- Industry News
- 08.07.2017
Circuit integrity that is! Circuit integrity is essential for communications to work during events where life safety is at risk to increase response time for first responders. If emergency systems cease to function during a fire, responders may not know critical information allowing them to reach those still in a building, understand where the fire started, and other information allowing them to respond to the most critical areas first and continue response until the event has been remedied. This information would not be accessible if the cable was burned to a point that data transmission stops.
The National Fire Protection Association (NFPA) first outlined this need in 1985. The requirements were outlined in NFPA 72.F (The National Fire Alarm and Signaling Code) and have continued to be revised in subsequent revisions of the code. The primary concern is to make sure that one area of the building will not be impacted in such a way that it can no longer warn other parts of the same building. For instance, should a fire break out in the east wing, the circuit should remain intact so that the system can warn the west wing. In 2016, the survivability terminology was further refined to stipulate, “the ability of any conductor, optic fiber, radio carrier or other means for transmitting system information to remain operational during fire conditions.”
Fire systems are rated as 2 hour, when the cable is designed to withstand 2 hours of fire, water, and other suppressing agents. These cables were first introduced about 15 years ago and the jacket turns to a ceramic like substance when they are subjected to heat. This is part of the reason that standard structured cabling is not allowed as part of the actual fire system itself. For more connected buildings, the communication happens over the networks from the fire system server to other systems, or outside of the two-hour fire system itself. Within the two-hour system, the CICs (Circuit Integrity Cables) are available in a variety of twisted pair configurations and gauges, but what surrounds the pairs is where the magic happens. There are wraps that also work, but due to the expense, they are designed for very short applications of a few feet.
The testing for these cables falls under the Standard Test Methods for Fire Tests of Construction Materials and testing occurs at Underwriters Laboratories (UL). In 2012, due to some concerns, UL retracted all approved cables forcing a retesting of cables under new, more stringent, testing guidelines requiring all components to pass testing 5 out of 5 times. New testing also tests EVERY component of the system under test. Certificates are issued very specifically to the configurations and brands under test. The tests cover both very high heat and the drastic temperature changes when water is applied to the fire.
As stated, these cables are specified when there is need to provide time to assure the safety of building occupants. So, any large building or area where large numbers of people can congregate will be required to use at least the 2-hour fire rated cables. In some areas, insurance companies are stepping up and requiring either 2-hour cables or 4-hour (cables in conduit) ratings. Today there is not a cable that has passed the UL 4-hour test as a stand-alone (not in conduit) channel.
These hour rated systems are required not only for the fire systems, but also for egress points, meeting areas, elevators and mass notification systems. The International Building Code (IBC) and International Fire Code (IFC) both reference these systems as specified in the NFPA. To be sure that you’re are meeting all the approved guidelines for your project, reach out to your AHJ (Authority Having Jurisdiction), your insurance company, or Paige. We are glad to point you in the right direction.
