Elevator Recall

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Sparky5150

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OK, just thrown for a loop by the elevator manufacturer. I have always thought that an elevator needed a battery to lower the cab to a designated floor upon loss of power or activation of fire devices in shaft or mechanical room.

I just spoke with the elevator rep and he said that is a nice feature but not required by code unless the elevator is in a medical facility or the building is a high rise.

Comments please
 
What happens if there is a fire and someone is on the elevator? Sounds like it should be required on all of them to me? I haven't messed with them much, but I do remember some of the old cotton mills added that as a safety feature back in the 60's. But I was only a child of 16 then...........
 
I've done lots of smaller, 2-10 floor elevators, and none have had a battery. I am not an elevator guy, so I dont know what they do, I suppose some kind of a braking system, but I don't have a clue.

Jim T
 
So what is supposed to happen per code with an occupied electric (not hydraulic) elevator during a utility failure? El Stucko?
 
Descends and brakes at the next nearest floor and unlatches the door. You are on your own from there. If the floor is ablaze and you pry open the door, you become new fuel.
 
Sparky5150 said:
So what is supposed to happen per code with an occupied electric (not hydraulic) elevator during a utility failure? El Stucko?
Click to expand...


Jraef said:
Descends and brakes at the next nearest floor and unlatches the door. You are on your own from there.
Click to expand...

I don't believe so.

If the builders did not opt for a emergncy power supply for a cable elevator you are stuck until rescued or the power is restored.

If you where to manually release the break on a cable elevator and it did move you would not know which way it would go. Because of the counter balance it is very likely it would go up.

However it is not likely to move as often the reduction gear is worm drive, a worm drive gear box is all but impossable to drive by the load.

Another gear box would be a planatary gear box, again the reduction is so high that it would not likely be moved by the load.

The few buildings I have seen with emergency power for cable elevators had a way of selecting which car was connected to the genertor at any given time.
 
Thanks for the responses guys!

Does anyone know for sure that the code allows people to be stuck in an elevator during power failure, or whether code mandates battery operation to allow the occupants to travel to a specific floor and open the door?
 
Elevator Recall

First, I would go to the governing building code to understand if elevators are mandated or not to remain a viable means of egress, even during a power outage. Also, I would check NFPA 101 (life safety code).....

Second, if the elevator(s) are required to be on emergency power then that is the end of it. If they are not, then, yes the occupants would be "stuck". The question then for the Owner or the Engineer of Record could be: What is the likelyhood of a fire occuring and loss of power in the same time window which could jepordize the life of any elevator occupants?

By the way, when power is present and there is a fire alarm condition, the elevator(s) is required to go to a designated level as approved by the Fire Marshall and as stipulated in ANSI 17.1., doors remain open for occupants to egress, if the smoke detector at the designated floor is in alarm then the elevator must go to the next designated floor, etc etc, as approved by the Fire Marshall.

ps: my response above is meant to be for non-hydraulic elevators.
 
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When a motor is operated with a variable frequency drive, appropriate operation of the drive can cause the motor to operate as a generator. This is regenerative braking.

I believe that at least one elevator drive manufacturer has explored using such regenerative braking to provide the necessary power to get an elevator to _some_ floor in the event of mains power failure, without the use of batteries. I'd have to dig to find exact details.

-Jon
 
The last elevator that I put in was hydraulic for a two story building and we had to include an aux contact on the machine room disconnect switch to disconnect the battery.
 
Years ago in a 10 story on gramercy park in NYC They had an elevator that ran on water (truth) over 100 years old and I was told had never broken down,sounded like a toilet flushing while it was moving.
 
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