Visible appliances in a corridor must be rated at a minimum of how many candela?

The requirement for visible appliances in a corridor to be rated at a minimum of 15 candela is based on safety regulations aimed at ensuring that occupants can effectively perceive the signal in an emergency situation. The 15 candela rating is generally recognized as the threshold level that provides sufficient intensity for visual alerts to be seen clearly in various ambient light conditions. This is particularly important in corridors, which may have varying lighting environments and where occupants may be moving quickly during an evacuation.

A higher intensity helps in ensuring that individuals can see the alarms clearly, thus improving the chances that they will respond appropriately in the event of an emergency. Regulations, such as those from the National Fire Protection Association (NFPA), support this minimum for visible alarm appliances, emphasizing their crucial role in life safety systems.