Sprinkler Supervision and Monitoring: NFPA 13 and NFPA 72 Part 2

By John Swanson posted Jun 13, 2022 12:48 PM


Sprinkler Supervision and Monitoring: NFPA 13 and NFPA 72
Part 2

In Part 1 of the Sprinkler Supervision and Monitoring article, we discussed some of the basic requirements in the model codes, NFPA 13 and NFPA 72 for monitoring. To find Part 1, please click on the link below to learn more about some of the basic monitoring requirements in the codes and standards.  


Criteria for how to send sprinkler waterflow and fire alarm signals from the protected premises to the supervising station have caused confusion and raised many questions from installers and code officials alike. The intent of these articles is to clarify the installation requirements and different communication technologies outlined in NFPA 72, to ensure whatever method is chosen meets the requirements of the adopted codes and standards. This article will address requirements specific to digital alarm communicator transmitters, or DACTs.

Digital Alarm Communicator Transmitters (DACTs)

Digital alarm communicator transmitters, or DACTs for short, have been one of the primary methods of monitoring sprinkler waterflow and fire alarm systems for nearly 40 years. Originally approved in the fire alarm code back in the 1980s, DACTs quickly became the default method of monitoring up until a few years ago. Put simply, DACTs use phone lines to transfer the fire alarm signal from the protected premises to the supervising station. But do not let the name cause any confusion, the only thing “digital” about a digital alarm communicator transmitter is it dials digits (or a phone number). DACTs became such a common method of monitoring in the 1980s and 1990s that fire alarm manufacturers began adding phone jacks inside fire alarm panels during the manufacturing process to simplify installations.

Installation Requirements for DACTs

DACTs are required to be connected to the fire alarm panel upstream of any customer owned equipment. Customers with a private branch exchange (PBX) network, or a phone system that requires a person to dial 9 to get to an outside line, must be connected downstream of the fire alarm equipment. NFPA 72 does not want the fire panel to dial 9 to get an outside line. There is no requirement in NFPA 72 for the phone lines to be dedicated to the fire panel. The phone lines can be used by the customer for other business functions but monitoring of sprinkler waterflow and fire alarm signals must take precedence over all other uses. To meet this requirement, the phone line(s) must be connected to an RJ31x phone jack (see photo). This device allows the fire alarm panel to seize control of the phone line, disconnect any other uses, and send the signal to the supervising station.

Federal Laws vs. State Laws

One of the challenges was, how does the technical committee establish regulations for an industry (phone companies) regulated by the federal government (Federal Communications Commission)? Keep in mind, federal law supersedes state law. Most codes and standards adopted by jurisdictions are not applicable to federally owned properties or industries regulated by the federal government (there are some exceptions to this). In general, a fire inspector cannot enforce state laws (codes and standards) on federally owned buildings because the federal government is not subject to state law. Since the phone network is regulated by the FCC, there were concerns with how to apply prescriptive requirements in a standard to an industry where enforcement could be an issue. For this reason, proponents of DACTs were unsuccessful in getting their concept approved for use in the fire alarm code on two separate occasions in the 1980s. On the third attempt proponents were successful. They were successful because, unlike their first two attempts, the third proposal included a requirement that every installation have a primary and backup phone line, in case the primary failed. This is the reason NFPA 72 requires DACTs to have two transmission channels. It is important to keep in mind that DACTs are the only transmission option approved for use in NFPA 72 that requires two transmission channels.

2013 Edition of NFPA 72

The 2013 Edition of NFPA 72 made a change specific to DACTs that had a significant impact on their continued use. The backup transmission channel could no longer be a second phone line. The change required the secondary transmission channel to be cell, internet, or radio. In previous editions, and for many years prior to adoption of the 2013 edition, phone contractors would simply bring two phone lines to the fire alarm panel to meet NFPA 72’s requirement for a primary and backup phone line. However, upon adoption of the 2013 edition of NFPA 72 (or any of the more recent editions), this is no longer allowed. This change was made because technology used by phone companies changed/improved significantly over the past 40 years. DACTs were originally approved for use with plain-old telephone service (or POTS) phone lines. Phone companies previously used copper to provide phone service to their customers. However, due to cost, phone companies transitioned from copper to broadband and fiber-optic. This transition created new challenges from a monitoring perspective. Some of the issues include lack of secondary power supply by the phone companies for their equipment (see the 2019 Edition of NFPA 72 section and the inclusion of customer owned equipment at the protected premises that can be disconnected or switched off.

Voice Over Internet Protocol and DACTs

Voice over Internet Protocol, or VoIP for short, is technology that was first introduced in the mid to late 1990s but did not become prevalent as a phone service option for the public until the early 2000s. VoIP converts a person’s voice to a digital signal and allows the customer to make calls directly from a computer, VoIP phone or data-driven device. VoIP cannot be used or connected to a DACT. Because VoIP converts the signal to digital, the information being relayed from the panel to the supervising station will be distorted and delayed. When a customer converts from traditional land-line phone service to VoIP, it is only a matter of time until the panel initiates a trouble signal because the timer test cannot go through to the supervising station (see Part 1 of this series).

The End of the Era?

Since DACTs were the default method used for monitoring for many years, some were under the assumption that all methods used for monitoring needed to have two transmission channels. As mentioned in Part 1 of this series, cell, internet, and radio are all approved by NFPA 72 as single communication technologies and do not require a backup. However, you will still find authorities having jurisdiction that require two transmission means by policy. With the change in the 2013 edition requiring the backup channel to be cell, internet, or radio, why even use a DACT for monitoring? This was the rationale used by the technical committee for the change, which started the gradual decline of new DACT installations, to the point where cell communicators are now the predominant method for new installations.

What about cell, internet, and radio communicators?

Stay tuned for Part 3 of this series where we will discuss other monitoring options including cell, internet, and radio communicators and some of the pros and cons to each.