Whatâ€™s Wrong with This?Wally `Larman installed a fire alarm system that included a boiler room that measured 240 feet by 120 feet. He selected the correct heat detectors that were rated at 30-ft. spacings and laid them out them as shown in this diagram using 30-ft. spacing between detectors. When the fire marshal reviewed his plans, he rejected them. Can you see what Wally did wrong and what he must do to correct the problem?
1. Who has final say in the design of a fire alarm system?
a. NFPA 70
b. NFPA 101
c. Local AHJ
d. State codes
2. Trouble signals shall be indicated in how many seconds?
3. An alarm signal shall be indicated within how many seconds of waterflow?
4. Duct detectors are required on the supply side for HVAC units rated at how many cfm or higher?
5. You always should discard old code books as new ones are released.
6. DACTs shall have:
a. line seizure.
b. loop start lines.
c. two communication paths.
d. All of the above
e. None of the above
7. All building and fire codes incorporate the latest revisions of NFPA codes/standards.
8. Wiring issues for fire alarms are covered in which NFPA standard?
e. None of the above
9. Fire alarm systems may not share components with non-fire alarm systems.
10. DACRs require a minimum of two incoming telephone lines.
11. Exposed wiring shall be protected within how many feet above the finished floor?
12. The fire pump supply conductors do not require supervision.
13. FPLP cable can be used in riser applications.
14. Central station fire alarm systems shall be placarded.
15. In a coded local fire alarm system, an alarm signal shall consist of:
a. one repetition of one complete round.
b. two repetitions of two complete rounds.
c. three repetitions of three complete rounds.
5-Minute Tech Quiz AnswersHere are the answers to the 5-Minute Tech Quiz and What’s Wrong with This? that appears on page 49.
1. c â€” While you must follow all applicable codes, the local authority having jurisdiction, (AHJ) has the final say in system design and operation.
2. d â€” NFPA 72, 184.108.40.206.1 states, “Trouble signals and their restoration to normal shall be indicated within 200 seconds.”
3. c â€” NFPA 72, 5.10.2 states, “Initiating of the alarm signal shall occur within 90 seconds of waterflow at the alarm-initiating device when flow occurs.”
5. b â€” You should keep old code books because local codes frequently refer to a specific code year.
8. c â€” NFPA 70 is the National Electric Code (NEC) and covers wiring issues for fire alarm systems.
9. b â€” Although allowed by NFPA 72, 220.127.116.11, you should check with local AHJs to determine if they also allow fire alarm and non-fire alarm devices to be connected to a single control.
12. b â€” NFPA 72, 18.104.22.168.2 states, “Supervision of electric power supplying the pump shall be made on the line side of the motor starter. All phases and phase reversal shall be supervised.”
15. c â€” NFPA 72, 22.214.171.124 states, “A coded alarm signal shall consist of not less than three complete rounds of the number transmitted. Each round shall consist of not less than three impulses.”