The automatically actuated detection devices of a fire alarm system include the smoke detector, heat detectors, and duct detectors. Other automatically actuated detection devices include supervisory devices like water flow switches and tamper switches. Manually actuated detection devices would include manual pull stations. Testing of these detection devices is critical to the early detection of fire.
The smoke detector is tested by placing a specialized cup over the detector while an aerosol smoke is sprayed into the chamber. Duct detectors are tested in the same way. If a fire were to occur in a building’s duct system, the smoke in the ducts would be first detected by the smoke detectors located just outside of the duct system.
Pull stations are tested by being pulled as would normally occur during a fire and then reset by use of a key or screwdriver.
Flow switches and tamper switches are tested to verify that they are fully operational. Flow switches detect water movement in the piping system. The detection of water activates the fire alarm system. Tamper switches detect if a sprinkler valve has been closed. A trouble signal is sent to the fire alarm control panel if this occurs.
Not all buildings have heat detectors (more common on industrial equipment). These devices are tested using heat, typically from a heat gun depending on the application.