Followers Not Leaders

By Wayne D. Moore | Mar 15, 2010
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Typically, contractors know what codes and standards are in force in their market areas, and if they don’t, they should find out. But often this is limited to the code they use the most, the National Electrical Code (NEC). What is interesting is that most contractors are unsure why it matters which editions of the codes they need to use or which are specifically referenced for their work. One reason to use the right code or standard is to ensure the inspector will approve the installation, and there will not be any surprises, which, of course, leads to changes and cost overruns and lost profits or customers. The other reason to use the right code is to avoid any legal issues that may arise from the installation. Generally speaking, electricians know the NEC, and assuming that the installation is Code-compliant and professionally installed in a workmanlike manner, there is little likelihood of a lawsuit developing over their installation.

However, numerous issues can lead to litigation when installing a fire alarm system. Every owner expects the fire alarm system installation to not only meet code but detect a fire and call the fire department early in the fire development. This may be an unjustified expectation for many reasons, such as the owner asked you for the minimum system as required by the local building code. Keep in mind that the National Fire Alarm and Signaling Code does not require a fire alarm system be installed. But once the decision has been made (or required by another code, such as the building code) to install a fire alarm system, then the requirements found in NFPA 72 must be followed.

The installation portion of a fire alarm system is only half the battle. If the owner is asking for your opinion, you need to understand the application of each type of detector available and what would best suit the owner’s fire protection goals, which I have discussed in previous articles.

Many contractors fall into a trap thinking that, if the owner describes the protection he or she wants, that is all that needs to be installed. Unless the owner happens to be a fire protection engineer, a contractor should be cautious about following the owner’s direction as to the installed number of detection devices.

For example, many owners think that if one smoke detector is placed in a corridor, any fire on that floor will be detected early. Obviously, that is not going to happen unless the fire is in the same approximate area as the detector.

So what is your obligation as a contractor when confronted with such an owner? In my opinion, you need to explain that the NFPA 72 in force in your jurisdiction will not allow you to install just one detector where the owner thinks it should be. There are application requirements regarding the environment and spacing of every type of detector. Specifically Chapter 17 section 17.1.1 states, “The performance, selection, use, and location of automatic fire detection devices, sprinkler waterflow detectors, manually activated fire alarm stations, and supervisory signal-initiating devices (including guard tour reporting used to ensure timely warning for the purposes of life safety and the protection of a building, a space, a structure, an area, or an object) shall comply with the minimum requirements of this chapter.” (Emphasis added.)

The code also requires that the design account for the contribution of the following factors in predicting detector response to the anticipated fires to which the system is intended to respond:

1. Ceiling shape and surface

2. Ceiling height

3. Configuration of contents in the protected area

4. Combustion characteristics and probable equivalence ratio of the anticipated fires involving the fuel loads within the protected area

5. Compartment ventilation

6. Ambient temperature, pressure, altitude, humidity and atmosphere

Staying with our smoke detector example, the code requires that on smooth ceilings, spacing for spot-type smoke detectors must be in accordance with the code requirements that state: “In the absence of specific performance-based design criteria, smooth ceiling smoke detector spacing shall be a nominal 30 ft (9.1 m).” This spacing is essentially a guide for the prescriptive approach to design a layout consisting of smoke detectors. The code also advises that where there are explicit performance objectives for the response of the smoke-detection system, the performance based design methods outlined in Annex B of the code should be used.

This last item is what needs to be discussed with the owner trying to design his or her own system. It is your responsibility as the professional to understand the code in force in your jurisdiction and the requirements that will affect your design and to communicate that information to the owner.

MOORE, a licensed fire protection engineer, frequent speaker and an expert in the life safety field, is a co-editor of the current National Fire Alarm Code Handbook. Moore is a principal with Hughes Associates Inc. at the Warwick, R.I., office.

About The Author

MOORE, a licensed fire protection engineer, was a principal member and chair of NFPA 72, Chapter 24, NFPA 909 and NFPA 914. He is president of the Fire Protection Alliance in Jamestown, R.I. Reach him at [email protected]





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