ENGR403 FIRE ENGINEERING EXAM REVIEW
2026 FULL QUESTIONS AND CORRECT
ANSWERS
◉What is a fire safety system? Answer: System that activates in case of
fire
◉What is the objective of a fire safety system? Answer: Reduce the
consequence of fire
◉What are the fastest (most immediate) fire signature? (Signature 1).
Answer: Radiation (ultraviolet (specific bands), visible (not very useful),
infrared (specifc bands)
◉UV radiation. Answer: Free radicals (carbon particles) form. They
release energy as they heat and cool down repeatedly.
◉Infrared radiation. Answer: There is molecular movement. They have
less energy than free radicals but a higher wavelength.
◉Visable light radiation. Answer: In a yellow flame, soot forms. Solid
particles get heated and glow.
,◉Premix flame. Answer: Fuel and air mix before combustion (e.g
bunsen burner)
◉Diffusion flame. Answer: Air mixes with fuel outside (real-life fire)
◉Signature 2: Fire gases, aerosols, heat. Answer: Gases - CO, CO2
Aerosols - Soot
Heat - Temperature
◉Gases types. Answer: Carbon-based fuels (CO2, CO) and special
fuels (PVS (HCl), Wool (HCN))
◉Aerosols from different fires. Answer: Flaming fires: solid soot
particles that stick together and can be seen above.
Smouldering fires: Liquid drops (tar and oil)
◉Temperature from different fires. Answer: Flaming fires: Lots of heat
Smouldering fires: Limited heat
◉Signauture 3: Sound in air and materials. Answer: Sound comes from
compression and rarefaction in air, and fuel thermal expansion upon
heating.
,◉Types of fire detectors (e.g point...). Answer: Point detector, line
detector, volume detector, and aspirating detector
◉Types of fire detectors. Answer: Flame detectors (radiation), gas
detectors (gases), smoke detectors (aerosols), thermal detectors (heat),
aspirating detectors (aerosols), multiple source detectors, special
application detectors.
◉Types of smoke detectors. Answer: 1. Ionisation chamber smoke
detector
2. Photoelectric smoke detector
3. Linear beam detector
◉Ionisation chamber smoke detector. Answer: The detector ionises the
air, which makes a current (completes the circuit). The ions and
electrons stick to soot particles as they pass through the detector, which
reduces the current.
Issue: They used to go off frequently, so are not used as much anymore.
◉Photoelectric smoke detector. Answer: The detector emits light
towards a light trap. If a soot particle enters the detector, light is
deflected down to a light receiver that is at 125 degrees. Bugger particles
scatter more light while smaller particles cannot scatter it.
, The detector is good for brighter smoke.
◉Linear beam detector. Answer: A light emitter directs light towards a
light receiver. If a soot particle enters the detector, the intensity of the
light reduces.
Notes: This detector requires big particles. Usually, IR is used. It is slow
but good for a factory or large warehouse.
◉Smoke detector: Effect of size. Answer: Choose a detector based on
the fuel and where it is installed.
Flaming fire: Has smaller particles; therefore, the ionisation detector is
best suited. (But it can cause false alarms for smaller particles created
when cooking).
Smouldering fire: Has big (tar droplets) particles; therefore, the
photoelectric detector is best suited.
◉Types of thermal detectors. Answer: 1. Fixed alarm threshold
(activation at T)
2. Rate of rise [RoR] (activation at change in T)
3. Combined fixed at RoR
4. Point detector
5. Line detector (big wire that if melted, alarm goes off)
2026 FULL QUESTIONS AND CORRECT
ANSWERS
◉What is a fire safety system? Answer: System that activates in case of
fire
◉What is the objective of a fire safety system? Answer: Reduce the
consequence of fire
◉What are the fastest (most immediate) fire signature? (Signature 1).
Answer: Radiation (ultraviolet (specific bands), visible (not very useful),
infrared (specifc bands)
◉UV radiation. Answer: Free radicals (carbon particles) form. They
release energy as they heat and cool down repeatedly.
◉Infrared radiation. Answer: There is molecular movement. They have
less energy than free radicals but a higher wavelength.
◉Visable light radiation. Answer: In a yellow flame, soot forms. Solid
particles get heated and glow.
,◉Premix flame. Answer: Fuel and air mix before combustion (e.g
bunsen burner)
◉Diffusion flame. Answer: Air mixes with fuel outside (real-life fire)
◉Signature 2: Fire gases, aerosols, heat. Answer: Gases - CO, CO2
Aerosols - Soot
Heat - Temperature
◉Gases types. Answer: Carbon-based fuels (CO2, CO) and special
fuels (PVS (HCl), Wool (HCN))
◉Aerosols from different fires. Answer: Flaming fires: solid soot
particles that stick together and can be seen above.
Smouldering fires: Liquid drops (tar and oil)
◉Temperature from different fires. Answer: Flaming fires: Lots of heat
Smouldering fires: Limited heat
◉Signauture 3: Sound in air and materials. Answer: Sound comes from
compression and rarefaction in air, and fuel thermal expansion upon
heating.
,◉Types of fire detectors (e.g point...). Answer: Point detector, line
detector, volume detector, and aspirating detector
◉Types of fire detectors. Answer: Flame detectors (radiation), gas
detectors (gases), smoke detectors (aerosols), thermal detectors (heat),
aspirating detectors (aerosols), multiple source detectors, special
application detectors.
◉Types of smoke detectors. Answer: 1. Ionisation chamber smoke
detector
2. Photoelectric smoke detector
3. Linear beam detector
◉Ionisation chamber smoke detector. Answer: The detector ionises the
air, which makes a current (completes the circuit). The ions and
electrons stick to soot particles as they pass through the detector, which
reduces the current.
Issue: They used to go off frequently, so are not used as much anymore.
◉Photoelectric smoke detector. Answer: The detector emits light
towards a light trap. If a soot particle enters the detector, light is
deflected down to a light receiver that is at 125 degrees. Bugger particles
scatter more light while smaller particles cannot scatter it.
, The detector is good for brighter smoke.
◉Linear beam detector. Answer: A light emitter directs light towards a
light receiver. If a soot particle enters the detector, the intensity of the
light reduces.
Notes: This detector requires big particles. Usually, IR is used. It is slow
but good for a factory or large warehouse.
◉Smoke detector: Effect of size. Answer: Choose a detector based on
the fuel and where it is installed.
Flaming fire: Has smaller particles; therefore, the ionisation detector is
best suited. (But it can cause false alarms for smaller particles created
when cooking).
Smouldering fire: Has big (tar droplets) particles; therefore, the
photoelectric detector is best suited.
◉Types of thermal detectors. Answer: 1. Fixed alarm threshold
(activation at T)
2. Rate of rise [RoR] (activation at change in T)
3. Combined fixed at RoR
4. Point detector
5. Line detector (big wire that if melted, alarm goes off)
