Designing Systems

toCompensate

forThermal

Expansionand

Contraction

Things We Have Learned From Being Sued

6 Model MC - 6 CorrugationsAnchor Load @ 150psi - 11,600#

This is why you should use guides

RiserF3Floor425Room24

Use Any Natural Flexibility In The piping layout

2008 ASHRAE Handbook

Heating, Ventilating, and Air Conditioning Systems and Equipment

Chapter 45

Or this can be simplified to

L = 6.225 D

L = 3DE(144in/ft)SA

Where = Thermal expansion of leg ABD = Pipe Outside DiameterE = Modulus of ElasticitySA = Allowable Stress

For a Basic Expansion ElbowHard Pipe

L

Anchor

Anchor

A

B

C

L = 4 D Where = Thermal expansion of leg ABD = Pipe Outside DiameterE = Modulus of ElasticitySA = Allowable Stress

For a Basic Expansion Z Bend Hard Pipe

X

X

Guide

Guide

AnchorAnchor

L

L

L

A

B

Anchor to Anchor Expansion

So what kind of expansion joint to use?

L = 6.225 D

W = L/5H = 2*W

Where = Thermal expansion of runD = Pipe Outside DiameterE = Modulus of ElasticitySA = Allowable Stress

For a Basic Expansion Loop Hard Pipe

XX

AnchorAnchor

Guide

Guide

Anchor to Anchor Expansion

2H 2H

W

H

Hard Loops Pro/Con

Same material as the rest of piping

Constructed on site, costly to fabricate, hang and insulate

Grandfather used em

Medium anchor loads

Constructed on site

Pro

Needs lots of room

High lateral loads on moment guides.

Con

Flexible Expansion Loop

V Loops

The flexible pipe loop is also smaller and has less anchor load than a hard pipe loop

Hose Basics

Corrugated stainless steel hose by itself

has great hoop strength, but poor tensile

strength

Virtually any amount of movement

Cap weld,

welding the

hose, braid and

collar together

Weld the End Fitting to the Hose

On a flex loop the braid is the anchor

XX

1

6

5

F

e

e

t

2

.

8

5

E

x

p

.

50 Feet

.59 Exp.

1

9

F

e

e

t

19 Feet

Guides

4 Sch 40 Carbon Steel With Hard Pipe Expansion 90

Anchor with 582 pounds force

X

X

1

6

5

F

e

e

t

2

.

8

5

E

x

p

.

50 Feet

.59 Exp.

3

F

e

e

t

3 Feet

Guides

4 Sch 40 Carbon Steel With H&B Dog Leg

Anchor with 180 pounds force

Hose & Braid

Flexible Loop Pro/Con

Very compact Some pressure limitations

No maintenance

Minimal guiding requirements

Lowest anchor loads, almost no structural considerations.

Least expensive optionStandard or custom fit

Large movement

Seismic capable

Pro Con

Axial movement Lateral movement Angular movement

Theres a lot of choices of Bellows

Axial Bellows Externally Pressurized Axial BellowsUntied Double

Bellows Gimbal Bellows

Dual Tied BellowsDouble Hinged

BellowsSingle Hinge

Bellows

Internally Pressurized

Externally Pressurized

Axial movement onlyCapable of Axial, Lateral and

Angular movements.

Expansion

Compensators

externally

pressurized

Atmosphere

Built in Liner

Squirm- Strut Instability - Limits the movement of internally pressurized bellows

The balance between the number of convolutions needed for the movement exceeds the stability of the bellows

Internally Pressurized Bellows

Axial

Are Primarily Designed to Handle

Axial Movement

On the other hand,a dual-tied bellows moves

And laterally

Axially

Dual-tied bellows joint

Anchors

Pressure ThrustPressure X effective area ( Use test pressure if greater )

Calculating forces on anchors

Deflection Load Published Spring Rate X movement of the joint

Frictional ResistanceTotal weight of pipe, media, insulation & equip. X coefficient

Pressure ThrustPressure X effective area ( Use test pressure if greater )

Example:4= 35.96 sq. in effective area x 125 PSI = 4495 #.

Calculating forces on anchors

To calculate the thrust load:Effective Areas

Pressure Thrust for the Model MC Ring Controlled Self-Equalizing

Expansion Joint The average car weighs only

3000#

Deflection Load (spring rate)

Totally independent of pressure or temperature

Published Spring Rate X Actual movement of the joint

Example:4 with 6 Axial = Spring rate of 143 lbs/in

X4.3 (total amount of expansion)

= 614.9 lbs

Deflection Load on Anchors

Frictional ResistanceTotal weight of pipe, media, insulation & equip. X coeff.

Example4 sch. 40 pipe at 10.8 #/ft x 75 ft = 1890 #

4 pipe internal area 12.73 sq.in. / 144 in. per sq.ft. = 0.088 cu.ft. x 175 linear ft. = 15.4 cu.ft. total volume

125 PSI steam = 3.23 cu.ft. per pound = 4.76# weightadd guides & joint & insulation at 500#

Total 2395# x 0.3 Coeff. = 719# frictional resistance

Calculating forces on anchors

Total Anchor Force

4495 Pressure Thrust614 Deflection Load719 Friction Resistance5,828.9 lbs force

The engineer may add other loads such as snow, ice, wind, based on project conditions

Intermediate AnchorsIntermediate anchors between expansion devices do not see the full load.

X

Intermediate Anchor

MainAnchor

X X

MainAnchor

Expansion Joint

EJMA recommends to design intermediate anchors for the spring load of one of the joints

XMainAnchor

X

X

Expansion Joint

Anchors at fittings can have multi-directional loads

Force

Force

Expansion Joint

Location

Makes a Difference

Guiding

Column strength of pipe.

Total Anchor Force

4495 Pressure Thrust614 Deflection Load719 Friction Resistance5,828.9 lbs force

Remember our Example

LINERSWhen velocity is high and could set up vibration in bellows

Compressed air lines

Exhaust gases

Abrasive flow media

Rule of Thumb :When velocity > 10 FPS

Install 1st. Guide a max. of 4 pipe dia. From the expansion joint.Install 2nd. Guide a max. of 14 pipe dia. From the 1st. Guide. Additional guides as per EJMA recommendations

Bellows Pro/Con

Low/ no pressure drop High anchor loads

Externally pressurized-large movement

Easy to insulate

Custom fit

No maintenance

Very compact Engineered anchors

Considerable guiding requirements

Pro Con

Torque can be a problem

Slip type Joints

Slip Type Joint

Slip Joint construction detail

Ball Joints

Always in, at least pairs

Similar construction with Slip joints

Same maintenance issues

Slip Type Pro/Con

Low/ no pressure drop High anchor loads

Custom fit

Large movementVery compact

Very expensive

Low or no cycling is a detriment.

Very High maintenance packing frequently needed

Crucial and Considerable guiding requirements

Engineered anchors

Pro Con

128

6

250 75

85 75

1

5

0

1

5

0

7

5

Lets Start With Determining The Pipe Size and Pipe Dimensions

To Calculate Expansion

1 Determine design temperature for example 200 F.

2 Establish installation temperature - For example 50 F

3 Find the expansion rate per 100 feet 1.179 / 100 feet for steel 1.728 / 100 feet for copper

4 Determine the length of pipe run for example 165 feet

5 Multiply the expansion rate by the length.(165 / 100) X 1.179 = 1.94 Expansion

6 If the joint is for both thermal and seismic, the values must be added together!

For An Example

Lets use

Pipe Material Carbon SteelService Hot WaterDesign Temperature 200FInstallation Temperature 50 FTemperature Difference T 150FExpansion Rate L 1.179 inches / 100 Feet

128

6

250 75

85 75

1

5

0

1

5

0

7

5

2.95

1.0

1

.

7

7

1

.

7

7

0

.

8

8

0.88

0.88

Lets Calculate How Much The Pipe Will Expand

128

6

250 75

85 75

1

5

0

1

5

0

7

5

2.95

1.0

1

.

7

7

1

.

7

7

0

.

8

8

0.88

0.88

Lets Establish The Anchor Points

X

X X

X

X

X

Anchor(typ)

Anchor(typ)

First check for Natural

Flexibility

First check for Natural

Flexibility

Keep in Mind

90 changes in direction are the most efficient piping configuration to use to take up thermal expansion or contraction.

Smaller angles will compound the movements!

128

6

250 75

85 75

1

5

0

1

5

0

7

5

2.95

1.0

1

.

7

7

1

.

7

7

0

.

8

8

0.88

0.88

Next, Use Any Natural Flexibility Of The System

X

X X

X

X

X

Anchor(typ)

Anchor(typ)

2

2

1

3

128

6

250 75

85 75

1

5

0

1

5

0

7

5

2.95

1.0

1

.

7

7

1

.

7

7

0

.

8

8

0.88

0.88

Next, Complete The System WithFlexible Pipe Loops

X

X X

X

X

X

Anchor(typ)

Anchor(typ)

2

2

1

3

MLW81200

MLW80800

MLW30600

128

6

250 75

85 75

1

5

0

1

5

0

7

5

2.95

1.0

1

.

7

7

1

.

7

7

0

.

8

8

0.88

0.88

X

X X

X

X

X

Anchor(typ)

Anchor(typ)

2

2

1

3

Or, Complete The System WithExpansion Joints

Dont forget about the guides. Note the placementof the Metragators

128

6

250 75

85 75

1

5

0

1

5

0

7

5

2.95

1.0

1

.

7

7

1

.

7

7

0

.

8

8

0.88

0.88

What if the 75 foot run was only 18 feet?

X

X X

X

X

X

Anchor(typ)

Anchor(typ)

2

2

1

3

128

6

250 18

85 75

1

5

0

1

5

0

7

5

2.95

1.0

1

.

7

7

1

.

7

7

0

.

8

8

0.21

0.88

Option 1Use a Hose & Braid Dog Leg

X

X X

X

X

X

Anchor(typ)

Anchor(typ)

4

0

1

3

128

6

250 18

85 75

1

5

0

1

5

0

7

5

2.95

1.0

1

.

7

7

1

.

7

7

0

.

8

8

0.21

0.88

Option 2Add an Anchor, and another expansion device

X

X X

X

X

X

Anchor(typ)

Anchor(typ)

1

8

1

3

X

128

6

250 18

85 75

1

5

0

1

5

0

7

5

2.95

1.0

1

.

7

7

1

.

7

7

0

.

8

8

0.21

0.88

Next, Complete The System WithFlexible Pipe Loops

X

X X

X

X

X

Anchor(typ)

Anchor(typ)

1

8

1

3

MLW81200

MLW80800

MLW30600

X

MLW30800

128

6

250 18

85 75

1

5

0

1

5

0

7

5

2.95

1.0

1

.

7

7

1

.

7

7

0

.

8

8

0.21

0.88

Or with Expansion Joints

X

X X

X

X

X

Anchor(typ)

Anchor(typ)

2

2

1

3

X