What must be provided if a system has a discharge delay?

In the context of NFPA 17, when a dry chemical extinguishing system is equipped with a discharge delay, it is essential to provide both audible and visual alarms to warn personnel of the impending discharge. This requirement ensures that individuals in the vicinity are adequately alerted to take necessary safety precautions, such as evacuating the area or avoiding exposure to the chemicals being released.

Providing both types of alarms enhances the effectiveness of the warning system, accommodating different situations where one form of alarm may not be sufficient due to background noise or visibility conditions. For example, in a noisy environment, audible alarms alone may not be heard, whereas visual alarms can still signal the imminent discharge. Conversely, in areas where visibility is poor, audible alarms help to alert individuals who may not see the visual signals.

The combination of audible and visual alarms helps to ensure a comprehensive warning system that enhances safety and complies with NFPA standards. This is crucial in minimizing the risk of injury or harm during the activation of the extinguishing system, reinforcing the need for both types of alerts whenever a discharge delay is present.