Discussions begin for 2013 NFPA 72 code revision
The National Fire Protection Association currently is accepting comments from the public for the 2013 edition of National Fire Alarm code, or, NFPA 72, that sets standards for fire alarm systems, said Dan Decker, president of Safety Systems Inc. In 1990, Decker was appointed to the NFPA 72 technical committee on fire alarm systems. He has been involved in the co-development of the code for more than 20 years and said the committee now is meeting to discuss the 2013 edition of the code.
Decker said building and fire codes reference NFPA 72 regarding how to install a fire alarm system, including requirements on how to handle off-premise signaling. Decker said the building code states the system must be monitored and that technologies used must be able to transmit the alarm signal from the protected premise to the supervising station.
“It’s fairly detailed about the specifics, how the station operates and how you transmit signals from point A to point B,” he said.
Prior to the mid-1980s, Decker said most fire alarm systems were run over leased phone lines that went from the protected premise to the supervising station. After Ma Bell broke up under antitrust rules, the company changed their rates, which led to the development of a less expensive option for sending alarm signals: a digital communicator. The communicator used regular voice phone lines on the premise to call a receiver at a supervising station and transmit data.
“It was a lot like a fax machine, where a number was called, data was sent and the line hung up,” Decker said. “That didn’t have monthly costs for the phone lines, so it became pretty attractive but from a code standpoint … but if the phone system was down and the call couldn’t get through, the supervising station wouldn’t know about an alarm.”
As a result, the code was adapted to require those who use a digital communicator to have two phone lines connected so if one line goes down, the other can carry the signal. As the code progressed throughout the 1990s, cellular communicators were approved. As a result, wireless systems became legitimate options per the code and often can be used as the only option, if it can report an alarm within five minutes as required by the code.
Decker said future alarm applications include voice-over-IP communicators, which use an internet connection from the subscriber’s location to the supervising location to connect two IP devices that communicate every 60 to 90 seconds. However, VoIP presents problems for digital communications because the data doesn’t come through via a stream. Instead, the process of digitizing chops up data into packets that don’t always reassemble within the time frame needed, he said.
“Data gets lost, gets distorted and you either don’t get a signal or one is received many times,” Decker said. “So cellular is certainly one of the directions the industry will have to go.”
User feedback to NFPA 72 should be submitted via the NFPA document proposal form by mid-November, Decker said.
