Fire Sprinkler Gauges
Author: Chris Logan
Fire Sprinkler Systems are required to have gauges at various locations throughout the system. The control valve and main drain are the primary location for gauges to be read in order to simplify inspections, and make discovering issues with the sprinkler system easier. Gauges can help identify issues such as a closed or broken isolation valves, obstructions on the incoming water supply, or deteriorated water supplies. It is important to identify when and where you should be able to locate gauges on sprinkler systems.
Pressure gauges are located at locations on the sprinkler systems that are important to the operation of the system. Wet sprinkler systems are required to have gauges installed on the incoming water supply (the source) and the system side of the of the alarm valve, or system riser check valve (where present). Pressure reducing valves require gauges to be located on either side of the check valve as well, to monitor that the pressure reducing valve is operating as installed. Dry and pre-action valves are required to have gauges on the incoming water supply (the source) as well as the system side of the dry pipe valve, or on the pilot line of the pre-action. Gauge located at the air source is required for set up and compressor servicing, as well as at any quick opening devices that may be installed on the dry pipe system. Although not required, installing a gauge on the air maintenance device is common to allow the inspector/service technician to trouble shoot issues as they arise.
Gauges, while seemingly a minor component of the sprinkler system, are useful in identifying issues with the sprinkler system during regular inspections. These take place at regular intervals per NFPA 25.
Pressure gauges are used to identify the water or air pressure within a given system. The sprinkler system inspection tag will identify the static, and residual pressures that where present at the time of the most recent inspection. The main drain test is a flow test used to identify deteriorated incoming water supplies. The residual (flowing) pressure shall not degrade more than 10% from the original installation test to the annual test being performed. Changes more then 10% require further investigation.
Sprinkler systems are required to have pressure gauges on them, with one exception. NFPA 13D sprinkler systems do not require gauges to be installed.