Changes in Communications Technologies Affecting Final Acceptance by AHJs

By Wayne D. Moore | Nov 22, 2022
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The transition from plain old telephone service (POTS) to modern communications technology has shifted the way fire alarm systems are installed and approved by the AHJ.

Every project comes with large responsibilities, and life safety fire alarm systems most often represent a small portion of the total quote for work in the building. It is most often the last system installed in the building, and the fire alarm system installation often gets overlooked in terms of technology changes and quality control.

As stated in Section 901.6.3 of the 2018 International Building Code (IBC), “Fire alarm systems required by the provisions of Section 907.2 of this code and Sections 907.2 and 907.9 of the International Fire Code shall be monitored by an approved supervising station in accordance with Section 907.6.6 of this code.”

Most likely you have been relying on your equipment supplier to ensure the fire alarm system could make the appropriate connections. However, the code and marketplace have made changes that have caused some confusion with the authorities having jurisdiction (AHJs), and systems approvals are hitting a snag due to circumstances beyond our control.

Before the breakup of AT&T, the portion of the connection from the fire alarm system to the supervising station was treated as a “black box.” The technical committee had met with AT&T and determined that the phone line connections from the fire alarm system had a 0.99999 reliability factor, and although the code had no jurisdiction regarding the connection between the fire alarm system and the supervising station, the technical committee felt confident of the connection and used a digital alarm communicator transmitter (DACT) to make the necessary connections as required by the IBC and NFPA 72, the National Fire Alarm and Signaling Code.

These connections were made over what was called (by the communications industry) plain old telephone service (POTS) through the public switched telephone network (PSTN) interconnection points.

Then the breakup of AT&T occurred. We now have communications provided by telephone and cable TV companies, and a new definition of connection to the supervising station.

We start with the NFPA 72-2022 definition of a managed facilities-based voice network (MFVN). The code defines the MFVN as “a physical facilities-based network capable of transmitting real time signals with formats unchanged that is managed, operated, and maintained by the service provider to ensure service quality and reliability from the subscriber location to the interconnection point with other MFVN peer networks or the supervising station.”

MFVN has replaced PSTN, which was used in the requirements for DACTs in Chapter 26 of NFPA 72-2022.

The Annex (A.3.3.161) in NFPA 72-2022 provides the following:

“[A] Managed facilities-based voice network service is functionally equivalent to traditional PSTN-based services provided by authorized common carriers (public utility telephone companies or local exchange carriers [LECs]) with respect to dialing, dial plan, call completion, carriage of signals and protocols, and loop voltage treatment and provides all of the following features:

  1. A loop start telephone circuit service interface.

  2. Pathway reliability that is assured by proactive management, operation, and maintenance by the MFVN provider.

  3. 8 hours of standby power supply capacity for MFVN communications equipment either located at the protected premises or field deployed. Industry standards followed by the authorized common carriers (public utility telephone companies), and the other communications service providers that operate MFVNs, specifically engineer the selection of the size of the batteries, or other permanently located standby power source, in order to provide 8 hours of standby power with a reasonable degree of accuracy. Of course, over time, abnormal ambient conditions and battery aging can always have a potentially adverse effect on battery capacity. The MFVN field-deployed equipment typically monitors the condition of the standby battery and signals potential battery failure to permit the communications service provider to take appropriate action.

  4. 24 hours of standby power supply capacity for MFVN communications equipment located at the communications service provider’s central office.

  5. Installation of network equipment at the protected premises with safeguards to prevent unauthorized access to the equipment and its connections. When providing telephone service to a new customer, MFVN providers [must] give notice to the telephone service subscriber of the need to have any connected alarm system tested by authorized fire alarm service personnel in accordance with Chapter 14 to make certain that all signal transmission features have remained operational. These features include the proper functioning of line seizure and the successful transmission of signals to the supervising station. In this way, the MFVN providers assist their new customers in complying with a testing procedure similar to that outlined in 26.2.7 for changes to providers of supervising station service. The evolution of the deployment of telephone service has moved beyond the sole use of metallic conductors connecting a telephone subscriber’s premises with the nearest telephone service provider’s control and routing point (wire center). In the last 25 years, telephone service providers have introduced a variety of technologies to transport multiple, simultaneous telephone calls over shared communication pathways. In order to facilitate the further development of the modernization of the telephone network, the authorized common carriers (public utility telephone companies) have transitioned their equipment into a managed facilities-based voice network (MFVN) capable of providing a variety of communications services in addition to the provision of traditional telephone service.

“Similarly, the evolution of digital communications technology has permitted entities other than the authorized common carriers (public utility telephone companies) to deploy robust communications networks and offer a variety of communications services, including telephone.

“These alternate service providers fall into two broad categories: those entities that have emulated the MFVN provided by the authorized common carriers and those entities that offer telephone service using means that do not offer the rigorous quality assurance, operational stability and consistent features provided by an MFVN and are not regulated by the state public utilities commission.

“The code intends to only recognize the use of the telephone network transmission of alarm, supervisory, trouble and other emergency signals by means of MFVNs.

“For example, the code intends to permit an MFVN to provide facilities-based telephone (voice) service that interfaces with the premises fire alarm or emergency signal control unit through a digital alarm communicator transmitter (DACT) using an emulated loop start telephone circuit and signaling protocols fully compatible with and equivalent to those used in public switched telephone networks. The loop-start telephone circuit and associated signaling can be provided through traditional copper wire telephone service POTS or by means of equipment that emulates the loop start telephone circuit and associated signaling and then transmits the signals over a pathway using packet switched (IP) networks or other communications methods that are part of an MFVN.

“Providers of MFVNs must have disaster recovery plans to address individual customer outages and widespread events such as tornados, ice storms, or other natural disasters, which include specific network power restoration procedures equivalent to those of traditional landline telephone services.”

The important take-away from this discussion is that the MFVN is not a part of the fire alarm system and is not listed as a fire alarm device.

The UL listing of a currently listed MFVN product on the market states that the product is a POTS replacement “that connects to LAN and 4G to provide service to all traditional analog devices. This product acts as a managed facilities-based voice network (MFVN) and is considered part of the communication infrastructure, not the fire alarm system.”

Telephone service that is not provided using a traditional POTS line or with an MFVN would not be permitted for connection to a DACT in accordance with NFPA 72, Section

MFVN testing and coordination with the building fire alarm interface is the building owner’s responsibility to arrange and coordinate. This last requirement inevitably falls into your lap to ensure compliance.

All the above, even with the quotes from NFPA 72, proves troublesome to the AHJ, and this single issue will have an impact on the final approval of your installed fire alarm system. To ensure approval by the AHJ, make sure the MFVN provider is a public utility telephone company or an authorized (by the state public utilities commission) local exchange carrier. Additionally, conduct the necessary tests to ensure the alarm, supervisory and trouble signals are transmitted to the supervising station.

About The Author

MOORE, a licensed fire protection engineer, was a principal member and chair of NFPA 72, Chapter 24, NFPA 909 and NFPA 914. He is president of the Fire Protection Alliance in Jamestown, R.I. Reach him at [email protected]





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