Duct Detector Requirements

How well do you know the installation and testing requirements for duct smoke detectors? This quiz is based on the 2019 NFPA 72, 2018 NFPA 90A and 2018 International Building Code (IBC).

1. You are allowed to use a remote test switch for testing duct smoke detectors to meet the requirements of NFPA 72.

Correct Answer: False

2. In accordance with NFPA 90A, smoke detectors listed for use in air distribution systems shall be located downstream of the air filters and before any branch connection in air supply systems having a capacity ______.

Correct Answer: greater than 2,000 cfm

3. In accordance with the IBC, duct smoke detectors are only required in the main return air or exhaust air plenum, not on the supply side.

Correct Answer: True

4. Detectors that are installed in the supply air duct system ______ as a substitute for open area protection.

Correct Answer: are not permitted to be used

5. In accordance with NFPA 90A, if you have multiple air handlers servicing a common area that collectively, but not individually, exceeds the minimum air volume required, you are required to install duct smoke detectors on each of them.

Correct Answer: True

6. If you must install smoke detectors at a 36-in.—high-by-72-in.-wide opening where the return air enters the common return air system, how many detectors listed for the air velocity must be installed?

Correct Answer: 2

7. In accordance with NFPA 90A, smoke detectors are required to be installed on the return side of the air handler unit when the capacity is greater than ______ and the air handler serves ______ story.

Correct Answer: 15,000 cfm, more than one story

8. If duct smoke detectors are installed downstream of any filters, the primary purpose of the detector shutting down the air handler is ______. (Choose two.)

Correct Answer: to prevent smoke from a fire outside of the building from entering
Correct Answer: to protect occupants from smoke spread from a fire in the air handler unit (fan, filters, etc.)

9. The sampling tube of a duct smoke detector must extend through the side of the ductwork on ducts more than ______ inches wide.

Correct Answer: 36

10. In Group R-1 and R-2 occupancies, a smoke detector is allowed to be used in each return air riser carrying not more than ______ cfm and serving not more than ______ air-inlet openings.

Correct Answer: 5,000, 10