Waterflow Switch Alarm Delay on a Wet-Pipe Riser
You are witnessing the annual test of a wet-pipe sprinkler system in a 12-story high-rise. The technician opens the inspector's test valve at the most remote point on the 9th floor. The waterflow switch is a vane-type device on the 4-inch riser, and the fire alarm control unit is programmed with a 30-second waterflow alarm delay. The switch's retard chamber is set to 90 seconds. The technician times 118 seconds from opening the valve to annunciation at the panel. He says the retard chamber is set to 90 seconds and the panel has a 30-second delay, so 120 seconds is normal and within the manufacturer's listing. The building's insurance carrier requires alarms within 90 seconds. The panel history shows no prior trouble, and the switch is listed for the service. The technician proposes to remove the panel delay.
1. Is the 118-second waterflow alarm acceptable? Support your answer.
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No. The standard requires a waterflow alarm within 90 seconds of flow at the inspector's test valve. The measured 118 seconds exceeds that limit. The cause is the combination of a 90-second retard chamber and a 30-second panel delay; even if each component is listed, the installed system can take up to 120 seconds, and the measured time confirms it. The insurance carrier's 90-second requirement is consistent with the code. The technician's statement that 120 seconds is normal does not make it compliant. The system must be adjusted so that the total time from flow to annunciation is 90 seconds or less, and then retested.
2. The technician proposes to remove the panel delay only. What else must be verified, and what is the risk?
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Removing the 30-second panel delay leaves the 90-second retard chamber plus the switch and panel processing time, so the total may still exceed 90 seconds. The retard chamber should be set lower, or the switch replaced, and the actual time remeasured. Also verify that the panel delay is not serving other waterflow switches or auxiliary functions; changing it may affect those devices. Retest at the most remote inspector's test valve, not at the riser, because the most remote location produces the longest delay. The risk of leaving it is a delayed alarm and a failed inspection.
3. How should the deficiency be documented and communicated?
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Record the measured time, the test location, the device model, the retard setting, the panel delay, and the code limit. State the corrective action and the retest time. Notify the owner in writing and provide a copy to the AHJ if required. Because the system still alarms, it is not a total impairment, but the delay is a code deficiency; the owner should schedule correction promptly. If the AHJ considers the delay an impairment, follow the fire watch policy until the retest passes.