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#120 - Help! My Fire Sprinkler Was Painted. What Should I Do?

Posted by Jason Hugo on 8/7/2018 to How a Fire Sprinkler Works

What to Do if Fire Sprinkler is Painted

Replacement of painted fire sprinklers is the only safe — and completely sanctioned — option


It’s bad news when fresh paint meets a fire sprinkler. Whether it happens during a remodel, renovation, or home or office improvement, paint – even in small amounts – can delay or prevent sprinklers from deploying and containing fires. And any DIY fix of a painted sprinkler is a warranty-voiding move that could put lives or property at risk – while giving inspectors immediate cause to take a sprinkler out of service. 

If you’re looking for a replacement sprinkler head, check out our selection of commercial or residential fire sprinklers. To understand why, when, and how to replace fire sprinklers that have been painted, read on.

Bad things happen to those who paint (fire sprinklers)


In 2018, Woodbury, Minnesota-based Dyne Fire Protection Labs tested the response time of three fire sprinklers to see how quickly painted fire sprinklers activate in the presence of heat. These tests, known as plunge tests or “oven heat tests,” measure the time (in seconds) required for a room-temperature fire sprinkler to activate when exposed to a stream of hot air.

Dyne tested each sprinkler model eight times: four times with paint – specifically, a coat of Rust-Oleum Painter’s Touch 2X spray paint – and four times without. 

As expected, each of the unpainted sprinklers responded at the appropriate time. But more than half of the painted sprinklers had problems. They activated late, lost water pressure, or never released at all. A video of Dyne’s entire test can be viewed here:


“There is significant variability in the performance of aftermarket painted sprinklers,” says Grant Lobdell, Dyne’s lab manager, in his summary of these tests, “and there is potential for even a drop of paint in the right spot to impact thermal performance.”

Painted fire sprinkler
Some fire sprinkler heads are available in a white finish, but the white on the bulb of this one is a sure sign that the sprinkler has been painted and should be removed from service. 

While there are instances where paint may be harmless – a document explaining Dyne’s testing methodology adds that paint on the arms of a sprinkler head shouldn’t have any impact on performance – fire authorities and fire code take a stringent view on painted sprinklers. 

In particular, the National Fire Protection Association (NFPA), which authors the basis of most of the fire code used in the United States and abroad, has issued guidelines that require inspectors to remove from service any fire sprinkler with any amount of aftermarket paint. NFPA 25: Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems, details the requirements of a sprinkler system's required annual inspection:

From the 2017 Edition of NFPA 25

 5.2.1.1.1* Any sprinkler that shows signs of any of the following shall be replaced: 

 (1) Leakage 
 (2) Corrosion detrimental to sprinkler performance 
 (3) Physical damage 
 (4) Loss of fluid in the glass bulb heat-responsive element 
 (5) Loading detrimental to sprinkler performance 
 (6) Paint other than that applied by the sprinkler manufacturer

 5.2.1.1.4 Any sprinkler shall be replaced that has signs of leakage; is painted, other than by the sprinkler manufacturer, corroded, damaged, or loaded; or is in the improper orientation.

 5.4.1.6* Sprinklers shall not be altered in any respect or have any type of ornamentation, paint or coatings applied after shipment from the place of manufacture.

Only the manufacturer can apply coatings to fire sprinklers; sprinklers altered after sale, including those that have been painted, should be identified and removed from service during any ad hoc sighting or annual inspection. The impact of painting and other replacement-worthy offenses is explained later in Annex A:

From the 2017 Edition of NFPA 25

 A.5.2.1.1.1 The conditions described in this section can have a detrimental effect on the performance of sprinklers by adversely impacting water distribution patterns, insulating thermal elements delaying operation, or otherwise rendering the sprinkler inoperable or ineffectual. 

In short, water might not go to the right places or at the right time when there’s paint on a sprinkler head. It’s as simple as that.

Fire Sprinkler Head Components

A brief note on the function of fire sprinkler parts


Two features of fire sprinklers explain why paint can cause a malfunction:

One: sprinkler heads are triggered by heat-sensitive components, usually a glass tube filled with a liquid that expands as it warms or sometimes a metal link that melts as it heats up. As these elements reach specific temperatures, they detach from the sprinkler head, allowing water to flow into a room. Paint insulates these heat-sensitive elements; as a result, that glass tube or metal link may stay in place far too long, allowing fire to spread.

Two: water pouring from a sprinkler head is distributed throughout a room by a small grooved plate called a deflector. Deflectors ensure that the water discharges in a pattern of a particular shape and size. Paint on a deflector may distort that pattern, rendering the sprinkler ineffective.


Using solvents and scrubbing painted fire sprinklers can do more harm than good


In only one scenario does the NFPA explicitly permit cleaning of a fire sprinkler head – and it’s not when it’s painted:

From the 2017 edition of NFPA 25

 A.5.2.1.1.2(5) – In lieu of replacing sprinklers that are loaded with a coating of dust, it is permitted to clean sprinklers with compressed air or by a vacuum provided that the equipment does not touch the sprinkler.

Touching the sprinkler head isn’t permitted even for a task as simple as dust removal, and with good reason: doing anything to a fire sprinkler head can be a risky business. The heat-sensitive components that ensure sprinklers activate in a timely manner can often be fragile. In some cases, that little glass bulb – a component that’s both delicate and highly impacted by paint or heavy dust – is all that stands between a room and a deluge of water.  

In places as diverse as prisons, hotels, courtrooms, and college dormitories, unwanted sprinkler activations have caused tens of thousands of dollars in damage. Accidental discharge can be costly, unsanitary, and inconvenient. Any replacement heads should be installed by a licensed professional who can ensure a safe installation.

VERTEX, a forensic consulting and engineering design firm, surveyed more than 30 US fire marshals from 11 states in 2017. While all of those surveyed “consider any amount of paint on the actuator, frame or diffuser to be a ‘fouled’ head,” a minority of fire marshals allowed sprinkler heads to be salvaged through paint removal “by physically touching the sprinkler head or by the use of solvents … in direct opposition to NFPA directives.”

Even if some local authorities permit paint removal, both NFPA and sprinkler manufacturers instruct not to do it. In technical documents provided with their sprinkler heads, manufacturers Viking, Senju, and Reliable have each explicitly warned against cleaning or even touching heads with various unapproved substances, including solvents. 

Some warranties, such as Victaulic’s, are voided when the sprinkler is “used in a manner contrary to Victaulic’s instructions or recommendations.” These include warnings like these: “Do not clean sprinklers with soap and water, ammonia, or any other cleaning fluid. Do not use adhesives or solvents on sprinklers or their operating elements.”

Six digits can help you identify your replacement fire sprinkler


Many fire sprinklers can be identified by looking at the deflector plate. If yours is unpainted, check for a five-to-six-digit sprinkler identification number, or SIN, on the deflector plate. Searching for this model number on a SIN directory or your preferred search engine can make locating an exact replacement simple. 

Fire Sprinkler Diagram SIN
Looking up your model number (SIN) can streamline sprinkler replacement. 

If the deflector doesn’t have this information, the sprinkler may have been manufactured prior to the introduction of SIN numbers. See our complete guide to replacing older sprinkler models.

If your deflector has been painted over and you can’t see the SIN, nearby sprinklers that are in the same orientation may be identical. Once you’ve figured out what you need, check out our selection of commercial or residential fire sprinkler heads to find a match, or enter your query in the search bar at the top of this page.

If you’re not sure what you need, get in touch with us. We’ve helped a lot of people replace sprinklers of many types, including older ones that have been re-designated or are no longer manufactured.

Call QRFS at 888-392-3362 or fill out our contact form and we’d be happy to help. 

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