If sprinklers are installed in elevator hoistways, what is allowed prior to applying water?

When sprinklers are installed in elevator hoistways, it is critical to ensure safety and prevent potential electrical hazards before applying water. Opening the power supply to the affected elevator is crucial because it de-energizes the elevator system, mitigating the risk of electrical shock or equipment damage when water is introduced. This step is part of the safety protocols that must be followed to ensure that electrical systems do not interact with the water from the sprinkler system.

Other considerations, such as sealing the hoistway, activating the alarm system, or shutting down all elevators, may enhance safety, but none of these actions directly address the immediate risks posed by water interacting with electrical components of the elevator. Therefore, opening the power supply is the most critical and allowable step prior to applying water in this context.