Renovating commercial buildings that require fire alarm system updates presents many challenges. First, the upgrade that is designed and installed must comply with NFPA 72, National Fire Alarm and Signaling Code. The challenge comes from determining which edition should be followed. As I’ve written in this column many times before, it depends!
First, find out which edition of the building code has been adopted in the building’s jurisdiction. Then, determine which edition of NFPA 72 that building code edition references. Most likely, the NFPA 72 edition followed for the design and installation of the original system has changed.
In addition, the fire department may have developed additional requirements, which could affect the edition of the code. Regardless, I always recommend the most current edition of the code—in this case NFPA 72 2016.
The most recent code provides the latest thinking of the technical committees and includes recognition of new technology and research. You may need to get permission from the authority having jurisdiction (AHJ), but following the newest code whenever possible always has benefits.
In any case, do not assume the existing fire alarm system met the code when it was initially installed. Of course, the renovation may have added spaces or changed spaces that will dictate an alteration to the original design, but often the renovation does not change the layout of the space.
Starting from scratch is the most prudent approach when retrofitting or upgrading a system in a building under renovation. It might be tempting to replace all devices and notification appliances on a one-for-one basis using the old system’s design. The salesman in you might believe you will save the owner money—and provide a low bid—because the wiring already exists. Because the original system received approval from the AHJ, it might appear to be OK to proceed with the replacement on a one-for-one basis.
However, even if the AHJ had approved the original design and installation, the codes will likely have changed. The original design may not meet current audibility requirements or, for the in-building fire emergency voice/alarm communications systems, intelligibility requirements. If the building is a high rise, you may need to install survivable circuit integrity cable for the speaker riser circuits and other control circuits.
The most recent International Building Code requires the installation of bidirectional amplifiers to ensure the firefighter radios work throughout the building, while the code does not allow the installation of firefighter telephones.
Remember to discuss the existing systems’ past performance with the owner and the fire department. Over time, numerous nuisance alarms might have occurred. This should cause a pause in the design process and a review of the overall ambient conditions in each space of the building to determine if the types of detectors had contributed to a nuisance-alarm problem.
While considering the types of detectors used in the original system, consider whether the system designer chose the proper detectors for each space. Most systems will have used spot-type smoke detection. Review all of the smoke detectors in the original design to determine if the designer had made the appropriate choices for the application. New smoke detector technology may provide more economical options for nuisance-alarm-free and more reliable detection.
Notification appliances in older systems may not have provided the audibility or intelligibility for speaker systems the code now requires. Were the notification appliances designed for public or private mode signaling? For public mode, the notification appliances must “have a sound level at least 15 dB above the average ambient sound level or 5 dB above the maximum sound level having a duration of at least 60 seconds, whichever is greater, measured 5 ft. above the floor in the area required to be served by the system using the A-weighted scale (dBA).”
Once it is determined whether the existing notification appliance locations will provide the correct measured audibility, you can design the audible notification appliances. If the replacement fire alarm system will serve a residential building, the code now requires the installation of a low frequency notification appliances in each bedroom that will provide a minimum sound level of 75 dBA measured at the level of the pillow.
The visible notification appliances for most older systems used incandescent lights and not strobes. The code specifically requires where and how many strobes the designer must provide to ensure proper signaling for the hard of hearing or deaf individuals.
When designing and installing a new fire alarm system in a building under renovation, make certain that you thoroughly understand both the code and the building’s fire protection goals. Follow these guidelines, and you will continue to install profitable fire alarm system projects.