Sunday, March 20, 2011

Elevator Pit Dangers

A New Potentially Dangerous Electrocution Problem Found With Elevator Pits
A Continuing Look At Why We Need To Take a Hard Look At Elevator Codes and Revise Them.

By Nick Markowitz Jr.

I have previously written about the dangers sprinklers and shunt trip breakers pose to people riding in the cars of elevators, which I will review later in this article. However, a new hazard I have found involves a dangerous electrocution hazard to the people who service the cars, the elevator mechanics.

With all the precautions taken to prevent electrocution hazards to service personnel, which includes the use of Ground Fault Circuit Interrupters, one area has been overlooked. The alarm system used in the sump pump pit which warns when the sump pump has failed and the elevator pit is filling with water has been overlooked. What I have found in a majority of the cases is theses alarms are not UL Listed assemblies and that 120 volts is present on the wire lead which goes to the float down in the pit. This could seriously injure a service man if he accidentally cuts into the cord by bumping it with something or if the cord going to the pit deteriorates. Additionally since this alarm is not UL Listed there is no way of assuring they have been properly designed and protected. I can tell you from examining these units there is no way they would ever pass UL Listing as they are currently made. They are in too small a junction box and have no fuse protection and allow high voltage on the probe.

A far better way to do this would be to use a Class 2 low voltage alarm assembly which could also then be backed up with a battery. Better yet, since it is an essential part of the safety system serving the elevator, tie a float probe to a addressable monitor module of the fire system to supervise it. So flooding can be identified well before the pit has filled and starts going into the pits lighting fixtures plugs and hydraulic fittings. So once again another chapter of poor judgment when it comes to developing codes goes into my grand jury file for future use in prosecuting those who have failed to put the public’s safety above there own.

Also, talking about safety and elevators, the codes have failed to address serious life threatening issues when it comes to allowing sprinkler heads in shafts and allowing a shunt trip breaker to be used to shut off power to the elevator. This situation could trap its occupants between floors to die of smoke inhalation. In the first place, there is absolutely no reason why a sprinkler head is needed in a top of an elevator shaft which has an all metal car and 2 hour fire rated wall assembly, period. There has never been a documented fire in a fire protected elevator shaft other than a minor paper fire from accumulated debris in the pit. It makes sense to have a sprinkler head there, but not at the top. And then to allow them in there using an unproven system to shut off power with a device which is known to fail and does not allow for interlocking to make sure occupants are out of the car before the power shuts off makes absolutely no sense. I can tell you this, the first time I hear of a serious injury or death due to this failure of code officials to review and revamp this code my grand jury file on this matter will be turned over to the district attorneys office and plaintiff attorneys representing the injured. I will personally see to it there is such a stink made in the media that reckless endangerment or homicide charges are filed against every person involved in that codes decision.

The problem starts with the way the power is shut off to the car when sprinklers activate. Instead of using a flow switch with dual contacts interlocked to the controller, which is a sure way to know water is moving in the line. They instead rely on a heat detector 20 degrees lower then the sprinkler head is set that is mounted within 2 ft of the sprinkler to do the job of initiating the shunt trip breaker to shut off power. Shunt trip breakers are known to fail
and are no longer permitted by NEC code to shut off electrical services which are remote from each other. Because of this known high failure rate a heavy duty contactor should be used instead. Then we have the sprinkler head in the elevator mechanical room again. Why? This is a 2hr fire rated room and all the electrical and controls are contained within metal pipe and cabinets which prevent a fire from getting serious. When the sprinkler head does come on it can present a serious environmental hazard because of all the hydraulic oil and greases which are stored in these rooms which are combustible not flammable.

Then there is the problem of the sprinklers accidently activating and the shunt never energizing because a fitting has cracked or head blown off. A flow switch should be used for this operation not a heat detector which is not interlocked. You also have the problem with this whole shunt trip nonsense of it not being properly wired. Many electricians have not been properly trained to wire in a shunt trip breaker and are not familiar with fire systems. Fire systems techs are not electricians and the shunt trip circuits on elevators are complex. Many never do work properly as they should without extensive trouble shooting. I have never had the problem being cross trained but most personnel are not.
If the code panels are seriously concerned about fires in elevator shafts they need to do a total and complete revamp and look regarding this issue and then make sure all existing setups are modified to prevent problems.

Here are some suggestions to the code making panel if they’re really serious about fires in shafts and mechanical rooms.

1# Replace the heat detector with a flow switch. This ensures any water flow will be detected and power shut off.

2# Before a power shut off to a car takes place, insure it has stopped at the closest landing so occupants can safely exit.

3# Eliminate the shunt trip and install a heavy duty contractor instead. This way you are assured power is off.

4# Look at Deionized Water systems which prevent electrical shock in shaft areas which they’re worried about and use a clean agent or dry powder in the equipment room to prevent damage to environment.

Of course it is going to take some one being killed before this code is finally reviewed and fixed but what worries me most is how professional engineers which sit on many of these panels ever approved it in the first place. They should all have their licenses removed in my opinion for passing such a law. If a plain ole electrician / volunteer firefighter can see the dangers why can they not.

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