NEBOSH Fire Safety Management 4 — Questions and Answers
Question 1: What is the 'fire tetrahedron' and how does it differ from the fire triangle?
- It replaces oxygen with nitrogen
- It adds a fourth element — the chemical chain reaction — to the three elements of the fire triangle (Correct answer)
- It removes the fuel element
- It is a different name for the same concept
Correct answer: It adds a fourth element — the chemical chain reaction — to the three elements of the fire triangle
The fire tetrahedron adds a fourth element to the fire triangle: the uninhibited chemical chain reaction. While the fire triangle explains fire initiation, the tetrahedron explains fire sustainment. Some extinguishing agents such as dry powder work by interrupting this chain reaction (chemical inhibition) rather than removing heat, fuel, or oxygen.
Question 2: Step 2 of a fire risk assessment requires identification of people at risk. Which groups need special consideration?
- Only full-time employees
- Persons with disabilities, lone workers, night workers, visitors, contractors, children, and people sleeping on premises (Correct answer)
- Only fire wardens
- Only people working on the ground floor
Correct answer: Persons with disabilities, lone workers, night workers, visitors, contractors, children, and people sleeping on premises
Step 2 requires identifying everyone who may be at risk, with special consideration for vulnerable groups including persons with mobility, hearing or visual impairments, lone workers, sleeping occupants, young persons, elderly persons, visitors unfamiliar with the building, contractors, and anyone in remote or high-risk areas.
Question 3: What type of fire detection device is most suitable for areas where fast-flaming fires are the primary risk?
- Optical (photoelectric) smoke detector
- Ionisation smoke detector (Correct answer)
- Line-type heat detector
- Aspirating smoke detection system
Correct answer: Ionisation smoke detector
Ionisation smoke detectors contain a small radioactive source that ionises the air in a sensing chamber. Small particles from fast-flaming fires (such as burning paper or flammable liquids) disrupt the ion current, triggering the alarm. They respond more quickly to fast-flaming fires than optical detectors but are prone to false alarms from cooking fumes.
Question 4: A foam extinguisher has which colour band and is suitable for which fire classes?
- Black band, suitable for Class C and electrical fires
- Cream band, suitable for Class A and Class B fires (Correct answer)
- Blue band, suitable for Class D fires
- Yellow band, suitable for Class F fires
Correct answer: Cream band, suitable for Class A and Class B fires
Foam extinguishers have a cream colour band and are suitable for Class A fires (solid combustibles such as wood, paper, textiles) and Class B fires (flammable liquids such as petrol, oil, solvents). They should not be used on electrical fires unless they are di-electrically tested, or on Class F cooking fat fires.
Question 5: What structural fire protection measure divides a building into compartments to limit fire spread?
- Emergency lighting
- Compartmentation using fire-resisting walls, floors, and doors (Correct answer)
- Smoke ventilation systems
- Manual call points
Correct answer: Compartmentation using fire-resisting walls, floors, and doors
Compartmentation divides a building into fire-resistant compartments using walls, floors, ceilings, and doors with specified fire resistance ratings. Each compartment acts as a barrier to contain fire and smoke, limiting damage, protecting escape routes, and providing time for evacuation and firefighting. Breaches from cable trays or pipes must be fire-stopped.
Question 6: Under the Regulatory Reform (Fire Safety) Order 2005, who is the 'responsible person' for fire safety in a workplace?
- The local fire and rescue service
- The employer, owner, or any person who has control of the premises (Correct answer)
- The building insurance company
- The most senior employee present
Correct answer: The employer, owner, or any person who has control of the premises
Under the RR(FS)O 2005, the responsible person is the employer (for workplaces), the person in control of the premises (for non-workplaces), or the owner. They must carry out a fire risk assessment, implement preventive and protective measures, provide information and training, and maintain fire safety measures.
NEBOSH Fire Safety Management 4
What is the 'fire tetrahedron' and how does it differ from the fire triangle?