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Hot work, cylinders and pressure questions for the Pipefitting and welding (PFW) specialist test

5 free questions on Hot work, cylinders and pressure, from section E. Specialist: HVACR – pipefitting and welding. Every question is original and explains why each option is right or wrong.

Last verified against HSE guidance and the law ·How we write our questions

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Question 1

Harder ·Link to this question (question 1)

An acetylene cylinder has been heated in a fire. A worker wants to open the valve to let the pressure out.

What does HSE say?

Choose one answer.

  1. A. Don't try to vent it or move it anywhere
  2. B. Vent it straight away to stop it bursting
  3. C. Roll it outside, then vent it
  4. D. Cool it down and put it back in the store
Show the answer and explanation

Answer: A

  • A. Right: Right. HSE strongly advises not to move a heated acetylene cylinder or try to release its pressure. Evacuate 200 metres and call the fire service.
  • B. Wrong: Wrong. HSE says don't try to vent it.
  • C. Wrong: Wrong. HSE says don't try to move it.
  • D. Wrong: Wrong. Keep clear and leave it to the fire service.

Explanation

A heated acetylene cylinder: don't move or vent it. Clear 200 m and call the fire service.

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Question 2

Medium ·Link to this question (question 2)

Oxygen and fuel gas cylinders will be stored inside a building during a refit.

What does HSE say?

Choose one answer.

  1. A. Store them in an escape route, near the exit
  2. B. Extra fire precautions are needed for them
  3. C. Store them anywhere, as cylinders are sealed
  4. D. Store them next to the site heater to keep warm
Show the answer and explanation

Answer: B

  • A. Wrong: Wrong. Never block escape routes.
  • B. Right: Right. HSE says extra precautions are needed for flammable liquids, gases and oxygen cylinders, especially when stored inside.
  • C. Wrong: Wrong. Indoor storage needs extra precautions.
  • D. Wrong: Wrong. Heat makes cylinders more dangerous.

Explanation

Oxygen and flammable gas cylinders need extra precautions, especially when stored inside.

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Question 3

Medium ·Link to this question (question 3)

A compressed air system for testing pipework runs at 7 bar.

Is compressed air covered by PSSR?

Choose one answer.

  1. A. Only above 100 bar
  2. B. Only if it is used outdoors
  3. C. Yes, above 0.5 bar
  4. D. No, air is never a pressure hazard
Show the answer and explanation

Answer: C

  • A. Wrong: Wrong. The threshold is 0.5 bar.
  • B. Wrong: Wrong. Location doesn't matter.
  • C. Right: Right. HSE says PSSR covers compressed or liquefied gas, including air, at more than 0.5 bar above atmospheric pressure.
  • D. Wrong: Wrong. Compressed air above 0.5 bar is covered.

Explanation

PSSR covers compressed gases, including air, above 0.5 bar.

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Question 4

Harder ·Link to this question (question 4)

A competent person is examining a pressure system under its written scheme.

What authority must they have?

Choose one answer.

  1. A. To set the price of repairs
  2. B. To hire and fire the operators of the plant
  3. C. None, as they only advise
  4. D. To stop the equipment being used
Show the answer and explanation

Answer: D

  • A. Wrong: Wrong. They need authority to stop use.
  • B. Wrong: Wrong. They need authority to stop use.
  • C. Wrong: Wrong. They need authority to stop use.
  • D. Right: Right. HSE says the competent person must have sufficient authority to stop the use of the pressure equipment if needed, and be independent of operating functions.

Explanation

The competent person under PSSR must be independent and able to stop the equipment being used.

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Question 5

Easier ·Link to this question (question 5)

You are about to weld a pipe bracket near stored insulation and timber.

Which precaution does HSE list?

Choose one answer.

  1. A. Keep a careful watch throughout the work
  2. B. Start welding, then look around afterwards
  3. C. Leave the area as soon as the arc is struck
  4. D. Switch off the smoke detectors to stop alarms
Show the answer and explanation

Answer: A

  • A. Right: Right. HSE lists clearing combustibles, suitable extinguishers and maintaining a careful watch throughout as hot work precautions.
  • B. Wrong: Wrong. Keep watch throughout the work.
  • C. Wrong: Wrong. Keep watch throughout the work.
  • D. Wrong: Wrong. Detectors must stay on.

Explanation

Keep a careful watch throughout hot work, with combustibles cleared and an extinguisher ready.

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