NFPA: Residential fire sprinkler maintenance is more about “what not to do than what to do”

If you were to flip through NFPA 25, the National Fire Protection Association’s standard that governs the inspection, testing, and maintenance of commercial fire sprinklers, the upkeep requirements might impress and possibly confuse you. Businesses usually hire fire protection contractors or use highly qualified in-house experts to take care of these complex tasks and ensure they stay compliant.

Fortunately for homeowners, maintaining residential fire sprinklers is much, much simpler. NFPA designed all of its guidance for home sprinklers with one goal in mind: to save as many lives as possible through the widespread adoption of the systems. The resulting NFPA 13D standard has enabled effective, reliable, lower-cost, and virtually maintenance-free home fire sprinkler systems.

If you have residential fire sprinklers and read nothing else in this article, take this guidance from NFPA to heart:

“[M]aintaining a sprinkler system is mostly about common sense. Keeping the control valve open, not hanging items from the sprinklers, and making sure that the sprinklers do not get painted or obstructed are the most important items. It is also important to know the function of the main control valve and where the control valve is located.”

Are you looking to buy components for a home fire sprinkler system? If so, feel free to skip directly to QRFS’ selection of residential fire sprinklers, preassembled risers, cover plates, escutcheons, CPVC fittings, and more — or use the search bar at the top of the page.

Home fire sprinkler systems have a record of reliability

Residential fire sprinkler systems have gotten a little better in the past few decades and, in some cases, simpler. Newer, multipurpose systems that integrate with cold-water plumbing have become the simplest set-up, both maintenance- and operation-wise. But even the first major wave of home sprinklers installed decades ago have proven easy to maintain and incredibly reliable.

In 1985, Scottsdale, Arizona passed a law “requiring every commercial and multi-family building to be outfitted with a complete fire sprinkler system. The ordinance also requires that single-family residences, built after Jan. 1, 1986, be fully outfitted with an approved fire sprinkler system.”

Fifteen years later, the city assessed the impact of home sprinklers, and found that the “civilian fire fatality rate has been reduced by a minimum of 50%” and “[t]he average [property] loss for a fire incident in a building protected with an automatic sprinkler system was over 90% less than the average” for those without one.

Equally impressive is the reliability of the residential fire sprinkler systems. Twenty-three years after the ordinance, the City of Scottsdale Fire Department surveyed residents who had systems that were installed within two years of the law’s passage. Only 11% of those who answered “yes” or “no” reported that their system had ever had a maintenance problem, and 100% of respondents said that their “fire sprinkler system [was] still in operation.”

And fortunately, as NFPA puts it, the maintenance is pretty simple, focusing more on “what not to do than what to do.”

Maintaining residential fire sprinklers: the Don’ts!

• Don’t block sprinkler heads with furniture, home renovations, exercise equipment, or anything else that could obstruct the pattern of water discharge.

• Don’t paint over sprinkler heads or any cover plates that conceal them. Painting heads can block water flow, mess with the heat sensor, or gum up the deflector that fans the water out over a room, and painting over the seams of cover plates means they will likely fail to deploy.

• Don’t hang any objects from sprinkler heads (or pipes, for that matter).

• Don’t damage sprinkler heads. If sprinkler heads hang exposed in certain areas like unfinished basements, consider installing a cage (head guard) around them to prevent an accidental bump from causing damage.

• Don’t turn off the system. Make sure the control valve (aka the “water shut-off valve”) stays in the open position. In standalone sprinkler systems with a dedicated control valve, it’s recommended that this valve is clearly marked and locked to prevent it from accidentally being shut.

The Dos of home fire sprinkler maintenance:

Make sure you have the essential documents

The first piece of guidance from NFPA is that every homeowner should receive “instructions on inspecting, testing, and maintaining the system” from the installer. They should include any specific instructions from the installer, any manufacturer’s instructions, and the name and contact information of the installer and any other contractors that may be involved.

These documents will provide clear guidance that can be passed on to new homeowners in the event of a sale, plus records allow the homeowner, the fire department, or a new contractor to contact the original installer if there are questions about the design of the residential fire sprinkler system.

Follow the regular inspection and testing recommendations for maintaining residential fire sprinklers

Exactly how many of these recommendations apply to you will depend on what type of system you have and its specific components.

If you have a multipurpose system with no pump, for example, the only thing on the list below that is relevant is visually inspecting the system to make sure nothing is damaged or obstructed, and making sure the control valve is open – which it likely will be, since closing it can shut off your overall plumbing.

NFPA recommends, but does not require, the following (explanatory text from QRFS is below each item):

From the 2022 Edition of NFPA 13D

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:

(1) Monthly inspection of all valves to ensure that they are open

Again, if you have a multipurpose system, you’ll likely know if the control valve is closed because your plumbing won’t work. If you have a standalone system, you should clearly mark and probably lock the control valve so it stays open.

(2) Monthly inspection of tanks and other stored water sources, if present, to confirm they are full

If you have a water tank or another finite source, it must have enough water to provide at least 10 minutes of coverage for most homes and 7 minutes of coverage for residences under 2,000 square feet and only one story in height. A 300-gallon tank is big enough for most homes. To make sure the water level is always full, you can manually inspect it or install a water-level alarm.

(3) Monthly testing of pumps, if present, to make sure they operate properly and do not trip circuit breakers when starting

Testing a pump can be as simple as turning it on, and it can also coincide with any regular flow test of the system. As with all of NFPA 13D’s guidance for maintaining home sprinklers, the monthly testing interval is a recommended ideal.

(4) Testing of all waterflow devices, when provided, every 6 months including monitoring service (note that notification of the monitoring service is essential to make sure that the fire department is not called due to testing)

If you have a waterflow alarm installed, testing it involves opening the test connection valve and letting the water flow until you hear the bell sound. Some local authorities require waterflow alarms, and some also require that these alarms automatically notify emergency services. If the latter is the case with your system, call your local monitoring service and warn them you are running a test.

(5) Ongoing visual inspection of all sprinklers to make sure they are not obstructed, damaged, corroded, covered with foreign materials, field painted, or showing signs of leakage, and that decorations are not attached to them

Pretty simple. Keep your eyes open and pay attention to your sprinklers, especially if you make any changes to your home.

(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

Pressure-reducing valves are usually used in multistory buildings, where high floors require more pressure from the system to offset gravity. They reduce the pressure on lower floors to create the right flow, and testing them makes sure they aren’t cutting it too much. These are less likely to apply to a home system — but if your system has a backflow preventer, that form of “check valve” can reduce available pressure.

More generally speaking, this is a basic flow test, regardless of whether you have any pressure-reducing valves. Annually test your system to make sure it has enough pressure and flow, especially if it is a standalone system with a pump.

(7) Inspect systems by individuals knowledgeable and trained in such systems when there is a change in ownership

If you buy a home with a fire sprinkler system, get it inspected – and make sure you get those installer and manufacturer documents from the previous owner.

Protect existing sprinkler heads and replace broken ones

Small collisions with fire sprinkler heads can lead to malfunctions and even possibly trigger a deluge. In places where impacts are likely, such as low-ceilinged stairwells, fire sprinkler head guards can provide an additional measure of protection.

If someone in your household or a previous owner has damaged a sprinkler head, you need to replace it as soon as possible. This, of course, includes any sprinkler head that has deployed, as the trigger is designed to break to release the water when it senses the heat from a fire.

From the 2022 Edition of NFPA 13D

12.3.2 Any sprinkler that is operated, damaged, corroded, covered with foreign materials, or showing signs of leakage shall be replaced with a new listed sprinkler having the same performance characteristics as the original equipment.

Whenever possible, try to replace a sprinkler with the exact same model. But the key here is choosing one “having the same performance characteristics as the original equipment.” This means that if it was a pendent sprinkler with a 155F temperature rating, residential fast response element, and a certain K-factor (rate of discharge), you need to replicate those characteristics in the new sprinkler to make sure you are getting the right performance for the sprinkler’s location.

NFPA allows for some variance if the exact sprinkler head is no longer available:

From the 2022 Edition of NFPA 13D

12.3.2.1* Where replacing residential sprinklers manufactured prior to 2003 that are no longer available from the manufacturer and are installed using a design density less than 0.05 gpm/ft2 (2.04 mm/min), a residential sprinkler with an equivalent K-factor (± 5 percent) shall be permitted to be used provided the currently listed coverage area for the replacement sprinkler is not exceeded.

A.12.3.2.1 It is recognized that the flow and pressure available to the replacement sprinkler might be less than its current flow and pressure requirement.

“[T]he currently listed coverage area for the replacement sprinkler [should] not [be] exceeded” because a sprinkler head is designed to cover a certain area while not interfering with another one, which is why they are placed at very specific distances from each other. If two sprinkler heads are too close together or a new one sprays a wider path of water, the deployment of one could cause the other one to fail to sense the heat required for it to go off. And in many scenarios, both of those sprinklers will be needed to fully cover a room.

Nevertheless, sprinklers spraying too far is way less of a concern than sprinklers not spraying far enough, and thus not protecting a sufficient area. You can read more about the rules for replacing residential fire sprinklers with old or missing k-factors here.

Remember, sprinkler heads and any cover plates can be irrevocably damaged if you paint them, which will require replacement. To avoid this when painting a room, “the sprinklers should be protected by covering them with a bag, which should be removed immediately after painting is finished. For concealed-type sprinklers, the cover plates should be removed (most are designed to be unscrewed) and then the sprinklers should be protected underneath from paint and overspray with a bag. After the painting is finished, the bags should be removed from the sprinklers and the cover plates should be replaced.”

Handy paint covers are also available to protect sprinklers during construction or home improvement projects.

Winterize home fire sprinkler systems when necessary

The most complex aspect of maintaining a home fire sprinkler system involves protecting the pipes from freezing during winter in northern climates.

Many commercial systems in settings that are subject to low temperatures use “dry” or “preaction” systems to prevent freezing. Instead of most of the pipes being filled with water, they are filled with pressurized gas (air or nitrogen), and water only rushes into the network when the system deploys. Dry systems can be used in a residence and NFPA 13D provides guidance on installing and maintaining them, but they are more complex than wet systems – and thus are much less common in homes.

Commonly used “wet” systems will require steps to protect the water in the pipes from freezing.

From the 2022 Edition of NFPA 13D

12.3.4* Wet Pipe Systems. A wet pipe system shall be maintained above 40°F (4°C), including areas properly insulated to maintain 40°F (4°C).

Make sure to insulate any pipe that sits outside of a climate-controlled area (like an unfinished attic). As an extra precaution, contractors often either find a way to hide the pipe and insulation under floorboards, or simply secure the insulation down with wire to make sure that it isn’t accidentally disturbed. Many systems sidestep the problem altogether by using sidewall sprinklers which avoid having to run horizontal pipe through attic areas exposed to cold.

Regardless, every winter, you may want to inspect your home for any “cracks in the walls, broken windows, insufficient insulation, exposed roof areas, and loose siding — all of which make your system more susceptible to freezing by allowing cold air to penetrate the building.”

If your fire sprinkler system is properly winterized and you plan to leave on a lengthy vacation, you could shut off and drain the system. Since most fires are caused by people and their use of items in the home, the risks of fire in an empty house are drastically reduced. You could also keep the heat on and set the thermostat at a lower, energy-efficient setting that is warm enough to keep any pipes from freezing.

Use listed, premixed antifreeze

If regular winterization steps aren’t enough, systems can use listed antifreeze solutions in the pipes, along with some other manufacturer-premixed solutions with very specific mixes for existing systems.

Antifreeze solutions must be used carefully because traditional solutions contain a mixture of water and either propylene glycol or glycerin at very specific ratios. If the proportion of the active ingredients becomes too high relative to the water, antifreeze can actually serve as fuel for a fire when the sprinklers discharge.

After launching an investigation into these issues in 2010, NFPA eventually issued new guidelines for use of antifreeze in systems. Essentially, it lowered the allowable concentration of active ingredients, all details about the antifreeze must be recorded and labeled, multiple samples need to be taken and concentration-tested on an annual basis, and all new antifreeze solutions must be safety “listed” and premixed from the manufacturer — which would lower the possibility of an improper, potentially-flammable ratio of active ingredients.

The bottom line about antifreeze in home fire sprinkler systems: 

• Never mix your own antifreeze solution and add it to the sprinkler system — unless you want to risk a flash fire when a system deploys.
• Attempt to winterize all sections of pipes in a different way (usually climate control).
• Always consult with a qualified fire protection professional before using antifreeze.

Maintaining residential fire sprinklers is simple

To make sure your fire sprinkler system stays in working order for years to come, remember these quick rules for maintaining residential fire sprinklers:

• Don’t paint, obstruct, or otherwise damage the sprinkler heads, and don’t shut off the supply of water by closing the control valve.
• Do visually inspect the system for leaks or damage every so often, make sure the water tank remains full if you have one, and run a flow/pressure/pump test (and a waterflow alarm test, if applicable) on a regular basis.

If you’re looking to buy components for a home fire sprinkler system, check out QRFS’ selection of residential fire sprinklers, preassembled risers, cover plates, escutcheons, CPVC fittings, and more — or use the search bar at the top of the page.

If you have any other questions about residential fire sprinklers or need help finding an item, add a comment below, give us a call at 888.361.6662, or fill out our contact form and we’d be happy to assist.

This blog was originally posted at QRFS.com/blog. If this article helped you, check us out at Facebook.com/QuickResponseFireSupply or on Twitter @QuickResponseFS.