ENGR403 FIRE ENGINEERING ACTUAL EXAM
2026 QUESTIONS WITH ANSWERS GRADED
A+
◉3 types of Fire safety systems . Answer: Detection
Suppression
Smoke Management
◉3 ways a fire can be discovered . Answer: Radiation
Gases, aerosols, heat
Sound
◉What are the 3 types of radiation and which ones are useful? . Answer:
Ultraviolet - useful
Visible - not useful (visible light from non-fires can flicker e.g. static
TV)
Infrared - useful
◉4 types of smoke detectors . Answer: Point detector (slow but cheap)
Line detector (covers more area than point)
Volume detector (detector sees fire)
Aspirating detector (air is piped out and detected)
, ◉Explain how an ionisation chamber smoke detector works . Answer: -
two plates in a circuit, one positive and one negative
- no current between plates so include radioactive material (Am-241) to
ionise the air (creates charged particles between the charged plates) and
creates a current
- when soot enters the chamber, because it has static electricity, as it goes
through, it picks up the charged particles and therefore reduces the
current
- when the current is reduced to a certain level, the detector will activate
- being phased out because it uses a nuclear material
◉Explain how a photoelectric smoke detector works . Answer: - Emitter
shoots light to a light trap (if there is nothing in the chamber)
- if there are soot particles in the chamber, some light particles will
bounce off and hit the receiver
- if there is enough light going into the receiver, the detector will activate
◉Explain how a Linear beam smoke detector works . Answer: - similar
to photoelectric w/o the trap
- doesn't look at the reflected light but how much light is absorbed by
soot particles
- with lots of smoke, the light intensity decreases between the emitter
and reciever.
2026 QUESTIONS WITH ANSWERS GRADED
A+
◉3 types of Fire safety systems . Answer: Detection
Suppression
Smoke Management
◉3 ways a fire can be discovered . Answer: Radiation
Gases, aerosols, heat
Sound
◉What are the 3 types of radiation and which ones are useful? . Answer:
Ultraviolet - useful
Visible - not useful (visible light from non-fires can flicker e.g. static
TV)
Infrared - useful
◉4 types of smoke detectors . Answer: Point detector (slow but cheap)
Line detector (covers more area than point)
Volume detector (detector sees fire)
Aspirating detector (air is piped out and detected)
, ◉Explain how an ionisation chamber smoke detector works . Answer: -
two plates in a circuit, one positive and one negative
- no current between plates so include radioactive material (Am-241) to
ionise the air (creates charged particles between the charged plates) and
creates a current
- when soot enters the chamber, because it has static electricity, as it goes
through, it picks up the charged particles and therefore reduces the
current
- when the current is reduced to a certain level, the detector will activate
- being phased out because it uses a nuclear material
◉Explain how a photoelectric smoke detector works . Answer: - Emitter
shoots light to a light trap (if there is nothing in the chamber)
- if there are soot particles in the chamber, some light particles will
bounce off and hit the receiver
- if there is enough light going into the receiver, the detector will activate
◉Explain how a Linear beam smoke detector works . Answer: - similar
to photoelectric w/o the trap
- doesn't look at the reflected light but how much light is absorbed by
soot particles
- with lots of smoke, the light intensity decreases between the emitter
and reciever.
