It's A Process!

Providing fire alarm system design services can prove troublesome for some contractors. Many states allow you to design a fire alarm system for projects you sell and install yourself, but the engineering licensing laws of most states prohibit designing systems if you will not be performing the installation.

Whether you perform the system design or not, the actual task of designing fire alarm systems involves more than just drawing circles and squares on a floor plan. It is a process, and don’t count on NFPA 72 2013, National Fire Alarm and Signaling Code, to fully explain it for any specific project. 

Recall that NFPA 72 does not require a building owner to install a fire alarm system in his or her building. Only the building codes or the Life Safety Code, as adopted into statute for a particular jurisdiction, will provide such a requirement.

Of course, the requirements in NFPA 72 2013 provide some limited guidance for the design process. This code also includes the criteria necessary to be a qualified designer.

NFPA 72 defines a system designer as the “individual responsible for the development of fire alarm and signaling system plans and specifications in accordance with this code.” A designer must prove he or she has experience in the proper design, application, installation and testing of the fire alarm systems and the capability of developing the fire alarm system and emergency communication system plans and specifications in accordance with the code requirements.

The word “experience” can take on many meanings. Do you have one year’s experience repeated five times or five years of realistic and progressively more advanced fire alarm system design experience?

NFPA 72 states, “Fire alarm system and emergency communications system plans and specifications shall be developed in accordance with this code by persons who are experienced in the proper design, application, installation, and testing of the systems.” The code recognizes certain experiences that meet the intent of designer qualifications.

First, the qualified designer must follow state or local licensure regulations to determine qualified personnel. These regulations include, but are not limited to, one or more of the following:

1. Personnel who are registered, licensed or certified by a state or local authority

2. Personnel who are certified by a nationally recognized certification organization acceptable to the authority having jurisdiction (AHJ)

3. Personnel who are factory-trained and certified for fire alarm system design and/or emergency communication system design of the specific type and brand of system and who are acceptable to the AHJ

Reviewing these three statements, you will likely agree that they seem broad and do not address the fire protection experience you need to properly design a fire alarm system. In fact, just being licensed in any field does not guarantee system designer qualifications. A combination of meeting the above requirements and specific system design experience will go a long way to improve your ability to properly design a fire alarm system.

The code requires the system design documents to clearly identify the system designer. When required by the AHJ, the system designer must provide evidence of his or her qualifications and certifications.

I began this article by emphasizing that designing a fire alarm system involves a design process. This begins with understanding how each of the various types of detection devices operate, what fire signatures each one will detect and what stimuli might cause them to actuate under nonfire conditions. Know the notification needs, the types of notification appliances that can best meet those needs and the emergency control functions that the fire alarm system will have to provide.

To select the most appropriate detection device, know as much about the building’s fire protection goals, design, use and operations as possible. Think through the system detection and notification appliance layout, and carefully plan the wiring installation. These items all represent important steps in the design process. You must follow them carefully to ensure the fire alarm system operates reliably.

At first, you may assume that the only fire protection goal the owner has is to meet the code. I have discussed this issue in great detail in previous columns, but I suggest you start the design process by describing to the owner what fire protection makes the most sense to ensure he or she will not suffer any life or property loss from a fire. Explain that the Building Code and Life Safety Code present only minimum requirements. You may discover that, to properly protect his or her interest in the property, the owner may not want to install a system that only meets the minimum requirements. Instead, the owner may want to plan for a future mass notification system, even though the building may not require an emergency communications system at this time.

Two important factors—the building design and occupancy—determine which types of detection devices and notification appliances you need to include in your design. A high-rise building, a large assembly building or a new K–12 school building will require an emergency communications system. All others will most likely use nonvoice fire alarm systems.

As most contractors know, NFPA 72 requires the installation of all fire alarm system wiring and equipment—including all circuits controlled and powered by the fire alarm system—to meet the requirements of NFPA 72 and Article 760 of NFPA 70, National Electrical Code.

Although fire alarm systems include fire detection and alarm notification, they can also connect sprinkler water flow switches and sprinkler supervisory systems. Additionally, circuits controlled and powered by the fire alarm system include circuits for the control of building systems safety functions, elevator capture, elevator shutdown, and door release, to name a few. Fire alarm systems can also control or monitor smoke doors and damper control, fire doors and damper control, and fan shutdown.

Include all these other systems in your design where required, and ensure that these systems operate reliably after the integration. The code gives some guidance for these connections, but you will ultimately need to coordinate very closely with the other affected trades to ensure all of these systems will work together as planned.

By knowing the building’s intended operation, you can address the detector location so that a false alarm will not occur during normal building use. The building operations may require the use of multicriteria smoke detectors to ensure stability of detection in the building’s environment. Building codes do not address adverse environmental issues. Instead, Annex A of NFPA 72 2013 discusses these concerns.

When you finally get to developing the circuit layouts for the building, begin by determining the designations of each type of circuit. The code requires that you designate initiating-device circuits, notification appliance circuits and signaling-line circuits by class, depending on the circuit’s capability to continue to operate during specified fault conditions, as indicated in Chapter 23 of the code: “The class of pathways shall be determined from an evaluation based on the path performance as required by governing laws, codes, standards, and a site-specific engineering analysis.”

Chapter 23 assists in determining the integrity and reliability of the interconnecting signaling paths (circuits) installed within the protected premises. NFPA 72 actually requires you to evaluate the following so that you may ensure reliability of the systems’ operation:

1. Transmission media used

2. Length of the circuit conductors

3. Total building area covered by—and the quantity of initiating devices and notification appliances connected to—a single circuit

4. Effect of a fault in the fire alarm system that would hinder the performance objectives of the system that protects the occupants, mission and property of the protected premises

5. Nature of hazards present within the protected premises

6. Functional system requirements that are necessary to provide the level of protection required for the system

7. Size and nature of the population of the protected premises

Since the fire alarm system must address all of these concerns, you now realize that designing such a system entails much more than drawing circles and squares. Learn to incorporate not only code requirements but also your knowledge of fire protection to ensure your design will perform reliably.

About the Author

Wayne D. Moore

Fire/Life Safety Columnist
Wayne D. Moore, a licensed fire protection engineer, frequent speaker and an expert in the life safety field, is a principal member and past chair of NFPA 72, Chapter 24. Moore is a vice president with JENSEN HUGHES at the Warwick, R.I., office. He c...

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