Elevator Shunt Trip

[vd_2kil_cm]

The situation: I have a four-pack of elevators arranged two per shaft on opposing sides of a corridor. These elevators are served by controllers located in a common machine room. I am to install heat detectors for shunt trip adjacent to each sprinkler head in both the machine room and the top and bottom of each shaft. The heats in each shaft are to trip only the two elevators in that shaft. The heats in the machine room are to trip all four elevators.
My question: Can I match phases from the elevators main breakers to the primary side of a single control transormer(each through a set of fuse blocks) and then do what I need to with switch legs and such?

[iwire]

The shunt trips I am familiar with are independent from the breaker power.

Typically 2 leads hanging out of the breaker that need 120 volt to trip the breaker even though the breaker might be 480 volt.

[vd_2kil_cm]

Understood, however this shunt trip system cannot be arranged such that interruption of shunt trip power is not dependant upon interrupting power to all controllers served, i.e. power cannot come from source separate from that of the controllers. Also, opening the breaker to one controller cannot affect shunt trip power for the others.

[iwire]

I see your problem now, are these heats part of a fire system or stand alone.

If part of a system you should be able to add control modules for each controller, with the battery back up and supervision this might be acceptable.

If these are stand alone heats it might be easiest to use more then one heat at each location as in two at the top and bottom of each shaft and four in the machine room.

In this way all power is kept separate and independent. If you try the phase matching idea when you shut one unit down it will be getting a back feed from the others so it will have live components with the switch off not a good thing.

[ March 13, 2003, 09:34 PM: Message edited by: iwire ]

[txsparky]

You could do it using 3 relays .Heat detector in shaft 1 energizes relay 1(R1). 1 n/o contact on R1 closes and energizes shunt trips for equipment in shaft 1. Heat detector in shaft 2 would energize coil of relay 2(R2). 1 n/o contact on R2 closes and energizes shunt trips for equipment in shaft 2. Heat detector in equipment room energizes R3.R3 has 1 n/o contact wired in parallel with n/o contact of R1 and 1 n/o contact wired in parallel with n/o contact of R2.This would then shut down equipment in both shafts.

[roger]

I may be missing something here. The shunt trip for each elevator should only occure after the recall has been done by each unit affected by the initiation device.

This should be accomplished through the controller(s) after the F.A. device has picked the control module(s) and the controller(s) has seen both or all four elevators recall to the floor of safety.

Roger

[ron]

Elevator recall is somewhat seperate from the shunt trip. The shunt trip is supposed to happen prior to or simulataneously with the application of water. Recall hopefully occurs first with the alarm condition of smoke detectors in the shaft, machine rooms and elevator lobbies.

[iwire]

txsparky, which controler would you pick the control power from?

[roger]

Ron, you are right. Thanks

Roger

[vd_2kil_cm]

A little more info: These heats are not connected to the fire alarm system in any way, per engineering specs. They are for shunt trip only and act independantly of elevator recall status. There are six heats in the machine room and two each at the top and bottom of each shaft. I feel that treating each set of detectors as a "zone", if you will, would be the best way to go given the need for the same action to occur if any one of the heats in a zone is tripped. Protection from backfeed would come in two ways: the breakers serving the elevators would be marked as backfed devices and separate means of disconnect would be provided for each feed to the control transformer, which would be located immediately adjacent to the panel. Good, bad, or ugly?

[roger]

This is really different. :confused:

Roger

[vd_2kil_cm]

I'm not saying I like any of it. Ours is not to question why.... ;)

[iwire]

With this many heats why would you need to mix the feeds at all

Shaft 1 cars a and b
one heat at the top and one heat at the bottom of the shaft 1 shuts down car a and the other heats at the top and bottom of shaft 1 shut down car b There should be no requirement for the cars to shutdown at the same instant. Same thing with shaft 2

But why is this your problem If this job has these detectors per engineering specs I would ask for a diagram from the engineer make him earn his pay.

[ March 13, 2003, 10:50 PM: Message edited by: iwire ]

[vd_2kil_cm]

Originally posted by iwire:
With this many heats why would you need to mix the feeds at all

Shaft 1 cars a and b
one heat at the top and one heat at the bottom of the shaft 1 shuts down car a and the other heats at the top and bottom of shaft 1 shut down car b There should be no requirement for the cars to shutdown at the same instant. Same thing with shaft 2

But why is this your problem If this job has these detectors per engineering specs I would ask for a diagram from the engineer make him earn his pay. All that really accomplishes is increasing the number of switch legs I have to deal with and since each is being treated as one shaft even though it serves two elevators, it won't work. Any elevator in that shaft has to shut down. My main issue is control power common to all four elevators. If any one of the four breakers feeding the elevators are closed, I have to have control power capable of tripping any that are still energized. Control power cannot come from a source that can be deenergized without also deenergizing all elevator controllers.

[iwire]

I am not explaining my self well.

You have 4 heats in each shaft with 2 elevators in each shaft

Use 2 of the heats to shut down 1 elevator and the remaining two heats will shut down the other elevator.

IMO I do not think matching phases and mixing control power is the way to go, as this is life safety equipment get it engineered.

If the power source is so important why would they except one control transformer, if that fails you have no protection.

When you get it done can you post what you come up with?

[ron]

You might just request to put in a small fire alarm control panel with battery backup. Then run a control module to each of the breakers serving the elevator. Be sure the shunt trip coil is 24V.
If you request a drawing from the engineer, it will take three weeks and the solution will cost more than your solution.

[don_resqcapt19]

Is this system really designed in a manner that will guarantee that the elevator car becomes a "people oven" if the elevator recall is not completed prior to the activation of the heat detector, or am I missing something????
Don

[vd_2kil_cm]

Yes, you are correct in your assumption that the cars are to become "people ovens" in case of shunt trip before recall. The theory behind this is apparently that before the heat trips the breaker, one of the smokes controlling recall will have already gone into alarm. I don't subscribe to this theory; I think the two should be interlocked to prevent this, but I didn't design this system. Speaking of designing the system, the reason I don't consult the engineer as iwire suggested is that I don't have the time to wait a month for an answer that is going to be expensive and wrong. I have done elevator shunt trips before, using basically the same method: control transformer off of load side of main breaker or disconnect supplies shunt trip power. The difference here is having more than one shaft served by one machine room.
Now that I think of it, what is the purpose of even having shunt trip on an elevator? Every new construction I've been on in Florida has had a shunt trip main. That would kill power to the elevators just as easily.

[roger]

VD, this is one of the hardest codes there is to keep up with. Talking to one of our Department of Labor inspectors he said the same thing.

In N.C. if all sprinklers are removed from the shaft, the heat detectors can be removed and the shaft protected by smoke detectors only with no shunt tripping involved. (recall happens and doors open) Don't quote me on this, see first paragraph.

Back to the sprinklers and heat detectors.

The sprinkler heads should be a lower heat level than the heat detectors as you know.

What will your local fire marshall or elevator inspector say when they get involved. You may use them for allies now. I have found that when an AHJ questions design issues, designers are quick to respond. ;)

Roger

[ March 14, 2003, 07:16 PM: Message edited by: roger ]

[Nick]

Roger,
The sprinkler heads should be a lower heat level than the heat detectors as you know.Huh? I thought the intent was to remove power to the elevators before the application of water. Or am I missing something.

I remeber a thread on this at the old IAEE board a while back. It went on for a long time and there never was an agreement to how the elevator, fire and electrical codes should mesh regarding this issue.

[roger]

Nick, I don't know.(go back to my first and second paragraphs) :D I asked this question awhile back and was told this was the way it was.

This made more sense to me. I would rather be wet than burnt.

I will ask our technology devision on Monday, I probably heard it the way I wanted it to sound.

Roger

[iwire]

Questions like this is why I say get the engineer to do his job, simply putting something on the print is not engineering as I know it.

In the jobs I work on asking for clarification on something like this would not cost me a dime, and as to delay that would be the EEs problem, unless I had waited till the last minute then I would be in a bad spot for delays.

[ron]

ANSI 17.1 does not identify the temp level of the heat detector to activate the shunt trip. Generally the heat detector is a standard 135 degree and the sprinkler head is at 165 degree.
The power needs to be removed from the elevator prior to application of water.
You could also activate the shunt trip with a water flow switch positioned to monitor water flow at the elevator shaft.

[Nick]

If you used a water flow switch to activate the shunt trip, you would be shunting the power a split second after the application of water. So now what about elevator recall? Is it the intent of the various codes on this subject that the occupants remain stuck between floors with water pouring down on them until emergency help can arrive? :confused:

[ron]

Shunt trip is a seperate function from recall. Recall is activated by smoke detectors, where shunt trip is activated by heat detectors or water flow (designers choice).
Generally, smoke detection will occur well in advance of 135 degree temperatures to activate shunt trip, or 165 degree to activate water flow/shunt trip.

[hornetd]

In addition to being an electrician I am a firefighter rescuer. The installation of shunt trips that are not integrated with the recall sequence turns the elevator into coffins on strings or coffins on tubes. The smoke detectors in the shaft, lobby, and machine room cause the elevators to return to their primary or alternate floor, firefighters arrive and initiate fireman's service, an entire company of firefighters is in the elevator when the shunt trip deprives the elevator of all power and it stops dead between floors or even in the blind portion of the shaft. The elevator code needs to be changed to require that the heat detectors cause recall from fireman's service and the water in the sprinklers would be controlled by a pre action valve. The pre action valve would only open after recall was complete. Yes I do know that that would cost more money. So tell me how much are the lives of an entire fire company worth?
--
Tom

[roger]

Thank you Tom.

Roger

[hornetd]

Originally posted by don_resqcapt19:
Is this system really designed in a manner that will guarantee that the elevator car becomes a "people oven" if the elevator recall is not completed prior to the activation of the heat detector, or am I missing something????
Don Don
I have gone through elevator inspections were the inspector tested the heat detector function with a lighter. It took me fifteen minutes to restore power to the elevator and get those dumb SOBs down. I told them that those fixed temperature heat detectors are one time use only and they replied that they had to test it anyway. We finally filed a written misconduct complaint in oder to get the practice stopped.

Shunt trips are what I call elevator inspectors revenge. We wouldn't keep our sprinklers out of their shafts so they booby trap the elevators so that we may have to hike the stairs to avoid becoming trapped.
--
Tom

[ March 22, 2003, 10:37 AM: Message edited by: hornetd ]

[iwire]

Lately the hydraulic elevators here in MA have been coming with a small battery back up that in the case of power failure opens the valve and brings the car to the primary floor then opens the door.

How or if this is integrated into recall I do not know, hopefully if the recall has called the car to the alternate floor it will stay there even with a power failure, but in general at least this gets people out of the car on a utility failure.

[ March 22, 2003, 03:52 PM: Message edited by: iwire ]

[hornetd]

Originally posted by iwire:
Lately the hydraulic elevators here in MA have been coming with a small battery back up that in the case of power failure opens the valve and brings the car to the primary floor then opens the door.

How or if this is integrated into recall I do not know, hopefully if the recall has called the car to the alternate floor it will stay there even with a power failure, but in general at least this gets people out of the car on a utility failure. Well at least that makes it less likely that people will suffocate or burn alive.