Stalling Elevator Recall

[Tainted]

I have a job that requires the elevator to be recalled by a heat detector to the first floor and then activate shunt trip to the elevator. Before the shunt trip activates, the elevator needs to finalize the recall and open the elevator doors.

We can't really rely on a timer for a shunt to to activate because what if someone stalls the elevator door delaying elevator to recall to first floor? Is it usually done with a timer? Is there a way around that? How would the fire alarm control panel know it's in the first floor and doors have opened? Do the elevator controllers typically provide the output signals for this?

 

[GoldDigger]

No way would a timer be acceptable, as you note.
I don't know whether an elevator controller typically provides a recall complete output, but you need it in this case. That or a totally independent sensor for first floor door open.

 

[Tainted]

No way would a timer be acceptable, as you note.
I don't know whether an elevator controller typically provides a recall complete output, but you need it in this case. That or a totally independent sensor for first floor door open.

But how is it typically done? I'm sure somebody has done it before without a timer... What kind of sensor do you have in mind?

I'm assuming we're going to need:
1. Recall relay
2. a monitor module to know when the elevator is in the first floor
3. a monitor module to know when the door is open
4. a shunt trip relay
5. a shunt trip power monitor module

If items 1,2, and 3 are active, then the shunt trip activates.

 

[hillbilly1]

Should be a dry contact provided by the elevator control put In series with the shuntrip control, when the elevator arrives, and door opens, contact closes, allowing shuntrip to activate.

 

[gadfly56]

Should be a dry contact provided by the elevator control put In series with the shuntrip control, when the elevator arrives, and door opens, contact closes, allowing shuntrip to activate.

That's a straightforward and logical solution. However. The point of the shunt trip is to keep electricity and water from mixing in the hoistway or elevator machine room. Once the heat detector is activated, it's only a matter of time, and probably a short time, before the sprinkler opens up. If someone is holding the door on a floor, you have no control over how long that goes for. Wait too long, and you have water + electricity.

 

[gadfly56]

But how is it typically done? I'm sure somebody has done it before without a timer... What kind of sensor do you have in mind?

I'm assuming we're going to need:
1. Recall relay
2. a monitor module to know when the elevator is in the first floor
3. a monitor module to know when the door is open
4. a shunt trip relay
5. a shunt trip power monitor module

If items 1,2, and 3 are active, then the shunt trip activates.

Items 2 and 3 are not currently part of the Phase I elevator recall strategy as outlined in ANSI 17.1. To my knowledge, no alarm sequence of operations can implement this because elevator controllers don't output signals for this purpose. The one occasion I was asked by the AHJ, I put a straight up timer in the shunt sequence. This did not guarantee the car would be at the recall floor if the firefighters were using their key, but just gave enough time for it to go from the top floor down.

 

[petersonra]

Wait too long, and you have water + electricity.

Which is not that horrible of a problem. You have sprinklers all over the building that will trip and get electrical stuff wet, so why is it a particular problem with an elevator?

You are going to have serious water damage whether the electricity is off or not when the stuff gets wet.

 

[hillbilly1]

That's a straightforward and logical solution. However. The point of the shunt trip is to keep electricity and water from mixing in the hoistway or elevator machine room. Once the heat detector is activated, it's only a matter of time, and probably a short time, before the sprinkler opens up. If someone is holding the door on a floor, you have no control over how long that goes for. Wait too long, and you have water + electricity.

But if someone is in the car, and it is between floors, they will probably not worry so much about the water and electricity mixing as much as getting the hell out of the car! LOL!

 

[gadfly56]

Which is not that horrible of a problem. You have sprinklers all over the building that will trip and get electrical stuff wet, so why is it a particular problem with an elevator?

You are going to have serious water damage whether the electricity is off or not when the stuff gets wet.

The problem could be an unpredictable response from the controller, for example, sending the car somewhere it shouldn't or opening the doors while moving. Also, water might compromise the safety brakes, and we all know that you only need your backup systems when everything else is already going to heck in a handcart.

 

[gadfly56]

But if someone is in the car, and it is between floors, they will probably not worry so much about the water and electricity mixing as much as getting the hell out of the car! LOL!

Doesn't everyone carry a personal floatation device with them wherever they go??

 

[petersonra]

The problem could be an unpredictable response from the controller, for example, sending the car somewhere it shouldn't or opening the doors while moving. Also, water might compromise the safety brakes, and we all know that you only need your backup systems when everything else is already going to heck in a handcart.

what is more of a hazard to the guy inside an elevator. Getting stuck in the elevator during a fire or getting wet? The critical thing would seem to be to get the elevator to a safe place, open the door, and then leave it there. A lot of bad things "could" happen during a fire, but getting stuck in an elevator that is on fire is probably about as bad as it gets.

 

[gadfly56]

what is more of a hazard to the guy inside an elevator. Getting stuck in the elevator during a fire or getting wet? The critical thing would seem to be to get the elevator to a safe place, open the door, and then leave it there. A lot of bad things "could" happen during a fire, but getting stuck in an elevator that is on fire is probably about as bad as it gets.

For civilians, this isn't a problem. The problems arise once the firefighters use their key to control the elevator. They are the ones exposed to this issue, and the whole point of the firefighters' key is to give them manual control; how do you take it back without creating a larger risk, say leaving a hose team on a floor and no way to retreat?

 

[petersonra]

For civilians, this isn't a problem. The problems arise once the firefighters use their key to control the elevator. They are the ones exposed to this issue, and the whole point of the firefighters' key is to give them manual control; how do you take it back without creating a larger risk, say leaving a hose team on a floor and no way to retreat?

the OP is talking about operating a shunt trip. I don't see how a key is going to give you manual control if the CB is tripped.

 

[gadfly56]

the OP is talking about operating a shunt trip. I don't see how a key is going to give you manual control if the CB is tripped.

Yes, that is the point. I call it the "krispy first responder syndrome". The FF's are tooling around with that shunt waiting in the wings. Currently the code cares more about water + electricity than leaving a path of egress for the FF's. Someone else can do the relative risk analysis, I just install to what the code says.

 

[Tainted]

Should be a dry contact provided by the elevator control put In series with the shuntrip control, when the elevator arrives, and door opens, contact closes, allowing shuntrip to activate.

I thought elevator controllers do not output signals indicating that it finalized recall to the first floor and door is open. I thought the only way to do this was would be with a timer... am I missing something? what if what you described cannot be done because the elevator controller cannot give us that output?

 

[Tainted]

Items 2 and 3 are not currently part of the Phase I elevator recall strategy as outlined in ANSI 17.1. To my knowledge, no alarm sequence of operations can implement this because elevator controllers don't output signals for this purpose. The one occasion I was asked by the AHJ, I put a straight up timer in the shunt sequence. This did not guarantee the car would be at the recall floor if the firefighters were using their key, but just gave enough time for it to go from the top floor down.

So the only solution is with a timer? how does this make sense, what if a person is trapped between the floors... would that be a violation? if you followed code, and someone dies because of the code, who is going to get sued here?!

 

[hillbilly1]

The best thing to do is to get with the elevator installer, they know the requirements. It’s been a long time since I’ve done an elevator, but the ones I have done, the elevator tech provided a dry set of contacts which closed when the elevator was stopped and doors open. Some when it was sent to the first floor, others in taller buildings would go to the nearest floor and stop.

 

[gadfly56]

the OP is talking about operating a shunt trip. I don't see how a key is going to give you manual control if the CB is tripped.

Here's the progression.
Elevator lobby or machine room or hoistway smoke detector goes off, Phase I recall elevator goes to primary or alternate recall floor and the door opens, no one can use it

If the fire is hot and fast enough, the heat detector in the hoistway or elevator machine room is activated, the shunt trip activates, and no one, even with the fire fighters key, can use the elevator.

If the fire fighters use their key after Phase I starts and before the shunt trip activates, they are rolling the dice. There is a chance that the shunt will activate while they are in the cab. There is nothing in the current code or available sequence of events to keep this from happening, unless you lock out the shunt somehow, and now you have a code violation.

 

[Tainted]

Here's the progression.
Elevator lobby or machine room or hoistway smoke detector goes off, Phase I recall elevator goes to primary or alternate recall floor and the door opens, no one can use it

If the fire is hot and fast enough, the heat detector in the hoistway or elevator machine room is activated, the shunt trip activates, and no one, even with the fire fighters key, can use the elevator.

If the fire fighters use their key after Phase I starts and before the shunt trip activates, they are rolling the dice. There is a chance that the shunt will activate while they are in the cab. There is nothing in the current code or available sequence of events to keep this from happening, unless you lock out the shunt somehow, and now you have a code violation.

If this is the case, this has got to be one of the top 5 worst codes I have ever seen

 

[gadfly56]

If this is the case, this has got to be one of the top 5 worst codes I have ever seen

The situation is addressed by designing one of the elevator cabs to be a Firefighters Access Elevator. That comes with 2-hour construction all around and the shunt is omitted.