Which type of initiating device is permitted to be single or double action?

Manually actuated initiating devices are designed to require human intervention to activate the fire alarm system. These devices can be configured as either single action or double action. A single action device requires only one motion, such as pulling a lever or pushing a button, to initiate an alarm. In contrast, a double action device requires two distinct actions, such as pushing and pulling a handle at the same time, ensuring that the user is intentionally activating the alarm, which can help prevent false alarms.

The versatility of manually actuated devices in being either single or double action allows for different applications based on the specific needs of a building or environment. Such devices are commonly found in places where immediate reporting of fire conditions is critical, providing a clear method for occupants to alert emergency services.

Other types of initiating devices, such as automatically actuated, pressure actuated, and magnetically actuated devices, do not typically fall under the classification of "action" systems since they operate based on specific conditions or triggers rather than manual activation. This distinguishes manually actuated devices and highlights their dual-action capability.