PMGILLESPIE
New member
Could somebody please direct me to where in the code it says that i must use an elevator shunt trip in RI?!?!?
Elevator Shut Trip in RI ?
- Thread starter PMGILLESPIE
- Start date
- Status
- Location
- Massachusetts
PMGILLESPIE said:
Last I knew we had been driving around RI disabling the existing shunt trips.
mdshunk
Senior Member
- Location
- Right here.
If you want a treat, read the code on elevators, escalators, and moving walks. Some things don't make sense to me. Why would you want the fire alarm system to knock off power to the elevator, trapping people inside? I know that many areas do just this, and it has never made sense to me. Why not have some sort of intelligent system that will open the doors at the first available floor, then dump the power? [/RANT]
The first "available" floor may be the floor ABOVE the floor that is now engulfed with flames.
I am working on 4 elevators now - just supplying power to disco for the elv. men - I "think" these cars will goto to "G" and open the doors when a fire alarm is activated. I'll have to ask the guys building the actual elevator.
I am working on 4 elevators now - just supplying power to disco for the elv. men - I "think" these cars will goto to "G" and open the doors when a fire alarm is activated. I'll have to ask the guys building the actual elevator.
- Location
- Lockport, IL
- Occupation
- Semi-Retired Electrical Engineer
I suppose it is because they haven't invented a system that is smart enough to know which floor has the fire, and at which floor it is safe to open the doors. A fire on one floor can fill another floor with smoke. At least the elevator shaft should be free of the "immediate danger to life of smoke and fire." However inconvenient and distressing it might be to the persons trapped in the elevator, they have a good chance of staying alive until the fire department, using their fire-override keys, can bring the elevators to a safe floor.mdshunk said:
ron
Senior Member
- Location
- New York, 40.7514,-73.9925
I believe the theory is, based on ANSI 17.1, that elevator lobby or machine room smoke detectors would activate elevator recall to either the primary or secondary evacuation floor (usually lobby is primary and secondary is either Basement if it has exterior access, or 2nd floor for secondary) dependant on which floor is in alarm.
Prior to application of sprinkler water, the power gets shunt tripped by either a heat detector in the shaft or machine room or water flow switch is active in the shaft.
Prior to application of sprinkler water, the power gets shunt tripped by either a heat detector in the shaft or machine room or water flow switch is active in the shaft.
- Location
- Massachusetts
charlie b said:
Well actually we do that now, in this area we call it elevator recall and basically if there is smoke in any elevator lobby the car immediately goes to the Primary floor and parks with the doors open.
Or if there is smoke on the primary floor it goes to the alternate floor.
The primary and Alternate floors are chosen by the FD in this area.
At this point the elevator is still powered but you need a fire key to run it.
Beyond that we also would install heat detectors in the top of the elevator shaft that would shunt trip the elevators feeder breaker.
I distinctly remember one of the other guys in the company running around RI disabling the shunts under direction of the elevator AHJ.
Last edited:
orgonfire
Member
- Location
- Portland, OR
The heat detector is required when the elevator shaft is sprinkled, and are both rated to trip at the same temp. When the sprink head pops and water saturates the shaft, hopefully the heat detector trips too, and shunts power to the elevator. That way no one gets electrifried. As for primary and alternate recall, the floors nearest the ground floor is utilized for life/safety and egress, and faster access for the FD.
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To add to the symphony....in Kentucky...
if there are sprinklers....there is a shunt trip
if there are no sprinklers a shunt trip is not necessary tho not a violation.
One confusing thing is that if you have no sprinklers, the inspectors here insist that the disconnect be FUSED, no cb, but will accept a cb if a shunt trip is required.
Puzzling....
if there are sprinklers....there is a shunt trip
if there are no sprinklers a shunt trip is not necessary tho not a violation.
One confusing thing is that if you have no sprinklers, the inspectors here insist that the disconnect be FUSED, no cb, but will accept a cb if a shunt trip is required.
Puzzling....
Is it a coffin on a string or a coffin on a tube?
Is it a coffin on a string or a coffin on a tube?
This shunt trip issue has been rolling along for several additions of the elevator code now with no really good solution in sight.
The first version of the shunt trip circuit was just revenge by the elevator inspectors for the fire inspectors intrusion into their turf. As soon as the exemption of elevator shafts was taken out of the sprinkler code (NFPA 13) the elevator code was amended to require shunt trips. The original version was not integrated into the elevator controls at all. Class one control wiring techniques were used to run the shunt trip current through heat detectors in the shafts and machine rooms. If the heat detector activated the elevator power was lost instantly.
The second version incorporated a delay with an indicator in the elevator car to warn the firefighters to get out of the car. Most firefighters were never trained on the presence or meaning of the indicator.
The third version was integrated with the elevator controls for normal operation but was not tied into the fireman's service so the danger of entrapment was limited to those using fireman's service or inspection service controls.
The fourth version used water flow switches to cause shunt trip with the heat detectors initiating return to the exit floor regardless of the control method being used.
The fifth version was fully integrated with the elevator controls to prevent entrapment but renewed concerns about sprinklers discharging onto the energized equipment thus causing a risk of electrocution and erratic operation.
The last version I'm aware of includes a pre-action control valve to keep the sprinklers from flowing water until the elevator is down to it's primary or alternate exit level with the doors open. The issue that raises is the possibility that the fire may spread beyond the designed demand area while the elevator is returning to the exit level.
Is it a coffin on a string or a coffin on a tube?
This shunt trip issue has been rolling along for several additions of the elevator code now with no really good solution in sight.
The first version of the shunt trip circuit was just revenge by the elevator inspectors for the fire inspectors intrusion into their turf. As soon as the exemption of elevator shafts was taken out of the sprinkler code (NFPA 13) the elevator code was amended to require shunt trips. The original version was not integrated into the elevator controls at all. Class one control wiring techniques were used to run the shunt trip current through heat detectors in the shafts and machine rooms. If the heat detector activated the elevator power was lost instantly.
The second version incorporated a delay with an indicator in the elevator car to warn the firefighters to get out of the car. Most firefighters were never trained on the presence or meaning of the indicator.
The third version was integrated with the elevator controls for normal operation but was not tied into the fireman's service so the danger of entrapment was limited to those using fireman's service or inspection service controls.
The fourth version used water flow switches to cause shunt trip with the heat detectors initiating return to the exit floor regardless of the control method being used.
The fifth version was fully integrated with the elevator controls to prevent entrapment but renewed concerns about sprinklers discharging onto the energized equipment thus causing a risk of electrocution and erratic operation.
The last version I'm aware of includes a pre-action control valve to keep the sprinklers from flowing water until the elevator is down to it's primary or alternate exit level with the doors open. The issue that raises is the possibility that the fire may spread beyond the designed demand area while the elevator is returning to the exit level.
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