4B Boiler Safety Devices Unit 3 4th class Power Engineering Questions and Answers

4B Boiler Safety Devices Unit 3 4th class Power Engineering
Questions and Answers


Question 1.
The discharge pipe from a boiler safety valve is supported independently of the safety
valve: Select one: a.Because the steam drum cannot support the extra mass of the
discharge pipe b.So the discharge pipe can drain more easily c.So the discharge pipe can
expand without putting force on the safety valve d.To prevent leakage at the pipe joint

Correct Answer: So the discharge pipe can expand without putting force on the
safety valve


Question 2.
Which part of ASME-BPVC.I states that the boiler manufacturer must ensure the lowest
visible water level in a gauge glass is at least 50 mm above the lowest permissible water
level? a.Part 6.3.1.1 b.Part PG-60.1 c.Part HG-603 d.Part PG-60.1.1.1

Correct Answer: Part PG-60.1


Question 3.
When a boiler steam outlet stop valve is required by code, the preferred style of valve is

Correct Answer: An outside screw and yoke, rising stem valve


Question 4.
o increase the opening pressure of a safety valve,

Correct Answer: Increase spring compression


Question 5.
A test connection for a boiler pressure gauge

Correct Answer: Is usually installed between the siphon and the pressure gauge


Question 6.
Every steam boiler must have a safety valve that is

Correct Answer: Fitted in a vertical position, directly connected to the top of the
boiler.


Question 7.
Temperature relief devices can open on a rise in temperature by the expansion of a
wax-filled rod or by the

Correct Answer: Melting of the alloy in a fusible plug

, Question 8.
If a shutdown occurs during normal firing of a boiler and the steam pressure is below the
normal cutout value, the problem could be

Correct Answer: An interlock, such as the combustion air proving switch, has
failed


Question 9.
Which of the following is NOT a category into which ASME-BPVC.I and ASME-B31.1 divide
high-pressure plant piping? a.Non-boiler external piping b.Boiler external piping c.Boiler
proper piping d.Boiler non-proper internal piping

Correct Answer: Boiler non-proper internal piping


Question 10.
One purpose of the small valve on top of the shell of most boilers, which is not required by
code, is to: Select one: a.Allow water into the boiler when the boiler is being drained or
cooled preventing the formation of a vacuum. b.Allow water to escape before the steam
stop valve is opened during the warm-up period. c.Allow air to escape from the boiler when
the boiler is being filled with water. d.Allow air into the boiler when the boiler is being filled
with water.

Correct Answer: Allow air to escape from the boiler when the boiler is being
filled with water.


Question 11.
The minimum DN size of the blowoff piping of a steam heating boiler is

Correct Answer: 20 mm


Question 12.
In the image for a natural gas fuel train for a boiler over 3000 kW, which letter indicates to
the main test firing valve?

Correct Answer: J


Question 13.
Why are steam boilers equipped with pressure limit controls? a.To increase the energy
input, should the pressure limit controls fail b.So the energy output of a boiler is always
equal to the energy demand c.To reduce or stop the energy input, should the pressure
limit controls fail d.To ensure steam boiler continues to fire at an excessive rate to attain
steam pressure

Correct Answer: To reduce or stop the energy input, should the pressure limit
controls fail


Question 14.
Automatically fired heating boilers are NOT equipped with which of the following switches?
a.Burner on-off b.Manual-automatic c.Damper positioning d.Low-fire/high-fire