NFPA Journal - November/December 2013 - (Page 47)

That's not to say committee members haven't attempted to develop provisions in NFPA 72 pertaining to these networks. During the last few code revision cycles, members have remained at odds over the reliability of these networks to do what is expected during an emergency, which is to provide appropriate alarm signals and notification of problems that may include open circuits, ground faults, or shorts. To resolve these concerns, the Correlating Committee on Signaling Systems for the Protection of Life and Property established a task group last year to develop code language for the 2016 edition of NFPA 72 that addresses the use of Ethernet, local area networks, and wide area networks in fire alarm systems, fire emergency voice and alarm communications systems, and mass notification systems. The SIG-PRO Committee reviewed those proposals at its latest meeting, held in September. "We had a number of meetings where people had to get comfortable with the technology," says Wayne Moore, vice president with Hughes Associates, a fire protection and life safety consulting firm, and NFPA Journal columnist (see his overview of using computer networks for fire alarm signals in the September/October "Buzzwords" column). Moore also chaired the Use of Networks in Fire Alarm and Emergency Communication Systems Task Group. "Once they were comfortable, we said, 'How can we allow it in the code?' " Something old, something new Conventional fire alarm systems typically rely on initiating device circuits that use dedicated copper wiring to connect a control panel to a series of devices, such as smoke detectors and pull stations. The wiring adheres to specific code requirements for installation and for the reporting of fault conditions as "trouble signals." An initiating device circuit provides a non-specific alarm signal to the control panel if any one of the connected devices operate. Signaling line circuits are newer to the alarm industry and, unlike initiating device circuits, assign "addresses" to devices on the circuit, thereby providing more information about the location of an incident and status of a device. No matter what kind of circuit is being used, all are required to be monitored for integrity according to the requirements in NFPA 72. "If we Photograph: Shutterstock Instead of InstallIng copper wiring throughout a building or campus to connect traditional alarm systems, networks use little more than an alarm panel, a computer server, and hardware or software to transmit data. have an open circuit, or ground fault, it is annunciated at the alarm panel and tells users something is wrong," says Merton Bunker, chair of the SIG-PRO Technical Committee. "That's been one of the tenets of the code for nearly 40 years." Regardless of their thoughts on how reliable an alarm system would perform via computer networks, committee members interviewed for this story acknowledged the potential benefits of that model for alarm communication. Instead of installing copper wiring throughout a building or campus to connect traditional alarm systems, networks use little more than an alarm panel, a computer server, and hardware or software to transmit data. "Ethernet has a lot more capability of reporting potential problems than fire alarm designers ever considered," says Horon, adding that his software transmits information about an incident and relevant floor plans to computers. "To a lot of end users, it seems like a real disadvantage to not have more information than what an LCD screen of an alarm panel gives them." When advocates for Ethernet technology stated their case for network inclusion in the code, committee members from the alarm industry remained skeptical as to whether these networks would produce proper alarm annunciations and signal transmissions. Extensive discussions on this issue occurred during previous NFPA code cycles and continued during the 2013 code cycle, as some committee members wanted additional clarity on the issue before allowing network performance and installation requirements in the code. "The committee is cautious and wants nfpa.org/72 Review the first draft committee report on the 2016 edition of nfPa 72®, National Fire Alarm and Signaling Code. NOVEMBER/DECEMBER 2013 NFPA JOURNAL 47 http://www.nfpa.org/72

Table of Contents for the Digital Edition of NFPA Journal - November/December 2013

Contents

NFPA Journal - November/December 2013