Unsafe Situations
25 free practice questions with explanations
PassNova has 25 free Gas Safe ACS practice questions on Unsafe Situations, each with a clear explanation. Practise them in the browser with instant feedback — 100% free, no sign-up, on any device. Updated for 2026.
Unsafe Situations: example questions & answers
12 worked examples with answers and explanations below. Practise all 25 Unsafe Situations questions free in the browser, with instant feedback on every answer.
What defines an 'At Risk' classification?
- ANot a real classification
- BA defect that poses potential danger but is not immediately life-threatening✓
- CJust observations
- DOnly for obvious hazards
Answer: At Risk situations could become dangerous and require remedial action.
What defines an 'Immediately Dangerous' situation?
- AMinor defect
- BA condition posing imminent risk of injury or death requiring urgent action✓
- CJust a warning
- DNot possible
Answer: Immediately Dangerous situations require urgent isolation and warning.
What must be done with an Immediately Dangerous appliance?
- ASchedule repairs
- BImmediately isolate the appliance and issue a warning notice to the occupant✓
- CContinue using with caution
- DJust document it
Answer: Immediately Dangerous appliances must be isolated immediately and the occupant warned.
What is a 'Not to Current Standards' (NCS) defect?
- ADangerous condition
- BAn installation not meeting current BS 6891 or regulations but not immediately dangerous✓
- CAcceptable variation
- DJust old age
Answer: NCS defects are non-compliant but not immediately dangerous, requiring attention.
What is a warning notice (CCNWS)?
- AA recommendation letter
- BA formal notice issued when a dangerous defect is found✓
- CJust a courtesy call
- DNot an official document
Answer: Warning notices formally alert occupants to dangerous gas defects.
What should be included on a warning notice?
- AJust the date
- BNature of hazard, appliance details, why it's dangerous, and required actions✓
- COnly the engineer name
- DNot specified
Answer: Warning notices detail the hazard, why it's dangerous, and what action is needed.
What is the procedure for an engineer discovering a gas leak?
- AJust warn the customer
- BIsolate the supply, warn occupants, issue warning notice, and report to the gas supplier if needed✓
- CContinue inspection
- DSchedule a repair later
Answer: Gas leaks require immediate isolation, warning, and supplier notification.
What is capping off in gas work?
- AJust closing a valve
- BPermanently isolating and sealing a gas supply or appliance when dangerous or no longer needed✓
- CTemporary isolation
- DNot allowed
Answer: Capping involves permanent isolation of dangerous gas pipes or appliances.
What must be done to cap off a gas installation?
- AJust close the valve
- BIsolate supply, test for tightness, and install permanent caps/plugs on all open ends✓
- CLeave it open
- DNo specific procedure
Answer: Capping requires testing tightness and installing permanent seals.
What is a customer handover document?
- ANot needed
- BA document explaining the safety status, any faults, and required actions given to the occupant✓
- CJust a receipt
- DOnly for sales
Answer: Handover documents inform customers of condition and any remedial needs.
What is the legal consequence of supplying gas to a dangerous appliance?
- ANo consequence
- BCriminal liability for the engineer and potentially the supplier✓
- CJust a fine
- DWarning only
Answer: Allowing dangerous appliances to operate creates criminal liability.
What should be done if an appliance is deemed Immediately Dangerous due to CO risk?
- AJust warn the customer
- BImmediately isolate, issue warning notice, advise occupants of CO danger, and require urgent repair✓
- CSchedule service
- DMonitor the situation
Answer: CO hazards require immediate isolation and clear warnings of the danger.