Designers and installers tend to fall into the same four traps when working on new fire alarm system installations. The first is not understanding NFPA 72, the National Fire Alarm and Signaling Code, and the code process. The second is developing or bidding on inadequate or incomplete bid documents. The third is not understanding the limitations of detection, and the fourth is not understanding your own limitations.
The most important thing to do when using NFPA 72 is to read the whole code. People often look up a specific piece of information and fail to realize that other portions of the code also need to be applied. NFPA 72 is not a design guide. It must be used in conjunction with the applicable building or Life Safety Code (NFPA 101) and the National Electrical Code .
The code process is simple. The building code spells out what kind of fire alarm system is needed, and the NEC and NFPA 72 describe the device and appliance application and installation requirements. For example, the building code states that the alarm notification appliances “shall be heard by all of the occupants,” and NFPA 72 establishes the audibility requirements for the notification appliances and establishes the intelligibility requirements for all in-building fire emergency voice/alarm communication systems. NFPA 72 is also where you look for information regarding how to deal with “nonrequired” fire alarm systems (hint: code requirements still apply!).
The NEC describes installation requirements for all wiring and electrical equipment and defines the mechanical execution of work in Article 760.24: “Fire alarm circuits shall be installed in a neat workmanlike manner. Cables and conductors installed exposed on the surface of ceilings and sidewalls shall be supported by the building structure in such a manner that the cable will not be damaged by normal building use. Such cables shall be supported by straps, staples, cable ties, hangers, or similar fittings designed and installed so as not to damage the cable. The installation shall also comply with Article 300.4(D).”
When you are involved in designing a fire alarm system, learn the requirements or the local jurisdiction in addition to national codes, and know when to ask for professional assistance. Ensure your design is on scaled drawings to assure the correct placement of devices and appliances.
It’s also important to understand that designing by walking around the building does not equal design/build! Do not finalize your design until you discuss system needs with the local authority having jurisdiction. Never assume that installing or designing only what the owner wants or thinks they want is the right thing to do. The owner is not a fire protection engineer, so why let them dictate smoke detector coverage? Remember that if you must defend your work in court, you will be considered the expert, not the owner.
In addition, laws in some states only allow fire alarm systems design by the contractor for systems sold and installed by the contractor and may also limit the size of projects you can design.
It can be problematic if you don’t understand the limitations of detection, for example if you installed partial coverage when the owner believes you have installed “complete coverage.”
There are limits to what detection can provide, so you know when to suggest automatic sprinkler protection in addition to smoke detection. Do not design a non-code-compliant system to save the owner money.
When bidding on an engineer’s set of design documents, make sure they are complete and code-compliant. If you install it as designed without explaining to the designer and the owner that the system is not code-compliant, you will be considered one of the parties at fault should someone take legal action. Be wary if the specifications put the design requirements on you. You can still bid the project, but do so with the options necessary to ensure code compliance.
In some cases, walking away is the best decision when the engineer does not agree to change the design to meet the codes.
You need to understand your limitations, because you do not know what you do not know. However, I am sure you do know what size projects you have completed successfully in the past. If the current project is three times as large as anything you previously worked on, you may have a problem. Be sure you know the manufacturer’s requirements for the equipment you sell and install and that your technicians have been trained on the proper installation techniques for that equipment.
Avoiding these common traps just requires you to do what is right, which applies to just about everything we do.