Probably the most common problem in the fire alarm installation business today is knowing where to place the various fire devices — both initiating and notification apparatus. Even veteran fire alarm installers are forced to review fire code in order to determine placement, especially in uncommon applications.

There are three basic codes that fire alarm technicians must consult when installing, servicing and testing fire alarm systems. They are NFPA 72, National Fire Alarm Code (NFAC); NFPA 101, Life Safety Code (LSC); and NFPA 70, National Electrical Code (NEC). It’s important for at least one technician on a crew to have them at their disposal. Otherwise, there’s no telling what kind of mistakes that could take place. 

Before you go out and buy a new set of codebooks, be sure to inquire with your local jurisdiction about the edition their inspectors refer to when inspecting fire alarm systems. The current edition for NFPA 101 is 2006; for NFPA 70, it’s 2005; and for NFPA 72, it’s 2007. However, your local jurisdiction may very well choose to use an earlier edition.

How to Deploy NAC Devices
Initiating devices like manual pulls and smoke detectors are important, but if the alarm signal is not conveyed to the occupants of a building in a timely manner, the system is ineffective and may as well not be there. For this reason it’s important fire alarm technicians to know when, where and how to install horns, strobes and speakers. 

Wall-mounted NAC devices should be placed no less than 80 inches and no more than 96 inches above floor level. However, when the height of a ceiling prevents you from doing this, Section 7.5.4.2, NFPA 72, 2007, says to mount them within 6 inches of the ceiling.

When it becomes necessary to mount your NAC devices below 80 inches, code says that you must reduce the room size by twice the difference between the code-specified 80 inches and the actual distance used. NFPA also offers an alternate method of determining mounting height using a performance-based method. For information, see Section 7.5.4.5 of NFPA 72, 2007. 

Generally speaking, audible notification appliance devices must be heard everywhere within a protected structure and visuals seen throughout as well. Fire inspectors worth their salt will work a little harder than normal on a new installation to assure that this is exactly the case.

Spacing within rooms can be determined using two tables provided in NFPA 72. Table 7.5.4.3.1(a) provides the minimum number of wall-mounted NAC devices for a given size room, whereas Table 7.5.4.3.1(b) provides spacing information for ceiling-mounted NAC devices.

Corridor spacing of NAC devices where the width is less than 20 feet wide can be determined either by using the two tables mentioned above or by using the additional information found in Section 7.5.4.4. 

NAC devices should be located no more than 15 feet from the end of a corridor. The distance between NAC devices within said corridor must not exceed 100 feet. In cases where the view of a visual NAC device is interrupted, the area in question should be equipped with its own visual device (Section 7.5.4.4.5 and 7.5.4.4.6, NFPA 72, 2007).

Start With the Mechanical Fire Pull
The most fundamental detection device utilized in all fire alarm systems is the mechanical fire pull, commonly known as a manual pull. According to Section 6.8.5.1.2, NFPA 72, 2007 Edition, there must be at least one manual pull in a protected premises fire alarm system that employs automatic detection.

Manual pulls are to be installed where people can easily see them. The pathway to a manual pull must be clear of obstructions, thus allowing occupants to quickly make their way to the nearest one (Section 5.13.5, NFPA 72, 2007 Edition). 

In most cases, code calls for a manual pull next to perimeter exits, allowing someone to warn others of a fire as they rush out of a burning building. The distance from perimeter door to manual pull must not exceed 5 feet (Section 5.13.6, NFPA 72, 2007). When there’s a group of doors that span a distance of 40 feet or more, however, NFAC calls for a manual pull on each side of such a grouping.

Code also requires the distance between fire pulls inside a facility not to exceed a distance of 200 feet. When in excess of this distance, you must add another manual pull (Section 5.13.8, NFPA 72, 2007). 

Another important aspect associated with device installation is mounting height, which is measured from the floor to the handle on the manual pull. Since the advent of the Americans With Disabilities Act (ADA), NFPA, UL and other code/standards-making bodies have harmonized their own guidelines to match the ADA rules. 

According to Section 5.13.4 of NFPA 72, 2007 Edition, mounting height must be between 3 1/2 and 4 1/2 feet from floor level, or 42 to 54 inches. Originally, ADA required manual pulls to be no less than 15 inches on the low side and 48 inches on the high side when it involves a forward approach. When approaching from the side, ADA specified a mounting height of no more than 54 inches. On a parallel approach using a wheelchair, ADA stipulates 9 inches to 54 inches.

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