Code and box requirements for fire alarm

Important Installation notes - FROM: PEAK ALARM

Item Height per NFPA 72 Box requirements WIRE D7024 Panel 66 inches to the top Provided - dimensions 20.8” x 15” x 4.3” Annunciators 60 inches to the top 4” sq. 2 1/8th deep with double gang P ring 18g4c FPL Smoke Detectors/Heat 4” sq. 2 1/8th deep with round device P ring 18g4c FPL Horn/Strobes 84-96 inches (8 per circuit) 4” sq. 2 1/8th deep with 2 gang P ring 14g2c FPL Speaker/Strobes 84-96 inches 4” sq. 2 1/8th deep with a box extension no P ring (see spec) Fire Pull Station 48 inches to top 4” sq. 2 1/8th deep with a single gang P ring 18g4c FPL Magnetic Door Holders (Not on battery backup) 4” sq. 2 1/8th deep with a single gang P ring 14g2c daisy Sprinkler Tamper mm 4” sq. 2 1/8th deep with no P ring Sprinkler Flow Valve mm 4” sq. 2 1/8th deep with no P ring Duct Smoke Detector mm/cm 4” sq. 2 1/8th deep with no P ring Water sensors/ Gas / CO mm etc.. 4” sq. 2 1/8th deep with no P ring Elevator Control Relays (Separate Circuit) Comes in it’s own box 2 – 18g4c FPL cables Damper Control (Separate Circuit) 18g4c separate circuit Phone CAT 5 4 Pair Zoned devices 18g4c FPL home run Addressable devices (Daisy Chain the Devices) 18g4c FPL loop


NEC (NFPA 70) lists the following as acceptable wire/cable for POWER LIMITED use which is low voltage :

FPL (Fire Rated wire for single story buildings) FPLR (Fire Rated riser wire that holds it’s own weight in a shaft and the wire is less likely to have fire climb the wire - multistory) FPLP (Fire Rated plenum wire for use in plenum ceilings. This wire exceeds the requirements for the prior 2 as well and can be used in place of FPLR – also can be used on multistory ) CMP (Fire Rated wire that meets the requirements for FPL, FPLR and FPLP- also acceptable for multistory buildings)

There is not a code requirement that requires red boxes or conduit although specifications or local jurisdictions may have separate requirements. Example: Park City requires Horn/Strobes inside front rooms of condos. Layton requires outside annunciators.

Some specifications require a large gauge wire, you will note that manufacturer guidelines are set so the wire will fit under the terminals on smokes, horn/strobes etc…. Example: If 12 gauge wire is used to avoid voltage line drop pigtails may have to be used and this could cause additional problems. Consider installation of booster NAC power supplies so 14 gauge wire can still be used.


RTU units 2000 cfm and higher are required to have a Duct Smoke Detector on the return air duct and be monitored RTU units 15000 cfm and higher are required to have a Duct Smoke Detector on both supply and return air ducts. If several duct detectors are on one zone then remote test switches need to be used. If they detectors are addressable then RTS are not needed unless the specification requires them.


Smoke Detectors have a 30 feet diameter coverage pattern (This can vary with deep beams and ceiling type) This means the smokes shall be within 15 feet of protected equipment such as FACP, NAC panels, Elevator doors etc…

Horn/Strobes are placed 15 feet from the end of hallways and not more than 100 feet apart Horn/Strobes or Speaker Strobes (In cases where the ceiling height is lower than 8 feet mount the box 6” to the top below finished ceiling height. FYI – Ceiling mounted Horn/Strobes have a higher current draw so only 4-5 per circuit depending on mA draw.

NFPA 72 (2007) Adopted by Utah 4.4.5 and R710 amended Smoke Detectors required at Fire Alarm Panels and NAC panels NFPA 72 Copy of the record of completion shall be stored at the Fire Alarm Panel or other location approved by AHJ R710 – Fire Alarm Panels must be green tagged and have a copy of the NFPA 72 form at the panel and inspection and testing shall be done by a Certified Fire Alarm Tech certified by the State of Utah Department of Public Safety. NFPA 72 Fire Alarm Detectors shall not be installed until after the construction cleanup of all trades is complete and final. IFC allows for omission of all Pulls on a Fully Sprinkled building except IFC also states that NFPA 72 shall be met and NFPA 72 requires at least one Pull Station see exception for elevator recall systems and 24 hour occupied in certain cases.

Call Larry Love with Questions, updates, comments, corrections or for a consultation at 801 898 6003