“CLASS “”E”” ALARM SYSTEMS”

CLASS “E” ALARM SYSTEMS

Class “E” alarm systems—the “E” refers to the business occupancy classification of the New York City Building Code—are similar in many respects to the high-rise fire alarm/voice communication systems found in other parts of the country. Essentially, Class “E” buildings more than 100 feet high are required to provide a system that can be summarized as follows:

• An electrically supervised direct wire or radio (or combination thereof) fire alarm signal system and voice communication system.
• The fire alarm signaling system includes manual pull stations, smoke detectors in air-handling systems that serve more than one floor, and smoke detectors at elevator landings.
• Visual and audible annunciation of fire alarm signals (from the manual pull stations/smoke detectors described be-
• low) or voice communication station activation at the fire command station, mechanical control center, and the “regularly assigned” location of the fire safety director.
• Transmission of alarm signals to FDNY via a central station.
• Activation of the alarm devices requires that a fire alarm signal be sounded on the floor of activation as well as the floor above.
• Activation of a manual pull station requires that a fire alarm signal be sounded on the floor of activation as well as the floor above.
• Activation of an air-handling smoke detector requires cessation of the supply air and return air to the floor of alarm activation and activation of the exhaust fans in smoke shafts or the fans in stairwell-pressurization systems.
• Activation of an elevator landing smoke detector requires recall of the elevator, cessation of the supply air and return air to the floor of alarm activation, and activation of the exhaust fans in smoke shafts or the fans in stairwell pressurization.

When an automatic sprinkler system is installed throughout the building, the installation of water flow alarm devices eliminates the need for smoke detectors in the elevator landings and return-air ducts. The water-flow alarms, however, must recall the elevators, stop the supply air and return air to the floor of alarm, activate the exhaust fans in smoke shafts or the fans in stairwell-pressurization systems, sound alarm signals on the floor of activation as well as the floor above, send a fire alarm signal to FDNY via a central station, and annunciate an alarm condition at the fire command station, the mechanical control center, and the regularly assigned location of the fire safety director.