Sprinkler Water System Gauge

This sprinkler water system pressure gauge is rated for 0 to 300 PSI and is designed for monitoring water or air pressure in automatic fire sprinkler systems, standpipes, and related water-based fire protection equipment. The 0-300 PSI range covers the full operating and supervisory pressure range of most wet-pipe and dry-pipe sprinkler systems, where normal operating pressure typically falls between 50 and 175 PSI and the gauge allows inspectors to verify the system is holding at the correct pressure during routine monthly checks and annual NFPA 25 inspections.

The gauge is UL listed and FM approved, both of which are required listings for pressure gauges installed on fire protection systems under NFPA 13 (installation standard) and NFPA 25 (inspection, testing, and maintenance standard). Construction uses impact and corrosion resistant casing, a polycarbonate lens, and brass and bronze internal components for long service life in building mechanical rooms and riser locations that may be subject to humidity and vibration. Connection is by standard 1/4-inch NPT lower-mount fitting, which is the most common configuration for sprinkler riser and valve assembly gauge ports.

• Sprinkler System Risers: Monitoring supply pressure at the main riser, alarm check valve, or backflow preventer on wet-pipe and dry-pipe sprinkler systems.
• Control Valve Assemblies: Installed on the downstream side of sprinkler control valves to verify system pressure is maintained when the valve is open.
• Standpipes: Monitoring water pressure at standpipe connections in multi-story buildings where pressure verification at specific floors is required.
• Dry-Pipe Systems: Monitoring air pressure on the system side of a dry-pipe valve, where the gauge reading confirms the system's supervisory air charge is intact.

• NFPA 13 and NFPA 25: Pressure gauges on fire sprinkler systems are required to be UL listed and FM approved per NFPA 13 installation requirements. NFPA 25 requires inspectors to verify gauge condition and readings during each required inspection interval.
• Monthly Inspection: Check the gauge reading as part of the monthly sprinkler system visual inspection to confirm system pressure is within the acceptable range for the specific system design.
• Gauge Replacement: Replace the gauge if the needle sticks, reads outside expected range, the lens is cracked or fogged, or if the gauge fails to read correctly during testing. NFPA 25 requires that gauges in poor condition be replaced.
• 5-Year Calibration: NFPA 25 requires gauges to be replaced or tested for accuracy every 5 years to confirm they are within 3 percent of full scale.

Why does a sprinkler gauge need to be UL listed and FM approved?

NFPA 13 requires that gauges installed on fire sprinkler systems be listed for the purpose. A listed gauge has been tested and verified to provide accurate readings within specified tolerances under the pressure and temperature conditions found in sprinkler systems. An unlisted gauge of the same size and range may not meet those accuracy or material standards.

What should the gauge read on a normal wet-pipe sprinkler system?

This varies by building and system design. The gauge reading should match or be near the supply pressure delivered to the system, which is set during commissioning and documented in the system's hydraulic calculations. Any reading significantly below the designed supply pressure may indicate a closed valve, a leak, or a supply problem and should be investigated.

How often does this gauge need to be replaced?

NFPA 25 requires that sprinkler system gauges be replaced or tested for accuracy every 5 years. Replace immediately if the gauge is damaged, reads erratically, or if the needle sticks or cannot be zeroed.