MIN 470 Final Exam April 27, 2017

Question 1.

(20 marks) Silica is one of the listed designated substances in Ontario legislation. What is the

significance of the term "designated substance"?

What are the four "routes of entry" categories for physical contaminants and the human

body?

Describe the "Swiss cheese" model as it relates to occupational health management.

What was your topic for the occupational health independent study project? What was the most important management strategy for dealing with this contaminant in the workplace?

Question 2.

(20 marks) A company has developed a novel ducting material with a K-factor of 0.0018 Ns2m4. They

propose to a client to change out an existing section of duct with their new product. The old product was round canvas material with a 1.055 m diameter. Because of some really complicated manufacturing process the new duct shape is square. Specify the dimension of the new duct so that the system resistance is unchanged. Ignore any shock losses due to the

change in shape.

VO

Question 3. (30 marks) A fan selection exercise is being done for a deep mine where the operating conditions are predicted to be 27 °C, 80% relative humidity, and 130 kPa atmospheric pressure.

Calculate the expected air density.

The following chart is for standard density of 1.200 kg /M3. Calculate a new performance

chart (flow, total pressure, power) for the density calculated in subsection "a".

Q [m3/s] Total Pressure [Pa] Power [kW]

19.36 2526 69.35

23.61 2240 74.57

28.33 1692 74.57

33.05 647 66.37

Question 4. (15 marks) The only equipment you have in the field is two pitot-static tubes, two pieces of hose, and a differential pressure gauge that can only read positive values (not a compound gauge). It is also important to note that you do not have enough tubing to reach from one end of the long section of the duct to the other. You only have enough to connect instruments right around the fan. Notate the positive (+) and negative (-) ports on the gauge.

Draw how you would hook up your equipment to measure fan total pressure under the following

three arrangements:

Fan and inlet bell located at the entrance / start of a long section of duct.

Fan located in the middle of a long section of duct.

Fan located at the exit / end of a long section of duct.

Question 5. (15 marks)

Describe the 5-3 rule when selecting a location to take a ventilation measurement. Why is this

important?

Question 6. (30 marks)

Consider the following fan and duct arrangement. The velocity pressures and pressure losses

(above duct) have been measured and provide in pascals.

10 290 50 200 180 20 600 40

.+ Pv=100

Pv=300

dLIJ Pv=50

Pv=200 -U,

A B C DE F G H Calculate the following:

Gauge static pressure and gauge total pressure at each labeled location

Fan total pressure and static pressure

Shock loss coefficient on entrance

Evasee efficiency on exit

91

Question 7.

(30 marks) Using the attached psychrometric chart (101 .325 kPa), solve the following graphically:

Locate Point A at 10 0C dry-bulb, 5 00 wet-bulb

Locate Point B at 35 °C dry-bulb, 30 % relative humidity

Locate Point C, which is an adiabatic mixture of A and B at 25 °C dry-bulb.

If the flow rate of A is 20 m3/s, what is the flow rate of B to create the mixture of C?

Complete the following table of psychrometric state-point properties:

Dry Bulb [°C]

R. H. [%]

Wet Bulb [°C]

Humidity Ratio [kg/kg]

A.S.V. [M3 /kg]

Enthalpy [kJ/kg]

Point A

Point B

Point C

Question 8. (30 marks)

Consider the following network with resistance values specified in Ns2/m8 for each segment:

Ri = 0.20 R2 = 0.20 R3 = 0.20

R4 = 0.30

FIVACKINCI

Simplify the network to a single resistance. Calculate the flow and pressure drop in each segment if the flow in the first segment is 01 =

100 m3/s.

PV iiRT ri = Md. = 28.966 kg/kmol M M = 18.015268 kg/kmol

I? P R = 8.3144598 kJ/(Kkmol) I?,spec,fie

= Rda 0.287042 kJ/(kgK)

R = 0.461523 kJ/(kg'K)

17:277 P,, = 0.6105(- 237. 3 IT

- Pu

p = 0.621945

11)

101) c baro -

Pharo - P, p = p, (1 + r) P pg/i

=

A + ptt + pgho + Pf07 , = P1 + pil l + pg/u + P1rict jon + Ps/jock

P5,0 + P1.o ± pgho + Pt. f00 P.1 + P0,1 + pgh + Pirictij ± Pshock

4.4 D =

pt,]3 Rc Pfrict(rl

1.325 KCLu2 p Pt P + Pr Id

(li/(i_ + 4))2 11

PJ I .1C W7 , 4

x1.2

3.7

1 2 P, -p

PRQ 2 KCL p >< Rf = 43 1.2

P1.= XP A 1 •

P = C p'ti. A0

X, =

RXp

0.6XA 11=QxP

- 942 L

- KC

Act u.a.1 Static' .P re.$ . ureRega.i n 100/) - _________

Ile The oretic'alSt aticPres .$ureRe gain '1 -

= (1 - 'r))P , ',ic(J(1ir1

Network Simplification

1

Rtotai R1 + R2 + + R Rtotai =

+ + +

Psychrometry & Thermodynamics

1 RdaT Vda = =

Pda Pl)aro - Pw h = 1.005 tdb + r [2501 + 1.884 S = 1.005 tdb+ r [2501 -4.262 twb+ 1.884tdb]

cop = Qoutput

IVITIPUt

Far \ffinity Laws

Q1 N Kr'

tevaporator COP arnot =

t condenser tevaporatol.

- '

P (D2 1J

Pi Kp2

t12 2 HI NI j

~~~2

DI Pi Kp2

He.. -y Cross

>1 - - (RQa Qa 1 - Pf(, n)

- (2RQ + Sf)

Capital Recovery Factor fl

(A/P. i. n) =

(1+i) —1

Atkinson Friction Factors

Airway K [Ns2/m4]

Ventilation piping (steel I fibreglass) 0.003

Concrete lined empty shaft 0.004

Straight rock tunnel 0.01

Concrete lined shaft with streamlined buntons 0.025

Concrete lined shaft with R.S.J. buntons 0.05

Heavily timbered rectangular shaft 0.08

Raise bored hole 0.0024

Duct Material K [Ns2/m4] K [1010 lb- min 2 I ft4 ]

Galvanized Ifiberglass, new 0.0028 15

Galvanized I fiberglass, used 0.0037 20

Canvas / plastic, new 0.0037 20

Canvas I plastic, used 0.0046 25

Spiral-Canvas, new 0.0111 60

Spiral-Canvas, used 0.0136 73.3

H ASHRAE PSYCHROMETRIC CHART NO.1 H

0 NORMAL TEMPERATURE "

& 8 6. --

E ® BAROMETRIC PRESSURE: 101.325 kPa

Copyright 1992 AMERICAN SOCIETY OF HEATING, REFRIGERATING AND AIR-CONDITIONING ENGINEERS, INC. 2/ /\. /.. / . *.,L '

SEA LEVEL

10 0.6

03 So 00 0.6 SENSIBLE HEAT Os so /. 7'- .. V 1 3o,

TOTAL HEAT Ot

/ 00

0 0

/ 02

J 02

ENTHALPY DjL HUMIDITY RATIO ow

00

60 2............../ ............

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/.................... -

Ly

-- 0

cr—uj

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----- vMtDlT --- -\ N /1O

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ENTHALPY - Ki PER KILOGRAM OF DRY AIR

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ENIHALPY- KJ PER KILOGRAM OF DRY AIR

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H ASH RAE PSYCHROMETRIC CHART NO.1 H

~(y NORMAL TEMPERATURE 0

E BAROMETRIC PRESSURE: 101.325 kPa E

Copyright 1992 AMERICAN SOCIETY OF HEATING, REFRIGERATING AND AIR-CONDITIONING ENGINEERS, INC.

10

SEA LEVEL 10 -

1.5 EOI - OJ So

SENSIBLE HEAT Os q.Ø - -So

0 TOTAL HEAT 01

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ENTHALPY

HUMIDITY RATIO DW / -.----.-

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