Elevator
Emergency power operation

Many elevator installations now feature emergency power systems such as uninterruptible power supply (UPS) which allow elevator use in blackout situations and prevent people from becoming trapped in elevators. To be compliant with BS 9999 safety standards, a passenger lift being used in an emergency situation must have a secondary source of power.

Where a generator is being used as the secondary power supply in a hospital, a UPS must also be present to meet regulations stating that healthcare facilities must test their emergency generators under load at least once per month. During the test period only one supply of power is feeding the lift, in a blackout situation without a UPS, the lifts would not be operational.
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