Let’s take a look at what happens to your elevator during a power outage. All elevators rely on an electric power supply to operate properly. A traction elevator requires electricity to operate the hoisting machine, and a hydraulic elevator uses electricity to power the pump unit.
Initially, the elevator will immediately shut down. This may be an abrupt stop between floors. This happens because elevators are equipped with electromagnetic brakes. In normal use, an electrical coil holds the brake open. As soon as power is lost, the brake engages and stops the elevator. The lights in the cab and the panel lights will go out, but emergency lights will come on.
Waiting it out
At this point, if the elevator is not equipped with a back-up form of power, the elevator will remain shut down until power is restored. Remember, when stuck in an elevator for any reason:
- Stay calm and don’t panic. You can safely wait for emergency service personnel to come. The elevator will not fall or plunge to the bottom of the shaft. The brake can safely hold the elevator in place. You won’t run out of oxygen. By code, all elevators must have adequate ventilation.
- Use the emergency phone to contact someone who can help you. The phone should automatically connect to a live person. The person on the other end should be able to hear or see the phone transmit your location. Alternatively, use the alarm bell or your cell phone to contact help.
- Do NOT attempt to exit the elevator on your own. Do not try to pry the doors or escape hatch open. The hatch in the ceiling of an elevator can only be opened from above.
- It bears repeating, stay calm and wait for emergency personnel to rescue you from the elevator during a power outage.
- After exiting the elevator, do not re-enter until it has been placed back in service by a licensed elevator mechanic.
A better way
However, it doesn’t have to go that way. An elevator can feature a battery lowering system. This system activates as soon as power is lost. Generally, the elevator will make one trip on battery power to a nearby floor or in most cases the ground floor. The doors will open properly, and the elevator will safely shut down. This allows passengers to swiftly exit, but the elevator will remain out of service until power is restored. Battery lowering is an especially cost-effective solution for hydraulic elevators.
Some buildings use a generator to allow emergency power operation. This feature is more common in especially tall or vital buildings, such as hospitals and government installations. The generator will allow for limited emergency use. Often only one elevator in the building may be used at a time, and the controller may be programmed to cycle through a bank of elevators in turn.
Elevators require a significant amount of electrical power during normal operation. In order to function properly, there must be enough power to accommodate a full load at any time. Hydraulic elevators will use more electricity in the up direction, but little power is needed to lower the car. Traction elevators offset power use with a counterweight. Also, elevators contain many electrical components that allow for smooth operation.
When the power comes back on
Ideally, when power returns, the elevator resumes operation. Unfortunately, this doesn’t always happen. A power outage may involve power surges or flickers that cause those delicate components to fail. By design, the elevator protects the more expensive components in this event. There may be blown fuses or tripped circuit breakers. The software that runs the elevator will often log faults that prevent the elevator from operating.
As a building owner or manager, what can you do to ensure that your tenants and the riding public are safe in your elevator during a power outage? First of all, be sure the elevator inspections are up to date. Be sure to enlist the services of a reputable elevator maintenance company. Your service technician will check the elevator emergency lights, alarms, and phones on a regular basis. The tech can also show you how to check these systems in between maintenance visits if needed. Consider installing a battery lowering system. This one upgrade can give you peace of mind.