You often hear the phrase “location, location, location” about choosing the right place for your business. The same mantra can be used for installing fire alarm equipment. All the equipment used in a fire alarm system has specific location requirements you must follow. Michael Johnston’s article “How High Is Too High?” in the July issue of ELECTRICAL CONTRACTOR brought this to mind for me.

Johnston discusses a key definition in Article 100 of the National Electrical Code that applies to more than just the fire alarm control unit (FACU). That definition has four “layers” or meanings, and they are included in the definition section of NFPA 72 (borrowed from the NEC), with some expansion:

“3.3.1 Accessible (as applied to equipment). Admitting close approach; not guarded by locked doors, elevation, or other effective means. [70:100] 

“3.3.2 Accessible (as applied to wiring methods). Capable of being removed or exposed without damaging the building structure or finish or not permanently closed in by the structure or finish of the building. [70:100] 

“3.3.3 Accessible, Readily (Readily Accessible). Capable of being reached quickly for operation, renewal, or inspections without requiring those to whom ready access is requisite to climb over or remove obstacles, or to resort to portable ladders, and so forth. [70:100]

“3.3.4 Accessible Spaces (as applied to detection coverage in Chapter 17). Spaces or concealed areas of construction that can be entered via openable panels, doors hatches, or other readily movable elements (e.g., ceiling tiles).”

Requirements abound

NFPA 72 has various height requirements. For example, the height above the finished floor of a manual fire alarm pull station is in Section 17.14.5, which states, “The operable part of a manually actuated alarm initiating device shall be not less than 42 in. and not more than 48 in. from the finished floor.”

A big problem with fire alarm systems is the spacing of spot-type smoke detectors on high ceilings. Annex A, Section A.17.7.3.2 gives some guidance: “In high-ceiling areas, such as atriums, where spot-type smoke detectors are not accessible for periodic maintenance and testing, projected beam–type or air sampling–­type detectors should be considered where access can be provided.” 

A spot-type smoke detector on a high ceiling is not effective detection and will not meet the definition of 3.3.3 above because it will not be tested or cleaned as needed because it is not “readily accessible.” 

This installation issue leads to false alarms, and eventually the detector will be removed. A good rule of thumb is that when the ceiling height is above 12 feet, use a line-type (beam) smoke detector. Another is if you need a lift to install any detector, stop! Detectors of any type will not be effective at these heights in providing the occupant warning that is needed to avoid a loss of life.

All equipment should be readily accessible for operation, testing and maintenance. This means the FACU must be at a height that allows access. It cannot be placed above a ceiling or 20 feet above the floor just because you are worried about someone on a forklift hitting the FACU. 

Additionally, this location requirement applies to remote power supplies. They cannot be installed above a suspended ceiling or too high on the wall to prevent ready access. Also, access to the fire alarm system control equipment (FACU, power supplies) should not be obstructed by other electrical or mechanical equipment. 

There are also environmental requirements. Section 10.3.5 specifies that equipment must be designed so it can perform at ambient temperatures of 32°F and 120°F with a relative of 85% at an ambient temperature of 86°F.

There are additional height restrictions for audible and visible notification appliances. For audible appliances, the code requires the tops of wall-mounted appliances to be not less than 90 inches above the finished floors and not less than 6 inches below the finished ceilings. For combination audible/visible appliances, the height is determined by the requirements for visible appliances.

Wall-mounted visible appliances that are required to be done so the entire lens is not less than 80 inches or greater than 96 inches above the finished floor. There are allowances in the code for using performance-­based alternatives and to accommodate low ceiling environments. 

When installing fire alarm systems, location means more than just the ceiling height and NFPA 72. Common sense should be your guide.

stock.adobe.com / Rob Goebel