Smoke detectors, sprinklers, heat detectors and Shunt trips in elevator environment

We recently had code training and one of the items that I tend to get a lot of questions on by our field teams, electricians and fire companies are smoke detectors, sprinklers, heat detectors and shunt trips. 

For all the items listed below please consult AHJ for specific rules to the area you are working in and items the AHJ may have taken exception to national/local codes.

Smoke detectors 

Smoke detectors on ceilings must be at least 4 inches from the wall.

Smoke detector on walls must be between 4 inches and 12 inches from the ceiling.

Smoke detectors are required in machine rooms.

Smoke detectors are required at the top of the hoist way when either a sprinkler is present or the passenger cab is not a fire-rated design.

No smoke detectors shall be provided in the elevator pits per NFPA 72.

Smoke detector may also be provided to operate hoist way smoke evacuation equipment, but it cannot be connected to the elevator system.

Sprinklers - Sprinklers may be located in the following elevator equipment areas:

•        Machine Room

•        Top of Hoistway – Sprinklers are not required when the passenger elevator cab is a fire rated design.

•        Pit – Sprinklers located within 24” of the pit floor do not require a heat sensor for shunt trip disconnects nor a smoke sensor.

[Sprinkler, heat & smoke]

Heat detectors - Heat detectors are required within 2 feet of each sprinkler head in elevator equipment areas and pit. Exception in pit when the sprinkler is within 24” of the pit floor.

Shunt Trip disconnect system

Shunt trip disconnect is required on any new or existing elevator where a sprinkler is located at the top of the hoistway or in the machine room. 

A properly located sprinkler in the pit only, will not cause shunt trip disconnect to be required.

Non-sprinklered elevators will not have a shunt trip disconnect system.

Operation of the shunt trip disconnect must cause disconnection of normal power and emergency/stand-by power.

Operation of the shunt trip disconnect must also cause disconnection of any internal auxiliary power operations, such as battery lowering devices on hydraulic elevators or anti-entrapment (TAP) devices on traction elevators if so equipped.  The shunt trip disconnect must have a set of contacts that signal the control system to prevent movement of the elevator.

Location of the shunt trip disconnect is not specified by code.  Shunt trip disconnect can be in a fire command center, elevator machine room, electrical room, or other location.  If in the machine room, it may be combined with the main disconnect.

Power to and operation of the shunt trip shall be independent of the elevator control and shall not be self-resetting.

[Shunt & disconnect seperate]

[Shunt/disconnect combination unit]

Reference - Joseph P. Donnelly, PE Elevator Education Program 2019

If you have any questions or would like additional information feel free to contact me at CraigZ@colleyelevator.com or 630-766-7230 ext. 107.

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