2016年9月29日星期四

The Elevator Code About Fires

For years, elevator code has dictated that placards be placed in elevator lobbies telling occupants to use the stairs in case of a fire. Elevator code however is more complicated than a simple sign, especially as it applies to passenger elevators and fires.

Elevator code is governed by the American Society of Mechanical Engineers (ASME). Formally dubbed the A17 Life Safety Code for Elevators and Escalators, A17 is the basis for most requirements adopted at the local level.

Under ASME standards, once a fire has been detected, elevators operate under either Phase I or Phase II regulations.elevator company

Elevator code dictates that under Phase I operation, elevators that are 25 feet or more above the main floor return either to a designated landing area or an alternate area. Phase I operation is activated either manually by a special key, or automatically by a fire alarm initiating device. A sensor could detect smoke in the hoistway or machine room, for example, and trigger Phase I. The goal is to remove the elevators from service so that building occupants do not use elevators during a fire and become trapped.




Phase II operation is an override meant for firefighters after Phase I has been activated. Under Phase II operation, firefighters can use a keyswitch to operate the elevator, provided the hoistway is clear of smoke and the elevator has electricity.

Elevator Code Updates

ASME has been conducting a hazard analysis since 2004 to determine whether to recommend changes to A17 that would allow elevators to be used for evacuation.

One reason the study has taken so long is the technological and behavioral challenges involved. For example, how would smoke be dealt with? Instructing occupants when it’s appropriate to evacuate via an elevator is no easy task because the decision could vary depending on the building, the type of emergency and where the occupants are located. That question would likely require changes to elevator control systems.

Compounding the difficulty in using elevators for evacuation is that any potential changes would likely impact fire codes, building codes and elevator codes, experts say.

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