A preaction system is a type of dry-pipe sprinkler requiring the preceding activation of an automatic detector before the preaction water valve will allow water to flow into the pipes. Which statement is correct?

A preaction system is a type of dry-pipe sprinkler requiring the preceding activation of an automatic detector before the preaction water valve will allow water to flow into the pipes. Which statement is correct?

• A. True
• B. False
• C. Not applicable
• D. Don’t know

Answer: (A)

Preaction systems keep water out of the piping until a triggering event occurs, usually a fire detector. The preaction valve stays closed and water isn’t released into the dry pipes until the detector sends a signal. In the common single-interlock design, that detector activation is the trigger that admits water into the system; in double-interlock designs, the detector activation is required first, with a subsequent action (such as sprinkler head actuation) completing the release. So stating that an automatic detector must activate before water can flow into the pipes correctly describes how a preaction system operates.

Preaction systems keep water out of the piping until a triggering event occurs, usually a fire detector. The preaction valve stays closed and water isn’t released into the dry pipes until the detector sends a signal. In the common single-interlock design, that detector activation is the trigger that admits water into the system; in double-interlock designs, the detector activation is required first, with a subsequent action (such as sprinkler head actuation) completing the release. So stating that an automatic detector must activate before water can flow into the pipes correctly describes how a preaction system operates.