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Rules Regarding Covering Fire Sprinkler Heads in Paint Booths

Posted June 25, 2018 by Koorsen Fire & Security

Rules Regarding Covering Fire Sprinkler Heads in Paint Booths

If fire sprinklers are to operate properly when you need them most, it seems only too obvious that they should never be covered, decorated, painted or otherwise tampered with. While seemingly stating the obvious, the NFPA still outlined these requirements in NFPA 25, 5.4.

While these may be obvious restrictions in common applications, these requirements actually pose a problem for a few very specific scenarios, such as when a fire sprinkler is in a paint booth, spray room, or resin application area. In these instances, overspray from paint or resin could gradually coat the fire sprinkler and prevent it from functioning properly or at all.

The dilemma: to not cover the sprinkler to protect it from overspray will result in the sprinkler’s failure to function properly when needed due to being coated in too much paint or residue. But covering it up to protect it from the damages of overspray could also result in its malfunction.

Fortunately, in both NFPA 25 and NFPA 33, this specific situation is addressed. However, there still seems to be a great deal of confusion about what exactly these rules mean and how to practically apply them.

If you work in or manage a building that has fire sprinklers in a spray area or paint booth, and you are unsure of whether you can or should cover them and how to do so properly, keep reading for better clarification of the rules and suggestions on how to best protect them.

Clarifying the Rules

In older editions of the NFPA guidelines, when they realized they needed a section specifically addressing fire sprinklers in spray areas and paint booths, they unfortunately used language that was a bit generic, leading to some confusion.

They had indicated that a “plastic” bag of no more than 0.003 inches thick (0.076 mm) could be used to cover and protect a fire sprinkler head in a room where overspray would be a problem. However, “plastic” allowed for a rather broad (and unsafe) interpretation of this rule, such as people believing they could use plastic sandwich bags from the grocery store as a protective covering. This was problematic for numerous reasons, which will be discussed further down.

Fortunately, as a result of further study, in the more recent editions, the NFPA updated their language to be very specific about the acceptable materials for fire sprinkler coverings. Between the newly revised NFPA 25 5.4 and NFPA 33 9.6.7, room for confusion is eliminated.

  • The Requirements in a Nutshell

    So, what are the exact rules about covering fire sprinklers in paint booths and spray areas? At the most basic, they are:
    • Fire sprinklers must be protected from overspray by proper covering if located in the same room or area
    • Protective coverings may be either:
      • Cellophane (not plastic) of 0.076 mm (0.003 in.) or less
      • Thin paper bags
    • Protective coverings for fire sprinklers must be replaced regularly to avoid build up of residue which could hinder sprinkler function

It should be noted that specifically cellophane or thin paper are the only materials approved as coverings, and the cellophane must be the appropriate thickness. “Plastic” bags, as such, are not acceptable coverings for fire sprinklers.

  • The Difference Between Cellophane and Plastic

The reason plastic bags (polymer-based material) are dangerous to use on fire sprinklers is because during a fire, the heat can cause the bag to shrink and melt even before the sprinkler is activated. As a result, once activated, the water spray coming from the sprinkler could be disrupted or blocked completely by the melted plastic, making the sprinkler less effective or completely non-functioning.

Cellophane, however, is constructed from plant-based material (organic cellulose, aka plant fibers) and is biodegradable (unlike plastic). As a result, moisture can permeate it (unlike plastic), and it is typically weaker than plastic as well. When under testing by the NFPA, lightweight cellophane bags caused no adverse effects on the function of fire sprinklers.

  • Inspection and Replacement


    Since it is never ideal for fire sprinklers to be covered at all, and since overspray will still result in chemical and resin buildup on the protective bags, regular inspection of the sprinklers and replacement of the bags are required at a much more frequent rate than annually.

    According to the NFPA, depending on the specific spray area and degree of use, it may be necessary for the bags to be changed out daily to prevent excessive and harmful buildup.

Practical Application

While the rules now are quite clear, applying them in your building may still seem difficult. Here are some of the biggest reasons why:

  • Cellophane is most often found in thicknesses much greater than 0.003 in.
  • During annual inspections, the authorities will want proof of appropriate thickness / material
  • Thickness of paper bags was not specified

With regards to cellophane thickness, it may be best to contact a manufacturer directly in order to attain cellophane bags with the proper thickness. If you are still unable to find them, then simply using thin paper bags may be the easiest solution if your fire sprinklers must be located in the spray area or paint booth.

Since no thickness is specified for the paper bags, finding the thinnest bags you can is likely the simplest and most cost-effective solution, as well as the easiest way to comply with the code.

So, all you need to remember is:

  • DON’T use plastic bags (sandwich or otherwise)
  • DO use cellophane bags IF 0.003 in. in thickness or less, or
  • DO use thin paper bags, and
  • DO check and change fire sprinkler protective bags frequently

Need Some Professional Assistance?

Staying up to code when it comes to fire protection can be difficult simply because of each property’s unique, complicated structures and settings. But going beyond the code to ensure true safety for your building and all those within is even harder.

For professional assistance to ensure your facility is safe, the experts at Koorsen Fire & Security are here for you. With over 70 years in the business, they not only know the ins and outs of the codes, but also the best ways to keep your property and people safe.

Don’t take any unnecessary risks – give the experts at Koorsen a call today.

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Topics: Fire Sprinkler Systems

Disclaimer: The information in this article is for informational purposes only. It is believed to be reliable, but Koorsen Fire & Security assumes no responsibility or liability for any errors or omissions in the content of this article. It does not constitute professional advice. The user of this article or the product(s) is responsible for verifying the information's accuracy from all available sources, including the product manufacturer. The authority having jurisdiction should be contacted for code interpretations.