Relays and Circuits for Life Safety Functions Raleigh NC

Q: Where in National Fire Protection Association (NFPA), Quincy, Mass., National Fire Alarm Code 72 can I find the rules for how to properly shut down a night club's stage lights when the fire alarm system is tripped? Where do I place the relays for unlocking stairwell doors to allow re-entry during a fire emergency?

A: Where lights and sounds interfere with a fire alarm signal, they should be reduced or eliminated. Chapter 7 of NFPA 72 (2007 edition) contains requirements for how notification appliances must function. Rules for making something not function are found in the protected premises, Chapter 6. Section 6.16 holds the secrets for how Protected Premises Fire Safety Functions are interconnected to the fire system. Fire safety functions can be performed by trained staff, but NFPA 72 also states that fire safety functions "shall be permitted to be performed automatically." The decision to power down equipment is up to the owner/designer and other standards. For example, the "Safety Code for Elevators and Escalators" requires elevator controls' power to be disconnected prior to the activation of sprinklers in the elevator's hoistway or machine room. Section 6.16 does state, however, that the power for general lighting and operation of elevators must not be interfered with.

Should you and the owner decide that it is desirable to interconnect the closed-circuit television surveillance (CCTV) system using pre-set pan-tilt-zoom positioning and/or control doors using the access control system, then section 6.16.2.1 backs you up, stating: "fire safety control functions shall not preclude the combination of fire alarm services with other services requiring monitoring of operations." This is accomplished by requiring the fire alarm system to use a listed relay or addressable module "to initiate control of protected premises fire safety functions" to be "located within three feet of the controlled circuit or appliance." Off the shelf "ice cube" relays are not permitted.

Section 6.16.2.4 of NFPA 72 allows the use of a relay that operates on loss of power when the wiring between the panel and the remote relay isn't monitored for integrity. However, when the relay used isn't fail-safe, then the wiring between the panel and the relay must be monitored for integrity but only to the extent described in section 4.4.7 and the applicable provisions of Article 760 of the National Electrical Code.

These same rules also pertain to the relays and circuits controlling electrified locksets used on high-rise stairwell doors:

• There is no requirement for the relay to be within three feet of each door when the relay is installed to properly control the electrical circuit powering these devices. — You must use the supplied wiring connections provided within the door hardware or provided with its "listed-for-the-purpose" power supply.
• There is no code requirement to monitor the fire safety device's wiring beyond the fire alarm system's relay or after a digitally controlled network interface.
• There is no limit to the distance between the fire alarm relay and the controlled device, as long as the relay is within three feet of the controlled circuit.
• No other system is allowed to control the fire alarm system.

Greg Kessinger, SET, CFPS, president of an alarm installing company since 1981, teaches NICET training classes to fire alarm system designers and installers and continuing education seminars for Ohio's fire alarm inspectors. You can reach him at 888-910-2272; e-mail: Greg@firealarm.org; or visit his website at www.FireAlarm.org.