# Questions

## 10.2 Pipes and Pipe Sizing

1 A boiler is operated at 10 bar g and is required to supply 500 kg/h of saturated steam at 9.8 bar g to equipment 110 m away. The pipe run is torturous and contains many fittings adding 20% to the equivalent length. What size pipe should be selected?
a) 100 mm nominal bore
b) 80 mm nominal bore
c) 50 mm nominal bore
d) 65 mm nominal bore
2 A 100 mm steam pipe has been selected for a particular steam flowrate with 8.3 bar g at the inlet and 7.7 bar g at the end of the run. Calculations show that, for this flowrate and size of pipe, the pressure at the end of the run will actually be 7.9 bar g. Which of the following is true?
a) The steam velocity is higher than expected, and could cause noise
c) The resistance to flow is higher than expected
d) A larger pipe is required
3 A 40 m long 5 bar g saturated steam pipe is to be sized to carry 850 kg/h of steam. Should the pipe be sized on velocity or pressure drop?
a) Pressure drop to limit the steam velocity
b) On a velocity over 40 m/s
c) On a velocity of about 25 m/s
d) Either, provided the steam velocity does not exceed, approximately 5 m/s
4 A 40 m pipe incorporating a number of bends and fittings is to be sized by the velocity method to handle 1 200 kg/h of saturated steam at 4 bar g. What size pipe is required?
a) 100 mm
b) 80 mm
c) 125 mm
d) The pipe should be sized on pressure drop, and not by velocity
5 A straight run of pipe 30 m long and carrying saturated steam at 10 bar g is to be sized by the velocity method to pass 20 000 kg/h. What size pipe is required?
a) 175 mm
b) 150 mm
c) 200 mm
d) 250 mm
6 From the following, what is the effect of sizing a 100 m long, 8 bar g steam pipe by the velocity method?
a) Sizing by velocity takes no account of pressure drop along the pipe
b) If the velocity is more than 40 m/s, the pressure drop along the pipe may be very small and in practice a small pipe may be used
c) If a low velocity is selected, the chosen pipe will probably be undersized resulting in steam starvation at the plant
d) Over a length of 100 m, the noise of steam flow can be unacceptable