The water flow switch can be employed at each nozzle of an extinguishment system to verify that water actually sprayed on a detection of a spark or ember. If water failed to flow on detection of a spark, a trouble condition will be initiated. The water flow switch can also be used during system testing to verify the flow of water when the spray is activated.

A heat detector is available to monitor for excessive heat in ducts or in the dust collector. The heat detector provides a contact closure when the temperature exceeds the detectors rating. The system may be programmed to spray water or to active an auxiliary fire suppression system on detection of excessive heat. This may be utilized to dump water or steam into the dust collector or activate a preaction sprinkler system.

A supervised shutoff valve can be used to detect when the waterline to the spray assembly has been shutoff. The valve provides a contact closure when closed and the system can give a supervisory trouble.