If the elevator controller is located in the shaft in a machine room-less configuration, a smoke detector must be placed above the controller. In any situation, if a smoke damper is installed at the top of the shaft, it’s permissible (even required) to be actuated by a smoke detector located in the shaft  Commonly, it is often not possible or desirable to get into the elevator shaft after completion of the elevator, so that the fire detection system cannot be serviced. Another problem is that due to the moving elevator car, differences in air pressure occur, so that possible smoke will spread very unpredictably.

The challenges for accurate fire detection in Elevators are

• Rapid air movement
• Oli and greasing products
• Risk of heat and friction generating smoke from moving parts
• Difficult access for maintenance and testing fire equipment
• Electric wiring

The Dutch NEN2535 recommends using aspirating systems because these can be placed outside the shaft because elevator shafts cannot contain any other installation than those required for elevator. 

Stratos

Because Stratos aspirating systems can be mounted in an adjacent, accessible space, commissioning and maintenance of such installations is possible without the technician having to be physically present in the elevator shaft. By mounting the aspirating pipe vertically in the elevator shaft, pressure differences due to the moving elevator are eliminated and any smoke that may build up under the elevator is also very quickly detected.

Extra filters like the CM10970 can be used for elevator shafts with excessive dust or dirt. these can be placed nearby the detector in line with the air sampling pipe which draws the air into the detection chamber of the Stratos detector, analyzing the air for the presence of smoke. The Stratos has a built-in delay for signaling flow faults to prevent faults when the elevator is moving. 

Air sampling

The ASD is connected to the air sampling pipe which will be located in the elevator shaft. the sampling holes are typically located at the top of the elevator shaft. In tall buildings the pipe runs down the shaft vertically to ensure air sampling at multiple levels. 

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