Alternative Pathways for Fire Signals
Using Ethernet and Networks for Fire Alarm and Emergency Communications Systems was presented by Wayne D. Moore, M.S., P.E, of Hughes Associates Inc. This report addressed the work being conducted by a task group for NFPA 72, The National Fire Alarm and Signaling Code. A question raised during the 2013 cycle of NFPA 72 concerned the acceptability of using Ethernet connections and other nonfire networks for fire alarm and signaling systems. While the 2013 edition includes a new designation for shared pathways, it does not define any performance or installation requirements.
Some of the concerns for these networks are:
- Ground detection and effects
- System management
- System availability
- Software control
- Testing and maintenance
The task group was given the charge to develop language for use within NFPA 72 that will address the use of Ethernet and local area networks (LANs) and wide area networks (WANs) in fire alarm, fire evacuation and mass notification systems.
Among items that the task group is to consider are:
- Network acceptance
- Reliability required
- Failure modes
- Conductor integrity
- End-to-end communication verification
The proposed networks would allow the use of a Category-5 Ethernet cable, with the Cat-5 being galvanically isolated at each end. This isolation would aid in the prevention of transient grounds and shorts on one cable from affecting other components. The task group must resolve how various fault conditions will be handled and reported. What fault conditions will still be required to be able to transmit a signal and which will halt a signal? Will alternate communication pathways be required, and if so, where and when?
The use of these networks must also address any routers or other equipment the pathway goes through. The presentation made it clear that the final answer to a number of these questions have not been finalized. The goal of the task group as presented was balancing reliability, risk and speed.
At press time, presentations of the task group’s work to date were scheduled to be shared at March’s Pre-First Draft Meetings for NFPA 72 in San Antonio. From these meetings, final proposals will be made and submitted for the NFPA First Draft Meetings to be held later this year.
Knowledge Shared on Many Topics
Other subjects covered during the detection and signaling portion of the symposium included:
- Use of Non-Fire Sensors for Fire Detection and Growth Predictions
- Detection of Cooking Fires
- Influence of Visual Signal Flash Intensity and Duration on Perception
- Mass Notification and Intelligent Response – The European Way
- Detection of Wild Land Fires for the Local to the Global Scale
SUPDET is held annually, usually in February or March (see sidebar for more info). Those who are interested in cutting-edge research in the field of detection and what the future may hold should consider attending a future symposium.
Shane Clary, Ph.D., has more than 37 years of security and fire alarm industry experience. He serves on a number of NFPA technical committees, and is Vice President of Codes and Standards Compliance for Pacheco, Calif.-headquartered Bay Alarm Co.
SUPDET Serves as Life-Safety Think Tank
This year’s 17th annual Suppression, Detection and Signaling Research and Applications Symposium (SUPDET 2013) took place Feb. 26-March 1 in Orlando, Fla. Organized by NFPA, the agenda featured more than 25 papers, addressing the latest developments, advances and research on topics including the latest in:
- Detection research including cooking fire detection research, a new strategy to address the unwanted alarm issue, and detection of wild land fires
- Sprinkler protection strategies including lithium ion batteries and other high hazard challenges
- Clean agent technology research including a case study on a Halon replacement system at a military jet engine test facility
The event is aimed at professionals in the fire alarm, suppression and emergency communication industries. The symposium provides attendees the opportunity to exchange ideas, innovations and current research information. For more info, go to nfpa.org.
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· Fire/Life Safety 2
Dr. Shane Clary
Fire Protection Research Foundation
Fire Side Chat with Shane Clary