S95 Initiating Devices 2

Question 1

Which type of smoke detector uses a small amount of radioactive material to ionize air and detect combustion particles?

Accepted Answer

Ionization detector

Answer

Ionization detectors use a small radioactive source (typically Americium-241) to ionize air between two charged plates; combustion particles disrupt the ion current and trigger an alarm.

Question 2

A photoelectric smoke detector is MOST effective at detecting which type of fire?

Accepted Answer

Slow smoldering fires that produce large smoke particles

Answer

Photoelectric detectors use a light-scattering principle that responds most effectively to large smoke particles generated by slow, smoldering fires.

Question 3

What is the maximum spacing between smoke detectors on a smooth, flat ceiling as specified by NFPA 72?

Accepted Answer

50 feet

Answer

NFPA 72 establishes a default maximum spacing of 30 feet (900 sq ft area) between smoke detectors on smooth, flat ceilings, but allows up to 50 feet in some listing conditions.

Question 4

A projected beam smoke detector consists of which two primary components?

Accepted Answer

Transmitter and receiver

Answer

A projected beam detector uses a transmitter that emits an infrared or laser beam and a receiver that measures beam obscuration caused by smoke.

Question 5

Where are duct smoke detectors required to be installed according to NFPA 72 and NFPA 90A?

Accepted Answer

In HVAC ducts to detect smoke and shut down air handling units

Answer

Duct smoke detectors are installed in HVAC supply and return air ducts primarily to detect smoke and initiate shutdown of the air handling unit to prevent smoke circulation.

(S95) Supervision of Fire Alarm System Practice Test

(S95) Supervision of Fire Alarm System Practice Test

S95 Initiating Devices 2