Permit to Work Systems Flashcards

When is it appropriate to bypass or override a permit to work requirement?

Answer: Never — permits must not be bypassed, regardless of urgency or instruction. Emergency situations have their own emergency procedures which are separate from PTW systems

Permit to work systems must never be bypassed. Emergency procedures are separate from PTW systems and are used in genuine emergencies. Even under pressure, bypassing a PTW creates the conditions for a catastrophic incident.

A permit for confined space entry in an excavation must confirm what atmospheric conditions?

Answer: Oxygen level is between 19.5% and 23.5%, carbon monoxide is below 20 ppm, hydrogen sulphide is below 5 ppm, and flammable gas levels are below 10% of the lower explosive limit

Safe atmospheric conditions for confined space entry require: oxygen 19.5–23.5% (below this is deficient, above 23.5% is enriched and a fire risk), CO below 20 ppm, H2S below 5 ppm, and flammable gas below 10% LEL. Continuous monitoring during entry is required.

Which of the following should cause the immediate suspension of a permit to work?

Answer: A change in conditions that introduces a new hazard not covered by the permit conditions — such as a gas escape nearby, structural deterioration, or a significant change in atmospheric readings

If conditions change in a way that introduces a new or different hazard not covered by the existing permit, the permit must be suspended immediately. Work stops, the area is made safe, and the permit is re-evaluated and re-issued with updated conditions if appropriate.

A site manager discovers that permit to work documentation has been backdated by a supervisor to show that a permit was in place before a task started, when it was not. This is:

Answer: A serious H&S management failure and may constitute falsification of records — the incident should be investigated and the supervisor disciplined; legal prosecution may follow if an incident occurred

Falsifying safety records (including backdating PTWs) is a serious disciplinary and potentially criminal matter. It may constitute perverting health and safety management, and if discovered following an incident could result in prosecution. It must be investigated and dealt with firmly.

What is the difference between a 'long-duration permit' and a 'short-duration permit' in a PTW system?

Answer: Some PTW systems use time-limited short-duration permits (e.g., shift-length) for work that must be re-authorised at each shift, and longer-duration permits for work that continues over multiple shifts with daily re-verification of conditions

Many PTW systems distinguish between short-duration permits (valid for a shift, typically up to 8–12 hours) and longer permits for extended work. Longer-duration permits require re-verification of conditions at regular intervals (typically each shift) to ensure precautions remain in place.

A permit to work for demolition near a live sewer must include which specific precaution?

Answer: Confirmation of the sewer location, measures to prevent vibration-induced collapse of the sewer, and emergency procedures if the sewer is accidentally breached including who to notify (e.g., the water company)

Demolition near live sewers or drains requires: confirming the sewer's location and condition, measures to prevent collapse (e.g., temporary support, hand breaking near the sewer), and clear emergency procedures for the scenario where the sewer is accidentally breached, including immediate notification of the water company.