Backflow preventers are an integral component in fire protection systems. However, they are too often overlooked in weekly, monthly, quarterly and annual inspection, testing and maintenance (ITM) programs, especially when located out of sight, such as in a concrete ground vault away from a building near a roadway. In this article, we will discuss backflow preventers in fire protection systems, their purpose and requirements.
Purpose
The purpose of a backflow preventer is to help protect the potable water system by preventing potentially contaminated water on its discharge, or system side, from flowing back into the potable water system on its supply, or water utility municipality supply side. More specific to this discussion, a fire protection backflow preventer is to help prevent fire protection water from contaminating the potable water system.
A backflow preventer is not required by the National Fire Protection Association’s NFPA 13, Standard for the Installation of Sprinkler Systems, and serves no fire protection-related benefit. However, 2025 NFPA 13, Section 5.1.7.1, does require that “the requirements of the public health authority having jurisdiction shall be determined and followed.”
Rather, a backflow preventer is required for fire protection systems by the 2024 International Plumbing Code (IPC) and described using the term backflow prevention assembly (BFPA) in Section 608.1, specifically 608.17.4, and other requirements of the IPC; and in accordance with the 2024 International Building Code (IBC) and 2024 International Fire Code (IFC), Sections 903.3.5 and 912.6.
The term backflow is defined by the IPC as a “pressure created by any means in the water distribution system, which by being in excess of the pressure in the water supply main causes a potential backflow condition.” It also defines the term backflow preventer as “a backflow prevention assembly, a backflow prevention device or other means or method to prevent backflow into the potable water supply.”
Based on the IPC BFPA requirement, the specification, type, installation arrangements and details are typically stipulated and or approved by the local water utility municipality to protect its potable water distribution system. Additionally, all backflow preventers, including those for fire protection service, are required to be inspected and tested annually by IPC Section 312.11 requirements and local municipality regulations for water quality standards by a licensed and certified backflow tester to ensure proper operation against backflow.
Based on this, it is important to contact the local municipality to determine its fire protection backflow design, installation, inspection and testing requirements for compliance purposes.
It is worth noting that the term for a backflow preventer (BFP) is not consistent between the relevant codes and standards, at least in terms of fire protection use. While the IPC consistently references the term BFPA in Section 608.17.4, the IBC and IFC references terms backflow preventer (BFP) and backflow prevention device (BFPD); NFPA 13 references terms BFP, BFPA and BFPD; and 2025 NFPA 25, Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems, consistently references BFPA.
For the purposes of this article, the term BFPA will be used as it pertains to the discussion of fire protection systems.
The BFPA required for fire protection systems is a component in the system regardless of its arrangement or location. As such, the BFPA must be listed for fire protection service per NFPA 13, Section 7.1.1.2, which requires “devices essential to successful system operation shall be listed.” However, Section 5.1.7.2 specifically states, “where equipment is installed to guard against possible contamination of the public water system, such equipment and devices shall be listed for fire protection service.”
A BFPA listed for fire protection service identifies it has met more stringent and comprehensive performance testing requirements from those provided only for domestic use. Testing agencies typically accepted by standard industry conventions and authorities having jurisdiction (AHJ) are Underwriter’s Laboratories (UL) and Factory Mutual (FM).
UL 1469, Standard for the Strength of Body and Hydraulic Pressure Loss Testing of Backflow Special Check Valves, is the standard from UL listing the BFPA, and Class No. 1221, Approval Standard for Backflow Preventers (Reduced Pressure Principle and Double Check Valve Types), is the approval from FM. A BFPA and its manufacturer’s literature meeting the UL listing and/or FM approval standards will bear the respective certification or approval marking for identification.
Domestic potable backflow preventers will not bear the fire protection certification or approval mark and, therefore, are not code-compliant or acceptable for fire protection service.
Design
The listing or approval of a BFPA includes limitations on maximum flow rates and minimum friction loss factors associated with different devices and sizes found in the manufacturer’s product literature (data sheet). Depending on the system demand it is serving, the demand may exceed the listed or approved maximum flow rate of the BFPA. In this instance, two BFPAs may be necessary and designed in parallel to maintain compliance with its listing or approval.
Regardless of a BFPA installation arrangement or location, a method to perform a forward flow test of the BFPA must be provided to comply with NFPA 13, Section 6.11.2.5.1. The test connection required by Section 16.14.5.1 must consist of one 2 1/2-inch hose valve downstream of the BFPA for every 250 gallons/minute of flow rate required by the system demand, including hose allowance requirements, where applicable, per NFPA 13, Sections 16.14.5.1.1 and 6.11.2.5.2.
There are instances when a new BFPA must be installed into an existing fire protection system. This typically occurs on an aged system when it was designed and installed prior to the requirement for a BFPA, when an AHJ identifies such a system or a design alteration is to be performed on such a system.
When a new BFPA is retroactively installed on an existing system, its hydraulic characteristics must be considered and accounted for by NFPA 13, Sections 30.1.4 and 30.6.6 requirements, to verify the water supply is adequate to meet the greatest system demand. This may result in significant system alteration and larger pipe sizes for compliance.
Valves that control the water supply to fire protection systems must be electronically supervised and monitored by the protected premises’ fire alarm system per IBC/IFC 903.4 and 903.4.1 requirements, respectively, with few exceptions. This includes the valve on the BFPA, regardless of its location, such as in a concrete ground vault away from a building near a roadway.
Although NFPA 13, Section 16.9.3.3.1, addresses valve supervision, simply chain-locking the BFPA valves, or any valves controlling the fire protection water supply for that matter, in the open position is not code-compliant with the IBC/IFC, which takes precedence. However, chain-locking the valves can be provided in addition to the electric supervision, but not in lieu of.
Inspection, testing and maintenance program
To verify that a BFPA continues to operate as designed and intended to remain reliable for the protection of life and property, it must have ITM enforced by the property owner or its authorized representative, such as a property maintenance company, in accordance with NFPA 25, per NFPA 13, Section 32.1. NFPA 25, Section 4.1.1, also stipulates the same requirement.
NFPA 25, Section 4.1.1.3, requires that all ITM be performed by qualified personnel. Qualified personnel is defined by NFPA 25, Section 3.3.35, as “competent and capable individual(s) having met the requirements and training for a given field acceptable to the AHJ.”
Qualified personnel are required to either (1) “meet the requirements and training for a given field acceptable to the AHJ;” (2) be “certified by a nationally recognized fire protection certification organization acceptable to the AHJ;” or (3) be “registered, licensed, or certified by a state or local authority to perform ITM of water-based fire protection systems.”
A property owner may choose to perform some individual ITM tasks in-house by staff members qualified to perform that task, such as weekly or monthly inspection and testing, or contract all the ITM tasks out to a qualified ITM service company. Either way, the ITM personnel must be qualified.
1. Inspection
NFPA 25, Section 13.7.1.1, requires reduced pressure and reduced-pressure detector BFPAs to be inspected on a weekly basis to verify that their differential-sensing valve relief port is not continuously discharging. Additionally, the control valves as part of the BFPA used to isolate the backflow device for maintenance and system control purposes must be inspected and tested in accordance with Section 13.3 requirements.
The BFPA control valves secured with locks are permitted to be inspected on a monthly basis, per Section 13.3.2.1.1, to verify they are secured, in the proper position and leak-free, per Section 13.3.2.2. Valves that are electronically supervised are permitted to be inspected on a quarterly basis, per Section 13.3.2.1.2, along with their supervisory alarm devices (tamper switch), per Section 13.3.2.1.3, to verify they are free from physical damage.
In addition, a BFPA is also required to be inspected internally every five years, per Section 13.7.3, to verify that all components operate correctly, move freely and are in good condition. This is an important but often overlooked inspection. If a BFPA is not performing adequately due to malfunctioning components or blockage by debris, it can reduce the available water supply necessary to meet the fire protection system demands and possibly create a single-point system failure rending a system or entire campus system impaired.
2. Testing
Testing of a BFPA is required to be performed on an annual basis, per Section 13.7.2 requirements. All BFPAs are to have a forward flow test performed at the minimal flow rate of the system demand, per Section 13.7.2.1, through the test connection required by NFPA 13, Section 16.14.5.1. However, there are a few exceptions.
One exception is when connections don’t permit accurate measurement of the minimum flow rate, the tests can be flowed at the maximum flow rate possible in accordance with Section 13.7.2.3, or when an annual fire pump test caused the system flow rate to flow through the BFPA, per Section 13.7.2.1.2.
Also, during times when water rationing during shortages lasts more than one year, an internal inspection of the BFPA performed in accordance with Section 13.7.2.1.1 is permitted in lieu of conducting the annual forward flow test.
Additionally, the supervisory switches on control valves as part of the BFPA used to isolate the backflow device for maintenance and system control purposes that are electrically supervised must be tested on a semiannually basis, per Section 13.3.3.5.1.
3. Maintenance
Maintenance of a BFPA is required to be performed in accordance with its manufacturer’s requirements and recommendations, per Section 13.7.3. Maintenance performed must be conducted by qualified personnel and the procedure and policies of the AHJ, per Section 13.7.3.
Additionally, control valves of the outside screw-and-yoke type as part of the BFPA used to isolate the backflow device for maintenance and system control purposes must have their operating stems lubricated annually, per Section 13.3.1.1, and be fully closed and fully opened to test their operation and distribute the lubricant, per Section 13.3.4.2.
The BFPA manufacturer’s data sheets and original acceptance test records, along with the system as-built installation drawings and hydraulic calculations, are required to be retained for the life of the system, per NFPA 25, Section 4.3.4. Additionally, the ITM records are required to be retained for a minimum of one year after the next inspection, test or maintenance, per Section 4.3.5.
However, it is prudent for the system owner to retain the ITM records for several years to observe fluctuations in test results and determine evidence of trending for evaluating the operational health of the BFPA among other system components. Many insurance companies require this as part of their property policies.
BFPAs are an integral component in fire protection systems and must not be neglected. Their importance cannot be over-emphasized or overlooked. Lack of the required listing and or approvals, or necessary ITM for the assembly can create both water quality issues for the potable distribution system and fire protection water supply reliability concerns.
Failure to verify the necessary ITM for the BFPA is properly and adequately performed can create an inadequate fire protection water supply and possibly lead to a single-point failure to a system or systems on an entire campus.
Providing the required ITM to verify its functionality and performance, regardless of where the BFPA is located, will increase its life cycle, reduce unwanted and unnecessary repair costs, minimize out-of-service impairments and ensure reliable operation during emergency events.
Retaining ITM reports is essential, and the responsibility of the property owner, to verify the required ITM has been performed and the results can be reviewed. l
Chris Butts, PE, FSFPE, AET, SET, CFPS, ARM, is a senior fire protection engineer with the U.S. operations of Senez Consulting Inc., a fire science and engineering firm.
