Question 4 of 7: Fire Hazards and Fire Protection

Question 4: Fire Hazards and Fire Protection (20 marks: 7/6/6)

Question text not reproduced: the examination questions are © Engineers and Geoscientists BC. Open the official past paper (linked at the top of this page) to read the question, then follow the worked solution below.

(i) Controlling Fire Hazards from Welding and Cutting (Hot Work)

• Hot-work permit system — authorization, inspection and sign-off before and after work.
• Remove or protect combustibles — clear the area (typically ≥ 11 m / 35 ft) of flammables; cover or shield what cannot be moved with fire-resistant blankets.
• Fire watch — a trained person with an extinguisher during work and for a period (e.g., 30–60 min) afterward to catch smouldering.
• Control ignition and sparks — spark screens, containment of slag/sparks, seal floor/wall openings.
• Ventilation and atmosphere testing — remove flammable vapours; test confined spaces/containers before hot work (never on sealed or previously flammable-holding vessels without purging).
• Ready fire extinguishers/hoses of the correct class at hand.
• Trained operators, proper equipment inspection, gas-cylinder handling and shutoff procedures.

(ii) Factors in Protecting Human Life from Fire

• Early detection and alarm — smoke/heat detectors, audible/visual alarms giving prompt warning.
• Means of egress — sufficient number, width and arrangement of exits; clearly marked, illuminated, unobstructed; travel distance limited; two ways out.
• Time to evacuate — occupant load and mobility (including disabled persons) versus available safe egress time.
• Compartmentation — fire-rated walls/doors to contain fire and protect escape routes.
• Suppression — sprinklers and extinguishers to control fire growth.
• Smoke control — the main killer; ventilation/pressurization of stairwells.
• Emergency planning and training — evacuation plans, drills, wardens, assembly points.
• Housekeeping — limit fuel load and ignition sources.

(iii) Typical Response to a Fire (diagram)

Discover fire
     |
     v
Raise ALARM  ---> Notify others / call fire dept (RACE: Rescue, Alarm)
     |
     v
Assess size / risk
     |
   +------------------+
   |                  |
 Small &            Large / spreading /
 controllable?      unsafe?
   |                  |
   v                  v
Fight with        EVACUATE via marked
extinguisher      exits -> proceed to
(if trained,      ASSEMBLY POINT
back to exit)         |
   |                  v
   +----------->  Account for all persons;
                  await & assist fire brigade

The sequence follows the "RACE" principle—Rescue anyone in immediate danger, Alarm, Confine (close doors), Extinguish only if small and safe, otherwise Evacuate.