In a pneumatic-type continuous-loop fire detection system, what activates the alarm switch during a test?

In a pneumatic-type continuous-loop fire detection system, what activates the alarm switch during a test?

• A. Release of sufficient gas from the heated element.
• B. A mechanical whistle.
• C. Electrical stage gating.
• D. Manual switch to test.

Answer: (A)

In a pneumatic-type continuous-loop fire detection system, detectors rely on gas-filled capsules and a heated element. When a test is performed, the heater is allowed to release some of the gas from the detector, creating a pressure change inside the loop. That pressure rise moves a diaphragm or bellows, which activates the alarm switch and produces the fire indication. The test does not rely on an audible whistle, electrical gating, or a manual switch to trigger the alarm; those elements are not what actuates the alarm switch during testing. The controlled gas release is the mechanism that drives the switch to signal a fire condition.

In a pneumatic-type continuous-loop fire detection system, detectors rely on gas-filled capsules and a heated element. When a test is performed, the heater is allowed to release some of the gas from the detector, creating a pressure change inside the loop. That pressure rise moves a diaphragm or bellows, which activates the alarm switch and produces the fire indication. The test does not rely on an audible whistle, electrical gating, or a manual switch to trigger the alarm; those elements are not what actuates the alarm switch during testing. The controlled gas release is the mechanism that drives the switch to signal a fire condition.