SRL10 & HSRL10
SRL8 & HSRL8
SRL5 & HSRL5
SRL3 & HSRL3
Cable OutputversusTemperature
40
Tem
per
aTu
re
man
agem
enT
SOLu
TIO
nS
Hea
t tR
aCe
DeS
IGN
GU
IDe
Co
pyr
igh
t ©
20
02-2
007
, 20
09
-201
2, 2
015,
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rom
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rig
hts
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ed
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go
are
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itts
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Table 2 Insulation Adjustment Factors
Insulation Factor
Pipe Insulation TypePipe Insulation TypeInsulation Factor
Glass fiber (ASTM C547) 1.00
Calcium silicate (ASTM C533) 1.48
Cellular glass (ASTM C552) 1.48
Rigid cellular urethane (ASTM C591) 0.64
Foamed elastomer (ASTM C534) 1.16
Mineral fiber blanket (ASTM C553) 1.16
Expanded perlite (ASTM C610) 1.90
1. Basic Heat Loss: After determining the difference between the ambient and desired pipe maintenance
temperature, Tm, use Table 1 to figure the basic heat loss for the pipe size and insulation thickness.
2. Insulation Adjustment: Using Table 2, find the type of insulation being used and its insulation factor.
Hea
tTr
ace
Des
ign
Gui
de
A Pipe Heat Loss Calculations
•He
atTr
ace
Syst
emDe
sign
•M
ater
ials
&Co
mpo
nent
s
•Sp
ecifi
catio
nTa
bles
3. Calculate QF: Multiply the basic heat loss figure from Table 1 by the adjustment factor from Table 2 to
calculate the estimated heat loss, QF, in watts per foot of pipe length.
4. Correct for Indoor Location/ Wind Speed: If location is indoors, multiply QF by 0.9. Table 1 is based on
10% safety factor and 20 mph wind speed; add 5% margin for each 5 mph over 20 mph wind speed.
Table 1 Pipe Heat Loss QP in W/ft Based on Temperature Differential and Insulation Thickness
NominalPipe Size,
in. (ID)
Temperature Difference Between Pipe and Ambient
DegºF 40ºF 50ºF 60ºF 70ºF 80ºF 90ºF 100ºF 120ºF 140ºF 160ºF 180ºF 200ºF 220ºF 240ºF 260ºF
1" Insulation Thickness1/2" W/ft 1.4 1.8 2.1 2.5 2.8 3.2 3.5 4.2 5.1 5.9 6.6 7.7 8.5 9.2 10.03/4" W/ft 1.6 2.0 2.4 2.8 3.2 3.6 4.0 4.8 5.9 6.7 7.6 8.8 9.7 10.6 11.4
1" W/ft 1.8 2.3 2.8 3.2 3.7 4.1 4.6 5.5 6.8 7.7 8.7 10.1 11.1 12.1 13.2
11/2" W/ft 2.4 3.1 3.7 4.3 4.9 5.5 6.1 7.3 9.0 10.2 11.5 13.4 14.8 16.1 17.4
2" W/ft 2.8 3.5 4.1 4.8 5.5 6.2 6.9 8.3 10.1 11.6 13.0 15.2 16.7 18.2 19.7
21/2" W/ft 3.2 4.0 4.8 5.6 6.4 7.2 8.0 9.6 11.8 13.4 15.1 17.6 19.4 21.1 22.9
3" W/ft 3.7 4.7 5.6 6.5 7.4 8.4 9.3 11.2 13.7 15.6 17.6 20.5 22.5 24.6 26.6
4" W/ft 4.6 5.8 6.9 8.1 9.2 10.4 11.5 13.8 16.9 19.3 21.7 25.3 27.8 30.4 32.9
6" W/ft 6.4 8.0 9.6 11.2 12.8 14.4 16.0 19.2 23.5 26.9 30.2 35.2 38.7 42.2 45.8
8" W/ft 8.1 10.1 12.1 14.1 16.2 18.2 20.2 24.2 29.7 33.9 38.2 44.4 48.9 53.3 57.8
10" W/ft 9.9 12.4 14.8 17.3 19.8 22.2 24.7 29.6 36.3 41.5 46.7 54.3 59.8 65.2 70.6
12" W/ft 11.6 14.5 17.4 20.3 23.2 26.1 29.0 34.8 42.6 48.7 54.8 63.8 70.2 76.6 82.9
14" W/ft 12.6 15.8 19.0 22.1 25.3 28.4 31.6 37.9 46.5 53.1 59.7 69.5 76.5 83.4 90.4
16" W/ft 14.3 17.9 21.5 25.1 28.7 32.3 35.9 43.0 52.7 60.2 67.8 78.9 86.8 94.6 102.5
18" W/ft 16.0 20.1 24.1 28.1 32.1 36.1 40.1 48.1 58.9 67.4 75.8 88.2 97.0 105.9 114.7
20" W/ft 17.7 22.2 26.6 31.0 35.4 39.9 44.3 53.2 65.1 74.4 83.7 97.5 107.2 117.0 126.7
22" W/ft 19.4 24.3 29.1 34.0 38.8 43.7 48.5 58.2 71.3 81.5 91.7 106.7 117.4 128.0 138.7
24" W/ft 21.1 26.4 31.6 36.9 42.2 47.4 52.7 63.2 77.5 88.5 99.6 115.9 127.5 139.1 150.7
1.5" Insulation Thickness1/2" W/ft 1.1 1.4 1.7 2.0 2.2 2.5 2.8 3.5 4.1 4.7 5.5 6.2 6.8 7.4 8.03/4" W/ft 1.2 1.6 1.9 2.2 2.5 2.8 3.1 3.9 4.6 5.2 6.1 6.8 7.5 8.2 8.9
1" W/ft 1.4 1.8 2.2 2.5 2.9 3.2 3.6 4.5 5.3 6.0 7.1 7.9 8.7 9.5 10.3
11/2" W/ft 1.8 2.3 2.8 3.2 3.7 4.1 4.6 5.8 6.8 7.7 9.1 10.1 11.1 12.1 13.2
2" W/ft 2.1 2.6 3.1 3.6 4.2 4.7 5.2 6.6 7.6 8.7 10.3 11.4 12.6 13.7 14.9
21/2" W/ft 2.4 3.0 3.5 4.1 4.7 5.3 5.9 7.4 8.7 9.9 11.7 13.0 14.3 15.6 16.9
3" W/ft 2.7 3.4 4.1 4.8 5.4 6.1 6.8 8.6 10.0 11.4 13.5 15.0 16.5 18.0 19.4
4" W/ft 3.3 4.2 5.0 5.8 6.6 7.5 8.3 10.5 12.2 13.9 16.4 18.3 20.1 21.9 23.7
6" W/ft 4.5 5.7 6.8 7.9 9.0 10.2 11.3 14.2 16.6 19.0 22.4 24.9 27.3 29.8 32.3
8" W/ft 5.6 7.1 8.5 9.9 11.3 12.7 14.1 17.8 20.7 23.7 27.9 31.0 34.1 37.2 40.3
10" W/ft 6.8 8.0 10.3 12.0 13.7 15.4 17.1 21.5 25.1 28.7 33.9 37.6 41.4 45.1 48.9
12" W/ft 8.0 10.0 12.0 14.0 16.0 18.0 20.0 25.2 29.4 33.6 39.6 44.0 48.4 52.8 57.2
14" W/ft 8.7 10.9 13.0 15.2 17.4 19.5 21.7 27.3 31.9 36.5 43.0 47.7 52.5 57.3 62.1
16" W/ft 9.8 12.3 14.8 17.2 19.7 22.1 24.6 31.0 36.2 41.3 48.7 54.1 59.5 64.9 70.4
18" W/ft 11.0 13.7 16.4 19.2 21.9 24.7 27.4 34.5 40.3 46.0 54.3 60.3 66.3 72.3 78.4
20" W/ft 12.1 15.1 18.1 21.1 24.2 27.2 30.2 38.1 44.4 50.7 59.8 66.4 73.1 79.7 86.4
22" W/ft 13.2 16.5 19.8 23.1 26.4 29.7 33.0 41.6 48.5 55.4 65.3 72.6 79.9 87.1 94.4
24" W/ft 14.3 17.9 21.5 25.1 28.6 32.2 35.8 45.1 52.6 60.1 70.9 78.8 86.6 94.5 102.4
2" Insulation Thickness1/2" W/ft 1.0 1.2 1.4 1.7 1.9 2.2 2.4 3.0 3.5 4.0 4.8 5.3 5.8 6.3 7.23/4" W/ft 1.1 1.4 1.6 1.9 2.2 2.4 2.7 3.4 4.0 4.5 5.3 5.9 6.5 7.1 8.1
1" W/ft 1.2 1.5 1.8 2.1 2.4 2.7 3.0 3.8 4.4 5.0 5.9 6.6 7.3 7.9 9.0
11/2" W/ft 1.5 1.9 2.3 2.7 3.0 3.4 3.8 4.8 5.6 6.4 7.5 8.4 9.2 10.0 11.4
2" W/ft 1.7 2.2 2.6 3.0 3.4 3.9 4.3 5.4 6.3 7.2 8.5 9.5 10.4 11.4 12.9
21/2" W/ft 1.9 2.4 2.9 3.4 3.8 4.3 4.8 6.0 7.1 8.1 9.5 10.6 11.6 12.7 14.4
3" W/ft 2.2 2.8 3.3 3.9 4.4 5.0 5.5 6.9 8.1 9.2 10.9 12.1 13.3 14.5 16.4
4" W/ft 2.6 3.3 4.0 4.6 5.3 5.9 6.6 8.3 9.7 11.1 13.1 14.5 16.0 17.4 19.7
6" W/ft 3.6 4.5 5.3 6.2 7.1 8.0 8.9 11.2 13.1 15.0 17.6 19.6 21.5 23.5 26.6
8" W/ft 4.4 5.6 6.7 7.8 8.9 10.0 11.1 14.0 16.3 18.6 22.0 24.4 26.9 29.3 33.2
10" W/ft 5.3 6.7 8.0 9.3 10.6 12.0 13.3 16.8 19.6 22.3 26.3 29.3 32.2 35.1 39.8
12" W/ft 6.2 7.8 9.3 10.9 12.4 14.0 15.5 19.5 22.8 26.0 30.7 34.1 37.5 40.9 46.3
14" W/ft 6.7 8.4 10.1 11.8 13.4 15.1 16.8 21.2 24.7 28.2 33.3 37.0 40.7 44.4 50.2
16" W/ft 7.6 9.5 11.3 13.2 15.1 17.0 18.9 23.8 27.8 31.8 37.4 41.6 45.7 49.9 56.5
18" W/ft 8.4 10.5 12.6 14.7 16.8 18.9 21.0 26.5 30.9 35.3 41.6 46.2 50.8 55.4 62.8
20" W/ft 9.2 11.6 13.9 16.2 18.5 20.8 23.1 29.1 34.0 38.8 45.7 50.8 55.9 61.0 69.1
22" W/ft 10.1 12.6 15.2 17.7 20.2 22.7 25.3 31.8 37.1 42.4 50.0 55.6 61.1 66.7 75.5
24" W/ft 11.0 13.7 16.4 19.2 21.9 24.7 27.4 34.5 40.3 46.0 54.3 60.3 66.3 72.3 81.9
609.6 mm W/m 36.1 44.9 53.8 63.0 71.9 3" (76.2 mm) Insulation Thickness1/2" W/ft 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.5 2.9 3.4 4.0 4.4 4.8 5.5 6.03/4" W/ft 0.9 1.1 1.3 1.5 1.8 2.0 2.2 2.8 3.2 3.7 4.4 4.8 5.3 6.1 6.67
1" W/ft 1.0 1.3 1.5 1.8 2.0 2.3 2.5 3.2 3.7 4.2 5.0 5.5 6.1 6.9 7.5
11/2" W/ft 1.2 1.5 1.8 2.1 2.4 2.7 3.0 3.8 4.4 5.0 5.9 6.6 7.3 8.3 9.0
2" W/ft 1.3 1.7 2.0 2.3 2.6 3.0 3.3 4.2 4.9 5.5 6.5 7.3 8.0 9.1 9.9
21/2" W/ft 1.5 1.9 2.2 2.6 3.0 3.3 3.7 4.7 5.4 6.2 7.3 8.1 9.0 10.2 11.1
3" W/ft 1.7 2.1 2.5 2.9 3.4 3.8 4.2 5.3 6.2 7.1 8.3 9.2 10.2 11.6 12.6
4" W/ft 2.0 2.5 3.0 3.5 4.0 4.5 5.0 6.3 7.4 8.4 9.9 11.0 12.1 13.8 15.0
6" W/ft 2.6 3.3 3.9 4.6 5.2 5.9 6.5 8.2 9.6 10.9 12.9 14.3 15.7 17.9 19.4
8" W/ft 3.2 4.0 4.8 5.6 6.4 7.2 8.0 10.1 11.8 13.4 15.8 17.6 19.4 22.1 23.9
10" W/ft 3.8 4.8 5.7 6.7 7.6 8.6 9.5 12.0 14.0 16.0 18.8 20.9 23.0 26.2 28.4
12" W/ft 4.4 5.5 6.5 7.6 8.7 9.8 10.9 13.7 16.0 18.3 21.6 24.0 26.4 30.1 32.6
14" W/ft 4.7 5.9 7.1 8.3 9.4 10.6 11.8 14.9 17.3 19.8 23.4 26.0 28.6 32.6 35.3
16" W/ft 5.3 6.7 8.0 9.3 10.6 12.0 13.3 16.8 19.6 22.3 26.3 29.3 32.2 36.7 39.8
18” W/ft 5.9 7.4 8.8 10.3 11.8 13.2 14.7 18.5 21.6 24.7 29.1 32.3 35.6 40.6 44.0
20" W/ft 6.4 8.1 9.7 11.3 12.9 14.5 16.1 20.3 23.7 27.0 31.9 35.4 39.0 44.4 48.1
22" W/ft 7.0 8.8 10.5 12.3 14.0 15.8 17.5 22.1 25.7 29.4 34.7 38.5 42.4 48.3 52.3
24" W/ft 7.6 9.5 11.3 13.2 15.1 17.0 18.9 23.8 27.8 31.8 37.4 41.6 45.7 52.2 56.5
NominalPipe Size,
in. (ID)
Temperature Difference Between Pipe and Ambient
DegºF 40ºF 50ºF 60ºF 70ºF 80ºF 90ºF 100ºF 120ºF 140ºF 160ºF 180ºF 200ºF 220ºF 240ºF 260ºF
3” Insulation Thickness
Inst
alla
tion
Tips
•Do
nott
wis
tbus
sw
ires
toge
ther
aten
dof
circ
uit
•In
sula
teal
lcon
duct
ive
part
s
•Se
alal
lele
ctric
alco
nnec
tions
agai
nstm
oist
ure
•Se
alen
dsof
expo
sed
cabl
edu
ring
inst
alla
tion
•Do
note
xpos
eca
bles
tote
mpe
ratu
res
abov
eth
eirm
axim
umra
tings
•In
stal
lcab
lew
ithal
umin
umta
pefo
ruse
onpl
astic
pipe
s
•Lo
cate
ambi
entt
empe
ratu
rese
nsor
sin
cold
est
expe
cted
area
•Lo
cate
pipe
tem
pera
ture
sens
ors
atlo
wes
tex
pect
edlin
ete
mpe
ratu
re
•Us
esu
ffici
entc
able
totra
cead
ditio
nalh
eats
inks
•In
stal
lcab
leso
that
valv
esca
nbe
rem
oved
with
outr
emov
ing
cabl
e
Impo
rtan
tSaf
egua
rds
Mec
hani
calI
nspe
ctio
n
•In
spec
tall
insu
latio
nan
dw
eath
erpr
oofin
g
•In
spec
tall
junc
tion
box,
conn
ectio
nbo
xan
dse
nsor
conn
ectio
ns
•Ve
rify
allc
ircui
tsha
vebe
enpr
oper
lygr
ound
ed
•Ve
rify
allc
ircui
tsar
eco
nnec
ted
inpr
oper
pane
lloc
atio
ns
•Ve
rify
prop
erci
rcui
tbre
aker
sar
ein
plac
e(a
lway
sus
e30
mA
trip
GFI-t
ype
brea
kers
)
•Ve
rify
allc
ircui
tlen
gths
are
with
inm
anuf
actu
rer’s
spec
ified
limits
•Ve
rify
allp
rope
rsaf
ety
war
ning
sar
ein
plac
e
•Ve
rify
alle
ndse
al,s
plic
e/te
elo
catio
nsar
em
arke
don
lagg
ing
Elec
tric
alTe
sts
•In
sula
tion
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Chromalox Cable Selection
1. Select Heating Cable Family: Based on the maximum maintenance temperature rating, maximumexposure temperature rating, and area classification, select the heating cable family from Table 3. (SeeChromalox Heat Trace Cable Product Information Sheets for cable construction options, voltage ratings,and wattage outputs available.)
2. Select Thermal Output Rating:
(a) For Metal Pipes – Use Figures 1, 2 or 4(b) For Plastic Pipes – Use Figure 3 by finding the intersection of the calculated heat loss, QF, and pipe
maintenance temperature, Tm. Select the cable with a thermal output that equals or exceeds QF at Tm.
Pipe Temperature (ºF)Maintenance Temperature
0 10 20 30 50 60 70 80 90 100 110 120 130 140 150
Ther
mal
Out
put
(W/f
t)
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
4.88
SRL10 & HSRL10
SRL8 & HSRL8
SRL5 & HSRL5
SRL3 & HSRL3
Cable OutputversusTemperature
40
Figure 1 SRL & HSRL – Thermal OutputRatings on Insulated Metal Pipe Figure 2 SRM/E & HSRM – Thermal Output
Ratings on Insulated Metal Pipe Figure 3 SRL & HSRL – Thermal Output Ratingson Plastic Pipe with Aluminum Tape
B3. Determine Total Cable Length: In addition to pipe length, in-line components such as valves, flanges,
and pipe supports require additional heat tracing to maintain Tm. See Table 4. Calculate the totalcable length required by combining the pipe length with the additional lengths needed for all theother components.
Table 3 Heating Cable Families
NOTE: It is the responsibility of the facility manager or engineer to determine the classification of an area where heat trace will be installed. The factory can help determine a suitablecable based on the information provided.
Table 4Additional Cable Lengths Required for In-Line ComponentsBased on Pipe IPS (Iron Pipe Size)
1/2 in. 1.00 1.00 1.00 1.00 1.00 1.00 1.00 0.30
3/4 in. 1.50 1.00 1.00 1.00 1.50 1.00 1.00 0.30
1 in. 2.00 1.00 1.00 1.00 1.50 1.00 1.00 0.30
11/2 in. 2.50 1.50 1.50 1.50 2.00 2.00 2.00 0.30
2 in. 2.50 2.00 2.00 2.00 2.00 2.00 2.00 0.30
21/2 in. 2.50 2.00 2.00 2.00 2.00 2.00 2.00 0.30
3 in. 3.00 2.50 2.50 2.50 2.00 2.00 2.00 0.50
4 in. 4.00 3.00 3.00 3.00 2.50 2.50 2.50 0.50
6 in. 5.00 3.50 3.50 3.50 2.50 2.50 2.50 0.80
8 in. 7.00 4.00 4.00 4.00 2.50 2.50 2.50 0.80
10 in. 8.00 4.50 4.50 4.50 3.00 3.00 3.00 0.80
12 in. 9.00 5.00 5.00 5.00 3.00 3.00 3.00 0.80
14 in. 10.00 5.50 5.50 5.50 3.00 3.00 3.00 1.00
16 in. 11.00 6.00 6.00 6.00 3.50 3.50 3.50 1.00
18 in. 12.00 7.00 7.00 7.00 3.50 3.50 3.50 1.00
20 in. 13.00 7.50 7.50 7.50 3.50 3.50 3.50 1.00
22 in. 13.00 7.50 7.50 7.50 3.50 3.50 3.50 1.00
24 in. 15.00 8.00 8.00 8.00 4.00 4.00 4.00 1.00
Piping Size Gate Valve Globe Valve Ball Valve Butterfly Valve Hanger SupportShoe Support Sleeper Support Flange Pair
ft
0 10 20 30 50 60 70 80 90 100 110 120 130 140 15040
Pipe Temperature (ºF)
SRL10 & HSRL10
Ther
mal
Out
put
(W/f
t)
9
8
7
6
5
4
3
2
1
0
SRL8 &HSRL8
SRL5 & HSRL5
SRL3 & HSRL3
Cable OutputversusTemperature
Figure 4 SRP – Thermal Output Ratingson Insulated Metal Pipe
Pipe Temperature (ºF)
Hea
tO
utp
ut(W
/ft)
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
15 W/ft
10 W/ft
5 W/ft
Cable OutputversusTemperature
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230
Heating CableFamily
AreaClassification
PipeMaterial
MaximumMaintenanceTemperature
Maximum ExposureTemperature(Power Off)
Approvals
U.S. Other
SRL(Self-RegulatingLow Temperature)
Ordinary
Plastic/Metal 150ºF / 65ºC 185ºF / 85ºC
UL, CSA, FM GOST, Cenelec,CE, ATEX
Class I, Div.2, Gr. B, C, D CSA, FM, (Gr. A, CSA Only) GOST, Cenelec,CE, ATEX
Class II, Div.2, Gr. E, F, G CSA, FM, (Gr. E, CSA Only) GOST, Cenelec,CE
Class III, Div.2 FM Only GOST, Cenelec,CE, ATEX
SRM/E(Self-RegulatingMediumTemperature)
Ordinary
Metal Only 302ºF / 150ºC 420ºF / 215ºC
UL, CSA, FM GOST, Cenelec,CE, ATEX
Class I Div.2, Gr. A, B, C, D CSA, FM, (Gr. A, CSA Only) GOST, Cenelec,CE, ATEX
Class II, Div.2, Gr. F, G CSA Only GOST, Cenelec,CE, ATEX
SRP(Self-RegulatingMediumTemperature)
Ordinary
Metal Only 225ºF / 110ºC 275ºF / 135ºC UL, CSA, FMPending
GOST, Cenelec, CE,ATEX Pending
Class I, Div.2, Gr. B, C, D
Class II, Div.2, Gr. F, G
Class III
HSRL(H-Self-RegulatingLow Temperature)
Class I, Div.1, Gr. B, C, D
Plastic/Metal 150ºF / 65ºC 185ºF / 85ºC
CSA, FM
Class II, Div.1, Gr. E, F, G CSA, FM
Class III, Div.1 CSA, FM
HSRM(H-Self-RegulatingMediumTemperature)
Class I, Div.1, Gr. B, C, D
Metal Only 302ºF / 150ºC 420ºF / 215ºC
CSA, FM
Class II, Div.1, Gr. E, F, G CSA, FM
Class III, Div.1 CSA, FM
CWM(Constant Wattage)
OrdinaryMetal Only Consult Factory 392ºF / 200ºC
UL, CSA
Hazardous Area, Consult Factory
MI (MineralInsulated)
Ordinary
Metal Only Consult Factory 1,100ºF / 595ºC
CSA, FM
Class I, Div.2, Gr. B, C, D CSA, FM
Class II, Div.2, Gr. E, F, G CSA, FM
Class III CSA, FM
0 50 100 150 200 250 300
Pipe Temperature (ºF)
SRM/E20 &HSRM20
Pow
erO
utp
ut(W
/ft)
24
20
16
12
8
4
0
SRM/E15 &HSRM15
SRM/E10 &HSRM10
SRM/E8 & HSRM8
SRM/E5 & HSRM5
SRM/E3 & HSRM3
Cable OutputversusTemperature
Table 2 Insulation Adjustment Factors
Insulation Factor
Pipe Insulation TypePipe Insulation TypeInsulation Factor
Glass fiber (ASTM C547) 1.00
Calcium silicate (ASTM C533) 1.48
Cellular glass (ASTM C552) 1.48
Rigid cellular urethane (ASTM C591) 0.64
Foamed elastomer (ASTM C534) 1.16
Mineral fiber blanket (ASTM C553) 1.16
Expanded perlite (ASTM C610) 1.90
1. Basic Heat Loss: After determining the difference between the ambient and desired pipe maintenance
temperature, Tm, use Table 1 to figure the basic heat loss for the pipe size and insulation thickness.
2. Insulation Adjustment: Using Table 2, find the type of insulation being used and its insulation factor.
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3. Calculate QF: Multiply the basic heat loss figure from Table 1 by the adjustment factor from Table 2 to
calculate the estimated heat loss, QF, in watts per foot of pipe length.
4. Correct for Indoor Location/ Wind Speed: If location is indoors, multiply QF by 0.9. Table 1 is based on
10% safety factor and 20 mph wind speed; add 5% margin for each 5 mph over 20 mph wind speed.
Table 1 Pipe Heat Loss QP in W/ft Based on Temperature Differential and Insulation Thickness
NominalPipe Size,
in. (ID)
Temperature Difference Between Pipe and Ambient
DegºF 40ºF 50ºF 60ºF 70ºF 80ºF 90ºF 100ºF 120ºF 140ºF 160ºF 180ºF 200ºF 220ºF 240ºF 260ºF
1" Insulation Thickness1/2" W/ft 1.4 1.8 2.1 2.5 2.8 3.2 3.5 4.2 5.1 5.9 6.6 7.7 8.5 9.2 10.03/4" W/ft 1.6 2.0 2.4 2.8 3.2 3.6 4.0 4.8 5.9 6.7 7.6 8.8 9.7 10.6 11.4
1" W/ft 1.8 2.3 2.8 3.2 3.7 4.1 4.6 5.5 6.8 7.7 8.7 10.1 11.1 12.1 13.2
11/2" W/ft 2.4 3.1 3.7 4.3 4.9 5.5 6.1 7.3 9.0 10.2 11.5 13.4 14.8 16.1 17.4
2" W/ft 2.8 3.5 4.1 4.8 5.5 6.2 6.9 8.3 10.1 11.6 13.0 15.2 16.7 18.2 19.7
21/2" W/ft 3.2 4.0 4.8 5.6 6.4 7.2 8.0 9.6 11.8 13.4 15.1 17.6 19.4 21.1 22.9
3" W/ft 3.7 4.7 5.6 6.5 7.4 8.4 9.3 11.2 13.7 15.6 17.6 20.5 22.5 24.6 26.6
4" W/ft 4.6 5.8 6.9 8.1 9.2 10.4 11.5 13.8 16.9 19.3 21.7 25.3 27.8 30.4 32.9
6" W/ft 6.4 8.0 9.6 11.2 12.8 14.4 16.0 19.2 23.5 26.9 30.2 35.2 38.7 42.2 45.8
8" W/ft 8.1 10.1 12.1 14.1 16.2 18.2 20.2 24.2 29.7 33.9 38.2 44.4 48.9 53.3 57.8
10" W/ft 9.9 12.4 14.8 17.3 19.8 22.2 24.7 29.6 36.3 41.5 46.7 54.3 59.8 65.2 70.6
12" W/ft 11.6 14.5 17.4 20.3 23.2 26.1 29.0 34.8 42.6 48.7 54.8 63.8 70.2 76.6 82.9
14" W/ft 12.6 15.8 19.0 22.1 25.3 28.4 31.6 37.9 46.5 53.1 59.7 69.5 76.5 83.4 90.4
16" W/ft 14.3 17.9 21.5 25.1 28.7 32.3 35.9 43.0 52.7 60.2 67.8 78.9 86.8 94.6 102.5
18" W/ft 16.0 20.1 24.1 28.1 32.1 36.1 40.1 48.1 58.9 67.4 75.8 88.2 97.0 105.9 114.7
20" W/ft 17.7 22.2 26.6 31.0 35.4 39.9 44.3 53.2 65.1 74.4 83.7 97.5 107.2 117.0 126.7
22" W/ft 19.4 24.3 29.1 34.0 38.8 43.7 48.5 58.2 71.3 81.5 91.7 106.7 117.4 128.0 138.7
24" W/ft 21.1 26.4 31.6 36.9 42.2 47.4 52.7 63.2 77.5 88.5 99.6 115.9 127.5 139.1 150.7
1.5" Insulation Thickness1/2" W/ft 1.1 1.4 1.7 2.0 2.2 2.5 2.8 3.5 4.1 4.7 5.5 6.2 6.8 7.4 8.03/4" W/ft 1.2 1.6 1.9 2.2 2.5 2.8 3.1 3.9 4.6 5.2 6.1 6.8 7.5 8.2 8.9
1" W/ft 1.4 1.8 2.2 2.5 2.9 3.2 3.6 4.5 5.3 6.0 7.1 7.9 8.7 9.5 10.3
11/2" W/ft 1.8 2.3 2.8 3.2 3.7 4.1 4.6 5.8 6.8 7.7 9.1 10.1 11.1 12.1 13.2
2" W/ft 2.1 2.6 3.1 3.6 4.2 4.7 5.2 6.6 7.6 8.7 10.3 11.4 12.6 13.7 14.9
21/2" W/ft 2.4 3.0 3.5 4.1 4.7 5.3 5.9 7.4 8.7 9.9 11.7 13.0 14.3 15.6 16.9
3" W/ft 2.7 3.4 4.1 4.8 5.4 6.1 6.8 8.6 10.0 11.4 13.5 15.0 16.5 18.0 19.4
4" W/ft 3.3 4.2 5.0 5.8 6.6 7.5 8.3 10.5 12.2 13.9 16.4 18.3 20.1 21.9 23.7
6" W/ft 4.5 5.7 6.8 7.9 9.0 10.2 11.3 14.2 16.6 19.0 22.4 24.9 27.3 29.8 32.3
8" W/ft 5.6 7.1 8.5 9.9 11.3 12.7 14.1 17.8 20.7 23.7 27.9 31.0 34.1 37.2 40.3
10" W/ft 6.8 8.0 10.3 12.0 13.7 15.4 17.1 21.5 25.1 28.7 33.9 37.6 41.4 45.1 48.9
12" W/ft 8.0 10.0 12.0 14.0 16.0 18.0 20.0 25.2 29.4 33.6 39.6 44.0 48.4 52.8 57.2
14" W/ft 8.7 10.9 13.0 15.2 17.4 19.5 21.7 27.3 31.9 36.5 43.0 47.7 52.5 57.3 62.1
16" W/ft 9.8 12.3 14.8 17.2 19.7 22.1 24.6 31.0 36.2 41.3 48.7 54.1 59.5 64.9 70.4
18" W/ft 11.0 13.7 16.4 19.2 21.9 24.7 27.4 34.5 40.3 46.0 54.3 60.3 66.3 72.3 78.4
20" W/ft 12.1 15.1 18.1 21.1 24.2 27.2 30.2 38.1 44.4 50.7 59.8 66.4 73.1 79.7 86.4
22" W/ft 13.2 16.5 19.8 23.1 26.4 29.7 33.0 41.6 48.5 55.4 65.3 72.6 79.9 87.1 94.4
24" W/ft 14.3 17.9 21.5 25.1 28.6 32.2 35.8 45.1 52.6 60.1 70.9 78.8 86.6 94.5 102.4
2" Insulation Thickness1/2" W/ft 1.0 1.2 1.4 1.7 1.9 2.2 2.4 3.0 3.5 4.0 4.8 5.3 5.8 6.3 7.23/4" W/ft 1.1 1.4 1.6 1.9 2.2 2.4 2.7 3.4 4.0 4.5 5.3 5.9 6.5 7.1 8.1
1" W/ft 1.2 1.5 1.8 2.1 2.4 2.7 3.0 3.8 4.4 5.0 5.9 6.6 7.3 7.9 9.0
11/2" W/ft 1.5 1.9 2.3 2.7 3.0 3.4 3.8 4.8 5.6 6.4 7.5 8.4 9.2 10.0 11.4
2" W/ft 1.7 2.2 2.6 3.0 3.4 3.9 4.3 5.4 6.3 7.2 8.5 9.5 10.4 11.4 12.9
21/2" W/ft 1.9 2.4 2.9 3.4 3.8 4.3 4.8 6.0 7.1 8.1 9.5 10.6 11.6 12.7 14.4
3" W/ft 2.2 2.8 3.3 3.9 4.4 5.0 5.5 6.9 8.1 9.2 10.9 12.1 13.3 14.5 16.4
4" W/ft 2.6 3.3 4.0 4.6 5.3 5.9 6.6 8.3 9.7 11.1 13.1 14.5 16.0 17.4 19.7
6" W/ft 3.6 4.5 5.3 6.2 7.1 8.0 8.9 11.2 13.1 15.0 17.6 19.6 21.5 23.5 26.6
8" W/ft 4.4 5.6 6.7 7.8 8.9 10.0 11.1 14.0 16.3 18.6 22.0 24.4 26.9 29.3 33.2
10" W/ft 5.3 6.7 8.0 9.3 10.6 12.0 13.3 16.8 19.6 22.3 26.3 29.3 32.2 35.1 39.8
12" W/ft 6.2 7.8 9.3 10.9 12.4 14.0 15.5 19.5 22.8 26.0 30.7 34.1 37.5 40.9 46.3
14" W/ft 6.7 8.4 10.1 11.8 13.4 15.1 16.8 21.2 24.7 28.2 33.3 37.0 40.7 44.4 50.2
16" W/ft 7.6 9.5 11.3 13.2 15.1 17.0 18.9 23.8 27.8 31.8 37.4 41.6 45.7 49.9 56.5
18" W/ft 8.4 10.5 12.6 14.7 16.8 18.9 21.0 26.5 30.9 35.3 41.6 46.2 50.8 55.4 62.8
20" W/ft 9.2 11.6 13.9 16.2 18.5 20.8 23.1 29.1 34.0 38.8 45.7 50.8 55.9 61.0 69.1
22" W/ft 10.1 12.6 15.2 17.7 20.2 22.7 25.3 31.8 37.1 42.4 50.0 55.6 61.1 66.7 75.5
24" W/ft 11.0 13.7 16.4 19.2 21.9 24.7 27.4 34.5 40.3 46.0 54.3 60.3 66.3 72.3 81.9
609.6 mm W/m 36.1 44.9 53.8 63.0 71.9 3" (76.2 mm) Insulation Thickness1/2" W/ft 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.5 2.9 3.4 4.0 4.4 4.8 5.5 6.03/4" W/ft 0.9 1.1 1.3 1.5 1.8 2.0 2.2 2.8 3.2 3.7 4.4 4.8 5.3 6.1 6.67
1" W/ft 1.0 1.3 1.5 1.8 2.0 2.3 2.5 3.2 3.7 4.2 5.0 5.5 6.1 6.9 7.5
11/2" W/ft 1.2 1.5 1.8 2.1 2.4 2.7 3.0 3.8 4.4 5.0 5.9 6.6 7.3 8.3 9.0
2" W/ft 1.3 1.7 2.0 2.3 2.6 3.0 3.3 4.2 4.9 5.5 6.5 7.3 8.0 9.1 9.9
21/2" W/ft 1.5 1.9 2.2 2.6 3.0 3.3 3.7 4.7 5.4 6.2 7.3 8.1 9.0 10.2 11.1
3" W/ft 1.7 2.1 2.5 2.9 3.4 3.8 4.2 5.3 6.2 7.1 8.3 9.2 10.2 11.6 12.6
4" W/ft 2.0 2.5 3.0 3.5 4.0 4.5 5.0 6.3 7.4 8.4 9.9 11.0 12.1 13.8 15.0
6" W/ft 2.6 3.3 3.9 4.6 5.2 5.9 6.5 8.2 9.6 10.9 12.9 14.3 15.7 17.9 19.4
8" W/ft 3.2 4.0 4.8 5.6 6.4 7.2 8.0 10.1 11.8 13.4 15.8 17.6 19.4 22.1 23.9
10" W/ft 3.8 4.8 5.7 6.7 7.6 8.6 9.5 12.0 14.0 16.0 18.8 20.9 23.0 26.2 28.4
12" W/ft 4.4 5.5 6.5 7.6 8.7 9.8 10.9 13.7 16.0 18.3 21.6 24.0 26.4 30.1 32.6
14" W/ft 4.7 5.9 7.1 8.3 9.4 10.6 11.8 14.9 17.3 19.8 23.4 26.0 28.6 32.6 35.3
16" W/ft 5.3 6.7 8.0 9.3 10.6 12.0 13.3 16.8 19.6 22.3 26.3 29.3 32.2 36.7 39.8
18” W/ft 5.9 7.4 8.8 10.3 11.8 13.2 14.7 18.5 21.6 24.7 29.1 32.3 35.6 40.6 44.0
20" W/ft 6.4 8.1 9.7 11.3 12.9 14.5 16.1 20.3 23.7 27.0 31.9 35.4 39.0 44.4 48.1
22" W/ft 7.0 8.8 10.5 12.3 14.0 15.8 17.5 22.1 25.7 29.4 34.7 38.5 42.4 48.3 52.3
24" W/ft 7.6 9.5 11.3 13.2 15.1 17.0 18.9 23.8 27.8 31.8 37.4 41.6 45.7 52.2 56.5
NominalPipe Size,
in. (ID)
Temperature Difference Between Pipe and Ambient
DegºF 40ºF 50ºF 60ºF 70ºF 80ºF 90ºF 100ºF 120ºF 140ºF 160ºF 180ºF 200ºF 220ºF 240ºF 260ºF
3” Insulation Thickness
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Chromalox Cable Selection
1. Select Heating Cable Family: Based on the maximum maintenance temperature rating, maximumexposure temperature rating, and area classification, select the heating cable family from Table 3. (SeeChromalox Heat Trace Cable Product Information Sheets for cable construction options, voltage ratings,and wattage outputs available.)
2. Select Thermal Output Rating:
(a) For Metal Pipes – Use Figures 1, 2 or 4(b) For Plastic Pipes – Use Figure 3 by finding the intersection of the calculated heat loss, QF, and pipe
maintenance temperature, Tm. Select the cable with a thermal output that equals or exceeds QF at Tm.
Pipe Temperature (ºF)Maintenance Temperature
0 10 20 30 50 60 70 80 90 100 110 120 130 140 150
Ther
mal
Out
put
(W/f
t)
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
4.88
SRL10 & HSRL10
SRL8 & HSRL8
SRL5 & HSRL5
SRL3 & HSRL3
Cable OutputversusTemperature
40
Figure 1 SRL & HSRL – Thermal OutputRatings on Insulated Metal Pipe Figure 2 SRM/E & HSRM – Thermal Output
Ratings on Insulated Metal Pipe Figure 3 SRL & HSRL – Thermal Output Ratingson Plastic Pipe with Aluminum Tape
B3. Determine Total Cable Length: In addition to pipe length, in-line components such as valves, flanges,
and pipe supports require additional heat tracing to maintain Tm. See Table 4. Calculate the totalcable length required by combining the pipe length with the additional lengths needed for all theother components.
Table 3 Heating Cable Families
NOTE: It is the responsibility of the facility manager or engineer to determine the classification of an area where heat trace will be installed. The factory can help determine a suitablecable based on the information provided.
Table 4Additional Cable Lengths Required for In-Line ComponentsBased on Pipe IPS (Iron Pipe Size)
1/2 in. 1.00 1.00 1.00 1.00 1.00 1.00 1.00 0.30
3/4 in. 1.50 1.00 1.00 1.00 1.50 1.00 1.00 0.30
1 in. 2.00 1.00 1.00 1.00 1.50 1.00 1.00 0.30
11/2 in. 2.50 1.50 1.50 1.50 2.00 2.00 2.00 0.30
2 in. 2.50 2.00 2.00 2.00 2.00 2.00 2.00 0.30
21/2 in. 2.50 2.00 2.00 2.00 2.00 2.00 2.00 0.30
3 in. 3.00 2.50 2.50 2.50 2.00 2.00 2.00 0.50
4 in. 4.00 3.00 3.00 3.00 2.50 2.50 2.50 0.50
6 in. 5.00 3.50 3.50 3.50 2.50 2.50 2.50 0.80
8 in. 7.00 4.00 4.00 4.00 2.50 2.50 2.50 0.80
10 in. 8.00 4.50 4.50 4.50 3.00 3.00 3.00 0.80
12 in. 9.00 5.00 5.00 5.00 3.00 3.00 3.00 0.80
14 in. 10.00 5.50 5.50 5.50 3.00 3.00 3.00 1.00
16 in. 11.00 6.00 6.00 6.00 3.50 3.50 3.50 1.00
18 in. 12.00 7.00 7.00 7.00 3.50 3.50 3.50 1.00
20 in. 13.00 7.50 7.50 7.50 3.50 3.50 3.50 1.00
22 in. 13.00 7.50 7.50 7.50 3.50 3.50 3.50 1.00
24 in. 15.00 8.00 8.00 8.00 4.00 4.00 4.00 1.00
Piping Size Gate Valve Globe Valve Ball Valve Butterfly Valve Hanger SupportShoe Support Sleeper Support Flange Pair
ft
0 10 20 30 50 60 70 80 90 100 110 120 130 140 15040
Pipe Temperature (ºF)
SRL10 & HSRL10
Ther
mal
Out
put
(W/f
t)
9
8
7
6
5
4
3
2
1
0
SRL8 &HSRL8
SRL5 & HSRL5
SRL3 & HSRL3
Cable OutputversusTemperature
Figure 4 SRP – Thermal Output Ratingson Insulated Metal Pipe
Pipe Temperature (ºF)
Hea
tO
utp
ut(W
/ft)
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
15 W/ft
10 W/ft
5 W/ft
Cable OutputversusTemperature
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230
Heating CableFamily
AreaClassification
PipeMaterial
MaximumMaintenanceTemperature
Maximum ExposureTemperature(Power Off)
Approvals
U.S. Other
SRL(Self-RegulatingLow Temperature)
Ordinary
Plastic/Metal 150ºF / 65ºC 185ºF / 85ºC
UL, CSA, FM GOST, Cenelec,CE, ATEX
Class I, Div.2, Gr. B, C, D CSA, FM, (Gr. A, CSA Only) GOST, Cenelec,CE, ATEX
Class II, Div.2, Gr. E, F, G CSA, FM, (Gr. E, CSA Only) GOST, Cenelec,CE
Class III, Div.2 FM Only GOST, Cenelec,CE, ATEX
SRM/E(Self-RegulatingMediumTemperature)
Ordinary
Metal Only 302ºF / 150ºC 420ºF / 215ºC
UL, CSA, FM GOST, Cenelec,CE, ATEX
Class I Div.2, Gr. A, B, C, D CSA, FM, (Gr. A, CSA Only) GOST, Cenelec,CE, ATEX
Class II, Div.2, Gr. F, G CSA Only GOST, Cenelec,CE, ATEX
SRP(Self-RegulatingMediumTemperature)
Ordinary
Metal Only 225ºF / 110ºC 275ºF / 135ºC UL, CSA, FMPending
GOST, Cenelec, CE,ATEX Pending
Class I, Div.2, Gr. B, C, D
Class II, Div.2, Gr. F, G
Class III
HSRL(H-Self-RegulatingLow Temperature)
Class I, Div.1, Gr. B, C, D
Plastic/Metal 150ºF / 65ºC 185ºF / 85ºC
CSA, FM
Class II, Div.1, Gr. E, F, G CSA, FM
Class III, Div.1 CSA, FM
HSRM(H-Self-RegulatingMediumTemperature)
Class I, Div.1, Gr. B, C, D
Metal Only 302ºF / 150ºC 420ºF / 215ºC
CSA, FM
Class II, Div.1, Gr. E, F, G CSA, FM
Class III, Div.1 CSA, FM
CWM(Constant Wattage)
OrdinaryMetal Only Consult Factory 392ºF / 200ºC
UL, CSA
Hazardous Area, Consult Factory
MI (MineralInsulated)
Ordinary
Metal Only Consult Factory 1,100ºF / 595ºC
CSA, FM
Class I, Div.2, Gr. B, C, D CSA, FM
Class II, Div.2, Gr. E, F, G CSA, FM
Class III CSA, FM
0 50 100 150 200 250 300
Pipe Temperature (ºF)
SRM/E20 &HSRM20
Pow
erO
utp
ut(W
/ft)
24
20
16
12
8
4
0
SRM/E15 &HSRM15
SRM/E10 &HSRM10
SRM/E8 & HSRM8
SRM/E5 & HSRM5
SRM/E3 & HSRM3
Cable OutputversusTemperature
Table 2 Insulation Adjustment Factors
Insulation Factor
Pipe Insulation TypePipe Insulation TypeInsulation Factor
Glass fiber (ASTM C547) 1.00
Calcium silicate (ASTM C533) 1.48
Cellular glass (ASTM C552) 1.48
Rigid cellular urethane (ASTM C591) 0.64
Foamed elastomer (ASTM C534) 1.16
Mineral fiber blanket (ASTM C553) 1.16
Expanded perlite (ASTM C610) 1.90
1. Basic Heat Loss: After determining the difference between the ambient and desired pipe maintenance
temperature, Tm, use Table 1 to figure the basic heat loss for the pipe size and insulation thickness.
2. Insulation Adjustment: Using Table 2, find the type of insulation being used and its insulation factor.
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3. Calculate QF: Multiply the basic heat loss figure from Table 1 by the adjustment factor from Table 2 to
calculate the estimated heat loss, QF, in watts per foot of pipe length.
4. Correct for Indoor Location/ Wind Speed: If location is indoors, multiply QF by 0.9. Table 1 is based on
10% safety factor and 20 mph wind speed; add 5% margin for each 5 mph over 20 mph wind speed.
Table 1 Pipe Heat Loss QP in W/ft Based on Temperature Differential and Insulation Thickness
NominalPipe Size,
in. (ID)
Temperature Difference Between Pipe and Ambient
DegºF 40ºF 50ºF 60ºF 70ºF 80ºF 90ºF 100ºF 120ºF 140ºF 160ºF 180ºF 200ºF 220ºF 240ºF 260ºF
1" Insulation Thickness1/2" W/ft 1.4 1.8 2.1 2.5 2.8 3.2 3.5 4.2 5.1 5.9 6.6 7.7 8.5 9.2 10.03/4" W/ft 1.6 2.0 2.4 2.8 3.2 3.6 4.0 4.8 5.9 6.7 7.6 8.8 9.7 10.6 11.4
1" W/ft 1.8 2.3 2.8 3.2 3.7 4.1 4.6 5.5 6.8 7.7 8.7 10.1 11.1 12.1 13.2
11/2" W/ft 2.4 3.1 3.7 4.3 4.9 5.5 6.1 7.3 9.0 10.2 11.5 13.4 14.8 16.1 17.4
2" W/ft 2.8 3.5 4.1 4.8 5.5 6.2 6.9 8.3 10.1 11.6 13.0 15.2 16.7 18.2 19.7
21/2" W/ft 3.2 4.0 4.8 5.6 6.4 7.2 8.0 9.6 11.8 13.4 15.1 17.6 19.4 21.1 22.9
3" W/ft 3.7 4.7 5.6 6.5 7.4 8.4 9.3 11.2 13.7 15.6 17.6 20.5 22.5 24.6 26.6
4" W/ft 4.6 5.8 6.9 8.1 9.2 10.4 11.5 13.8 16.9 19.3 21.7 25.3 27.8 30.4 32.9
6" W/ft 6.4 8.0 9.6 11.2 12.8 14.4 16.0 19.2 23.5 26.9 30.2 35.2 38.7 42.2 45.8
8" W/ft 8.1 10.1 12.1 14.1 16.2 18.2 20.2 24.2 29.7 33.9 38.2 44.4 48.9 53.3 57.8
10" W/ft 9.9 12.4 14.8 17.3 19.8 22.2 24.7 29.6 36.3 41.5 46.7 54.3 59.8 65.2 70.6
12" W/ft 11.6 14.5 17.4 20.3 23.2 26.1 29.0 34.8 42.6 48.7 54.8 63.8 70.2 76.6 82.9
14" W/ft 12.6 15.8 19.0 22.1 25.3 28.4 31.6 37.9 46.5 53.1 59.7 69.5 76.5 83.4 90.4
16" W/ft 14.3 17.9 21.5 25.1 28.7 32.3 35.9 43.0 52.7 60.2 67.8 78.9 86.8 94.6 102.5
18" W/ft 16.0 20.1 24.1 28.1 32.1 36.1 40.1 48.1 58.9 67.4 75.8 88.2 97.0 105.9 114.7
20" W/ft 17.7 22.2 26.6 31.0 35.4 39.9 44.3 53.2 65.1 74.4 83.7 97.5 107.2 117.0 126.7
22" W/ft 19.4 24.3 29.1 34.0 38.8 43.7 48.5 58.2 71.3 81.5 91.7 106.7 117.4 128.0 138.7
24" W/ft 21.1 26.4 31.6 36.9 42.2 47.4 52.7 63.2 77.5 88.5 99.6 115.9 127.5 139.1 150.7
1.5" Insulation Thickness1/2" W/ft 1.1 1.4 1.7 2.0 2.2 2.5 2.8 3.5 4.1 4.7 5.5 6.2 6.8 7.4 8.03/4" W/ft 1.2 1.6 1.9 2.2 2.5 2.8 3.1 3.9 4.6 5.2 6.1 6.8 7.5 8.2 8.9
1" W/ft 1.4 1.8 2.2 2.5 2.9 3.2 3.6 4.5 5.3 6.0 7.1 7.9 8.7 9.5 10.3
11/2" W/ft 1.8 2.3 2.8 3.2 3.7 4.1 4.6 5.8 6.8 7.7 9.1 10.1 11.1 12.1 13.2
2" W/ft 2.1 2.6 3.1 3.6 4.2 4.7 5.2 6.6 7.6 8.7 10.3 11.4 12.6 13.7 14.9
21/2" W/ft 2.4 3.0 3.5 4.1 4.7 5.3 5.9 7.4 8.7 9.9 11.7 13.0 14.3 15.6 16.9
3" W/ft 2.7 3.4 4.1 4.8 5.4 6.1 6.8 8.6 10.0 11.4 13.5 15.0 16.5 18.0 19.4
4" W/ft 3.3 4.2 5.0 5.8 6.6 7.5 8.3 10.5 12.2 13.9 16.4 18.3 20.1 21.9 23.7
6" W/ft 4.5 5.7 6.8 7.9 9.0 10.2 11.3 14.2 16.6 19.0 22.4 24.9 27.3 29.8 32.3
8" W/ft 5.6 7.1 8.5 9.9 11.3 12.7 14.1 17.8 20.7 23.7 27.9 31.0 34.1 37.2 40.3
10" W/ft 6.8 8.0 10.3 12.0 13.7 15.4 17.1 21.5 25.1 28.7 33.9 37.6 41.4 45.1 48.9
12" W/ft 8.0 10.0 12.0 14.0 16.0 18.0 20.0 25.2 29.4 33.6 39.6 44.0 48.4 52.8 57.2
14" W/ft 8.7 10.9 13.0 15.2 17.4 19.5 21.7 27.3 31.9 36.5 43.0 47.7 52.5 57.3 62.1
16" W/ft 9.8 12.3 14.8 17.2 19.7 22.1 24.6 31.0 36.2 41.3 48.7 54.1 59.5 64.9 70.4
18" W/ft 11.0 13.7 16.4 19.2 21.9 24.7 27.4 34.5 40.3 46.0 54.3 60.3 66.3 72.3 78.4
20" W/ft 12.1 15.1 18.1 21.1 24.2 27.2 30.2 38.1 44.4 50.7 59.8 66.4 73.1 79.7 86.4
22" W/ft 13.2 16.5 19.8 23.1 26.4 29.7 33.0 41.6 48.5 55.4 65.3 72.6 79.9 87.1 94.4
24" W/ft 14.3 17.9 21.5 25.1 28.6 32.2 35.8 45.1 52.6 60.1 70.9 78.8 86.6 94.5 102.4
2" Insulation Thickness1/2" W/ft 1.0 1.2 1.4 1.7 1.9 2.2 2.4 3.0 3.5 4.0 4.8 5.3 5.8 6.3 7.23/4" W/ft 1.1 1.4 1.6 1.9 2.2 2.4 2.7 3.4 4.0 4.5 5.3 5.9 6.5 7.1 8.1
1" W/ft 1.2 1.5 1.8 2.1 2.4 2.7 3.0 3.8 4.4 5.0 5.9 6.6 7.3 7.9 9.0
11/2" W/ft 1.5 1.9 2.3 2.7 3.0 3.4 3.8 4.8 5.6 6.4 7.5 8.4 9.2 10.0 11.4
2" W/ft 1.7 2.2 2.6 3.0 3.4 3.9 4.3 5.4 6.3 7.2 8.5 9.5 10.4 11.4 12.9
21/2" W/ft 1.9 2.4 2.9 3.4 3.8 4.3 4.8 6.0 7.1 8.1 9.5 10.6 11.6 12.7 14.4
3" W/ft 2.2 2.8 3.3 3.9 4.4 5.0 5.5 6.9 8.1 9.2 10.9 12.1 13.3 14.5 16.4
4" W/ft 2.6 3.3 4.0 4.6 5.3 5.9 6.6 8.3 9.7 11.1 13.1 14.5 16.0 17.4 19.7
6" W/ft 3.6 4.5 5.3 6.2 7.1 8.0 8.9 11.2 13.1 15.0 17.6 19.6 21.5 23.5 26.6
8" W/ft 4.4 5.6 6.7 7.8 8.9 10.0 11.1 14.0 16.3 18.6 22.0 24.4 26.9 29.3 33.2
10" W/ft 5.3 6.7 8.0 9.3 10.6 12.0 13.3 16.8 19.6 22.3 26.3 29.3 32.2 35.1 39.8
12" W/ft 6.2 7.8 9.3 10.9 12.4 14.0 15.5 19.5 22.8 26.0 30.7 34.1 37.5 40.9 46.3
14" W/ft 6.7 8.4 10.1 11.8 13.4 15.1 16.8 21.2 24.7 28.2 33.3 37.0 40.7 44.4 50.2
16" W/ft 7.6 9.5 11.3 13.2 15.1 17.0 18.9 23.8 27.8 31.8 37.4 41.6 45.7 49.9 56.5
18" W/ft 8.4 10.5 12.6 14.7 16.8 18.9 21.0 26.5 30.9 35.3 41.6 46.2 50.8 55.4 62.8
20" W/ft 9.2 11.6 13.9 16.2 18.5 20.8 23.1 29.1 34.0 38.8 45.7 50.8 55.9 61.0 69.1
22" W/ft 10.1 12.6 15.2 17.7 20.2 22.7 25.3 31.8 37.1 42.4 50.0 55.6 61.1 66.7 75.5
24" W/ft 11.0 13.7 16.4 19.2 21.9 24.7 27.4 34.5 40.3 46.0 54.3 60.3 66.3 72.3 81.9
609.6 mm W/m 36.1 44.9 53.8 63.0 71.9 3" (76.2 mm) Insulation Thickness1/2" W/ft 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.5 2.9 3.4 4.0 4.4 4.8 5.5 6.03/4" W/ft 0.9 1.1 1.3 1.5 1.8 2.0 2.2 2.8 3.2 3.7 4.4 4.8 5.3 6.1 6.67
1" W/ft 1.0 1.3 1.5 1.8 2.0 2.3 2.5 3.2 3.7 4.2 5.0 5.5 6.1 6.9 7.5
11/2" W/ft 1.2 1.5 1.8 2.1 2.4 2.7 3.0 3.8 4.4 5.0 5.9 6.6 7.3 8.3 9.0
2" W/ft 1.3 1.7 2.0 2.3 2.6 3.0 3.3 4.2 4.9 5.5 6.5 7.3 8.0 9.1 9.9
21/2" W/ft 1.5 1.9 2.2 2.6 3.0 3.3 3.7 4.7 5.4 6.2 7.3 8.1 9.0 10.2 11.1
3" W/ft 1.7 2.1 2.5 2.9 3.4 3.8 4.2 5.3 6.2 7.1 8.3 9.2 10.2 11.6 12.6
4" W/ft 2.0 2.5 3.0 3.5 4.0 4.5 5.0 6.3 7.4 8.4 9.9 11.0 12.1 13.8 15.0
6" W/ft 2.6 3.3 3.9 4.6 5.2 5.9 6.5 8.2 9.6 10.9 12.9 14.3 15.7 17.9 19.4
8" W/ft 3.2 4.0 4.8 5.6 6.4 7.2 8.0 10.1 11.8 13.4 15.8 17.6 19.4 22.1 23.9
10" W/ft 3.8 4.8 5.7 6.7 7.6 8.6 9.5 12.0 14.0 16.0 18.8 20.9 23.0 26.2 28.4
12" W/ft 4.4 5.5 6.5 7.6 8.7 9.8 10.9 13.7 16.0 18.3 21.6 24.0 26.4 30.1 32.6
14" W/ft 4.7 5.9 7.1 8.3 9.4 10.6 11.8 14.9 17.3 19.8 23.4 26.0 28.6 32.6 35.3
16" W/ft 5.3 6.7 8.0 9.3 10.6 12.0 13.3 16.8 19.6 22.3 26.3 29.3 32.2 36.7 39.8
18” W/ft 5.9 7.4 8.8 10.3 11.8 13.2 14.7 18.5 21.6 24.7 29.1 32.3 35.6 40.6 44.0
20" W/ft 6.4 8.1 9.7 11.3 12.9 14.5 16.1 20.3 23.7 27.0 31.9 35.4 39.0 44.4 48.1
22" W/ft 7.0 8.8 10.5 12.3 14.0 15.8 17.5 22.1 25.7 29.4 34.7 38.5 42.4 48.3 52.3
24" W/ft 7.6 9.5 11.3 13.2 15.1 17.0 18.9 23.8 27.8 31.8 37.4 41.6 45.7 52.2 56.5
NominalPipe Size,
in. (ID)
Temperature Difference Between Pipe and Ambient
DegºF 40ºF 50ºF 60ºF 70ºF 80ºF 90ºF 100ºF 120ºF 140ºF 160ºF 180ºF 200ºF 220ºF 240ºF 260ºF
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Chromalox Cable Selection
1. Select Heating Cable Family: Based on the maximum maintenance temperature rating, maximumexposure temperature rating, and area classification, select the heating cable family from Table 3. (SeeChromalox Heat Trace Cable Product Information Sheets for cable construction options, voltage ratings,and wattage outputs available.)
2. Select Thermal Output Rating:
(a) For Metal Pipes – Use Figures 1, 2 or 4(b) For Plastic Pipes – Use Figure 3 by finding the intersection of the calculated heat loss, QF, and pipe
maintenance temperature, Tm. Select the cable with a thermal output that equals or exceeds QF at Tm.
Pipe Temperature (ºF)Maintenance Temperature
0 10 20 30 50 60 70 80 90 100 110 120 130 140 150
Ther
mal
Out
put
(W/f
t)
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
4.88
SRL10 & HSRL10
SRL8 & HSRL8
SRL5 & HSRL5
SRL3 & HSRL3
Cable OutputversusTemperature
40
Figure 1 SRL & HSRL – Thermal OutputRatings on Insulated Metal Pipe Figure 2 SRM/E & HSRM – Thermal Output
Ratings on Insulated Metal Pipe Figure 3 SRL & HSRL – Thermal Output Ratingson Plastic Pipe with Aluminum Tape
B3. Determine Total Cable Length: In addition to pipe length, in-line components such as valves, flanges,
and pipe supports require additional heat tracing to maintain Tm. See Table 4. Calculate the totalcable length required by combining the pipe length with the additional lengths needed for all theother components.
Table 3 Heating Cable Families
NOTE: It is the responsibility of the facility manager or engineer to determine the classification of an area where heat trace will be installed. The factory can help determine a suitablecable based on the information provided.
Table 4Additional Cable Lengths Required for In-Line ComponentsBased on Pipe IPS (Iron Pipe Size)
1/2 in. 1.00 1.00 1.00 1.00 1.00 1.00 1.00 0.30
3/4 in. 1.50 1.00 1.00 1.00 1.50 1.00 1.00 0.30
1 in. 2.00 1.00 1.00 1.00 1.50 1.00 1.00 0.30
11/2 in. 2.50 1.50 1.50 1.50 2.00 2.00 2.00 0.30
2 in. 2.50 2.00 2.00 2.00 2.00 2.00 2.00 0.30
21/2 in. 2.50 2.00 2.00 2.00 2.00 2.00 2.00 0.30
3 in. 3.00 2.50 2.50 2.50 2.00 2.00 2.00 0.50
4 in. 4.00 3.00 3.00 3.00 2.50 2.50 2.50 0.50
6 in. 5.00 3.50 3.50 3.50 2.50 2.50 2.50 0.80
8 in. 7.00 4.00 4.00 4.00 2.50 2.50 2.50 0.80
10 in. 8.00 4.50 4.50 4.50 3.00 3.00 3.00 0.80
12 in. 9.00 5.00 5.00 5.00 3.00 3.00 3.00 0.80
14 in. 10.00 5.50 5.50 5.50 3.00 3.00 3.00 1.00
16 in. 11.00 6.00 6.00 6.00 3.50 3.50 3.50 1.00
18 in. 12.00 7.00 7.00 7.00 3.50 3.50 3.50 1.00
20 in. 13.00 7.50 7.50 7.50 3.50 3.50 3.50 1.00
22 in. 13.00 7.50 7.50 7.50 3.50 3.50 3.50 1.00
24 in. 15.00 8.00 8.00 8.00 4.00 4.00 4.00 1.00
Piping Size Gate Valve Globe Valve Ball Valve Butterfly Valve Hanger SupportShoe Support Sleeper Support Flange Pair
ft
0 10 20 30 50 60 70 80 90 100 110 120 130 140 15040
Pipe Temperature (ºF)
SRL10 & HSRL10
Ther
mal
Out
put
(W/f
t)
9
8
7
6
5
4
3
2
1
0
SRL8 &HSRL8
SRL5 & HSRL5
SRL3 & HSRL3
Cable OutputversusTemperature
Figure 4 SRP – Thermal Output Ratingson Insulated Metal Pipe
Pipe Temperature (ºF)
Hea
tO
utp
ut(W
/ft)
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
15 W/ft
10 W/ft
5 W/ft
Cable OutputversusTemperature
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230
Heating CableFamily
AreaClassification
PipeMaterial
MaximumMaintenanceTemperature
Maximum ExposureTemperature(Power Off)
Approvals
U.S. Other
SRL(Self-RegulatingLow Temperature)
Ordinary
Plastic/Metal 150ºF / 65ºC 185ºF / 85ºC
UL, CSA, FM GOST, Cenelec,CE, ATEX
Class I, Div.2, Gr. B, C, D CSA, FM, (Gr. A, CSA Only) GOST, Cenelec,CE, ATEX
Class II, Div.2, Gr. E, F, G CSA, FM, (Gr. E, CSA Only) GOST, Cenelec,CE
Class III, Div.2 FM Only GOST, Cenelec,CE, ATEX
SRM/E(Self-RegulatingMediumTemperature)
Ordinary
Metal Only 302ºF / 150ºC 420ºF / 215ºC
UL, CSA, FM GOST, Cenelec,CE, ATEX
Class I Div.2, Gr. A, B, C, D CSA, FM, (Gr. A, CSA Only) GOST, Cenelec,CE, ATEX
Class II, Div.2, Gr. F, G CSA Only GOST, Cenelec,CE, ATEX
SRP(Self-RegulatingMediumTemperature)
Ordinary
Metal Only 225ºF / 110ºC 275ºF / 135ºC UL, CSA, FMPending
GOST, Cenelec, CE,ATEX Pending
Class I, Div.2, Gr. B, C, D
Class II, Div.2, Gr. F, G
Class III
HSRL(H-Self-RegulatingLow Temperature)
Class I, Div.1, Gr. B, C, D
Plastic/Metal 150ºF / 65ºC 185ºF / 85ºC
CSA, FM
Class II, Div.1, Gr. E, F, G CSA, FM
Class III, Div.1 CSA, FM
HSRM(H-Self-RegulatingMediumTemperature)
Class I, Div.1, Gr. B, C, D
Metal Only 302ºF / 150ºC 420ºF / 215ºC
CSA, FM
Class II, Div.1, Gr. E, F, G CSA, FM
Class III, Div.1 CSA, FM
CWM(Constant Wattage)
OrdinaryMetal Only Consult Factory 392ºF / 200ºC
UL, CSA
Hazardous Area, Consult Factory
MI (MineralInsulated)
Ordinary
Metal Only Consult Factory 1,100ºF / 595ºC
CSA, FM
Class I, Div.2, Gr. B, C, D CSA, FM
Class II, Div.2, Gr. E, F, G CSA, FM
Class III CSA, FM
0 50 100 150 200 250 300
Pipe Temperature (ºF)
SRM/E20 &HSRM20
Pow
erO
utp
ut(W
/ft)
24
20
16
12
8
4
0
SRM/E15 &HSRM15
SRM/E10 &HSRM10
SRM/E8 & HSRM8
SRM/E5 & HSRM5
SRM/E3 & HSRM3
Cable OutputversusTemperature
Table 2 Insulation Adjustment Factors
Insulation Factor
Pipe Insulation TypePipe Insulation TypeInsulation Factor
Glass fiber (ASTM C547) 1.00
Calcium silicate (ASTM C533) 1.48
Cellular glass (ASTM C552) 1.48
Rigid cellular urethane (ASTM C591) 0.64
Foamed elastomer (ASTM C534) 1.16
Mineral fiber blanket (ASTM C553) 1.16
Expanded perlite (ASTM C610) 1.90
1. Basic Heat Loss: After determining the difference between the ambient and desired pipe maintenance
temperature, Tm, use Table 1 to figure the basic heat loss for the pipe size and insulation thickness.
2. Insulation Adjustment: Using Table 2, find the type of insulation being used and its insulation factor.
Hea
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ater
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3. Calculate QF: Multiply the basic heat loss figure from Table 1 by the adjustment factor from Table 2 to
calculate the estimated heat loss, QF, in watts per foot of pipe length.
4. Correct for Indoor Location/ Wind Speed: If location is indoors, multiply QF by 0.9. Table 1 is based on
10% safety factor and 20 mph wind speed; add 5% margin for each 5 mph over 20 mph wind speed.
Table 1 Pipe Heat Loss QP in W/ft Based on Temperature Differential and Insulation Thickness
NominalPipe Size,
in. (ID)
Temperature Difference Between Pipe and Ambient
DegºF 40ºF 50ºF 60ºF 70ºF 80ºF 90ºF 100ºF 120ºF 140ºF 160ºF 180ºF 200ºF 220ºF 240ºF 260ºF
1" Insulation Thickness1/2" W/ft 1.4 1.8 2.1 2.5 2.8 3.2 3.5 4.2 5.1 5.9 6.6 7.7 8.5 9.2 10.03/4" W/ft 1.6 2.0 2.4 2.8 3.2 3.6 4.0 4.8 5.9 6.7 7.6 8.8 9.7 10.6 11.4
1" W/ft 1.8 2.3 2.8 3.2 3.7 4.1 4.6 5.5 6.8 7.7 8.7 10.1 11.1 12.1 13.2
11/2" W/ft 2.4 3.1 3.7 4.3 4.9 5.5 6.1 7.3 9.0 10.2 11.5 13.4 14.8 16.1 17.4
2" W/ft 2.8 3.5 4.1 4.8 5.5 6.2 6.9 8.3 10.1 11.6 13.0 15.2 16.7 18.2 19.7
21/2" W/ft 3.2 4.0 4.8 5.6 6.4 7.2 8.0 9.6 11.8 13.4 15.1 17.6 19.4 21.1 22.9
3" W/ft 3.7 4.7 5.6 6.5 7.4 8.4 9.3 11.2 13.7 15.6 17.6 20.5 22.5 24.6 26.6
4" W/ft 4.6 5.8 6.9 8.1 9.2 10.4 11.5 13.8 16.9 19.3 21.7 25.3 27.8 30.4 32.9
6" W/ft 6.4 8.0 9.6 11.2 12.8 14.4 16.0 19.2 23.5 26.9 30.2 35.2 38.7 42.2 45.8
8" W/ft 8.1 10.1 12.1 14.1 16.2 18.2 20.2 24.2 29.7 33.9 38.2 44.4 48.9 53.3 57.8
10" W/ft 9.9 12.4 14.8 17.3 19.8 22.2 24.7 29.6 36.3 41.5 46.7 54.3 59.8 65.2 70.6
12" W/ft 11.6 14.5 17.4 20.3 23.2 26.1 29.0 34.8 42.6 48.7 54.8 63.8 70.2 76.6 82.9
14" W/ft 12.6 15.8 19.0 22.1 25.3 28.4 31.6 37.9 46.5 53.1 59.7 69.5 76.5 83.4 90.4
16" W/ft 14.3 17.9 21.5 25.1 28.7 32.3 35.9 43.0 52.7 60.2 67.8 78.9 86.8 94.6 102.5
18" W/ft 16.0 20.1 24.1 28.1 32.1 36.1 40.1 48.1 58.9 67.4 75.8 88.2 97.0 105.9 114.7
20" W/ft 17.7 22.2 26.6 31.0 35.4 39.9 44.3 53.2 65.1 74.4 83.7 97.5 107.2 117.0 126.7
22" W/ft 19.4 24.3 29.1 34.0 38.8 43.7 48.5 58.2 71.3 81.5 91.7 106.7 117.4 128.0 138.7
24" W/ft 21.1 26.4 31.6 36.9 42.2 47.4 52.7 63.2 77.5 88.5 99.6 115.9 127.5 139.1 150.7
1.5" Insulation Thickness1/2" W/ft 1.1 1.4 1.7 2.0 2.2 2.5 2.8 3.5 4.1 4.7 5.5 6.2 6.8 7.4 8.03/4" W/ft 1.2 1.6 1.9 2.2 2.5 2.8 3.1 3.9 4.6 5.2 6.1 6.8 7.5 8.2 8.9
1" W/ft 1.4 1.8 2.2 2.5 2.9 3.2 3.6 4.5 5.3 6.0 7.1 7.9 8.7 9.5 10.3
11/2" W/ft 1.8 2.3 2.8 3.2 3.7 4.1 4.6 5.8 6.8 7.7 9.1 10.1 11.1 12.1 13.2
2" W/ft 2.1 2.6 3.1 3.6 4.2 4.7 5.2 6.6 7.6 8.7 10.3 11.4 12.6 13.7 14.9
21/2" W/ft 2.4 3.0 3.5 4.1 4.7 5.3 5.9 7.4 8.7 9.9 11.7 13.0 14.3 15.6 16.9
3" W/ft 2.7 3.4 4.1 4.8 5.4 6.1 6.8 8.6 10.0 11.4 13.5 15.0 16.5 18.0 19.4
4" W/ft 3.3 4.2 5.0 5.8 6.6 7.5 8.3 10.5 12.2 13.9 16.4 18.3 20.1 21.9 23.7
6" W/ft 4.5 5.7 6.8 7.9 9.0 10.2 11.3 14.2 16.6 19.0 22.4 24.9 27.3 29.8 32.3
8" W/ft 5.6 7.1 8.5 9.9 11.3 12.7 14.1 17.8 20.7 23.7 27.9 31.0 34.1 37.2 40.3
10" W/ft 6.8 8.0 10.3 12.0 13.7 15.4 17.1 21.5 25.1 28.7 33.9 37.6 41.4 45.1 48.9
12" W/ft 8.0 10.0 12.0 14.0 16.0 18.0 20.0 25.2 29.4 33.6 39.6 44.0 48.4 52.8 57.2
14" W/ft 8.7 10.9 13.0 15.2 17.4 19.5 21.7 27.3 31.9 36.5 43.0 47.7 52.5 57.3 62.1
16" W/ft 9.8 12.3 14.8 17.2 19.7 22.1 24.6 31.0 36.2 41.3 48.7 54.1 59.5 64.9 70.4
18" W/ft 11.0 13.7 16.4 19.2 21.9 24.7 27.4 34.5 40.3 46.0 54.3 60.3 66.3 72.3 78.4
20" W/ft 12.1 15.1 18.1 21.1 24.2 27.2 30.2 38.1 44.4 50.7 59.8 66.4 73.1 79.7 86.4
22" W/ft 13.2 16.5 19.8 23.1 26.4 29.7 33.0 41.6 48.5 55.4 65.3 72.6 79.9 87.1 94.4
24" W/ft 14.3 17.9 21.5 25.1 28.6 32.2 35.8 45.1 52.6 60.1 70.9 78.8 86.6 94.5 102.4
2" Insulation Thickness1/2" W/ft 1.0 1.2 1.4 1.7 1.9 2.2 2.4 3.0 3.5 4.0 4.8 5.3 5.8 6.3 7.23/4" W/ft 1.1 1.4 1.6 1.9 2.2 2.4 2.7 3.4 4.0 4.5 5.3 5.9 6.5 7.1 8.1
1" W/ft 1.2 1.5 1.8 2.1 2.4 2.7 3.0 3.8 4.4 5.0 5.9 6.6 7.3 7.9 9.0
11/2" W/ft 1.5 1.9 2.3 2.7 3.0 3.4 3.8 4.8 5.6 6.4 7.5 8.4 9.2 10.0 11.4
2" W/ft 1.7 2.2 2.6 3.0 3.4 3.9 4.3 5.4 6.3 7.2 8.5 9.5 10.4 11.4 12.9
21/2" W/ft 1.9 2.4 2.9 3.4 3.8 4.3 4.8 6.0 7.1 8.1 9.5 10.6 11.6 12.7 14.4
3" W/ft 2.2 2.8 3.3 3.9 4.4 5.0 5.5 6.9 8.1 9.2 10.9 12.1 13.3 14.5 16.4
4" W/ft 2.6 3.3 4.0 4.6 5.3 5.9 6.6 8.3 9.7 11.1 13.1 14.5 16.0 17.4 19.7
6" W/ft 3.6 4.5 5.3 6.2 7.1 8.0 8.9 11.2 13.1 15.0 17.6 19.6 21.5 23.5 26.6
8" W/ft 4.4 5.6 6.7 7.8 8.9 10.0 11.1 14.0 16.3 18.6 22.0 24.4 26.9 29.3 33.2
10" W/ft 5.3 6.7 8.0 9.3 10.6 12.0 13.3 16.8 19.6 22.3 26.3 29.3 32.2 35.1 39.8
12" W/ft 6.2 7.8 9.3 10.9 12.4 14.0 15.5 19.5 22.8 26.0 30.7 34.1 37.5 40.9 46.3
14" W/ft 6.7 8.4 10.1 11.8 13.4 15.1 16.8 21.2 24.7 28.2 33.3 37.0 40.7 44.4 50.2
16" W/ft 7.6 9.5 11.3 13.2 15.1 17.0 18.9 23.8 27.8 31.8 37.4 41.6 45.7 49.9 56.5
18" W/ft 8.4 10.5 12.6 14.7 16.8 18.9 21.0 26.5 30.9 35.3 41.6 46.2 50.8 55.4 62.8
20" W/ft 9.2 11.6 13.9 16.2 18.5 20.8 23.1 29.1 34.0 38.8 45.7 50.8 55.9 61.0 69.1
22" W/ft 10.1 12.6 15.2 17.7 20.2 22.7 25.3 31.8 37.1 42.4 50.0 55.6 61.1 66.7 75.5
24" W/ft 11.0 13.7 16.4 19.2 21.9 24.7 27.4 34.5 40.3 46.0 54.3 60.3 66.3 72.3 81.9
609.6 mm W/m 36.1 44.9 53.8 63.0 71.9 3" (76.2 mm) Insulation Thickness1/2" W/ft 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.5 2.9 3.4 4.0 4.4 4.8 5.5 6.03/4" W/ft 0.9 1.1 1.3 1.5 1.8 2.0 2.2 2.8 3.2 3.7 4.4 4.8 5.3 6.1 6.67
1" W/ft 1.0 1.3 1.5 1.8 2.0 2.3 2.5 3.2 3.7 4.2 5.0 5.5 6.1 6.9 7.5
11/2" W/ft 1.2 1.5 1.8 2.1 2.4 2.7 3.0 3.8 4.4 5.0 5.9 6.6 7.3 8.3 9.0
2" W/ft 1.3 1.7 2.0 2.3 2.6 3.0 3.3 4.2 4.9 5.5 6.5 7.3 8.0 9.1 9.9
21/2" W/ft 1.5 1.9 2.2 2.6 3.0 3.3 3.7 4.7 5.4 6.2 7.3 8.1 9.0 10.2 11.1
3" W/ft 1.7 2.1 2.5 2.9 3.4 3.8 4.2 5.3 6.2 7.1 8.3 9.2 10.2 11.6 12.6
4" W/ft 2.0 2.5 3.0 3.5 4.0 4.5 5.0 6.3 7.4 8.4 9.9 11.0 12.1 13.8 15.0
6" W/ft 2.6 3.3 3.9 4.6 5.2 5.9 6.5 8.2 9.6 10.9 12.9 14.3 15.7 17.9 19.4
8" W/ft 3.2 4.0 4.8 5.6 6.4 7.2 8.0 10.1 11.8 13.4 15.8 17.6 19.4 22.1 23.9
10" W/ft 3.8 4.8 5.7 6.7 7.6 8.6 9.5 12.0 14.0 16.0 18.8 20.9 23.0 26.2 28.4
12" W/ft 4.4 5.5 6.5 7.6 8.7 9.8 10.9 13.7 16.0 18.3 21.6 24.0 26.4 30.1 32.6
14" W/ft 4.7 5.9 7.1 8.3 9.4 10.6 11.8 14.9 17.3 19.8 23.4 26.0 28.6 32.6 35.3
16" W/ft 5.3 6.7 8.0 9.3 10.6 12.0 13.3 16.8 19.6 22.3 26.3 29.3 32.2 36.7 39.8
18” W/ft 5.9 7.4 8.8 10.3 11.8 13.2 14.7 18.5 21.6 24.7 29.1 32.3 35.6 40.6 44.0
20" W/ft 6.4 8.1 9.7 11.3 12.9 14.5 16.1 20.3 23.7 27.0 31.9 35.4 39.0 44.4 48.1
22" W/ft 7.0 8.8 10.5 12.3 14.0 15.8 17.5 22.1 25.7 29.4 34.7 38.5 42.4 48.3 52.3
24" W/ft 7.6 9.5 11.3 13.2 15.1 17.0 18.9 23.8 27.8 31.8 37.4 41.6 45.7 52.2 56.5
NominalPipe Size,
in. (ID)
Temperature Difference Between Pipe and Ambient
DegºF 40ºF 50ºF 60ºF 70ºF 80ºF 90ºF 100ºF 120ºF 140ºF 160ºF 180ºF 200ºF 220ºF 240ºF 260ºF
3” Insulation Thickness
Inst
alla
tion
Tips
•Do
nott
wis
tbus
sw
ires
toge
ther
aten
dof
circ
uit
•In
sula
teal
lcon
duct
ive
part
s
•Se
alal
lele
ctric
alco
nnec
tions
agai
nstm
oist
ure
•Se
alen
dsof
expo
sed
cabl
edu
ring
inst
alla
tion
•Do
note
xpos
eca
bles
tote
mpe
ratu
res
abov
eth
eirm
axim
umra
tings
•In
stal
lcab
lew
ithal
umin
umta
pefo
ruse
onpl
astic
pipe
s
•Lo
cate
ambi
entt
empe
ratu
rese
nsor
sin
cold
est
expe
cted
area
•Lo
cate
pipe
tem
pera
ture
sens
ors
atlo
wes
tex
pect
edlin
ete
mpe
ratu
re
•Us
esu
ffici
entc
able
totra
cead
ditio
nalh
eats
inks
•In
stal
lcab
leso
that
valv
esca
nbe
rem
oved
with
outr
emov
ing
cabl
e
Impo
rtan
tSaf
egua
rds
Mec
hani
calI
nspe
ctio
n
•In
spec
tall
insu
latio
nan
dw
eath
erpr
oofin
g
•In
spec
tall
junc
tion
box,
conn
ectio
nbo
xan
dse
nsor
conn
ectio
ns
•Ve
rify
allc
ircui
tsha
vebe
enpr
oper
lygr
ound
ed
•Ve
rify
allc
ircui
tsar
eco
nnec
ted
inpr
oper
pane
lloc
atio
ns
•Ve
rify
prop
erci
rcui
tbre
aker
sar
ein
plac
e(a
lway
sus
e30
mA
trip
GFI-t
ype
brea
kers
)
•Ve
rify
allc
ircui
tlen
gths
are
with
inm
anuf
actu
rer’s
spec
ified
limits
•Ve
rify
allp
rope
rsaf
ety
war
ning
sar
ein
plac
e
•Ve
rify
alle
ndse
al,s
plic
e/te
elo
catio
nsar
em
arke
don
lagg
ing
Elec
tric
alTe
sts
•In
sula
tion
Resi
stan
ce(M
egge
r)–
Befo
retr
acin
gpi
pes
–Af
teri
nsta
lling
term
inat
ions
–Be
fore
insu
latin
gpi
pes
–Af
teri
nsul
atin
gpi
pes
–Be
fore
ener
gizi
ngsy
stem
•Ci
rcui
tVol
tage
•In
itial
Curr
ent
–No
team
bien
ttem
pan
dpi
pete
mp
•St
abili
zed
Curr
ent(
15m
inut
esof
oper
atio
n)–
Note
ambi
entt
emp
and
pipe
tem
p
•Al
way
sus
egr
ound
faul
tcirc
uitb
reak
ers
(30m
Atr
iple
vel)
Tool
sNe
eded
•W
ireCu
tters
/Str
ippe
rs
•M
egge
r
•Ph
illip
sHe
adSc
rew
driv
er
•St
anda
rdSc
rew
driv
er
•Vo
ltmet
er
•Ut
ility
Knife
•Ha
mm
er
SRL
Cabl
e•
150º
F/6
5o CM
axim
umM
aint
enan
ce
•18
5ºF
/85o C
Max
imum
Expo
sure
•3-
10W
/ft/1
0-33
W/m
•16
AWG
with
Optio
nalT
PEor
Fluo
ropo
lym
erJa
cket
SRM
Cabl
e•
302º
F/1
50o C
Max
imum
Mai
nten
ance
•42
0ºF
/215
o CM
axim
umEx
posu
re
•5-
20W
/ft/1
6-66
W/m
•16
AWG
with
Optio
nalF
luor
opol
ymer
Jack
et
103
Gam
ma
Dri
veP
ittsb
urg
h,P
A15
238
US
AChr
omal
ox®
PR
EC
ISIO
NH
EA
TA
ND
CO
NT
RO
L
Co
pyr
ight
©20
02-2
007,
2009
-201
2,C
hro
mal
ox,
Inc.
All
rig
hts
rese
rved
.
Pho
ne:(
412)
967-
3800
Fax
:(41
2)96
7-51
48To
ll-F
ree:
1-80
0-44
3-26
40
ww
w.c
hro
mal
ox.
com
PJ1
30-6
HEAT
TRAC
ETH
ERM
ALDE
SIGN
SRP
Cabl
e•
225°
F/1
10°C
Mai
nten
ance
Tem
pera
ture
•27
5°F
/135
°CM
axim
umEx
posu
reTe
mpe
ratu
re
•5-
15W
/ft/1
6-49
W/m
•16
AWG
with
Optio
nalF
luor
opol
ymer
Jack
et
Chromalox Cable Selection
1. Select Heating Cable Family: Based on the maximum maintenance temperature rating, maximumexposure temperature rating, and area classification, select the heating cable family from Table 3. (SeeChromalox Heat Trace Cable Product Information Sheets for cable construction options, voltage ratings,and wattage outputs available.)
2. Select Thermal Output Rating:
(a) For Metal Pipes – Use Figures 1, 2 or 4(b) For Plastic Pipes – Use Figure 3 by finding the intersection of the calculated heat loss, QF, and pipe
maintenance temperature, Tm. Select the cable with a thermal output that equals or exceeds QF at Tm.
Pipe Temperature (ºF)Maintenance Temperature
0 10 20 30 50 60 70 80 90 100 110 120 130 140 150
Ther
mal
Out
put
(W/f
t)
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
4.88
SRL10 & HSRL10
SRL8 & HSRL8
SRL5 & HSRL5
SRL3 & HSRL3
Cable OutputversusTemperature
40
Figure 1 SRL & HSRL – Thermal OutputRatings on Insulated Metal Pipe Figure 2 SRM/E & HSRM – Thermal Output
Ratings on Insulated Metal Pipe Figure 3 SRL & HSRL – Thermal Output Ratingson Plastic Pipe with Aluminum Tape
B3. Determine Total Cable Length: In addition to pipe length, in-line components such as valves, flanges,
and pipe supports require additional heat tracing to maintain Tm. See Table 4. Calculate the totalcable length required by combining the pipe length with the additional lengths needed for all theother components.
Table 3 Heating Cable Families
NOTE: It is the responsibility of the facility manager or engineer to determine the classification of an area where heat trace will be installed. The factory can help determine a suitablecable based on the information provided.
Table 4Additional Cable Lengths Required for In-Line ComponentsBased on Pipe IPS (Iron Pipe Size)
1/2 in. 1.00 1.00 1.00 1.00 1.00 1.00 1.00 0.30
3/4 in. 1.50 1.00 1.00 1.00 1.50 1.00 1.00 0.30
1 in. 2.00 1.00 1.00 1.00 1.50 1.00 1.00 0.30
11/2 in. 2.50 1.50 1.50 1.50 2.00 2.00 2.00 0.30
2 in. 2.50 2.00 2.00 2.00 2.00 2.00 2.00 0.30
21/2 in. 2.50 2.00 2.00 2.00 2.00 2.00 2.00 0.30
3 in. 3.00 2.50 2.50 2.50 2.00 2.00 2.00 0.50
4 in. 4.00 3.00 3.00 3.00 2.50 2.50 2.50 0.50
6 in. 5.00 3.50 3.50 3.50 2.50 2.50 2.50 0.80
8 in. 7.00 4.00 4.00 4.00 2.50 2.50 2.50 0.80
10 in. 8.00 4.50 4.50 4.50 3.00 3.00 3.00 0.80
12 in. 9.00 5.00 5.00 5.00 3.00 3.00 3.00 0.80
14 in. 10.00 5.50 5.50 5.50 3.00 3.00 3.00 1.00
16 in. 11.00 6.00 6.00 6.00 3.50 3.50 3.50 1.00
18 in. 12.00 7.00 7.00 7.00 3.50 3.50 3.50 1.00
20 in. 13.00 7.50 7.50 7.50 3.50 3.50 3.50 1.00
22 in. 13.00 7.50 7.50 7.50 3.50 3.50 3.50 1.00
24 in. 15.00 8.00 8.00 8.00 4.00 4.00 4.00 1.00
Piping Size Gate Valve Globe Valve Ball Valve Butterfly Valve Hanger SupportShoe Support Sleeper Support Flange Pair
ft
0 10 20 30 50 60 70 80 90 100 110 120 130 140 15040
Pipe Temperature (ºF)
SRL10 & HSRL10
Ther
mal
Out
put
(W/f
t)
9
8
7
6
5
4
3
2
1
0
SRL8 &HSRL8
SRL5 & HSRL5
SRL3 & HSRL3
Cable OutputversusTemperature
Figure 4 SRP – Thermal Output Ratingson Insulated Metal Pipe
Pipe Temperature (ºF)H
eat
Out
put
(W/f
t)
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
15 W/ft
10 W/ft
5 W/ft
Cable OutputversusTemperature
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230
Heating CableFamily
AreaClassification
PipeMaterial
MaximumMaintenanceTemperature
Maximum ExposureTemperature(Power Off)
Approvals
U.S. Other
SRL(Self-RegulatingLow Temperature)
Ordinary
Plastic/Metal 150ºF / 65ºC 185ºF / 85ºC
UL, CSA, FM GOST, Cenelec,CE, ATEX
Class I, Div.2, Gr. B, C, D CSA, FM, (Gr. A, CSA Only) GOST, Cenelec,CE, ATEX
Class II, Div.2, Gr. E, F, G CSA, FM, (Gr. E, CSA Only) GOST, Cenelec,CE
Class III, Div.2 FM Only GOST, Cenelec,CE, ATEX
SRM/E(Self-RegulatingMediumTemperature)
Ordinary
Metal Only 302ºF / 150ºC 420ºF / 215ºC
UL, CSA, FM GOST, Cenelec,CE, ATEX
Class I Div.2, Gr. A, B, C, D CSA, FM, (Gr. A, CSA Only) GOST, Cenelec,CE, ATEX
Class II, Div.2, Gr. F, G CSA Only GOST, Cenelec,CE, ATEX
SRP(Self-RegulatingMediumTemperature)
Ordinary
Metal Only 225ºF / 110ºC 275ºF / 135ºC UL, CSA, FMPending
GOST, Cenelec, CE,ATEX Pending
Class I, Div.2, Gr. B, C, D
Class II, Div.2, Gr. F, G
Class III
HSRL(H-Self-RegulatingLow Temperature)
Class I, Div.1, Gr. B, C, D
Plastic/Metal 150ºF / 65ºC 185ºF / 85ºC
CSA, FM
Class II, Div.1, Gr. E, F, G CSA, FM
Class III, Div.1 CSA, FM
HSRM(H-Self-RegulatingMediumTemperature)
Class I, Div.1, Gr. B, C, D
Metal Only 302ºF / 150ºC 420ºF / 215ºC
CSA, FM
Class II, Div.1, Gr. E, F, G CSA, FM
Class III, Div.1 CSA, FM
CWM(Constant Wattage)
OrdinaryMetal Only Consult Factory 392ºF / 200ºC
UL, CSA
Hazardous Area, Consult Factory
MI (MineralInsulated)
Ordinary
Metal Only Consult Factory 1,100ºF / 595ºC
CSA, FM
Class I, Div.2, Gr. B, C, D CSA, FM
Class II, Div.2, Gr. E, F, G CSA, FM
Class III CSA, FM
0 50 100 150 200 250 300
Pipe Temperature (ºF)
SRM/E20 &HSRM20
Pow
erO
utp
ut(W
/ft)
24
20
16
12
8
4
0
SRM/E15 &HSRM15
SRM/E10 &HSRM10
SRM/E8 & HSRM8
SRM/E5 & HSRM5
SRM/E3 & HSRM3
Cable OutputversusTemperature
1.
2.
a3.
4.
pIpe HeaT LOSS CaLCuLaTIOnS
Basic Heat Loss: After determining the difference between the ambient and desired pipe maintenance
temperature, Tm, use Table 1 to figure the basic heat loss for the pipe size and insulation thickness.
Calculate QF: Multiply the basic heat loss figure from Table 1 by the adjustment factor from Table 2 to calculate the estimated heat loss, QF, in watts per foot of pipe length.
Correct for Indoor Location/ Wind Speed: If location is indoors, multiply QF by 0.9. Table 1 is based on 10% safety factor and 20 mph wind speed; add 5% margin for each 5 mph over 20 mph wind speed.
Insulation Adjustment: Using Table 2, find the type of insulation being used and its insulation factor.
Insulation Adjustment Factors
B3.1.
2.
CHrOmaLOx CaBLe SeLeCTIOn
Select Heating Cable Family: Based on the maximum maintenance temperature rating, maximum exposure temperature rating, and area classification, select the heating cable family from Table 3. (See Chromalox Heat Trace Cable Product Information Sheets for cable construction options, voltage ratings, and wattage outputs available.)
Determine Total Cable Length: In addition to pipe length, in-line components such as valves, flanges, and pipe supports require additional heat tracing to maintain Tm. See Table 4. Calculate the total cable length required by combining the pipe length with the additional lengths needed for all the other components.
Select Thermal Output Rating:
(a) For Metal Pipes – Use Figures 1, 2 or 4 (b) For Plastic Pipes – Use Figure 3 by finding the intersection of the calculated heat loss, QF, and pipe maintenance temperature, Tm. Select the cable with a thermal output that equals or exceeds QF at Tm.
Table 4Additional Cable Lengths Required for In-Line ComponentsBased on Pipe IPS (Iron Pipe Size)Table 3
Table 1
Table 2
Heating Cable Families
Pipe Heat Loss QP in W/ft Based on Temperature Differential and Insulation Thickness
Inst
alla
tion
Tip
s •
Do n
ot tw
ist b
uss
wire
s to
geth
er a
t end
of c
ircui
t
• In
sula
te a
ll co
nduc
tive
part
s
• Se
al a
ll el
ectri
cal c
onne
ctio
ns a
gain
st m
oist
ure
• Se
al e
nds
of e
xpos
ed c
able
dur
ing
inst
alla
tion
• Do
not
exp
ose
cabl
es to
tem
pera
ture
s ab
ove
thei
r max
imum
ratin
gs
• In
stal
l cab
le w
ith a
lum
inum
tape
for u
se o
n pl
astic
pip
es
• Lo
cate
am
bien
t tem
pera
ture
sen
sors
in c
olde
st e
xpec
ted
area
• Lo
cate
pip
e te
mpe
ratu
re s
enso
rs a
t low
est e
xpec
ted
line
te
mpe
ratu
re
• Us
e su
ffici
ent c
able
to tr
ace
addi
tiona
l hea
t sin
ks
• In
stal
l cab
le s
o th
at v
alve
s ca
n be
rem
oved
with
out r
emov
ing
cabl
e
Impo
rtan
t Saf
egua
rds
Mec
hani
cal I
nspe
ctio
n •
Insp
ect a
ll in
sula
tion
and
wea
ther
proo
fing
• In
spec
t all
junc
tion
box,
con
nect
ion
box,
and
sen
sor c
onne
ctio
ns
• Ve
rify
all c
ircui
ts h
ave
been
pro
perly
gro
unde
d
• Ve
rify
all c
ircui
ts a
re c
onne
cted
in p
rope
r pan
el lo
catio
ns
• Ve
rify
prop
er c
ircui
t bre
aker
s ar
e in
pla
ce (a
lway
s us
e 30
mA
trip
GFI-t
ype
brea
kers
)
• Ve
rify
all c
ircui
t len
gths
are
with
in m
anuf
actu
rer’s
spe
cifie
d lim
its
• Ve
rify
all p
rope
r saf
ety
war
ning
s ar
e in
pla
ce
• Ve
rify
all e
nd s
eal,
splic
e/te
e lo
catio
ns a
re m
arke
d on
lagg
ing
Elec
tric
al T
ests
• In
sula
tion
Resi
stan
ce (M
egge
r) ✓
Bef
ore
traci
ng p
ipes
✓ A
fter i
nsta
lling
term
inat
ions
✓ B
efor
e in
sula
ting
pipe
s
✓ A
fter i
nsul
atin
g pi
pes
✓
Bef
ore
ener
gizin
g sy
stem
• Ci
rcui
t Vol
tage
• In
itial
Cur
rent
✓ N
ote
ambi
ent t
emp
and
pipe
tem
p
• St
abiliz
ed C
urre
nt (1
5 m
inut
es o
f ope
ratio
n)
✓
Not
e am
bien
t tem
p an
d pi
pe te
mp
• Al
way
s us
e gr
ound
faul
t circ
uit b
reak
ers
(30
mA
trip
leve
l)
Tool
s N
eede
d •
Wire
Cut
ters
/Stri
pper
s
• M
egge
r
• Ph
illip
s He
ad S
crew
driv
er
• St
anda
rd S
crew
driv
er
• Vo
ltmet
er
• Ut
ility
Kni
fe
• Ha
mm
er
SrL
Cab
le
• 15
0ºF
/ 65º
C M
axim
um M
aint
enan
ce
• 18
5ºF
/ 85º
C M
axim
um E
xpos
ure
• 3
to 1
0 W
/ft /
10 to
33
W/m
• 16
AW
G w
ith O
ptio
nal T
PE o
r Flu
orop
olym
er J
acke
t
Srp
Cab
le
• 22
5°F
/ 110
°C M
aint
enan
ce T
empe
ratu
re
• 27
5°F
/ 135
°C M
axim
um E
xpos
ure
Tem
pera
ture
• 5
to 1
5 W
/ft /
16 to
49
W/m
• 16
AW
G w
ith O
ptio
nal F
luor
opol
ymer
Jac
ket
Srm
Cab
le
• 30
2ºF
/ 150
ºC M
axim
um M
aint
enan
ce
• 42
0ºF
/ 215
ºC M
axim
um E
xpos
ure
• 5
to 2
0 W
/ft /
16 to
66
W/m
• 16
AW
G w
ith O
ptio
nal F
luor
opol
ymer
Jac
ket
Figure 1 Figure 2 Figure 3 Figure 4SRL & HSRL – Thermal Output Ratings on Insulated Metal Pipe
SRM/E & HSRM – Thermal Output Ratings on Insulated Metal Pipe
SRL & HSRL – Thermal Output Ratings on Plastic Pipe with Aluminum Tape
SRP – Thermal Output Ratings on Insulated Metal Pipe
Pipe Temperature (ºF)
Hea
t O
utp
ut (W
/ft)
21
20
19
18
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
15 W/ft
10 W/ft
5 W/ft
Cable OutputversusTemperature
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230
0 10 20 30 50 60 70 80 90 100 110 120 130 140 15040
Pipe Temperature (ºF)
SRL10 & HSRL10
Ther
mal
Out
put
(W/f
t)
9
8
7
6
5
4
3
2
1
0
SRL8 & HSRL8
SRL5 & HSRL5
SRL3 & HSRL3
Cable OutputversusTemperature
0 50 100 150 200 250 300
Pipe Temperature (ºF)
SRM/E20 & HSRM20
Pow
er O
utp
ut (W
/ft)
24
20
16
12
8
4
0
SRM/E15 & HSRM15
SRM/E10 & HSRM10
SRM/E8 & HSRM8
SRM/E5 & HSRM5
SRM/E3 & HSRM3
Cable OutputversusTemperature
Pipe Temperature (ºF)Maintenance Temperature
0 10 20 30 50 60 70 80 90 100 110 120 130 140 150
Ther
mal
Out
put
(W/f
t)
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
4.88
SRL10 & HSRL10
SRL8 & HSRL8
SRL5 & HSRL5
SRL3 & HSRL3
Cable OutputversusTemperature
40
Metallic Pipe
Fiberglass TapeFT-3
Self RegulatingHeating Cable
Low TemperatureSRL, HSRL, SRF
SRM/E, SRP, HSRM
Self RegulatingHeating Cable
Low TemperatureSRL, HSRL, SRF
SRM/E, SRP, HSRM
Fiberglass TapeFT-3
For multiple heaters placecontrol sensor 90˚ from nearest
heater or centered betweenequally spaced heaters.
ControlSensor
45˚
ThermalInsulation
Top
WeatherproofJacket
Cable located at nominal45˚ below horizontal
centerline.
Cable located at nominal45˚ below horizontal
centerline on either side.
45˚
Top
90˚
Top
45˚
Heating Cable/Sensor LocationSelf RegulatingHeating Cable
Low TemperatureSRL, HSRL, SRF
SRM/E, SRP, HSRM
Pipe Support
3 in. / 75 mm Typical
Step 2Metal Pipe
Support Shoe
Fiberglass TapeFT-3
Step 1
Self Regulating Heating CableLow Temperature SRL, HSRL, SRF
Metallic Pipe
Weatherproof Jacket
Thermal Insulation
Fiberglass TapeFT-3
Self RegulatingHeating Cable
Low TemperatureSRL, HSRL, SRF
SRM/E, SRP, HSRM
Step 1Start tracing at the end of the pipe and work your way back to spool.
Step 3
Metal Pipe
Spool
Metal Pipe
Self Regulating Heating CableLow TemperatureSRL, HSRL, SRF
SRM/E, SRP, HSRMFiberglass Tape
FT-3Fiberglass Tape
FT-3
Step 2Leave a loop of cable at heat sinks such asvalves, pipe supports and flange sets. UseFT-3 fiberglass tape to secure cable to pipeat 18 in. / 455 mm intervals.
PlasticPipe
Self RegulatingHeating Cable
Use Low TemperatureSRL, HSRL, SRF Cable
Aluminum TapeAL-1Plastic Pipe Installation
Note:over heating cable to spr .
Fiberglass TapeFT-3 Fiberglass Tape
FT-3
Heating Cable
Insulation
Pipe Strap
CautionLabels
Ask about Chromalox Class 1 Division 1.Cables & Accessories as well as a full line of High- Temperature Cables.
FOR TECHNICAL SUPPORT CALL 888-996-9258.
Chromalox and the Chromalox logo are trademarks of Chromalox, Inc.Copyright © 2002-2005, 2009-2012, 2015, Chromalox, Inc. All rights reserved.
Quick Install Guide is a specificationtool only. Always refer to properinstallation instructions wheninstalling heat trace cable.
DTS-HAZ Digital ThermoStat / Power Connection Line-
or Ambient-Sensing
UASAmbient-Sensing
UBCLine-Sensing
˚ ˚ ˚ ˚ ˚ ˚
Combination Single Point Temperature Controls & Power Connection Boxes
Installation Tips
ITC Controller
Power Connection Box(UPC)
Above Insulation
(UES)
Below Insulation
(RTES)
Multiple EntryConnection
(UMC)
W
TemperaTure managemenTSOLuTIOnS
Heat tRaCe DeSIGN GUIDe
Copyright © 2002-2007, 2009-2012, 2015, Chromalox, Inc. All rights reserved. Chromalox and the Chromalox logo are trademarks of Chromalox, Inc.
103 Gamma Drive Pittsburgh, PA 15238 USA
Phone: (412) 967-3800 Fax: (412) 967-5148 Toll-Free 1-800-443-2640
www.chromalox.com
PJ130-8
Table2
InsulationAdjustm
entFactors
Insulation
Factor
Pip
e Insulation Typ
eP
ipe Insulatio
n Type
Insulation
Factor
Glass fiber (A
STM
C547)
1.00
Calcium
silicate (AS
TM C
533)
1.48
Cellular glass (A
STM
C552)
1.48
Rigid cellular urethane (A
STM
C591)
0.64
Foamed elastom
er (AS
TM C
534) 1.16
Mineral fib
er blanket (A
STM
C553)
1.16
Expanded
perlite (A
STM
C610)
1.90
1.Basic
HeatLoss:Afterdeterm
iningthe
differencebetw
eenthe
ambientand
desiredpipe
maintenance
temperature,T
m ,useTable
1to
figurethe
basicheatloss
forthepipe
sizeand
insulationthickness.
2.Insulation
Adjustment:
UsingTable
2,findthe
typeofinsulation
beingused
andits
insulationfactor.
Heat Trace Design Guide
APipe
HeatLossCalculations
• Heat Trace System Design
• Materials & Components
• Specification Tables
3.Calculate
QF :
Multiply
thebasic
heatlossfigure
fromTable
1by
theadjustm
entfactorfromTable
2to
calculatethe
estimated
heatloss,QF ,in
watts
perfootofpipelength.
4.CorrectforIndoorLocation/W
indSpeed:
Iflocationis
indoors,multiply
QF by
0.9.Table
1is
basedon
10%safety
factorand20
mph
wind
speed;add5%
margin
foreach5
mph
over20m
phw
indspeed.
Table1
PipeHeatLoss
QP in
W/ftBased
onTem
peratureDifferentialand
InsulationThickness
Nominal
PipeSize,
in.(ID)
Temperature
DifferenceBetw
eenPipe
andAm
bient
DegºF40ºF
50ºF60ºF
70ºF80ºF
90ºF100ºF
120ºF140ºF
160ºF180ºF
200ºF220ºF
240ºF260ºF
1"Insulation
Thickness1/ 2"
W/ft
1.41.8
2.12.5
2.83.2
3.54.2
5.15.9
6.67.7
8.59.2
10.03/ 4"
W/ft
1.62.0
2.42.8
3.23.6
4.04.8
5.96.7
7.68.8
9.710.6
11.4
1"W
/ft1.8
2.32.8
3.23.7
4.14.6
5.56.8
7.78.7
10.111.1
12.113.2
11/ 2"
W/ft
2.43.1
3.74.3
4.95.5
6.17.3
9.010.2
11.513.4
14.816.1
17.4
2"W
/ft2.8
3.54.1
4.85.5
6.26.9
8.310.1
11.613.0
15.216.7
18.219.7
21/ 2"
W/ft
3.24.0
4.85.6
6.47.2
8.09.6
11.813.4
15.117.6
19.421.1
22.9
3"W
/ft3.7
4.75.6
6.57.4
8.49.3
11.213.7
15.617.6
20.522.5
24.626.6
4"W
/ft4.6
5.86.9
8.19.2
10.411.5
13.816.9
19.321.7
25.327.8
30.432.9
6"W
/ft6.4
8.09.6
11.212.8
14.416.0
19.223.5
26.930.2
35.238.7
42.245.8
8"W
/ft8.1
10.112.1
14.116.2
18.220.2
24.229.7
33.938.2
44.448.9
53.357.8
10"W
/ft9.9
12.414.8
17.319.8
22.224.7
29.636.3
41.546.7
54.359.8
65.270.6
12"W
/ft11.6
14.517.4
20.323.2
26.129.0
34.842.6
48.754.8
63.870.2
76.682.9
14"W
/ft12.6
15.819.0
22.125.3
28.431.6
37.946.5
53.159.7
69.576.5
83.490.4
16"W
/ft14.3
17.921.5
25.128.7
32.335.9
43.052.7
60.267.8
78.986.8
94.6102.5
18"W
/ft16.0
20.124.1
28.132.1
36.140.1
48.158.9
67.475.8
88.297.0
105.9114.7
20"W
/ft17.7
22.226.6
31.035.4
39.944.3
53.265.1
74.483.7
97.5107.2
117.0126.7
22"W
/ft19.4
24.329.1
34.038.8
43.748.5
58.271.3
81.591.7
106.7117.4
128.0138.7
24"W
/ft21.1
26.431.6
36.942.2
47.452.7
63.277.5
88.599.6
115.9127.5
139.1150.7
1.5"Insulation
Thickness1/ 2"
W/ft
1.11.4
1.72.0
2.22.5
2.83.5
4.14.7
5.56.2
6.87.4
8.03/ 4"
W/ft
1.21.6
1.92.2
2.52.8
3.13.9
4.65.2
6.16.8
7.58.2
8.9
1"W
/ft1.4
1.82.2
2.52.9
3.23.6
4.55.3
6.07.1
7.98.7
9.510.3
11/ 2"
W/ft
1.82.3
2.83.2
3.74.1
4.65.8
6.87.7
9.110.1
11.112.1
13.2
2"W
/ft2.1
2.63.1
3.64.2
4.75.2
6.67.6
8.710.3
11.412.6
13.714.9
21/ 2"
W/ft
2.43.0
3.54.1
4.75.3
5.97.4
8.79.9
11.713.0
14.315.6
16.9
3"W
/ft2.7
3.44.1
4.85.4
6.16.8
8.610.0
11.413.5
15.016.5
18.019.4
4"W
/ft3.3
4.25.0
5.86.6
7.58.3
10.512.2
13.916.4
18.320.1
21.923.7
6"W
/ft4.5
5.76.8
7.99.0
10.211.3
14.216.6
19.022.4
24.927.3
29.832.3
8"W
/ft5.6
7.18.5
9.911.3
12.714.1
17.820.7
23.727.9
31.034.1
37.240.3
10"W
/ft6.8
8.010.3
12.013.7
15.417.1
21.525.1
28.733.9
37.641.4
45.148.9
12"W
/ft8.0
10.012.0
14.016.0
18.020.0
25.229.4
33.639.6
44.048.4
52.857.2
14"W
/ft8.7
10.913.0
15.217.4
19.521.7
27.331.9
36.543.0
47.752.5
57.362.1
16"W
/ft9.8
12.314.8
17.219.7
22.124.6
31.036.2
41.348.7
54.159.5
64.970.4
18"W
/ft11.0
13.716.4
19.221.9
24.727.4
34.540.3
46.054.3
60.366.3
72.378.4
20"W
/ft12.1
15.118.1
21.124.2
27.230.2
38.144.4
50.759.8
66.473.1
79.786.4
22"W
/ft13.2
16.519.8
23.126.4
29.733.0
41.648.5
55.465.3
72.679.9
87.194.4
24"W
/ft14.3
17.921.5
25.128.6
32.235.8
45.152.6
60.170.9
78.886.6
94.5102.4
2"Insulation
Thickness1/ 2"
W/ft
1.01.2
1.41.7
1.92.2
2.43.0
3.54.0
4.85.3
5.86.3
7.23/ 4"
W/ft
1.11.4
1.61.9
2.22.4
2.73.4
4.04.5
5.35.9
6.57.1
8.1
1"W
/ft1.2
1.51.8
2.12.4
2.73.0
3.84.4
5.05.9
6.67.3
7.99.0
11/ 2"
W/ft
1.51.9
2.32.7
3.03.4
3.84.8
5.66.4
7.58.4
9.210.0
11.4
2"W
/ft1.7
2.22.6
3.03.4
3.94.3
5.46.3
7.28.5
9.510.4
11.412.9
21/ 2"
W/ft
1.92.4
2.93.4
3.84.3
4.86.0
7.18.1
9.510.6
11.612.7
14.4
3"W
/ft2.2
2.83.3
3.94.4
5.05.5
6.98.1
9.210.9
12.113.3
14.516.4
4"W
/ft2.6
3.34.0
4.65.3
5.96.6
8.39.7
11.113.1
14.516.0
17.419.7
6"W
/ft3.6
4.55.3
6.27.1
8.08.9
11.213.1
15.017.6
19.621.5
23.526.6
8"W
/ft4.4
5.66.7
7.88.9
10.011.1
14.016.3
18.622.0
24.426.9
29.333.2
10"W
/ft5.3
6.78.0
9.310.6
12.013.3
16.819.6
22.326.3
29.332.2
35.139.8
12"W
/ft6.2
7.89.3
10.912.4
14.015.5
19.522.8
26.030.7
34.137.5
40.946.3
14"W
/ft6.7
8.410.1
11.813.4
15.116.8
21.224.7
28.233.3
37.040.7
44.450.2
16"W
/ft7.6
9.511.3
13.215.1
17.018.9
23.827.8
31.837.4
41.645.7
49.956.5
18"W
/ft8.4
10.512.6
14.716.8
18.921.0
26.530.9
35.341.6
46.250.8
55.462.8
20"W
/ft9.2
11.613.9
16.218.5
20.823.1
29.134.0
38.845.7
50.855.9
61.069.1
22"W
/ft10.1
12.615.2
17.720.2
22.725.3
31.837.1
42.450.0
55.661.1
66.775.5
24"W
/ft11.0
13.716.4
19.221.9
24.727.4
34.540.3
46.054.3
60.366.3
72.381.9
609.6m
mW
/m36.1
44.953.8
63.071.9
3"(76.2
mm
)InsulationThickness
1/ 2"W
/ft0.8
1.01.2
1.41.6
1.82.0
2.52.9
3.44.0
4.44.8
5.56.0
3/ 4"W
/ft0.9
1.11.3
1.51.8
2.02.2
2.83.2
3.74.4
4.85.3
6.16.67
1"W
/ft1.0
1.31.5
1.82.0
2.32.5
3.23.7
4.25.0
5.56.1
6.97.5
11/ 2"
W/ft
1.21.5
1.82.1
2.42.7
3.03.8
4.45.0
5.96.6
7.38.3
9.0
2"W
/ft1.3
1.72.0
2.32.6
3.03.3
4.24.9
5.56.5
7.38.0
9.19.9
21/ 2"
W/ft
1.51.9
2.22.6
3.03.3
3.74.7
5.46.2
7.38.1
9.010.2
11.1
3"W
/ft1.7
2.12.5
2.93.4
3.84.2
5.36.2
7.18.3
9.210.2
11.612.6
4"W
/ft2.0
2.53.0
3.54.0
4.55.0
6.37.4
8.49.9
11.012.1
13.815.0
6"W
/ft2.6
3.33.9
4.65.2
5.96.5
8.29.6
10.912.9
14.315.7
17.919.4
8"W
/ft3.2
4.04.8
5.66.4
7.28.0
10.111.8
13.415.8
17.619.4
22.123.9
10"W
/ft3.8
4.85.7
6.77.6
8.69.5
12.014.0
16.018.8
20.923.0
26.228.4
12"W
/ft4.4
5.56.5
7.68.7
9.810.9
13.716.0
18.321.6
24.026.4
30.132.6
14"W
/ft4.7
5.97.1
8.39.4
10.611.8
14.917.3
19.823.4
26.028.6
32.635.3
16"W
/ft5.3
6.78.0
9.310.6
12.013.3
16.819.6
22.326.3
29.332.2
36.739.8
18”W
/ft5.9
7.48.8
10.311.8
13.214.7
18.521.6
24.729.1
32.335.6
40.644.0
20"W
/ft6.4
8.19.7
11.312.9
14.516.1
20.323.7
27.031.9
35.439.0
44.448.1
22"W
/ft7.0
8.810.5
12.314.0
15.817.5
22.125.7
29.434.7
38.542.4
48.352.3
24"W
/ft7.6
9.511.3
13.215.1
17.018.9
23.827.8
31.837.4
41.645.7
52.256.5
Nominal
PipeSize,
in.(ID)
Temperature
DifferenceBetw
eenPipe
andAm
bient
DegºF40ºF
50ºF60ºF
70ºF80ºF
90ºF100ºF
120ºF140ºF
160ºF180ºF
200ºF220ºF
240ºF260ºF
3”Insulation
Thickness
Installation Tips• Do not twist buss wires together at end
of circuit
• Insulate all conductive parts
• Seal all electrical connections against moisture
• Seal ends of exposed cable during installation
• Do not expose cables to temperatures abovetheir maximum ratings
• Install cable with aluminum tape for useon plastic pipes
• Locate ambient temperature sensors in coldestexpected area
• Locate pipe temperature sensors at lowestexpected line temperature
• Use sufficient cable to trace additional heat sinks
• Install cable so that valves can be removedwithout removing cable
Important SafeguardsMechanical Inspection
• Inspect all insulation and weatherproofing
• Inspect all junction box, connection box andsensor connections
• Verify all circuits have been properlygrounded
• Verify all circuits are connected in properpanel locations
• Verify proper circuit breakers are in place(always use 30mA trip GFI-type breakers)
• Verify all circuit lengths are within manufacturer’sspecified limits
• Verify all proper safety warnings are in place
• Verify all end seal, splice/tee locations are markedon lagging
Electrical Tests
• Insulation Resistance (Megger)– Before tracing pipes– After installing terminations– Before insulating pipes– After insulating pipes– Before energizing system
• Circuit Voltage
• Initial Current– Note ambient temp and pipe temp
• Stabilized Current (15 minutes of operation)– Note ambient temp and pipe temp
• Always use ground fault circuit breakers(30mA trip level)
Tools Needed• Wire Cutters/Strippers
• Megger
• Phillips Head Screwdriver
• Standard Screwdriver
• Voltmeter
• Utility Knife
• Hammer
SRL Cable• 150ºF / 65oC Maximum Maintenance
• 185ºF / 85oC Maximum Exposure
• 3-10 W/ft / 10-33 W/m
• 16 AWG with Optional TPE orFluoropolymer Jacket
SRM Cable• 302ºF / 150oC Maximum Maintenance
• 420ºF / 215oC Maximum Exposure
• 5-20 W/ft / 16-66 W/m
• 16 AWG with Optional Fluoropolymer Jacket
103 Gamma DrivePittsburgh, PA 15238USA
Chromalox®
PRECISION HEAT AND CONTROL
Copyright © 2002-2007, 2009-2012, Chromalox, Inc. All rights reserved.
Phone: (412) 967-3800Fax: (412) 967-5148Toll-Free: 1-800-443-2640
www.chromalox.com
PJ130-6
HEAT TRACE THERMAL DESIGN
SRP Cable• 225°F / 110°C Maintenance Temperature
• 275°F / 135°C Maximum Exposure Temperature
• 5-15 W/ft / 16-49 W/m
• 16 AWG with Optional Fluoropolymer Jacket
Chromalox
CableSelection
1.SelectHeating
CableFam
ily:Based
onthe
maxim
umm
aintenancetem
peraturerating,m
aximum
exposuretem
peraturerating,and
areaclassification,selectthe
heatingcable
family
fromTable
3.(SeeChrom
aloxHeatTrace
CableProductInform
ationSheets
forcableconstruction
options,voltageratings,
andw
attageoutputs
available.)
2.SelectTherm
alOutputRating:
(a)ForMetalPipes
–Use
Figures1,2
or4(b)ForPlastic
Pipes–
UseFigure
3by
findingthe
intersectionofthe
calculatedheatloss,Q
F ,andpipe
maintenance
temperature,T
m .Selectthecable
with
atherm
aloutputthatequalsorexceeds
QF atT
m .
Pip
eTem
perature
(ºF)M
aintenanceTem
perature
010
2030
5060
7080
90100
110120
130140
150
Thermal Output (W/ft)
14131211109876543210
4.88
SRL10&
HSRL10
SRL8&
HSRL8
SRL5&
HSRL5
SRL3&
HSRL3
CableOutput
versusTem
perature
40
Figure1
SRL&
HSRL–
ThermalOutput
Ratingson
InsulatedM
etalPipeFigure
2SRM
/E&
HSRM–
ThermalOutput
Ratingson
InsulatedM
etalPipeFigure
3SRL
&HSRL
–Therm
alOutputRatingson
PlasticPipe
with
Aluminum
Tape
B3.
Determine
TotalCableLength:
Inaddition
topipe
length,in-linecom
ponentssuch
asvalves,flanges,
andpipe
supportsrequire
additionalheattracingto
maintain
Tm .
SeeTable
4.Calculatethe
totalcable
lengthrequired
bycom
biningthe
pipelength
with
theadditionallengths
neededforallthe
othercomponents.
Table3
HeatingCable
Families
NOTE:Itis
theresponsibility
ofthefacility
managerorengineerto
determine
theclassification
ofanarea
where
heattracew
illbeinstalled.The
factorycan
helpdeterm
inea
suitablecable
basedon
theinform
ationprovided.
Table4
AdditionalCableLengths
Requiredfor
In-LineCom
ponentsBased
onPipe
IPS(Ir on
PipeSize)
1/ 2 in.1.00
1.001.00
1.001.00
1.001.00
0.30
3/ 4 in.1.50
1.001.00
1.001.50
1.001.00
0.30
1in.
2.001.00
1.001.00
1.501.00
1.000.30
11/ 2 in.
2.501.50
1.501.50
2.002.00
2.000.30
2in.
2.502.00
2.002.00
2.002.00
2.000.30
21/ 2 in.
2.502.00
2.002.00
2.002.00
2.000.30
3in.
3.002.50
2.502.50
2.002.00
2.000.50
4in.
4.003.00
3.003.00
2.502.50
2.500.50
6in.
5.003.50
3.503.50
2.502.50
2.500.80
8in.
7.004.00
4.004.00
2.502.50
2.500.80
10in.
8.004.50
4.504.50
3.003.00
3.000.80
12in.
9.005.00
5.005.00
3.003.00
3.000.80
14in.
10.005.50
5.505.50
3.003.00
3.001.00
16in.
11.006.00
6.006.00
3.503.50
3.501.00
18in.
12.007.00
7.007.00
3.503.50
3.501.00
20in.
13.007.50
7.507.50
3.503.50
3.501.00
22in.
13.007.50
7.507.50
3.503.50
3.501.00
24in.
15.008.00
8.008.00
4.004.00
4.001.00
PipingSize
GateValve
GlobeValve
BallValveButterfly
ValveHanger
SupportShoe
SupportSleeperSupport
FlangePair
ft
010
2030
5060
7080
90100
110120
130140
15040
Pip
eTem
perature
(ºF)
SRL10&
HSRL10
Thermal Output (W/ft)
9876543210
SRL8&
HSRL8SRL5&
HSRL5
SRL3&
HSRL3
CableOutput
versusTem
perature
Figure4
SRP–
ThermalOutputRatings
onInsulated
MetalPipe
Pip
eTem
perature
(ºF)
Heat Output (W/ft)
2120191817161514131211109876543210
15W
/ft
10W
/ft
5W
/ft
CableOutput
versusTem
perature
010
2030
4050
6070
8090
100110
120130
140150
160170
180190
200210
220230
HeatingCable
Family
AreaClassification
PipeM
aterial
Maxim
umM
aintenanceTem
perature
Maxim
umExposure
Temperature
(PowerOff)
Approvals
U.S.Other
SRL(Self-RegulatingLow
Temperature)
Ordinary
Plastic/Metal
150ºF/65ºC
185ºF/85ºC
UL,CSA,FMGOST,Cenelec,CE,ATEX
ClassI,Div.2,Gr.B,C,D
CSA,FM,(Gr.A,CSA
Only)GOST,Cenelec,CE,ATEX
ClassII,Div.2,Gr.E,F,G
CSA,FM,(Gr.E,CSA
Only)GOST,Cenelec,CE
ClassIII,Div.2
FMOnly
GOST,Cenelec,CE,ATEX
SRM/E
(Self-RegulatingM
ediumTem
perature)
Ordinary
MetalOnly
302ºF/150ºC
420ºF/215ºC
UL,CSA,FMGOST,Cenelec,CE,ATEX
ClassIDiv.2,Gr.A,B,C,D
CSA,FM,(Gr.A,CSA
Only)GOST,Cenelec,CE,ATEX
ClassII,Div.2,Gr.F,G
CSAOnly
GOST,Cenelec,CE,ATEX
SRP(Self-RegulatingM
ediumTem
perature)
Ordinary
MetalOnly
225ºF/110ºC
275ºF/135ºC
UL,CSA,FMPending
GOST,Cenelec,CE,ATEX
Pending
ClassI,Div.2,Gr.B,C,D
ClassII,Div.2,Gr.
F,G
ClassIII
HSRL(H-Self-RegulatingLow
Temperature)
ClassI,Div.1,Gr.B,C,D
Plastic/Metal
150ºF/65ºC
185ºF/85ºC
CSA,FM
ClassII,Div.1,Gr.E,F,G
CSA,FM
ClassIII,Div.1
CSA,FM
HSRM(H-Self-RegulatingM
ediumTem
perature)
ClassI,Div.1,Gr.B,C,D
MetalOnly
302ºF/150ºC
420ºF/215ºC
CSA,FM
ClassII,Div.1,Gr.E,F,G
CSA,FM
ClassIII,Div.1
CSA,FM
CWM
(ConstantWattage)
OrdinaryM
etalOnlyConsultFactory
392ºF/200ºC
UL,CSA
HazardousArea,ConsultFactory
MI(M
ineralInsulated)
Ordinary
MetalOnly
ConsultFactory1,100ºF
/595ºC
CSA,FM
ClassI,Div.2,Gr.B,C,D
CSA,FM
ClassII,Div.2,Gr.E,F,G
CSA,FM
ClassIII
CSA,FM
050
100150
200250
300
Pip
eTem
perature
(ºF)
SRM/E20
&HSRM
20
Power Output (W/ft)
24201612840
SRM/E15
&HSRM
15
SRM/E10
&HSRM
10
SRM/E8
&HSRM
8
SRM/E5
&HSRM
5
SRM/E3
&HSRM
3
CableOutput
versusTem
perature
Table2
InsulationAdjustm
entFactors
Insulation
Factor
Pip
e Insulation Typ
eP
ipe Insulatio
n Type
Insulation
Factor
Glass fiber (A
STM
C547)
1.00
Calcium
silicate (AS
TM C
533)
1.48
Cellular glass (A
STM
C552)
1.48
Rigid cellular urethane (A
STM
C591)
0.64
Foamed elastom
er (AS
TM C
534) 1.16
Mineral fib
er blanket (A
STM
C553)
1.16
Expanded
perlite (A
STM
C610)
1.90
1.Basic
HeatLoss:Afterdeterm
iningthe
differencebetw
eenthe
ambientand
desiredpipe
maintenance
temperature,T
m ,useTable
1to
figurethe
basicheatloss
forthepipe
sizeand
insulationthickness.
2.Insulation
Adjustment:
UsingTable
2,findthe
typeofinsulation
beingused
andits
insulationfactor.
Heat Trace Design Guide
APipe
HeatLossCalculations
• Heat Trace System Design
• Materials & Components
• Specification Tables
3.Calculate
QF :
Multiply
thebasic
heatlossfigure
fromTable
1by
theadjustm
entfactorfromTable
2to
calculatethe
estimated
heatloss,QF ,in
watts
perfootofpipelength.
4.CorrectforIndoorLocation/W
indSpeed:
Iflocationis
indoors,multiply
QF by
0.9.Table
1is
basedon
10%safety
factorand20
mph
wind
speed;add5%
margin
foreach5
mph
over20m
phw
indspeed.
Table1
PipeHeatLoss
QP in
W/ftBased
onTem
peratureDifferentialand
InsulationThickness
Nominal
PipeSize,
in.(ID)
Temperature
DifferenceBetw
eenPipe
andAm
bient
DegºF40ºF
50ºF60ºF
70ºF80ºF
90ºF100ºF
120ºF140ºF
160ºF180ºF
200ºF220ºF
240ºF260ºF
1"Insulation
Thickness1/ 2"
W/ft
1.41.8
2.12.5
2.83.2
3.54.2
5.15.9
6.67.7
8.59.2
10.03/ 4"
W/ft
1.62.0
2.42.8
3.23.6
4.04.8
5.96.7
7.68.8
9.710.6
11.4
1"W
/ft1.8
2.32.8
3.23.7
4.14.6
5.56.8
7.78.7
10.111.1
12.113.2
11/ 2"
W/ft
2.43.1
3.74.3
4.95.5
6.17.3
9.010.2
11.513.4
14.816.1
17.4
2"W
/ft2.8
3.54.1
4.85.5
6.26.9
8.310.1
11.613.0
15.216.7
18.219.7
21/ 2"
W/ft
3.24.0
4.85.6
6.47.2
8.09.6
11.813.4
15.117.6
19.421.1
22.9
3"W
/ft3.7
4.75.6
6.57.4
8.49.3
11.213.7
15.617.6
20.522.5
24.626.6
4"W
/ft4.6
5.86.9
8.19.2
10.411.5
13.816.9
19.321.7
25.327.8
30.432.9
6"W
/ft6.4
8.09.6
11.212.8
14.416.0
19.223.5
26.930.2
35.238.7
42.245.8
8"W
/ft8.1
10.112.1
14.116.2
18.220.2
24.229.7
33.938.2
44.448.9
53.357.8
10"W
/ft9.9
12.414.8
17.319.8
22.224.7
29.636.3
41.546.7
54.359.8
65.270.6
12"W
/ft11.6
14.517.4
20.323.2
26.129.0
34.842.6
48.754.8
63.870.2
76.682.9
14"W
/ft12.6
15.819.0
22.125.3
28.431.6
37.946.5
53.159.7
69.576.5
83.490.4
16"W
/ft14.3
17.921.5
25.128.7
32.335.9
43.052.7
60.267.8
78.986.8
94.6102.5
18"W
/ft16.0
20.124.1
28.132.1
36.140.1
48.158.9
67.475.8
88.297.0
105.9114.7
20"W
/ft17.7
22.226.6
31.035.4
39.944.3
53.265.1
74.483.7
97.5107.2
117.0126.7
22"W
/ft19.4
24.329.1
34.038.8
43.748.5
58.271.3
81.591.7
106.7117.4
128.0138.7
24"W
/ft21.1
26.431.6
36.942.2
47.452.7
63.277.5
88.599.6
115.9127.5
139.1150.7
1.5"Insulation
Thickness1/ 2"
W/ft
1.11.4
1.72.0
2.22.5
2.83.5
4.14.7
5.56.2
6.87.4
8.03/ 4"
W/ft
1.21.6
1.92.2
2.52.8
3.13.9
4.65.2
6.16.8
7.58.2
8.9
1"W
/ft1.4
1.82.2
2.52.9
3.23.6
4.55.3
6.07.1
7.98.7
9.510.3
11/ 2"
W/ft
1.82.3
2.83.2
3.74.1
4.65.8
6.87.7
9.110.1
11.112.1
13.2
2"W
/ft2.1
2.63.1
3.64.2
4.75.2
6.67.6
8.710.3
11.412.6
13.714.9
21/ 2"
W/ft
2.43.0
3.54.1
4.75.3
5.97.4
8.79.9
11.713.0
14.315.6
16.9
3"W
/ft2.7
3.44.1
4.85.4
6.16.8
8.610.0
11.413.5
15.016.5
18.019.4
4"W
/ft3.3
4.25.0
5.86.6
7.58.3
10.512.2
13.916.4
18.320.1
21.923.7
6"W
/ft4.5
5.76.8
7.99.0
10.211.3
14.216.6
19.022.4
24.927.3
29.832.3
8"W
/ft5.6
7.18.5
9.911.3
12.714.1
17.820.7
23.727.9
31.034.1
37.240.3
10"W
/ft6.8
8.010.3
12.013.7
15.417.1
21.525.1
28.733.9
37.641.4
45.148.9
12"W
/ft8.0
10.012.0
14.016.0
18.020.0
25.229.4
33.639.6
44.048.4
52.857.2
14"W
/ft8.7
10.913.0
15.217.4
19.521.7
27.331.9
36.543.0
47.752.5
57.362.1
16"W
/ft9.8
12.314.8
17.219.7
22.124.6
31.036.2
41.348.7
54.159.5
64.970.4
18"W
/ft11.0
13.716.4
19.221.9
24.727.4
34.540.3
46.054.3
60.366.3
72.378.4
20"W
/ft12.1
15.118.1
21.124.2
27.230.2
38.144.4
50.759.8
66.473.1
79.786.4
22"W
/ft13.2
16.519.8
23.126.4
29.733.0
41.648.5
55.465.3
72.679.9
87.194.4
24"W
/ft14.3
17.921.5
25.128.6
32.235.8
45.152.6
60.170.9
78.886.6
94.5102.4
2"Insulation
Thickness1/ 2"
W/ft
1.01.2
1.41.7
1.92.2
2.43.0
3.54.0
4.85.3
5.86.3
7.23/ 4"
W/ft
1.11.4
1.61.9
2.22.4
2.73.4
4.04.5
5.35.9
6.57.1
8.1
1"W
/ft1.2
1.51.8
2.12.4
2.73.0
3.84.4
5.05.9
6.67.3
7.99.0
11/ 2"
W/ft
1.51.9
2.32.7
3.03.4
3.84.8
5.66.4
7.58.4
9.210.0
11.4
2"W
/ft1.7
2.22.6
3.03.4
3.94.3
5.46.3
7.28.5
9.510.4
11.412.9
21/ 2"
W/ft
1.92.4
2.93.4
3.84.3
4.86.0
7.18.1
9.510.6
11.612.7
14.4
3"W
/ft2.2
2.83.3
3.94.4
5.05.5
6.98.1
9.210.9
12.113.3
14.516.4
4"W
/ft2.6
3.34.0
4.65.3
5.96.6
8.39.7
11.113.1
14.516.0
17.419.7
6"W
/ft3.6
4.55.3
6.27.1
8.08.9
11.213.1
15.017.6
19.621.5
23.526.6
8"W
/ft4.4
5.66.7
7.88.9
10.011.1
14.016.3
18.622.0
24.426.9
29.333.2
10"W
/ft5.3
6.78.0
9.310.6
12.013.3
16.819.6
22.326.3
29.332.2
35.139.8
12"W
/ft6.2
7.89.3
10.912.4
14.015.5
19.522.8
26.030.7
34.137.5
40.946.3
14"W
/ft6.7
8.410.1
11.813.4
15.116.8
21.224.7
28.233.3
37.040.7
44.450.2
16"W
/ft7.6
9.511.3
13.215.1
17.018.9
23.827.8
31.837.4
41.645.7
49.956.5
18"W
/ft8.4
10.512.6
14.716.8
18.921.0
26.530.9
35.341.6
46.250.8
55.462.8
20"W
/ft9.2
11.613.9
16.218.5
20.823.1
29.134.0
38.845.7
50.855.9
61.069.1
22"W
/ft10.1
12.615.2
17.720.2
22.725.3
31.837.1
42.450.0
55.661.1
66.775.5
24"W
/ft11.0
13.716.4
19.221.9
24.727.4
34.540.3
46.054.3
60.366.3
72.381.9
609.6m
mW
/m36.1
44.953.8
63.071.9
3"(76.2
mm
)InsulationThickness
1/ 2"W
/ft0.8
1.01.2
1.41.6
1.82.0
2.52.9
3.44.0
4.44.8
5.56.0
3/ 4"W
/ft0.9
1.11.3
1.51.8
2.02.2
2.83.2
3.74.4
4.85.3
6.16.67
1"W
/ft1.0
1.31.5
1.82.0
2.32.5
3.23.7
4.25.0
5.56.1
6.97.5
11/ 2"
W/ft
1.21.5
1.82.1
2.42.7
3.03.8
4.45.0
5.96.6
7.38.3
9.0
2"W
/ft1.3
1.72.0
2.32.6
3.03.3
4.24.9
5.56.5
7.38.0
9.19.9
21/ 2"
W/ft
1.51.9
2.22.6
3.03.3
3.74.7
5.46.2
7.38.1
9.010.2
11.1
3"W
/ft1.7
2.12.5
2.93.4
3.84.2
5.36.2
7.18.3
9.210.2
11.612.6
4"W
/ft2.0
2.53.0
3.54.0
4.55.0
6.37.4
8.49.9
11.012.1
13.815.0
6"W
/ft2.6
3.33.9
4.65.2
5.96.5
8.29.6
10.912.9
14.315.7
17.919.4
8"W
/ft3.2
4.04.8
5.66.4
7.28.0
10.111.8
13.415.8
17.619.4
22.123.9
10"W
/ft3.8
4.85.7
6.77.6
8.69.5
12.014.0
16.018.8
20.923.0
26.228.4
12"W
/ft4.4
5.56.5
7.68.7
9.810.9
13.716.0
18.321.6
24.026.4
30.132.6
14"W
/ft4.7
5.97.1
8.39.4
10.611.8
14.917.3
19.823.4
26.028.6
32.635.3
16"W
/ft5.3
6.78.0
9.310.6
12.013.3
16.819.6
22.326.3
29.332.2
36.739.8
18”W
/ft5.9
7.48.8
10.311.8
13.214.7
18.521.6
24.729.1
32.335.6
40.644.0
20"W
/ft6.4
8.19.7
11.312.9
14.516.1
20.323.7
27.031.9
35.439.0
44.448.1
22"W
/ft7.0
8.810.5
12.314.0
15.817.5
22.125.7
29.434.7
38.542.4
48.352.3
24"W
/ft7.6
9.511.3
13.215.1
17.018.9
23.827.8
31.837.4
41.645.7
52.256.5
Nominal
PipeSize,
in.(ID)
Temperature
DifferenceBetw
eenPipe
andAm
bient
DegºF40ºF
50ºF60ºF
70ºF80ºF
90ºF100ºF
120ºF140ºF
160ºF180ºF
200ºF220ºF
240ºF260ºF
3”Insulation
Thickness
Installation Tips• Do not twist buss wires together at end
of circuit
• Insulate all conductive parts
• Seal all electrical connections against moisture
• Seal ends of exposed cable during installation
• Do not expose cables to temperatures abovetheir maximum ratings
• Install cable with aluminum tape for useon plastic pipes
• Locate ambient temperature sensors in coldestexpected area
• Locate pipe temperature sensors at lowestexpected line temperature
• Use sufficient cable to trace additional heat sinks
• Install cable so that valves can be removedwithout removing cable
Important SafeguardsMechanical Inspection
• Inspect all insulation and weatherproofing
• Inspect all junction box, connection box andsensor connections
• Verify all circuits have been properlygrounded
• Verify all circuits are connected in properpanel locations
• Verify proper circuit breakers are in place(always use 30mA trip GFI-type breakers)
• Verify all circuit lengths are within manufacturer’sspecified limits
• Verify all proper safety warnings are in place
• Verify all end seal, splice/tee locations are markedon lagging
Electrical Tests
• Insulation Resistance (Megger)– Before tracing pipes– After installing terminations– Before insulating pipes– After insulating pipes– Before energizing system
• Circuit Voltage
• Initial Current– Note ambient temp and pipe temp
• Stabilized Current (15 minutes of operation)– Note ambient temp and pipe temp
• Always use ground fault circuit breakers(30mA trip level)
Tools Needed• Wire Cutters/Strippers
• Megger
• Phillips Head Screwdriver
• Standard Screwdriver
• Voltmeter
• Utility Knife
• Hammer
SRL Cable• 150ºF / 65oC Maximum Maintenance
• 185ºF / 85oC Maximum Exposure
• 3-10 W/ft / 10-33 W/m
• 16 AWG with Optional TPE orFluoropolymer Jacket
SRM Cable• 302ºF / 150oC Maximum Maintenance
• 420ºF / 215oC Maximum Exposure
• 5-20 W/ft / 16-66 W/m
• 16 AWG with Optional Fluoropolymer Jacket
103 Gamma DrivePittsburgh, PA 15238USA
Chromalox®
PRECISION HEAT AND CONTROL
Copyright © 2002-2007, 2009-2012, Chromalox, Inc. All rights reserved.
Phone: (412) 967-3800Fax: (412) 967-5148Toll-Free: 1-800-443-2640
www.chromalox.com
PJ130-6
HEAT TRACE THERMAL DESIGN
SRP Cable• 225°F / 110°C Maintenance Temperature
• 275°F / 135°C Maximum Exposure Temperature
• 5-15 W/ft / 16-49 W/m
• 16 AWG with Optional Fluoropolymer Jacket
Chromalox
CableSelection
1.SelectHeating
CableFam
ily:Based
onthe
maxim
umm
aintenancetem
peraturerating,m
aximum
exposuretem
peraturerating,and
areaclassification,selectthe
heatingcable
family
fromTable
3.(SeeChrom
aloxHeatTrace
CableProductInform
ationSheets
forcableconstruction
options,voltageratings,
andw
attageoutputs
available.)
2.SelectTherm
alOutputRating:
(a)ForMetalPipes
–Use
Figures1,2
or4(b)ForPlastic
Pipes–
UseFigure
3by
findingthe
intersectionofthe
calculatedheatloss,Q
F ,andpipe
maintenance
temperature,T
m .Selectthecable
with
atherm
aloutputthatequalsorexceeds
QF atT
m .
Pip
eTem
perature
(ºF)M
aintenanceTem
perature
010
2030
5060
7080
90100
110120
130140
150
Thermal Output (W/ft)
14131211109876543210
4.88
SRL10&
HSRL10
SRL8&
HSRL8
SRL5&
HSRL5
SRL3&
HSRL3
CableOutput
versusTem
perature
40
Figure1
SRL&
HSRL–
ThermalOutput
Ratingson
InsulatedM
etalPipeFigure
2SRM
/E&
HSRM–
ThermalOutput
Ratingson
InsulatedM
etalPipeFigure
3SRL
&HSRL
–Therm
alOutputRatingson
PlasticPipe
with
Aluminum
Tape
B3.
Determine
TotalCableLength:
Inaddition
topipe
length,in-linecom
ponentssuch
asvalves,flanges,
andpipe
supportsrequire
additionalheattracingto
maintain
Tm .
SeeTable
4.Calculatethe
totalcable
lengthrequired
bycom
biningthe
pipelength
with
theadditionallengths
neededforallthe
othercomponents.
Table3
HeatingCable
Families
NOTE:Itis
theresponsibility
ofthefacility
managerorengineerto
determine
theclassification
ofanarea
where
heattracew
illbeinstalled.The
factorycan
helpdeterm
inea
suitablecable
basedon
theinform
ationprovided.
Table4
AdditionalCableLengths
Requiredfor
In-LineCom
ponentsBased
onPipe
IPS(Ir on
PipeSize)
1/ 2 in.1.00
1.001.00
1.001.00
1.001.00
0.30
3/ 4 in.1.50
1.001.00
1.001.50
1.001.00
0.30
1in.
2.001.00
1.001.00
1.501.00
1.000.30
11/ 2 in.
2.501.50
1.501.50
2.002.00
2.000.30
2in.
2.502.00
2.002.00
2.002.00
2.000.30
21/ 2 in.
2.502.00
2.002.00
2.002.00
2.000.30
3in.
3.002.50
2.502.50
2.002.00
2.000.50
4in.
4.003.00
3.003.00
2.502.50
2.500.50
6in.
5.003.50
3.503.50
2.502.50
2.500.80
8in.
7.004.00
4.004.00
2.502.50
2.500.80
10in.
8.004.50
4.504.50
3.003.00
3.000.80
12in.
9.005.00
5.005.00
3.003.00
3.000.80
14in.
10.005.50
5.505.50
3.003.00
3.001.00
16in.
11.006.00
6.006.00
3.503.50
3.501.00
18in.
12.007.00
7.007.00
3.503.50
3.501.00
20in.
13.007.50
7.507.50
3.503.50
3.501.00
22in.
13.007.50
7.507.50
3.503.50
3.501.00
24in.
15.008.00
8.008.00
4.004.00
4.001.00
PipingSize
GateValve
GlobeValve
BallValveButterfly
ValveHanger
SupportShoe
SupportSleeperSupport
FlangePair
ft
010
2030
5060
7080
90100
110120
130140
15040
Pip
eTem
perature
(ºF)
SRL10&
HSRL10
Thermal Output (W/ft)
9876543210
SRL8&
HSRL8SRL5&
HSRL5
SRL3&
HSRL3
CableOutput
versusTem
perature
Figure4
SRP–
ThermalOutputRatings
onInsulated
MetalPipe
Pip
eTem
perature
(ºF)
Heat Output (W/ft)
2120191817161514131211109876543210
15W
/ft
10W
/ft
5W
/ft
CableOutput
versusTem
perature
010
2030
4050
6070
8090
100110
120130
140150
160170
180190
200210
220230
HeatingCable
Family
AreaClassification
PipeM
aterial
Maxim
umM
aintenanceTem
perature
Maxim
umExposure
Temperature
(PowerOff)
Approvals
U.S.Other
SRL(Self-RegulatingLow
Temperature)
Ordinary
Plastic/Metal
150ºF/65ºC
185ºF/85ºC
UL,CSA,FMGOST,Cenelec,CE,ATEX
ClassI,Div.2,Gr.B,C,D
CSA,FM,(Gr.A,CSA
Only)GOST,Cenelec,CE,ATEX
ClassII,Div.2,Gr.E,F,G
CSA,FM,(Gr.E,CSA
Only)GOST,Cenelec,CE
ClassIII,Div.2
FMOnly
GOST,Cenelec,CE,ATEX
SRM/E
(Self-RegulatingM
ediumTem
perature)
Ordinary
MetalOnly
302ºF/150ºC
420ºF/215ºC
UL,CSA,FMGOST,Cenelec,CE,ATEX
ClassIDiv.2,Gr.A,B,C,D
CSA,FM,(Gr.A,CSA
Only)GOST,Cenelec,CE,ATEX
ClassII,Div.2,Gr.F,G
CSAOnly
GOST,Cenelec,CE,ATEX
SRP(Self-RegulatingM
ediumTem
perature)
Ordinary
MetalOnly
225ºF/110ºC
275ºF/135ºC
UL,CSA,FMPending
GOST,Cenelec,CE,ATEX
Pending
ClassI,Div.2,Gr.B,C,D
ClassII,Div.2,Gr.
F,G
ClassIII
HSRL(H-Self-RegulatingLow
Temperature)
ClassI,Div.1,Gr.B,C,D
Plastic/Metal
150ºF/65ºC
185ºF/85ºC
CSA,FM
ClassII,Div.1,Gr.E,F,G
CSA,FM
ClassIII,Div.1
CSA,FM
HSRM(H-Self-RegulatingM
ediumTem
perature)
ClassI,Div.1,Gr.B,C,D
MetalOnly
302ºF/150ºC
420ºF/215ºC
CSA,FM
ClassII,Div.1,Gr.E,F,G
CSA,FM
ClassIII,Div.1
CSA,FM
CWM
(ConstantWattage)
OrdinaryM
etalOnlyConsultFactory
392ºF/200ºC
UL,CSA
HazardousArea,ConsultFactory
MI(M
ineralInsulated)
Ordinary
MetalOnly
ConsultFactory1,100ºF
/595ºC
CSA,FM
ClassI,Div.2,Gr.B,C,D
CSA,FM
ClassII,Div.2,Gr.E,F,G
CSA,FM
ClassIII
CSA,FM
050
100150
200250
300
Pip
eTem
perature
(ºF)
SRM/E20
&HSRM
20
Power Output (W/ft)
24201612840
SRM/E15
&HSRM
15
SRM/E10
&HSRM
10
SRM/E8
&HSRM
8
SRM/E5
&HSRM
5
SRM/E3
&HSRM
3
CableOutput
versusTem
perature
Table2
InsulationAdjustm
entFactors
Insulation
Factor
Pip
e Insulation Typ
eP
ipe Insulatio
n Type
Insulation
Factor
Glass fiber (A
STM
C547)
1.00
Calcium
silicate (AS
TM C
533)
1.48
Cellular glass (A
STM
C552)
1.48
Rigid cellular urethane (A
STM
C591)
0.64
Foamed elastom
er (AS
TM C
534) 1.16
Mineral fib
er blanket (A
STM
C553)
1.16
Expanded
perlite (A
STM
C610)
1.90
1.Basic
HeatLoss:Afterdeterm
iningthe
differencebetw
eenthe
ambientand
desiredpipe
maintenance
temperature,T
m ,useTable
1to
figurethe
basicheatloss
forthepipe
sizeand
insulationthickness.
2.Insulation
Adjustment:
UsingTable
2,findthe
typeofinsulation
beingused
andits
insulationfactor.
Heat Trace Design Guide
APipe
HeatLossCalculations
• Heat Trace System Design
• Materials & Components
• Specification Tables
3.Calculate
QF :
Multiply
thebasic
heatlossfigure
fromTable
1by
theadjustm
entfactorfromTable
2to
calculatethe
estimated
heatloss,QF ,in
watts
perfootofpipelength.
4.CorrectforIndoorLocation/W
indSpeed:
Iflocationis
indoors,multiply
QF by
0.9.Table
1is
basedon
10%safety
factorand20
mph
wind
speed;add5%
margin
foreach5
mph
over20m
phw
indspeed.
Table1
PipeHeatLoss
QP in
W/ftBased
onTem
peratureDifferentialand
InsulationThickness
Nominal
PipeSize,
in.(ID)
Temperature
DifferenceBetw
eenPipe
andAm
bient
DegºF40ºF
50ºF60ºF
70ºF80ºF
90ºF100ºF
120ºF140ºF
160ºF180ºF
200ºF220ºF
240ºF260ºF
1"Insulation
Thickness1/ 2"
W/ft
1.41.8
2.12.5
2.83.2
3.54.2
5.15.9
6.67.7
8.59.2
10.03/ 4"
W/ft
1.62.0
2.42.8
3.23.6
4.04.8
5.96.7
7.68.8
9.710.6
11.4
1"W
/ft1.8
2.32.8
3.23.7
4.14.6
5.56.8
7.78.7
10.111.1
12.113.2
11/ 2"
W/ft
2.43.1
3.74.3
4.95.5
6.17.3
9.010.2
11.513.4
14.816.1
17.4
2"W
/ft2.8
3.54.1
4.85.5
6.26.9
8.310.1
11.613.0
15.216.7
18.219.7
21/ 2"
W/ft
3.24.0
4.85.6
6.47.2
8.09.6
11.813.4
15.117.6
19.421.1
22.9
3"W
/ft3.7
4.75.6
6.57.4
8.49.3
11.213.7
15.617.6
20.522.5
24.626.6
4"W
/ft4.6
5.86.9
8.19.2
10.411.5
13.816.9
19.321.7
25.327.8
30.432.9
6"W
/ft6.4
8.09.6
11.212.8
14.416.0
19.223.5
26.930.2
35.238.7
42.245.8
8"W
/ft8.1
10.112.1
14.116.2
18.220.2
24.229.7
33.938.2
44.448.9
53.357.8
10"W
/ft9.9
12.414.8
17.319.8
22.224.7
29.636.3
41.546.7
54.359.8
65.270.6
12"W
/ft11.6
14.517.4
20.323.2
26.129.0
34.842.6
48.754.8
63.870.2
76.682.9
14"W
/ft12.6
15.819.0
22.125.3
28.431.6
37.946.5
53.159.7
69.576.5
83.490.4
16"W
/ft14.3
17.921.5
25.128.7
32.335.9
43.052.7
60.267.8
78.986.8
94.6102.5
18"W
/ft16.0
20.124.1
28.132.1
36.140.1
48.158.9
67.475.8
88.297.0
105.9114.7
20"W
/ft17.7
22.226.6
31.035.4
39.944.3
53.265.1
74.483.7
97.5107.2
117.0126.7
22"W
/ft19.4
24.329.1
34.038.8
43.748.5
58.271.3
81.591.7
106.7117.4
128.0138.7
24"W
/ft21.1
26.431.6
36.942.2
47.452.7
63.277.5
88.599.6
115.9127.5
139.1150.7
1.5"Insulation
Thickness1/ 2"
W/ft
1.11.4
1.72.0
2.22.5
2.83.5
4.14.7
5.56.2
6.87.4
8.03/ 4"
W/ft
1.21.6
1.92.2
2.52.8
3.13.9
4.65.2
6.16.8
7.58.2
8.9
1"W
/ft1.4
1.82.2
2.52.9
3.23.6
4.55.3
6.07.1
7.98.7
9.510.3
11/ 2"
W/ft
1.82.3
2.83.2
3.74.1
4.65.8
6.87.7
9.110.1
11.112.1
13.2
2"W
/ft2.1
2.63.1
3.64.2
4.75.2
6.67.6
8.710.3
11.412.6
13.714.9
21/ 2"
W/ft
2.43.0
3.54.1
4.75.3
5.97.4
8.79.9
11.713.0
14.315.6
16.9
3"W
/ft2.7
3.44.1
4.85.4
6.16.8
8.610.0
11.413.5
15.016.5
18.019.4
4"W
/ft3.3
4.25.0
5.86.6
7.58.3
10.512.2
13.916.4
18.320.1
21.923.7
6"W
/ft4.5
5.76.8
7.99.0
10.211.3
14.216.6
19.022.4
24.927.3
29.832.3
8"W
/ft5.6
7.18.5
9.911.3
12.714.1
17.820.7
23.727.9
31.034.1
37.240.3
10"W
/ft6.8
8.010.3
12.013.7
15.417.1
21.525.1
28.733.9
37.641.4
45.148.9
12"W
/ft8.0
10.012.0
14.016.0
18.020.0
25.229.4
33.639.6
44.048.4
52.857.2
14"W
/ft8.7
10.913.0
15.217.4
19.521.7
27.331.9
36.543.0
47.752.5
57.362.1
16"W
/ft9.8
12.314.8
17.219.7
22.124.6
31.036.2
41.348.7
54.159.5
64.970.4
18"W
/ft11.0
13.716.4
19.221.9
24.727.4
34.540.3
46.054.3
60.366.3
72.378.4
20"W
/ft12.1
15.118.1
21.124.2
27.230.2
38.144.4
50.759.8
66.473.1
79.786.4
22"W
/ft13.2
16.519.8
23.126.4
29.733.0
41.648.5
55.465.3
72.679.9
87.194.4
24"W
/ft14.3
17.921.5
25.128.6
32.235.8
45.152.6
60.170.9
78.886.6
94.5102.4
2"Insulation
Thickness1/ 2"
W/ft
1.01.2
1.41.7
1.92.2
2.43.0
3.54.0
4.85.3
5.86.3
7.23/ 4"
W/ft
1.11.4
1.61.9
2.22.4
2.73.4
4.04.5
5.35.9
6.57.1
8.1
1"W
/ft1.2
1.51.8
2.12.4
2.73.0
3.84.4
5.05.9
6.67.3
7.99.0
11/ 2"
W/ft
1.51.9
2.32.7
3.03.4
3.84.8
5.66.4
7.58.4
9.210.0
11.4
2"W
/ft1.7
2.22.6
3.03.4
3.94.3
5.46.3
7.28.5
9.510.4
11.412.9
21/ 2"
W/ft
1.92.4
2.93.4
3.84.3
4.86.0
7.18.1
9.510.6
11.612.7
14.4
3"W
/ft2.2
2.83.3
3.94.4
5.05.5
6.98.1
9.210.9
12.113.3
14.516.4
4"W
/ft2.6
3.34.0
4.65.3
5.96.6
8.39.7
11.113.1
14.516.0
17.419.7
6"W
/ft3.6
4.55.3
6.27.1
8.08.9
11.213.1
15.017.6
19.621.5
23.526.6
8"W
/ft4.4
5.66.7
7.88.9
10.011.1
14.016.3
18.622.0
24.426.9
29.333.2
10"W
/ft5.3
6.78.0
9.310.6
12.013.3
16.819.6
22.326.3
29.332.2
35.139.8
12"W
/ft6.2
7.89.3
10.912.4
14.015.5
19.522.8
26.030.7
34.137.5
40.946.3
14"W
/ft6.7
8.410.1
11.813.4
15.116.8
21.224.7
28.233.3
37.040.7
44.450.2
16"W
/ft7.6
9.511.3
13.215.1
17.018.9
23.827.8
31.837.4
41.645.7
49.956.5
18"W
/ft8.4
10.512.6
14.716.8
18.921.0
26.530.9
35.341.6
46.250.8
55.462.8
20"W
/ft9.2
11.613.9
16.218.5
20.823.1
29.134.0
38.845.7
50.855.9
61.069.1
22"W
/ft10.1
12.615.2
17.720.2
22.725.3
31.837.1
42.450.0
55.661.1
66.775.5
24"W
/ft11.0
13.716.4
19.221.9
24.727.4
34.540.3
46.054.3
60.366.3
72.381.9
609.6m
mW
/m36.1
44.953.8
63.071.9
3"(76.2
mm
)InsulationThickness
1/ 2"W
/ft0.8
1.01.2
1.41.6
1.82.0
2.52.9
3.44.0
4.44.8
5.56.0
3/ 4"W
/ft0.9
1.11.3
1.51.8
2.02.2
2.83.2
3.74.4
4.85.3
6.16.67
1"W
/ft1.0
1.31.5
1.82.0
2.32.5
3.23.7
4.25.0
5.56.1
6.97.5
11/ 2"
W/ft
1.21.5
1.82.1
2.42.7
3.03.8
4.45.0
5.96.6
7.38.3
9.0
2"W
/ft1.3
1.72.0
2.32.6
3.03.3
4.24.9
5.56.5
7.38.0
9.19.9
21/ 2"
W/ft
1.51.9
2.22.6
3.03.3
3.74.7
5.46.2
7.38.1
9.010.2
11.1
3"W
/ft1.7
2.12.5
2.93.4
3.84.2
5.36.2
7.18.3
9.210.2
11.612.6
4"W
/ft2.0
2.53.0
3.54.0
4.55.0
6.37.4
8.49.9
11.012.1
13.815.0
6"W
/ft2.6
3.33.9
4.65.2
5.96.5
8.29.6
10.912.9
14.315.7
17.919.4
8"W
/ft3.2
4.04.8
5.66.4
7.28.0
10.111.8
13.415.8
17.619.4
22.123.9
10"W
/ft3.8
4.85.7
6.77.6
8.69.5
12.014.0
16.018.8
20.923.0
26.228.4
12"W
/ft4.4
5.56.5
7.68.7
9.810.9
13.716.0
18.321.6
24.026.4
30.132.6
14"W
/ft4.7
5.97.1
8.39.4
10.611.8
14.917.3
19.823.4
26.028.6
32.635.3
16"W
/ft5.3
6.78.0
9.310.6
12.013.3
16.819.6
22.326.3
29.332.2
36.739.8
18”W
/ft5.9
7.48.8
10.311.8
13.214.7
18.521.6
24.729.1
32.335.6
40.644.0
20"W
/ft6.4
8.19.7
11.312.9
14.516.1
20.323.7
27.031.9
35.439.0
44.448.1
22"W
/ft7.0
8.810.5
12.314.0
15.817.5
22.125.7
29.434.7
38.542.4
48.352.3
24"W
/ft7.6
9.511.3
13.215.1
17.018.9
23.827.8
31.837.4
41.645.7
52.256.5
Nominal
PipeSize,
in.(ID)
Temperature
DifferenceBetw
eenPipe
andAm
bient
DegºF40ºF
50ºF60ºF
70ºF80ºF
90ºF100ºF
120ºF140ºF
160ºF180ºF
200ºF220ºF
240ºF260ºF
3”Insulation
Thickness
Installation Tips• Do not twist buss wires together at end
of circuit
• Insulate all conductive parts
• Seal all electrical connections against moisture
• Seal ends of exposed cable during installation
• Do not expose cables to temperatures abovetheir maximum ratings
• Install cable with aluminum tape for useon plastic pipes
• Locate ambient temperature sensors in coldestexpected area
• Locate pipe temperature sensors at lowestexpected line temperature
• Use sufficient cable to trace additional heat sinks
• Install cable so that valves can be removedwithout removing cable
Important SafeguardsMechanical Inspection
• Inspect all insulation and weatherproofing
• Inspect all junction box, connection box andsensor connections
• Verify all circuits have been properlygrounded
• Verify all circuits are connected in properpanel locations
• Verify proper circuit breakers are in place(always use 30mA trip GFI-type breakers)
• Verify all circuit lengths are within manufacturer’sspecified limits
• Verify all proper safety warnings are in place
• Verify all end seal, splice/tee locations are markedon lagging
Electrical Tests
• Insulation Resistance (Megger)– Before tracing pipes– After installing terminations– Before insulating pipes– After insulating pipes– Before energizing system
• Circuit Voltage
• Initial Current– Note ambient temp and pipe temp
• Stabilized Current (15 minutes of operation)– Note ambient temp and pipe temp
• Always use ground fault circuit breakers(30mA trip level)
Tools Needed• Wire Cutters/Strippers
• Megger
• Phillips Head Screwdriver
• Standard Screwdriver
• Voltmeter
• Utility Knife
• Hammer
SRL Cable• 150ºF / 65oC Maximum Maintenance
• 185ºF / 85oC Maximum Exposure
• 3-10 W/ft / 10-33 W/m
• 16 AWG with Optional TPE orFluoropolymer Jacket
SRM Cable• 302ºF / 150oC Maximum Maintenance
• 420ºF / 215oC Maximum Exposure
• 5-20 W/ft / 16-66 W/m
• 16 AWG with Optional Fluoropolymer Jacket
103 Gamma DrivePittsburgh, PA 15238USA
Chromalox®
PRECISION HEAT AND CONTROL
Copyright © 2002-2007, 2009-2012, Chromalox, Inc. All rights reserved.
Phone: (412) 967-3800Fax: (412) 967-5148Toll-Free: 1-800-443-2640
www.chromalox.com
PJ130-6
HEAT TRACE THERMAL DESIGN
SRP Cable• 225°F / 110°C Maintenance Temperature
• 275°F / 135°C Maximum Exposure Temperature
• 5-15 W/ft / 16-49 W/m
• 16 AWG with Optional Fluoropolymer Jacket
Chromalox
CableSelection
1.SelectHeating
CableFam
ily:Based
onthe
maxim
umm
aintenancetem
peraturerating,m
aximum
exposuretem
peraturerating,and
areaclassification,selectthe
heatingcable
family
fromTable
3.(SeeChrom
aloxHeatTrace
CableProductInform
ationSheets
forcableconstruction
options,voltageratings,
andw
attageoutputs
available.)
2.SelectTherm
alOutputRating:
(a)ForMetalPipes
–Use
Figures1,2
or4(b)ForPlastic
Pipes–
UseFigure
3by
findingthe
intersectionofthe
calculatedheatloss,Q
F ,andpipe
maintenance
temperature,T
m .Selectthecable
with
atherm
aloutputthatequalsorexceeds
QF atT
m .
Pip
eTem
perature
(ºF)M
aintenanceTem
perature
010
2030
5060
7080
90100
110120
130140
150
Thermal Output (W/ft)
14131211109876543210
4.88
SRL10&
HSRL10
SRL8&
HSRL8
SRL5&
HSRL5
SRL3&
HSRL3
CableOutput
versusTem
perature
40
Figure1
SRL&
HSRL–
ThermalOutput
Ratingson
InsulatedM
etalPipeFigure
2SRM
/E&
HSRM–
ThermalOutput
Ratingson
InsulatedM
etalPipeFigure
3SRL
&HSRL
–Therm
alOutputRatingson
PlasticPipe
with
Aluminum
Tape
B3.
Determine
TotalCableLength:
Inaddition
topipe
length,in-linecom
ponentssuch
asvalves,flanges,
andpipe
supportsrequire
additionalheattracingto
maintain
Tm .
SeeTable
4.Calculatethe
totalcable
lengthrequired
bycom
biningthe
pipelength
with
theadditionallengths
neededforallthe
othercomponents.
Table3
HeatingCable
Families
NOTE:Itis
theresponsibility
ofthefacility
managerorengineerto
determine
theclassification
ofanarea
where
heattracew
illbeinstalled.The
factorycan
helpdeterm
inea
suitablecable
basedon
theinform
ationprovided.
Table4
AdditionalCableLengths
Requiredfor
In-LineCom
ponentsBased
onPipe
IPS(Ir on
PipeSize)
1/ 2 in.1.00
1.001.00
1.001.00
1.001.00
0.30
3/ 4 in.1.50
1.001.00
1.001.50
1.001.00
0.30
1in.
2.001.00
1.001.00
1.501.00
1.000.30
11/ 2 in.
2.501.50
1.501.50
2.002.00
2.000.30
2in.
2.502.00
2.002.00
2.002.00
2.000.30
21/ 2 in.
2.502.00
2.002.00
2.002.00
2.000.30
3in.
3.002.50
2.502.50
2.002.00
2.000.50
4in.
4.003.00
3.003.00
2.502.50
2.500.50
6in.
5.003.50
3.503.50
2.502.50
2.500.80
8in.
7.004.00
4.004.00
2.502.50
2.500.80
10in.
8.004.50
4.504.50
3.003.00
3.000.80
12in.
9.005.00
5.005.00
3.003.00
3.000.80
14in.
10.005.50
5.505.50
3.003.00
3.001.00
16in.
11.006.00
6.006.00
3.503.50
3.501.00
18in.
12.007.00
7.007.00
3.503.50
3.501.00
20in.
13.007.50
7.507.50
3.503.50
3.501.00
22in.
13.007.50
7.507.50
3.503.50
3.501.00
24in.
15.008.00
8.008.00
4.004.00
4.001.00
PipingSize
GateValve
GlobeValve
BallValveButterfly
ValveHanger
SupportShoe
SupportSleeperSupport
FlangePair
ft
010
2030
5060
7080
90100
110120
130140
15040
Pip
eTem
perature
(ºF)
SRL10&
HSRL10
Thermal Output (W/ft)
9876543210
SRL8&
HSRL8SRL5&
HSRL5
SRL3&
HSRL3
CableOutput
versusTem
perature
Figure4
SRP–
ThermalOutputRatings
onInsulated
MetalPipe
Pip
eTem
perature
(ºF)
Heat Output (W/ft)
2120191817161514131211109876543210
15W
/ft
10W
/ft
5W
/ft
CableOutput
versusTem
perature
010
2030
4050
6070
8090
100110
120130
140150
160170
180190
200210
220230
HeatingCable
Family
AreaClassification
PipeM
aterial
Maxim
umM
aintenanceTem
perature
Maxim
umExposure
Temperature
(PowerOff)
Approvals
U.S.Other
SRL(Self-RegulatingLow
Temperature)
Ordinary
Plastic/Metal
150ºF/65ºC
185ºF/85ºC
UL,CSA,FMGOST,Cenelec,CE,ATEX
ClassI,Div.2,Gr.B,C,D
CSA,FM,(Gr.A,CSA
Only)GOST,Cenelec,CE,ATEX
ClassII,Div.2,Gr.E,F,G
CSA,FM,(Gr.E,CSA
Only)GOST,Cenelec,CE
ClassIII,Div.2
FMOnly
GOST,Cenelec,CE,ATEX
SRM/E
(Self-RegulatingM
ediumTem
perature)
Ordinary
MetalOnly
302ºF/150ºC
420ºF/215ºC
UL,CSA,FMGOST,Cenelec,CE,ATEX
ClassIDiv.2,Gr.A,B,C,D
CSA,FM,(Gr.A,CSA
Only)GOST,Cenelec,CE,ATEX
ClassII,Div.2,Gr.F,G
CSAOnly
GOST,Cenelec,CE,ATEX
SRP(Self-RegulatingM
ediumTem
perature)
Ordinary
MetalOnly
225ºF/110ºC
275ºF/135ºC
UL,CSA,FMPending
GOST,Cenelec,CE,ATEX
Pending
ClassI,Div.2,Gr.B,C,D
ClassII,Div.2,Gr.
F,G
ClassIII
HSRL(H-Self-RegulatingLow
Temperature)
ClassI,Div.1,Gr.B,C,D
Plastic/Metal
150ºF/65ºC
185ºF/85ºC
CSA,FM
ClassII,Div.1,Gr.E,F,G
CSA,FM
ClassIII,Div.1
CSA,FM
HSRM(H-Self-RegulatingM
ediumTem
perature)
ClassI,Div.1,Gr.B,C,D
MetalOnly
302ºF/150ºC
420ºF/215ºC
CSA,FM
ClassII,Div.1,Gr.E,F,G
CSA,FM
ClassIII,Div.1
CSA,FM
CWM
(ConstantWattage)
OrdinaryM
etalOnlyConsultFactory
392ºF/200ºC
UL,CSA
HazardousArea,ConsultFactory
MI(M
ineralInsulated)
Ordinary
MetalOnly
ConsultFactory1,100ºF
/595ºC
CSA,FM
ClassI,Div.2,Gr.B,C,D
CSA,FM
ClassII,Div.2,Gr.E,F,G
CSA,FM
ClassIII
CSA,FM
050
100150
200250
300
Pip
eTem
perature
(ºF)
SRM/E20
&HSRM
20
Power Output (W/ft)
24201612840
SRM/E15
&HSRM
15
SRM/E10
&HSRM
10
SRM/E8
&HSRM
8
SRM/E5
&HSRM
5
SRM/E3
&HSRM
3
CableOutput
versusTem
perature
Table2
InsulationAdjustm
entFactors
Insulation
Factor
Pip
e Insulation Typ
eP
ipe Insulatio
n Type
Insulation
Factor
Glass fiber (A
STM
C547)
1.00
Calcium
silicate (AS
TM C
533)
1.48
Cellular glass (A
STM
C552)
1.48
Rigid cellular urethane (A
STM
C591)
0.64
Foamed elastom
er (AS
TM C
534) 1.16
Mineral fib
er blanket (A
STM
C553)
1.16
Expanded
perlite (A
STM
C610)
1.90
1.Basic
HeatLoss:Afterdeterm
iningthe
differencebetw
eenthe
ambientand
desiredpipe
maintenance
temperature,T
m ,useTable
1to
figurethe
basicheatloss
forthepipe
sizeand
insulationthickness.
2.Insulation
Adjustment:
UsingTable
2,findthe
typeofinsulation
beingused
andits
insulationfactor.
Heat Trace Design Guide
APipe
HeatLossCalculations
• Heat Trace System Design
• Materials & Components
• Specification Tables
3.Calculate
QF :
Multiply
thebasic
heatlossfigure
fromTable
1by
theadjustm
entfactorfromTable
2to
calculatethe
estimated
heatloss,QF ,in
watts
perfootofpipelength.
4.CorrectforIndoorLocation/W
indSpeed:
Iflocationis
indoors,multiply
QF by
0.9.Table
1is
basedon
10%safety
factorand20
mph
wind
speed;add5%
margin
foreach5
mph
over20m
phw
indspeed.
Table1
PipeHeatLoss
QP in
W/ftBased
onTem
peratureDifferentialand
InsulationThickness
Nominal
PipeSize,
in.(ID)
Temperature
DifferenceBetw
eenPipe
andAm
bient
DegºF40ºF
50ºF60ºF
70ºF80ºF
90ºF100ºF
120ºF140ºF
160ºF180ºF
200ºF220ºF
240ºF260ºF
1"Insulation
Thickness1/ 2"
W/ft
1.41.8
2.12.5
2.83.2
3.54.2
5.15.9
6.67.7
8.59.2
10.03/ 4"
W/ft
1.62.0
2.42.8
3.23.6
4.04.8
5.96.7
7.68.8
9.710.6
11.4
1"W
/ft1.8
2.32.8
3.23.7
4.14.6
5.56.8
7.78.7
10.111.1
12.113.2
11/ 2"
W/ft
2.43.1
3.74.3
4.95.5
6.17.3
9.010.2
11.513.4
14.816.1
17.4
2"W
/ft2.8
3.54.1
4.85.5
6.26.9
8.310.1
11.613.0
15.216.7
18.219.7
21/ 2"
W/ft
3.24.0
4.85.6
6.47.2
8.09.6
11.813.4
15.117.6
19.421.1
22.9
3"W
/ft3.7
4.75.6
6.57.4
8.49.3
11.213.7
15.617.6
20.522.5
24.626.6
4"W
/ft4.6
5.86.9
8.19.2
10.411.5
13.816.9
19.321.7
25.327.8
30.432.9
6"W
/ft6.4
8.09.6
11.212.8
14.416.0
19.223.5
26.930.2
35.238.7
42.245.8
8"W
/ft8.1
10.112.1
14.116.2
18.220.2
24.229.7
33.938.2
44.448.9
53.357.8
10"W
/ft9.9
12.414.8
17.319.8
22.224.7
29.636.3
41.546.7
54.359.8
65.270.6
12"W
/ft11.6
14.517.4
20.323.2
26.129.0
34.842.6
48.754.8
63.870.2
76.682.9
14"W
/ft12.6
15.819.0
22.125.3
28.431.6
37.946.5
53.159.7
69.576.5
83.490.4
16"W
/ft14.3
17.921.5
25.128.7
32.335.9
43.052.7
60.267.8
78.986.8
94.6102.5
18"W
/ft16.0
20.124.1
28.132.1
36.140.1
48.158.9
67.475.8
88.297.0
105.9114.7
20"W
/ft17.7
22.226.6
31.035.4
39.944.3
53.265.1
74.483.7
97.5107.2
117.0126.7
22"W
/ft19.4
24.329.1
34.038.8
43.748.5
58.271.3
81.591.7
106.7117.4
128.0138.7
24"W
/ft21.1
26.431.6
36.942.2
47.452.7
63.277.5
88.599.6
115.9127.5
139.1150.7
1.5"Insulation
Thickness1/ 2"
W/ft
1.11.4
1.72.0
2.22.5
2.83.5
4.14.7
5.56.2
6.87.4
8.03/ 4"
W/ft
1.21.6
1.92.2
2.52.8
3.13.9
4.65.2
6.16.8
7.58.2
8.9
1"W
/ft1.4
1.82.2
2.52.9
3.23.6
4.55.3
6.07.1
7.98.7
9.510.3
11/ 2"
W/ft
1.82.3
2.83.2
3.74.1
4.65.8
6.87.7
9.110.1
11.112.1
13.2
2"W
/ft2.1
2.63.1
3.64.2
4.75.2
6.67.6
8.710.3
11.412.6
13.714.9
21/ 2"
W/ft
2.43.0
3.54.1
4.75.3
5.97.4
8.79.9
11.713.0
14.315.6
16.9
3"W
/ft2.7
3.44.1
4.85.4
6.16.8
8.610.0
11.413.5
15.016.5
18.019.4
4"W
/ft3.3
4.25.0
5.86.6
7.58.3
10.512.2
13.916.4
18.320.1
21.923.7
6"W
/ft4.5
5.76.8
7.99.0
10.211.3
14.216.6
19.022.4
24.927.3
29.832.3
8"W
/ft5.6
7.18.5
9.911.3
12.714.1
17.820.7
23.727.9
31.034.1
37.240.3
10"W
/ft6.8
8.010.3
12.013.7
15.417.1
21.525.1
28.733.9
37.641.4
45.148.9
12"W
/ft8.0
10.012.0
14.016.0
18.020.0
25.229.4
33.639.6
44.048.4
52.857.2
14"W
/ft8.7
10.913.0
15.217.4
19.521.7
27.331.9
36.543.0
47.752.5
57.362.1
16"W
/ft9.8
12.314.8
17.219.7
22.124.6
31.036.2
41.348.7
54.159.5
64.970.4
18"W
/ft11.0
13.716.4
19.221.9
24.727.4
34.540.3
46.054.3
60.366.3
72.378.4
20"W
/ft12.1
15.118.1
21.124.2
27.230.2
38.144.4
50.759.8
66.473.1
79.786.4
22"W
/ft13.2
16.519.8
23.126.4
29.733.0
41.648.5
55.465.3
72.679.9
87.194.4
24"W
/ft14.3
17.921.5
25.128.6
32.235.8
45.152.6
60.170.9
78.886.6
94.5102.4
2"Insulation
Thickness1/ 2"
W/ft
1.01.2
1.41.7
1.92.2
2.43.0
3.54.0
4.85.3
5.86.3
7.23/ 4"
W/ft
1.11.4
1.61.9
2.22.4
2.73.4
4.04.5
5.35.9
6.57.1
8.1
1"W
/ft1.2
1.51.8
2.12.4
2.73.0
3.84.4
5.05.9
6.67.3
7.99.0
11/ 2"
W/ft
1.51.9
2.32.7
3.03.4
3.84.8
5.66.4
7.58.4
9.210.0
11.4
2"W
/ft1.7
2.22.6
3.03.4
3.94.3
5.46.3
7.28.5
9.510.4
11.412.9
21/ 2"
W/ft
1.92.4
2.93.4
3.84.3
4.86.0
7.18.1
9.510.6
11.612.7
14.4
3"W
/ft2.2
2.83.3
3.94.4
5.05.5
6.98.1
9.210.9
12.113.3
14.516.4
4"W
/ft2.6
3.34.0
4.65.3
5.96.6
8.39.7
11.113.1
14.516.0
17.419.7
6"W
/ft3.6
4.55.3
6.27.1
8.08.9
11.213.1
15.017.6
19.621.5
23.526.6
8"W
/ft4.4
5.66.7
7.88.9
10.011.1
14.016.3
18.622.0
24.426.9
29.333.2
10"W
/ft5.3
6.78.0
9.310.6
12.013.3
16.819.6
22.326.3
29.332.2
35.139.8
12"W
/ft6.2
7.89.3
10.912.4
14.015.5
19.522.8
26.030.7
34.137.5
40.946.3
14"W
/ft6.7
8.410.1
11.813.4
15.116.8
21.224.7
28.233.3
37.040.7
44.450.2
16"W
/ft7.6
9.511.3
13.215.1
17.018.9
23.827.8
31.837.4
41.645.7
49.956.5
18"W
/ft8.4
10.512.6
14.716.8
18.921.0
26.530.9
35.341.6
46.250.8
55.462.8
20"W
/ft9.2
11.613.9
16.218.5
20.823.1
29.134.0
38.845.7
50.855.9
61.069.1
22"W
/ft10.1
12.615.2
17.720.2
22.725.3
31.837.1
42.450.0
55.661.1
66.775.5
24"W
/ft11.0
13.716.4
19.221.9
24.727.4
34.540.3
46.054.3
60.366.3
72.381.9
609.6m
mW
/m36.1
44.953.8
63.071.9
3"(76.2
mm
)InsulationThickness
1/ 2"W
/ft0.8
1.01.2
1.41.6
1.82.0
2.52.9
3.44.0
4.44.8
5.56.0
3/ 4"W
/ft0.9
1.11.3
1.51.8
2.02.2
2.83.2
3.74.4
4.85.3
6.16.67
1"W
/ft1.0
1.31.5
1.82.0
2.32.5
3.23.7
4.25.0
5.56.1
6.97.5
11/ 2"
W/ft
1.21.5
1.82.1
2.42.7
3.03.8
4.45.0
5.96.6
7.38.3
9.0
2"W
/ft1.3
1.72.0
2.32.6
3.03.3
4.24.9
5.56.5
7.38.0
9.19.9
21/ 2"
W/ft
1.51.9
2.22.6
3.03.3
3.74.7
5.46.2
7.38.1
9.010.2
11.1
3"W
/ft1.7
2.12.5
2.93.4
3.84.2
5.36.2
7.18.3
9.210.2
11.612.6
4"W
/ft2.0
2.53.0
3.54.0
4.55.0
6.37.4
8.49.9
11.012.1
13.815.0
6"W
/ft2.6
3.33.9
4.65.2
5.96.5
8.29.6
10.912.9
14.315.7
17.919.4
8"W
/ft3.2
4.04.8
5.66.4
7.28.0
10.111.8
13.415.8
17.619.4
22.123.9
10"W
/ft3.8
4.85.7
6.77.6
8.69.5
12.014.0
16.018.8
20.923.0
26.228.4
12"W
/ft4.4
5.56.5
7.68.7
9.810.9
13.716.0
18.321.6
24.026.4
30.132.6
14"W
/ft4.7
5.97.1
8.39.4
10.611.8
14.917.3
19.823.4
26.028.6
32.635.3
16"W
/ft5.3
6.78.0
9.310.6
12.013.3
16.819.6
22.326.3
29.332.2
36.739.8
18”W
/ft5.9
7.48.8
10.311.8
13.214.7
18.521.6
24.729.1
32.335.6
40.644.0
20"W
/ft6.4
8.19.7
11.312.9
14.516.1
20.323.7
27.031.9
35.439.0
44.448.1
22"W
/ft7.0
8.810.5
12.314.0
15.817.5
22.125.7
29.434.7
38.542.4
48.352.3
24"W
/ft7.6
9.511.3
13.215.1
17.018.9
23.827.8
31.837.4
41.645.7
52.256.5
Nominal
PipeSize,
in.(ID)
Temperature
DifferenceBetw
eenPipe
andAm
bient
DegºF40ºF
50ºF60ºF
70ºF80ºF
90ºF100ºF
120ºF140ºF
160ºF180ºF
200ºF220ºF
240ºF260ºF
3”Insulation
Thickness
Installation Tips• Do not twist buss wires together at end
of circuit
• Insulate all conductive parts
• Seal all electrical connections against moisture
• Seal ends of exposed cable during installation
• Do not expose cables to temperatures abovetheir maximum ratings
• Install cable with aluminum tape for useon plastic pipes
• Locate ambient temperature sensors in coldestexpected area
• Locate pipe temperature sensors at lowestexpected line temperature
• Use sufficient cable to trace additional heat sinks
• Install cable so that valves can be removedwithout removing cable
Important SafeguardsMechanical Inspection
• Inspect all insulation and weatherproofing
• Inspect all junction box, connection box andsensor connections
• Verify all circuits have been properlygrounded
• Verify all circuits are connected in properpanel locations
• Verify proper circuit breakers are in place(always use 30mA trip GFI-type breakers)
• Verify all circuit lengths are within manufacturer’sspecified limits
• Verify all proper safety warnings are in place
• Verify all end seal, splice/tee locations are markedon lagging
Electrical Tests
• Insulation Resistance (Megger)– Before tracing pipes– After installing terminations– Before insulating pipes– After insulating pipes– Before energizing system
• Circuit Voltage
• Initial Current– Note ambient temp and pipe temp
• Stabilized Current (15 minutes of operation)– Note ambient temp and pipe temp
• Always use ground fault circuit breakers(30mA trip level)
Tools Needed• Wire Cutters/Strippers
• Megger
• Phillips Head Screwdriver
• Standard Screwdriver
• Voltmeter
• Utility Knife
• Hammer
SRL Cable• 150ºF / 65oC Maximum Maintenance
• 185ºF / 85oC Maximum Exposure
• 3-10 W/ft / 10-33 W/m
• 16 AWG with Optional TPE orFluoropolymer Jacket
SRM Cable• 302ºF / 150oC Maximum Maintenance
• 420ºF / 215oC Maximum Exposure
• 5-20 W/ft / 16-66 W/m
• 16 AWG with Optional Fluoropolymer Jacket
103 Gamma DrivePittsburgh, PA 15238USA
Chromalox®
PRECISION HEAT AND CONTROL
Copyright © 2002-2007, 2009-2012, Chromalox, Inc. All rights reserved.
Phone: (412) 967-3800Fax: (412) 967-5148Toll-Free: 1-800-443-2640
www.chromalox.com
PJ130-6
HEAT TRACE THERMAL DESIGN
SRP Cable• 225°F / 110°C Maintenance Temperature
• 275°F / 135°C Maximum Exposure Temperature
• 5-15 W/ft / 16-49 W/m
• 16 AWG with Optional Fluoropolymer Jacket
Chromalox
CableSelection
1.SelectHeating
CableFam
ily:Based
onthe
maxim
umm
aintenancetem
peraturerating,m
aximum
exposuretem
peraturerating,and
areaclassification,selectthe
heatingcable
family
fromTable
3.(SeeChrom
aloxHeatTrace
CableProductInform
ationSheets
forcableconstruction
options,voltageratings,
andw
attageoutputs
available.)
2.SelectTherm
alOutputRating:
(a)ForMetalPipes
–Use
Figures1,2
or4(b)ForPlastic
Pipes–
UseFigure
3by
findingthe
intersectionofthe
calculatedheatloss,Q
F ,andpipe
maintenance
temperature,T
m .Selectthecable
with
atherm
aloutputthatequalsorexceeds
QF atT
m .
Pip
eTem
perature
(ºF)M
aintenanceTem
perature
010
2030
5060
7080
90100
110120
130140
150
Thermal Output (W/ft)
14131211109876543210
4.88
SRL10&
HSRL10
SRL8&
HSRL8
SRL5&
HSRL5
SRL3&
HSRL3
CableOutput
versusTem
perature
40
Figure1
SRL&
HSRL–
ThermalOutput
Ratingson
InsulatedM
etalPipeFigure
2SRM
/E&
HSRM–
ThermalOutput
Ratingson
InsulatedM
etalPipeFigure
3SRL
&HSRL
–Therm
alOutputRatingson
PlasticPipe
with
Aluminum
Tape
B3.
Determine
TotalCableLength:
Inaddition
topipe
length,in-linecom
ponentssuch
asvalves,flanges,
andpipe
supportsrequire
additionalheattracingto
maintain
Tm .
SeeTable
4.Calculatethe
totalcable
lengthrequired
bycom
biningthe
pipelength
with
theadditionallengths
neededforallthe
othercomponents.
Table3
HeatingCable
Families
NOTE:Itis
theresponsibility
ofthefacility
managerorengineerto
determine
theclassification
ofanarea
where
heattracew
illbeinstalled.The
factorycan
helpdeterm
inea
suitablecable
basedon
theinform
ationprovided.
Table4
AdditionalCableLengths
Requiredfor
In-LineCom
ponentsBased
onPipe
IPS(Ir on
PipeSize)
1/ 2 in.1.00
1.001.00
1.001.00
1.001.00
0.30
3/ 4 in.1.50
1.001.00
1.001.50
1.001.00
0.30
1in.
2.001.00
1.001.00
1.501.00
1.000.30
11/ 2 in.
2.501.50
1.501.50
2.002.00
2.000.30
2in.
2.502.00
2.002.00
2.002.00
2.000.30
21/ 2 in.
2.502.00
2.002.00
2.002.00
2.000.30
3in.
3.002.50
2.502.50
2.002.00
2.000.50
4in.
4.003.00
3.003.00
2.502.50
2.500.50
6in.
5.003.50
3.503.50
2.502.50
2.500.80
8in.
7.004.00
4.004.00
2.502.50
2.500.80
10in.
8.004.50
4.504.50
3.003.00
3.000.80
12in.
9.005.00
5.005.00
3.003.00
3.000.80
14in.
10.005.50
5.505.50
3.003.00
3.001.00
16in.
11.006.00
6.006.00
3.503.50
3.501.00
18in.
12.007.00
7.007.00
3.503.50
3.501.00
20in.
13.007.50
7.507.50
3.503.50
3.501.00
22in.
13.007.50
7.507.50
3.503.50
3.501.00
24in.
15.008.00
8.008.00
4.004.00
4.001.00
PipingSize
GateValve
GlobeValve
BallValveButterfly
ValveHanger
SupportShoe
SupportSleeperSupport
FlangePair
ft
010
2030
5060
7080
90100
110120
130140
15040
Pip
eTem
perature
(ºF)
SRL10&
HSRL10
Thermal Output (W/ft)
9876543210
SRL8&
HSRL8SRL5&
HSRL5
SRL3&
HSRL3
CableOutput
versusTem
perature
Figure4
SRP–
ThermalOutputRatings
onInsulated
MetalPipe
Pip
eTem
perature
(ºF)
Heat Output (W/ft)
2120191817161514131211109876543210
15W
/ft
10W
/ft
5W
/ft
CableOutput
versusTem
perature
010
2030
4050
6070
8090
100110
120130
140150
160170
180190
200210
220230
HeatingCable
Family
AreaClassification
PipeM
aterial
Maxim
umM
aintenanceTem
perature
Maxim
umExposure
Temperature
(PowerOff)
Approvals
U.S.Other
SRL(Self-RegulatingLow
Temperature)
Ordinary
Plastic/Metal
150ºF/65ºC
185ºF/85ºC
UL,CSA,FMGOST,Cenelec,CE,ATEX
ClassI,Div.2,Gr.B,C,D
CSA,FM,(Gr.A,CSA
Only)GOST,Cenelec,CE,ATEX
ClassII,Div.2,Gr.E,F,G
CSA,FM,(Gr.E,CSA
Only)GOST,Cenelec,CE
ClassIII,Div.2
FMOnly
GOST,Cenelec,CE,ATEX
SRM/E
(Self-RegulatingM
ediumTem
perature)
Ordinary
MetalOnly
302ºF/150ºC
420ºF/215ºC
UL,CSA,FMGOST,Cenelec,CE,ATEX
ClassIDiv.2,Gr.A,B,C,D
CSA,FM,(Gr.A,CSA
Only)GOST,Cenelec,CE,ATEX
ClassII,Div.2,Gr.F,G
CSAOnly
GOST,Cenelec,CE,ATEX
SRP(Self-RegulatingM
ediumTem
perature)
Ordinary
MetalOnly
225ºF/110ºC
275ºF/135ºC
UL,CSA,FMPending
GOST,Cenelec,CE,ATEX
Pending
ClassI,Div.2,Gr.B,C,D
ClassII,Div.2,Gr.
F,G
ClassIII
HSRL(H-Self-RegulatingLow
Temperature)
ClassI,Div.1,Gr.B,C,D
Plastic/Metal
150ºF/65ºC
185ºF/85ºC
CSA,FM
ClassII,Div.1,Gr.E,F,G
CSA,FM
ClassIII,Div.1
CSA,FM
HSRM(H-Self-RegulatingM
ediumTem
perature)
ClassI,Div.1,Gr.B,C,D
MetalOnly
302ºF/150ºC
420ºF/215ºC
CSA,FM
ClassII,Div.1,Gr.E,F,G
CSA,FM
ClassIII,Div.1
CSA,FM
CWM
(ConstantWattage)
OrdinaryM
etalOnlyConsultFactory
392ºF/200ºC
UL,CSA
HazardousArea,ConsultFactory
MI(M
ineralInsulated)
Ordinary
MetalOnly
ConsultFactory1,100ºF
/595ºC
CSA,FM
ClassI,Div.2,Gr.B,C,D
CSA,FM
ClassII,Div.2,Gr.E,F,G
CSA,FM
ClassIII
CSA,FM
050
100150
200250
300
Pip
eTem
perature
(ºF)
SRM/E20
&HSRM
20
Power Output (W/ft)
24201612840
SRM/E15
&HSRM
15
SRM/E10
&HSRM
10
SRM/E8
&HSRM
8
SRM/E5
&HSRM
5
SRM/E3
&HSRM
3
CableOutput
versusTem
perature
1.2.
a3.4.
pIpe HeaT LO
SS CaLCu
LaTIOn
S
Basic Heat Loss: After determining the difference betw
een the ambient and desired pipe m
aintenance
temperature, T
m , use Table 1 to figure the basic heat loss for the pipe size and insulation thickness.
Calculate QF : M
ultiply the basic heat loss figure from Table 1 by the adjustm
ent factor from Table 2 to
calculate the estimated heat loss, Q
F , in watts per foot of pipe length.
Correct for Indoor Location/ Wind Speed: If location is indoors, m
ultiply QF by 0.9. Table 1 is based on
10% safety factor and 20 m
ph wind speed; add 5%
margin for each 5 m
ph over 20 mph w
ind speed.Insulation Adjustm
ent: Using Table 2, find the type of insulation being used and its insulation factor.
Insulation Adjustment Factors
B3.
1.2.
CHr
Om
aLOx Ca
BLe SeLeCTIO
n
Select Heating Cable Family: Based on the m
aximum
maintenance tem
perature rating, maxim
um
exposure temperature rating, and area classification, select the heating cable fam
ily from Table 3. (See
Chromalox Heat Trace Cable Product Inform
ation Sheets for cable construction options, voltage ratings, and w
attage outputs available.)
Determine Total Cable Length: In addition to pipe length, in-line com
ponents such as valves, flanges, and pipe supports require additional heat tracing to m
aintain Tm. See Table 4. Calculate the total
cable length required by combining the pipe length w
ith the additional lengths needed for all the other com
ponents.
Select Thermal Output Rating:
(a) For Metal Pipes – Use Figures 1, 2 or 4
(b) For Plastic Pipes – Use Figure 3 by finding the intersection of the calculated heat loss, QF , and pipe
maintenance tem
perature, Tm . Select the cable w
ith a thermal output that equals or exceeds Q
F at Tm .
Table 4Additional Cable Lengths Required for In-Line Com
ponentsBased on Pipe IPS (Iron Pipe Size)
Table 3
Table 1
Table 2
Heating Cable Families
Pipe Heat Loss QP in W
/ft Based on Temperature Differential and Insulation Thickness
Installation Tips • Do not twist buss wires together at end of circuit
• Insulate all conductive parts
• Seal all electrical connections against moisture
• Seal ends of exposed cable during installation
• Do not expose cables to temperatures above their maximum ratings
• Install cable with aluminum tape for use on plastic pipes
• Locate ambient temperature sensors in coldest expected area
• Locate pipe temperature sensors at lowest expected line temperature
• Use sufficient cable to trace additional heat sinks
• Install cable so that valves can be removed without removing cable
Important Safeguards Mechanical Inspection • Inspect all insulation and weatherproofing
• Inspect all junction box, connection box, and sensor connections
• Verify all circuits have been properly grounded
• Verify all circuits are connected in proper panel locations
• Verify proper circuit breakers are in place (always use 30 mA trip GFI-type breakers)
• Verify all circuit lengths are within manufacturer’s specified limits
• Verify all proper safety warnings are in place
• Verify all end seal, splice/tee locations are marked on lagging
Electrical Tests
• Insulation Resistance (Megger) ✓ Before tracing pipes ✓ After installing terminations ✓ Before insulating pipes ✓ After insulating pipes ✓ Before energizing system
• Circuit Voltage
• Initial Current ✓ Note ambient temp and pipe temp
• Stabilized Current (15 minutes of operation) ✓ Note ambient temp and pipe temp
• Always use ground fault circuit breakers (30 mA trip level)
Tools Needed • Wire Cutters/Strippers
• Megger
• Phillips Head Screwdriver
• Standard Screwdriver
• Voltmeter
• Utility Knife
• Hammer
SrL Cable • 150ºF / 65ºC Maximum Maintenance
• 185ºF / 85ºC Maximum Exposure
• 3 to 10 W/ft / 10 to 33 W/m
• 16 AWG with Optional TPE or Fluoropolymer Jacket
Srp Cable • 225°F / 110°C Maintenance Temperature
• 275°F / 135°C Maximum Exposure Temperature
• 5 to 15 W/ft / 16 to 49 W/m
• 16 AWG with Optional Fluoropolymer Jacket
Srm Cable • 302ºF / 150ºC Maximum Maintenance
• 420ºF / 215ºC Maximum Exposure
• 5 to 20 W/ft / 16 to 66 W/m
• 16 AWG with Optional Fluoropolymer Jacket
Figure 1Figure 2
Figure 3Figure 4
SRL & HSRL – Therm
al Output Ratings on Insulated M
etal PipeSRM
/E & HSRM
– Thermal Output
Ratings on Insulated Metal Pipe
SRL & HSRL – Thermal Output Ratings
on Plastic Pipe with Alum
inum Tape
SRP – Thermal Output Ratings
on Insulated Metal Pipe
Pip
e Temp
erature (ºF)
Heat Output (W/ft)
2120191817161514131211109876543210
15 W/ft
10 W/ft
5 W/ft
Cable OutputversusTem
perature
0 10
20 30
40 50
60 70
80 90
100 110
120 130
140 150
160 170
180 190
200 210 220 230
010
2030
5060
7080
90100
110120
130140
15040
Pip
e Temp
erature (ºF)
SRL10 & HSRL10
Thermal Output (W/ft)
9876543210
SRL8 & HSRL8SRL5 & HSRL5
SRL3 & HSRL3
Cable OutputversusTem
perature
050
100150
200250
300
Pip
e Temp
erature (ºF)
SRM/E20 &
HSRM20
Power Output (W/ft)
24201612840
SRM/E15 &
HSRM15
SRM/E10 &
HSRM10
SRM/E8 & HSRM
8
SRM/E5 & HSRM
5
SRM/E3 & HSRM
3
Cable OutputversusTem
perature
Pip
e Temp
erature (ºF)M
aintenance Temperature
010
2030
5060
7080
90100
110120
130140
150
Thermal Output (W/ft)
14131211109876543210
4.88
SRL10 & HSRL10
SRL8 & HSRL8
SRL5 & HSRL5
SRL3 & HSRL3
Cable OutputversusTem
perature
40