Hot and Humid Elevator Control Rooms - How Does it Affect my Elevator?

 

We have had some blistering hot and humid days, that hit all of a sudden, and have gotten a lot of calls from equipment failure due to hot weather, no ventilation, controller failure, relay failure, door operator failure, motor failure, etc. Our elevator mechanics have been chasing calls since the heatwave began.  The original post was from 2017, reposted in 2018 and now edited for 2021.

This summer we have seen more frequent failure of solid state boards and equipment that has been exposed to extreme heat and cold.  Building owners frequently ask “why is this occurring”.   I always like to give some research and background when explaining to building owners, so they can be better educated, and came across a great article which I have taken some of the high points.  When reading this be aware that most issues with machine room environments will result in a shut down or needing a replacement board, but, incorrect machine temperatures can also cause malfunctions which could result in an elevator operating in an unsafe condition.

The subject of the operation of an elevator in an elevated high ambient machine room temperature is one of concern for elevator manufacturers, code writes, enforcing authorities, building owners and operators, elevator consultants and fire safety personnel.  Today’s solid-state design elevator control systems are able to maintain rated performance over a wide range of normal design operating temperatures but are vulnerable to elevated temperature conditions.

NEII Vertical Transportation Standard calls for machine room/or machinery spaced temperature to be between 55 and 80 degrees Fahrenheit.

NEMA has established a maximum temperature limit of 104 degrees Fahrenheit.

National Electrical Code[NEC] has published 86 degrees Fahrenheit as the standard ambient for conductor ampacity ratings.

Computer manufacturers recommend an ambient temperature of 60 to 90 degrees Fahrenheit.  Your elevator's microprocessor controller is a computer.

The effects on solid state components due to temperature may be classified in two areas; operating[reliability] and failure[life].  The manufacturer's recommendation for ambient temperature will allow the devices to operate in a repeatable and predictable fashion.  Temperatures above or below the recommended temperature will decrease the life of the solid-state system. 

Please note - Elevator controller temperatures are 10 to 15 degrees warmer inside the controller with the cover on. If an elevator machine room is 105 degrees, the temperature when you open the door to the controller could be over 120 degrees.

Causes of machine room over temperature

1.   Failure of machine room ventilation or no ventilation

2.   Failure of cabinet ventilation system – air condition or fan

3.   Increase in the elevator duty cycle beyond design criteria

4.   Sustained operation at low AC input levels

The recommendation of machine room temperature control comes from a few different areas

1.   Normal temperature in room – in Chicago we have hot summers and cold winters

2.   Amount of heat released from the elevator equipment in the machine room – depends on the equipment you have and amount of traffic in the building

3.   Amount of ventilation and/or air conditioning/heating provided in machine room.

Take away – Be aware of the machine room environment and make preparations i.e. air conditioning[best case] or ventilation in summer and heating in the winter.

Reference – “High temperature operation of elevators” by Nick Marchitto 

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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