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#127 - Fire Sprinkler Gauges: Where They Must Be and When to Replace Them

Posted by Jason Hugo on 9/25/2018 to Gauges
Fire Sprinkler Gauges

Air pressure gauges and water pressure gauges in fire sprinkler systems must be properly placed and kept in working order


Residential and commercial fire sprinkler systems require pressure gauges at check valves, control valves, the main drain, and a host of other locations. Keeping fire sprinkler gauges in working order simplifies inspections and makes spotting serious problems – from a lack of water pressure to a closed valve – much easier. In this article, we'll look at where these gauges are located in commercial and residential fire sprinkler systems and when they need to be replaced.
 
If you've already decided to buy a new gauge, click here to view our selection of fire sprinkler pressure gauges.

Most wet-pipe, dry-pipe, and other fire sprinkler systems include pressure gauges at critical valves and pipes

Fire sprinkler pressure gauges are located at pressure-reducing valves, the system main drain, and other main drains specified in NFPA 13: Standard for the Installation of Sprinkler Systems. These standards apply to factories, auditoriums, office spaces, and most other public buildings, except for smaller residential occupancies covered by NFPA 13R and NFPA 13D.

From the 2019 edition of NFPA 13

 16.13 Gauges.

 16.13.1 A pressure gauge with a connection not smaller than 1/4 in. (6 mm) shall be installed at the system main drain, at each main drain associated with a floor control valve, and on the inlet and outlet side of each pressure-reducing valve. 

Pressure gauges in wet-pipe fire sprinkler systems are required at each system riser check valve and alarm check valve –  both of which are essential components.

From the 2019 edition of NFPA 13

 8.1  Wet Pipe Systems.

 8.1.1  Pressure Gauges.
 
 8.1.1.1  An approved pressure gauge conforming to Section 16.13 shall be installed in each system riser.

 8.1.1.2*  Pressure gauges shall be installed above and below each alarm check valve or system riser check valve where such devices are present.

 8.1.1.2.2  Pressure gauges below check valves required by 16.9.11 and 16.15.2.2(1) shall not be required.

Each check valve monitors water pressure with two pressure gauges: one on the supply side of the valve, which offers a view of the air or water pressure between the supply and the valve, and another on the system side of the valve, which displays the pressure between the valve and the system's sprinklers. 

Riser Check Valve

A riser check valve, pictured with a supply-side gauge (below) and a system-side gauge (above). 

Pressure gauges in dry-pipe fire sprinkler systems are installed at the dry-pipe valve, air pumps and receivers, in some pipes between the dry pipe system and the system’s air supply, as well as at quick-opening devices. The gauges must be approved by the authority having jurisdiction (AHJ).

From the 2019 edition of NFPA 13

 8.2*  Dry Pipe Systems.

 8.2.1  Pressure Gauges.  Approved pressure gauges in accordance with Section 16.13 shall be connected as follows:

 (1)  On the water side and air side of the dry pipe valve 
 (2)  At the air pump supplying the air receiver where one is provided
 (3)  At the air receiver where one is provided 
 (4)  In each independent pipe from air supply to dry pipe system
 (5)  At quick-opening devices

Dry-Pipe Valve
Viking's F-2 dry-pipe valve, pictured with water and air-side pressure gauges. Source: Viking.

Preaction systems and deluge systems require approved gauges at the preaction or deluge valve and at the air supply to those valves.

From the 2019 edition of NFPA 13

 8.3  Preaction Systems and Deluge Systems.

 8.3.1.3  Pressure Gauges.  Approved pressure gauges conforming with Section 16.13 shall be installed as follows: 

 (1)  Above and below preaction valve and below deluge valve 
 (2)  On air supply to preaction and deluge valves

Exposure protection sprinkler systems which are used to guard a building's exterior from outdoor fires, including wildfires, require a pressure gauge below the control valve. 

From the 2019 edition of NFPA 13

 8.7  Outside Sprinklers for Protection Against Exposure Fires (Exposure Protection Sprinkler Systems).

 8.7.7  Gauge Connections.  A listed pressure gauge conforming to Section 16.13 shall be installed immediately below the control valve of each system.
 
Unlike some of the other gauges required by NFPA 13, these fire sprinkler gauges must be listed – that is, approved for a specific purpose by UL, FM, or another organization that specializes in the evaluation of these products for a specific application.

Large residential buildings require fire sprinkler gauges at selected drains and valves


Some fire sprinkler gauges are mandatory in sprinkler systems in multifamily residential occupancies, including apartment buildings, hotels, and mixed occupancies with up to four aboveground stories. These gauges are located at the system main drain, pressure-reducing valves, and near other critical system components. Low-rise residential systems also require gauges used to monitor system pressure and supply pressure.
 
Each gauge installed in accordance with NFPA 13R: Standard for the Installation of Sprinkler Systems in Low-Rise Residential Occupancies must be approved for service by the authority having jurisdiction.
 
From the 2019 edition of NFPA 13R

 5.2.15 Gauges.

 5.2.15.1 A pressure gauge with a connection not smaller than ¼ in. (6.4 mm) shall be installed at the system main drain, at each main drain associated with a floor control valve, and on the inlet and outlet side of each pressure-reducing valve.

 6.12 Pressure Gauges. 

 6.12.1 A pressure gauge with shutoff valve shall be provided to indicate pressure of the supply. 
 
 6.12.2 A pressure gauge with shutoff valve shall be provided to indicate pressure of the system.

Fire sprinkler gauges are less-commonly found in home fire sprinkler systems


A residential fire sprinkler system in a single-family home, duplex, or manufactured home requires fewer to no gauges and less frequent inspection than commercial or large residential sprinkler systems. 

Most home fire sprinkler systems installed in accordance with NFPA 13D are wet-pipe systems, which don’t require pressure gauges in this residential application. However, dry-pipe sprinkler systems or wet sprinkler systems that use a pressure tank for their water supply must have gauges. These gauges do not need to be listed.

From the 2019 edition of NFPA 13D

 5.1  General.

 5.1.2.1  The following devices and components shall not be required to be listed:
 …
 (7)  Gauges

 7.3  Pressure Gauges.

 7.3.1  Where a dry system is installed, a pressure gauge shall be installed to indicate system air pressure.

 7.3.2  Where a pressure tank is used for the water supply, a pressure gauge shall be installed to indicate tank pressure.

Regular inspection and periodic replacement or recalibration of inaccurate fire sprinkler gauges is required for most systems


Most fire sprinkler gauges – excluding those found in home fire sprinkler systems installed in accordance with NFPA 13D – must be replaced or reconditioned as soon as possible after damage, dysfunction, or defacement is observed. 

Although fire sprinkler systems remain operational when just a gauge is out of order, well-kept pressure gauges provide inspectors, fire professionals, and facilities managers a means to get an instant read on the sprinkler system's pressure and identify more pressing problems, such as a closed valve. At a minimum, issues with gauges should be identified and corrected during required the monthly and quarterly inspections outlined in NFPA 25: Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems.


NFPA 25, Chapter 3 categorizes problems as impairments, where an inoperable component may cause the fire sprinkler system to fail during a fire; or deficiencies, which are less severe than impairments but still may impact the system's performance (critical) or otherwise require correction (non-critical).

Very few problems with pressure gauges could cause a fire sprinkler system to fail to function during a fire. However, these issues may be a symptom of a larger problem that, if unaddressed, may damage critical fire sprinkler system components or spur total failure.


From the 2017 edition of NFPA 25

 4.1.5.1* The property owner or designated representative shall correct or repair deficiencies or impairments.

 A.4.1.5.1 System deficiencies not explained by normal wear and tear, such as hydraulic shock, can often be indicators of system problems and should be investigated and evaluated by a qualified person or engineer. Failure to address these issues could lead to catastrophic failure. Examples of deficiencies that can be caused by issues beyond normal wear and tear are as follows:

 (1) Pressure gauge deficiencies as follows:

 (a) Gauge not returning to zero 
 (b) Gauge off scale 
 (c) Gauge with bent needle

NFPA 25 also mandates gauge replacement or recalibration when accuracy or longevity are in question.

From the 2017 edition of NFPA 25

 13.2.7.2* Gauges shall be replaced every 5 years or tested every 5 years by comparison with a calibrated gauge.

 13.2.7.3 Gauges not accurate to within 3 percent of the full scale shall be recalibrated or replaced.

In a gauge designed to display readings between 0 PSI and 300 PSI, the full scale would be 300 minus 0, or 300. Section 13.2.7.3 requires that such a gauge display readings with no more than a 3% error in either direction or, in this case, 300 x 0.03 = 9 PSI. 

This error can be resolved – and a good gauge kept in service – by having the gauge calibrated at a professional calibration laboratory. Many people simply opt to replace the gauge, as it’s simpler and a new one is not expensive.

Fire sprinkler gauge replacement is not required in residential systems built to NFPA 13D standards 


While fire sprinkler systems in larger buildings require periodic inspection at prescribed intervals, inspections of fire sprinkler systems in single-family homes, duplexes, and manufactured homes follow no fixed protocol or timeline. Annual inspections of select pressure gauges, if they are present, are recommended but not required by NFPA 13D. Replacement of dysfunctional fire sprinkler gauges – during these inspections, when a gauge is inaccurate, or when a gauge is more than five years old – is not explicitly required.

From the 2019 edition of NFPA 13D

 12.2*  Inspections and Tests. The sprinkler system shall be inspected and tested periodically to make sure the system is in good working condition.

 A.12.2 The building owner or manager should understand the sprinkler system operation and conduct periodic inspections and tests to make sure that the system is in good working condition. A recommended inspection and testing program includes the following:

 …
 (6) Annually, fully open the test connection downstream of any pressure-reducing or pressure-regulating valve, and make sure that the pressure gauge reads a reasonable value.

What kind of replacement fire sprinkler gauge do I need?

The installation standards provided NFPA 13 or NFPA 13R – including those valve and system-specific standards detailed above – must be followed when replacing a defective or inoperable air or water pressure gauge in a large residential, commercial, or industrial fire sprinkler system. 

From the 2019 edition of NFPA 13

 16.13.1 A pressure gauge with a connection not smaller than 1/4 in. (6 mm) shall be installed at the system main drain, at each main drain associated with a floor control valve, and on the inlet and outlet side of each pressure-reducing valve. 

 16.13.2  Each gauge connection shall be equipped with a shutoff valve and provisions for draining.

 16.13.3 The required pressure gauges shall be approved and shall have a maximum limit not less than twice the normal system working pressure at the point where installed.

 16.13.4 Gauges shall be installed to permit removal and shall be located where they will not be subject to freezing.

To view QRFS's stock of water pressure gauges and air/water pressure gauges for fire sprinkler systems, click here. Each gauge complies with these standards, is UL and FM-listed, includes a 1/4" (6.35 mm) connection, and displays accurate readings in accordance with NFPA 25. QRFS' product line also includes a 300 PSI water pressure gauge and a 250 PSI air pressure gauge manufactured by Ashcroft, a Connecticut-based maker of precision fire sprinkler gauges. 

Ashcroft Air Gauge Fire Sprinkler

Ashcroft's air-only gauge for fire sprinkler systems. Buy one here.

If you have any questions about commercial or residential fire sprinkler gauges, or need help selecting them, give us a call at 888.361.6662, comment below, or fill out our contact form and we’d love to assist.

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