In every building taller than two stories-and in some two-story buildings as well-regulations will require you to provide elevator recall as part of the building's fire alarm system installation. Numerous codes interrelate to ensure that the recall functions as ultimately required by the ASME/ANSI A17.1 Safety Code for Elevators and Escalators. Building codes, elevator codes and fire alarm codes and standards all play a part to require recall and how the recall function should operate.
The ASME A17.1 Code provides requirements for operational sequences for Phase 1-Emergency Recall Operation and Power Shutdown-“Shunt Trip” Operation.
The code defines Phase I-Emergency Recall Operation as the operation of an elevator wherein it is automatically or manually recalled to a specific landing and removed from normal service because of activation of firefighters' service.
“Power Shutdown” (shunt trip) occurs when the control system disconnects the mainline elevator power to eliminate potential problems as a result of sprinkler actuation in the hoistway or elevator machine room.
NFPA 72, National Fire Alarm Code, serves as the primary guide for the electrical contractor. NFPA 72-2002 section 6.15.3 contains the fire alarm system recall interface requirements and smoke detector requirements as follows: “System-type smoke detectors or other automatic fire detection as permitted by 22.214.171.124 located in elevator lobbies, elevator hoistways, and elevator machine rooms including machine space, control room, and control space used to initiate fire fighters' service recall shall be connected to the building fire alarm system.”
The code also states that “only the elevator lobby, elevator hoistway and the elevator machine room smoke detectors or other automatic fire detection, as permitted by 126.96.36.199, shall be used to recall elevators for firefighters' service.” As with all code requirements, the authority having jurisdiction may change which detectors may recall the elevators. However, most jurisdictions follow the ASME A17.1 and NFPA 72 requirements.
Sometimes jurisdictions adopt different versions of ASME A17.1 and NFPA 72. This is complicated because the developers of ASME A17.1 revise it on a three- to four-year cycle with yearly addenda while the developers of NFPA 72 and NFPA 13 revise it on a three-year cycle.
To avoid last-minute changes to an installation, a professional contractor will ensure that he or she knows which codes the jurisdictions have adopted.
The spacing of smoke detectors becomes important in elevator lobbies. NFPA 72-2002 has requirements for such spacing. For normal ceiling heights, a contractor must locate the lobby smoke detectors on the ceiling-not the wall. The contractor must locate a detector within 21 feet of each elevator door in the elevator bank under control of the elevator.
Knowing specific requirements of the current edition of the code will also save aggravation because changes to the code have solved certain problems that may have plagued installations. For example, contractors commonly installed smoke detectors in the elevator hoistway, but the incursion of dust frequently caused false alarms. The 1999 edition of NFPA 72 removed that requirement. The current edition, NFPA 72-2002, definitively states “Smoke detectors shall not be installed in unsprinklered elevator hoistways unless they are installed to activate the elevator hoistway smoke relief equipment.” The professional contractor must understand that in new construction, the elevator hoistways must consist of fire-rated construction while the elevator cab must consist of noncombustible materials. NFPA 13-2002 states that with a fire-rated hoistway and a noncombustible elevator cab, the contractor does not need to provide automatic sprinkler protection for the elevator hoistway. Therefore, the elevator hoistway does not need a smoke detector.
When a smoke detector in an elevator lobby or machine room-and the hoistway, if protected-actuates, it must indicate an alarm condition on the building fire alarm system. Also, the detector must cause a separate and distinct visible annunciation at the control unit and require annunciators to alert fire fighters and other emergency personnel that they may no longer safely use the elevators. This need not actuate the system notification appliances as long as the alarm signal indicates at a constantly attended location. An exception exists in the requirements that permit the detectors in the machine room and elevator hoistway to initiate a supervisory signal rather than an alarm signal.
Interfacing the fire alarm system with the elevator recall system will maintain safety by preventing the occupants from using the elevator and possibly becoming trapped in the hoistway or riding in an elevator car called to the fire floor where they would likely perish when the doors of the cab open. Interfacing the fire alarm system with the elevator recall system also allows the firefighters to use the elevators as safely as possible during their fire fighting efforts.
Understanding the diverse and sometimes conflicting requirements for elevator recall will help a contractor ensure an on-time acceptance test and a happy building owner who will receive the occupancy permit for the building on time. EC
MOORE, a licensed fire protection engineer, frequent speaker and an expert in the life safety field, is a co-editor of the current National Fire Alarm Code Handbook. Moore is a principal with Hughes Associates Inc. at the Warwick, R.I., office.