Stalling Elevator Recall

[GoldDigger]

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.

And for a building with only one elevator, the firemen should probably not be using it during a fire anyway!?

 

[GoldDigger]

Also, before the firement arrive we would hope that there has been a local alarm and that the residents/tenants have been warned not to use the elevator under those circumstances, which may have been recalled already in any case.

The only situation that is tricky is if NO other sensors in the building have tripped at the time the heat detector goes off.
Sounds like just having a smoke detector in addition to the heat detector either mitigates or compeletely resolves the hypotheticals we have been struggling with.

Also, that the heat detector triggered recall should happen even if the elevator is on Firemen's Key operation at the time?

We have been concentratring on one part of what has to be an entire integrated system of actions.

 

[gadfly56]

Also, before the firement arrive we would hope that there has been a local alarm and that the residents/tenants have been warned not to use the elevator under those circumstances, which may have been recalled already in any case.

The only situation that is tricky is if NO other sensors in the building have tripped at the time the heat detector goes off.
Sounds like just having a smoke detector in addition to the heat detector either mitigates or compeletely resolves the hypotheticals we have been struggling with.

Also, that the heat detector triggered recall should happen even if the elevator is on Firemen's Key operation at the time?

We have been concentratring on one part of what has to be an entire integrated system of actions.

For the first bolded item, you almost always have a smoke detector anywhere you have a heat detector. It is unusual to run elevator recall on heat detection, not to say, probably not code-compliant. Unless you have a case where a smoke detector cannot be used due to environmental conditions. Smoke detectors are likely to activate long before heat detectors and will initiate Phase I recall. In most cases, general alarms do not initiate elevator recall. In fact, the code specifically says only a limited number of devices (elevator lobby, machine room, and elevator hoistway) are permitted to start recall, unless the AHJ specifically requires it.

In the second case, elevator manufacturers as well as the code committees will have to hammer this out. What happens if you have a hose team on the floor and the elevator is their only means of egress? Suddenly the door closes behind them, and they are about to have a really bad day.

 

[Suzuki360]

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.

I believe the elevator is sent to the 1st floor so the 1st responders can use it. The heat detector is meant to SHUNT the power source if heat is detected in the shaft or elevator control room, so the firemen are not in the elevator while the fire is close to engulfing them. Heat detectors are a matter-of-Fact device meaning it takes a hot fire to initiate it and if its sensing that heat set point there is almost no doubt you have fire where you don't want people.

also, the device in the pump room is because hot oil mixed with flames equals more fire

 

[Suzuki360]

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.

No. Heats are in the shaft to detect HEAT as in a Fire in the elevator shaft means "Please do not use the elevator any longer". The heat detector isn't like a smoke that can be set off inadvertently by cigarettes, or by smoke only oven fires and from small fires or burning combustibles. With heat detectors (purchased for a pre-determined heat point i.e.185 degrees) only heat sets off the device and when used to signal the SHUNT TRIP it is meant to remove the power and car movement from a situation that's hidden in the shaft and getting worse by the second,

I believe the elevator is sent to the 1st floor so the 1st responders can use it. The heat detector is meant to SHUNT the power source if heat is detected in the shaft or elevator control room, so the firemen are not in the elevator while the fire is close to engulfing them. Heat detectors are a matter-of-Fact device meaning it takes a hot fire to initiate it and if its sensing that heat set point there is almost no doubt you have fire where you don't want people.

also, the device in the pump room is because hot oil mixed with flames equals more fire

 

[gadfly56]

I believe the elevator is sent to the 1st floor so the 1st responders can use it. The heat detector is meant to SHUNT the power source if heat is detected in the shaft or elevator control room, so the firemen are not in the elevator while the fire is close to engulfing them. Heat detectors are a matter-of-Fact device meaning it takes a hot fire to initiate it and if its sensing that heat set point there is almost no doubt you have fire where you don't want people.

also, the device in the pump room is because hot oil mixed with flames equals more fire

This is not true, and it doesn't always go to the first floor. Usually the first floor is the primary recall floor, and the purpose of sending it there is to evacuate any passengers. Firefighters access is a secondary issue.

Your second statement suggests you do not fully understand elevator recall. It is entirely possible for the firefighters, using their key, to be operating the elevator when the heat detector signals for shunt trip operation. Nothing prevents this.

 

[gadfly56]

No. Heats are in the shaft to detect HEAT as in a Fire in the elevator shaft means "Please do not use the elevator any longer". The heat detector isn't like a smoke that can be set off inadvertently by cigarettes, or by smoke only oven fires and from small fires or burning combustibles. With heat detectors (purchased for a pre-determined heat point i.e.185 degrees) only heat sets off the device and when used to signal the SHUNT TRIP it is meant to remove the power and car movement from a situation that's hidden in the shaft and getting worse by the second,

I believe the elevator is sent to the 1st floor so the 1st responders can use it. The heat detector is meant to SHUNT the power source if heat is detected in the shaft or elevator control room, so the firemen are not in the elevator while the fire is close to engulfing them. Heat detectors are a matter-of-Fact device meaning it takes a hot fire to initiate it and if its sensing that heat set point there is almost no doubt you have fire where you don't want people.

also, the device in the pump room is because hot oil mixed with flames equals more fire

No, absolutely not. Smoke detectors in the shaft are for detecting the fire. In fact, NFPA 72 forbids the use of heat detectors in hoistways unless there are smoke detectors as well. The purpose of heat detectors is to activate the shunt before the sprinklers go off. That's it, all she wrote, end of statement.