CITB Specialists Fire Safety in Specialist Trades 1 — Questions and Answers
Question 1: What is the most common cause of fire on UK construction sites?
- Hot works (welding, cutting, grinding, and blowtorch use) (Correct answer)
- Arson by intruders
- Spontaneous combustion of waste materials
- Electrical faults in temporary supplies
Correct answer: Hot works (welding, cutting, grinding, and blowtorch use)
Hot works including welding, cutting, grinding, and use of blowtorches are the most common cause of construction site fires. Sparks and heat can ignite combustible materials, sometimes causing smouldering fires that are not discovered until hours later.
Question 2: What is a Hot Work Permit and who issues it?
- A document authorising hot work at specific locations for a defined time, issued by the site manager or fire safety coordinator (Correct answer)
- A licence from the fire brigade to conduct hot works
- A permit issued by the equipment manufacturer
- An insurance document for welding operations
Correct answer: A document authorising hot work at specific locations for a defined time, issued by the site manager or fire safety coordinator
A Hot Work Permit is a site safety document that authorises specific hot work operations at defined locations for a specific time period. It specifies fire precautions, fire watch requirements, and who is responsible for the work area.
Question 3: How long should a fire watch be maintained after hot work is completed?
- At least 60 minutes after hot work ceases, with a further check after returning later in the day (Correct answer)
- 5 minutes only
- Until the work area has cooled to room temperature — usually 10 minutes
- No fire watch is needed if water is available nearby
Correct answer: At least 60 minutes after hot work ceases, with a further check after returning later in the day
A fire watch of at least 60 minutes must be maintained after hot work ends because smouldering fires in concealed areas (wall cavities, insulation) may take time to develop. A further check at the end of the shift or day is also required.
Question 4: What fire extinguisher is appropriate for an electrical fire?
- CO2 (carbon dioxide) extinguisher (Correct answer)
- Water extinguisher
- Foam extinguisher
- Powder extinguisher unless no other is available
Correct answer: CO2 (carbon dioxide) extinguisher
CO2 extinguishers are the correct choice for electrical fires as they do not conduct electricity and leave no residue. Water extinguishers must never be used on live electrical equipment due to electrocution risk.
Question 5: What is a Class F fire and which specialist trade must consider it?
- A fire involving cooking oils and fats — relevant to catering equipment installers (Correct answer)
- A fire involving flammable gases
- A fire involving metals
- A fire involving electrical equipment
Correct answer: A fire involving cooking oils and fats — relevant to catering equipment installers
Class F fires involve cooking oils and fats. Catering equipment installers and kitchen extraction duct cleaners must be aware of Class F fire risks and use only Class F wet chemical extinguishers — standard water, foam, or CO2 extinguishers are ineffective.
Question 6: When must a fire risk assessment be updated on a construction site?
- When significant changes occur to the site, materials used, or work activities — and at regular intervals (Correct answer)
- Only annually
- Only after a fire incident
- Only when the site boundary changes
Correct answer: When significant changes occur to the site, materials used, or work activities — and at regular intervals
A construction site fire risk assessment must be reviewed whenever there is a significant change (new activity, new materials, new areas opened), after a fire or near-miss incident, and at regular intervals throughout the project.
CITB Specialists Fire Safety in Specialist Trades 1
What is the most common cause of fire on UK construction sites?