#104 – Residential Fire Sprinkler Systems: Maintaining Home Fire Sprinklers is Simple

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.”

Scottsdale Arizona
Scottsdale, Arizona’s experiment with home fire sprinklers has been a resounding success, reducing fatality rates while making a strong case for home fire sprinkler mandates. Image source: Joseph Plotz via Wikipedia (CC BY-SA 3.0)

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.
Painted sidewall sprinkler head
Paint on the thermal element of this fire sprinkler head may delay activation, allowing a fire to spread. Image source: Fire Protection Deficiencies

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.

Fire sprinkler headguard
You can buy a fire sprinkler head guard to protect sprinklers in locations where impact is a concern.

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* 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. 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.

Uninsulated attic
Fire sprinkler system piping placed in attics without insulation should be protected against changes in temperature. Source: Johannes W via Pixabay.

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.

34 thoughts on “#104 – Residential Fire Sprinkler Systems: Maintaining Home Fire Sprinklers is Simple”

  1. Hello
    We have a 2-year-old home sprinkler system and the drain to the sprinkler and the emergency overflow for the waterless tank smell like mould.
    The drain is located very near the furnace filter. It’s being spread throughout the house. We have had the HVAC and the ducts cleaned both parties agree its the drain. How do we solve this issue? Our lungs are feeling the mould in the house.

  2. I have a 20 year old two story house with fire sprinkles, is it normal to have the average psi at 120? Then when the grass sprinklers turn off we hear knocking in the walls coming from the fire sprinkler pipes and the psi jumps 5-10 plus psi. How can I solve this and have you heard of this issue before?

  3. I’m glad you brought up to avoid painting over the sprinkler heads because it will cover the water flow. My uncle is redoing the ceiling of his commercial facility, and he needs to remove the sprinkler system. I will let him know to be aware fo this, and maybe to buy some new pipe hangers because the ones holding the lines are rusty.

  4. We live in a single family home In MD with sprinklers and are selling our home. The buyer’s inspector said that the back flow preventer should be tested or replaced every 5 years. Our house is 5 years old. Can you comment?

    • Debbie, thanks for reaching out. Just like other components of a home inspection, a backflow preventer test can be handled by the current owner or the cost can be passed to the buyers. Local laws govern whether a backflow preventer is required in a residential fire sprinkler system, and how often this test must be completed. You can work with your local authority having jurisdiction (likely, the fire marshal or local water/building departments) to determine if it’s necessary. And you may need to contact a licensed fire sprinkler professional to conduct the test and prove that it was completed. Hope this helps!

  5. Hi Debbie, you should contact premier fire protection for your fire protection needs. We will be more than happy to replace that for you. There is a possibility that water from the system can be leaking back into the public water system if it’s failing. Depending on the type of assembly is whether it is a testable device.

  6. I have a 15 year old 2 story house with a CPVC system. Recently I replaced the water main and the house fire sprinkler drained. There is no vent for the system at any point, how do I get the air out of the system? Is it recommended to remove the farthest sprinkler head to do this, or is there a type of valve I can install?

    • Jason, thank for reaching out. For wet sprinkler systems, repressurizing the system requires water. You can work with a licensed fire sprinkler contractor if you need assistance repressurizing. Hope this helps!

  7. Thanks to your sharing, I need to have a professional to maintain my home fire sprinkler system. I have not ever maintained it since I installed it.

  8. Hello,

    Great information! I need to replace the backflow preventer in my home and will be draining the entire system. I was licensed plumber many years ago and have the tools and knowledge to do the job. I just want to make sure if I install a bleeder value will it be sufficient when repressurizing the system to remove any air.

    • Thanks for reaching out! In these instances, it always helps to talk to a fire protection expert. Through our “Ask a Pro” service, qrfs.com/ask-a-pro, you can receive expert guidance based on the specific design of your system. Click the link to submit your question with some information about your home, and a fire protection professional will provide a detailed answer. Our pros include AHJs, contractors, engineers, and code experts with 150+ years of combined experience!

  9. I had a sprinkler head with a small leak and discovered that there was no valve to cut the water supply to the sprinkler system (which I wanted to do until I could get a technician in to repair the head the next day). Is it legal to get such a valve installed? I don’t want to be faced with shutting off water to the entire house until I get a technician on site.

    • Bob R — What you describe is a “control valve,” which is perfectly legal (if installed by a qualified sprinkler contractor) and usually a fundamental part of a sprinkler system.

  10. It’s good to learn that a multipurpose sprinkler system only needs a visual inspection to be tested. My wife and I are wanting to renovate our house and we were wondering how we could make sure the new sprinkler system works in the home. I’ll be sure to tell her that we should do a visual inspection on the sprinkler system when it’s installed.

  11. I have 2 (150 gallon) tanks in my garage that supply the fire sprinkler system for my 11 year old house. I was told the tanks are supposed to have bladders in them. The bottom of one of the tanks has started very slowly leaking and since it is on a collar type stand, I cant see where the leak is from, but it definitely is from the tank. How long should tanks like these last?

    • Tom — Your best bet is to consult the manufacturer of your tank for an estimate on the product’s lifespan, or a competing manufacturer.

  12. That’s a good idea to take a look at the system to see if you can find leaks. I could see how undiscovered leaks could cause less pressure in the system, which could be bad if you ever need to use it. I’ll make sure to check those every once in a while so I can avoid any issues.

  13. I need a company that can check my fire sprinkler system because there is smelly, gross sents/gas? coming into my condo from the neighbor that shares my common wall! And they also have some way to talk through them!! This sounds nuts but it’s true!! Do you perform this type of service? And do reports on this for legal purposes. Thank You.

    • Karen — We do not provide inspection, testing, and maintenance services; you should contact a local sprinkler maintenance company. Also, we’re not sure how smells or sounds would be coming through sprinkler pipes—unless they are empty. If so and that is a common “wet” system (where the pipes must always be filled with water), then the system may be nonfunctional, in which case it would definitely need to be looked at. Best of luck!

  14. Great information! One question – if I drain the water from my system for either winterization or maintenance, is there a special procedure for refilling it? Otherwise, won’t there be a lot of trapped air if I just let the water flow back in without any place to bleed the air out of? Thanks!

    • Dave — trapped air in wet sprinkler systems is often released through vents, though we can’t comment on how common they are in residential systems overall or whether yours has any. Your best bet for winterization is to contact a professional fire sprinkler contractor and, at a minimum, let them conduct and demonstrate drainage and refilling the first time.

  15. We have a 4 year old house, that has a stand alone 300 gal. water tank. Does the tank, or water within need regular changing? I am concerned about mold in the system.

    • Paul — assuming you are saying the water tank specifically supplues the sprinkler system, how often the water needs to be changed depends on what the water tank is made of (e.g., non-corrosive material), whether it’s a completely closed tank, if the water is treated, etc. You should contact a fire sprinkler professional to assess your situation.

  16. I just had my 10 year old system inspected by my condo complex association and the technician noted there was no pressure gauge present. There was no discussion of correcting this because that was not the purpose of this visit. Are there ever any valid circumstances where a pressure gauge is not installed? Or did the installers just have a bad day? Everything else checked out okay. Is the purpose of the gauge merely for testing/monitoring?

    • Penny —

      Many standard residential systems have gauges, as contractors install them because they assume they’re needed (as in NFPA 13 commercial systems) or simply because they are good to have (giving a quick read on the water supply).

      But they are not required by NFPA 13D (the main home installation standard) unless it’s a dry (not wet) system (pressurized gas is in most of the pipes in dry systems instead of water to deal with freezing; the vast majority of home systems are wet), the water supply is from a pressure tank, or it is a standalone system with pressure-regulating or -reducing valves (NFPA 13D references are below).

      So, depending on your system, it’s likely one is not required.

      Thank you for the comment — we will update the blog to make this explicit!

      From the 2022 edition of NFPA 13D

      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.

      7.3.3 Where a pressure-reducing or pressure-regulating valve is installed on a stand-alone system, a pressure gauge shall be installed downstream of the device.

      • Thank you so much! Yes mine is a wet system. Good to know not required. Sorry for delay in responding. thought it might go thru email.

        Also, the outside alarm bell on the porch did not go off during testing. He heard it click, but no alarm. He said that was a common observation in the systems in this complex. I don’t know how common, but mine definitely wasn’t the only one.

        If the HOA insists that be fixed, is that a substantial ($) operation? It is an outside component, so I should be able to convince them it is common property for them to fix. I suppose that might be hard for you to answer, not knowing the underlying cause of the alarm failure.

        • Penny — We can’t provide an estimate or anything, but assuming it is just an outside waterflow alarm—paddle or vane type that mechanically sounds based on the movement of the water—it likely isn’t a massively complex fix; maybe just swapping out the old alarm for a new one. This would require draining the system or a portion of it, however.

          • QRFS Team, This issue is coming up again. The HOA is saying all gauges have to be replaced because they are over 5 years old. Sounds like hogwash to me. Does the standard include anything about that? I was looking the NFPA 13D you referenced and the title said it was for 1 and 2 family dwellings. Our condo units are triplex (3 attached) single level ranch style. Would that standard apply to us also? If not, which standard would apply.
            Thank you very much.

  17. Got it! Thanks. After the testing, I learned where the drain was!! Next time I will put a pail there to not swamp my garden! It landed right on a plant. Who knew!?!?!? :

    A neighbor mentioned she was outside during the draining part and she said the water really stunk. It made us wonder if it should be drained periodically to refresh it. If all that gunky water was to come out of the sprinkler heads on rugs/furniture (worst case scenario), that seemed to us it could make a bad situation worse. Are we overthinking it?

  18. A question related to Penny’s comment above. If a first-floor sprinkler discharges in a three-story house due to accidental damage (hit with a ladder), I can:
    1. Quickly turn off the control valve to stop the water flow.
    2. Drain any water remaining in the system with a hose connection (where) versus having it all drain out onto the floor?
    3. Is there anything I can stuff in the sprinkler head to slow or stop the water flow?
    I know this sounds like an “I Love Lucy” episode, but how can you minimize the damage from such a discharge?
    Thanks, Bill

    • Bill —

      Item 1: Yes, that is the basic move.

      Item 2: We can’t answer based on not knowing the system (e.g., all-in-one or separate plumbing/sprinkler pipes and the relevance of a “hose connection” in a residence). But, in principle, people often open up drain valves to get the water out of commercial systems elsewhere.

      Item 3: The best way to stop an unintentionally activated fire sprinkler FAST is by using a dedicated sprinkler shut-off tool (a QuickStop or Shutgun). The person using one will likely get wet, but it stops the water in seconds!


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