by Grant Lobdell

According to Chapter 4 of the 2016 edition of NFPA 11 Standard for Low-, Medium-, and High-Expansion Foam, the components of a foam system, including the foam concentrate itself, shall be listed.  Where listings for a component do not exist, the components shall be approved.

What does NFPA mean when it states a component needs to be listed or approved?

NFPA defines the term listed as follows:

Equipment, materials or services included in a list published by an organization that is acceptable to the authority having jurisdiction and concerned with evaluation of products or services, that maintains periodic inspection of production of listed equipment or materials or periodic evaluation of services, and whose listing states that either the equipment, materials or service meets appropriate designated standards or has been tested and found suitable for a specified purpose.

Simply put, a listed product or service is one that has been evaluated by a third party to do what it claims.  Furthermore, this third party is also tasked with periodically ensuring continued compliance to ensure no shortcuts in production or service are taken after achieving the listing.

Not all products or services are able to be listed.  To be listed, a standard of acceptance, a document that establishes minimum requirements, must be available to evaluate the product against.  If a standard has not been developed for the specific product or service in question, NFPA states that the product or service must at least be approved. 

NFPA defines approved simply as “acceptable to the authority have jurisdiction.”  Therefore, the authority having jurisdiction (AHJ), has the ability to approve unlisted products or services for use when needed.  The AHJ can come to a conclusion on acceptance by understanding the acceptance criteria of NFPA or other appropriate standards, the manufacturer’s definitions for proper installation and use, and/or the listing or labeling practices of organizations concerned with product evaluations.

Note that listing criteria does exist for foam concentrates at various 3rd party listing agency[KR1]  and as a result, NFPA 11 requires a listed product to be used.  An approved but not listed product is only allowed when listing criteria is not available.

Why does the 2016 edition of NFPA 11 require listed or approved components?

The 2016 edition of NFPA 11 requires listed or approved components to help ensure adequate performance of components in the fire protection system.  The listing process involves a plethora of testing to come to the conclusion on acceptable performance.  These tests can include but are not limited to the following: proportioning of foam concentrate, hydrostatic testing, corrosion resistance, and fire test performance.  The tests results as a whole help to answer the question, “Will it work?”

How to find the FM Approval listing details?

FM Approvals is an example of an organization that is concerned with the evaluation of products or services.  For information on Underwriter’s Laboratories (UL) listings, please reference the following article: How to find an interpret foam concentrate UL listings.  Products or services that are listed by FM Approvals can be found using their free online portal, Approval Guide.  Once logged on (registration is free), there are a variety of ways to search for a product or service on this portal as shown in Figure 1.

Figure 1: Some of the search options in FM Approvals Approval Guide portal.

What does the information on a FM Approval listing for a foam concentrate mean?

To answer this question, let’s consider an example – an Ansul foam liquid concentrate product.  Searching the company Ansul will result in several different divisions of products (Figure 2).

Figure 2: Ansul products listed with FM Approvals.

Let’s specifically look at Ansul’s listing for low expansion foam systems which can be found under the Fire Protection division.  At the top of the page (Figure 3), general information about foam extinguishing systems and, specifically, low expansion foam systems can be found.

Figure 3: General foam extinguishing system information found on FM Approval’s Approval Guide app.

Note FM Approval’s ensures compliance in part using FM Global data sheets 4-3 Medium and High Expansion Foam Systems, 4-7 Low Expansion Foam Systems and 4-12 Foam-Water Sprinkler Systems.  These FM Global Property Loss Prevention Data Sheets can be found online and downloaded for free for those curious as to recommendations for design and installation.   

Also note that foam concentrate and the equipment used with it such as the storage tank, proportioner, and discharge device are always listed together as a “foam system”.  Together the equipment has been proven to meet FM Approval’s requirements.  Equipment not listed with the foam liquid concentrate has not been evaluated.  Requirements for testing of foam systems are identified in FM Approval Standard Class 5130, Approval Standard for Foam Extinguishing Systems.

This is followed by a section of listed foam concentrates (Figure 4) and then sections of compatible equipment with those foam concentrates (Figure 5).

Figure 4: Ansul concentrates listed on FM Approval’s Approval Guide app.

Note the foam concentrate percent the foam should be used at and the fuel’s the foam has been approved to be effective against.  Also note FM Approval’s does denote products considered “sustainable” by certain outside organizations with a GREEN symbol.  This quick identification of these products may be beneficial as environmental regulations regarding firefighting foam continue to grow.

Figure 5: Some of the equipment listed for use with Ansul concentrates per FM Approval’s Approval Guide app.

Note there is a variety of equipment the foam concentrate can be used with and the communication of the relevant variables (flow range, pressure range, size, etc.) of that equipment.

For information on foam concentrates for use with specific sprinklers as a discharge device in a foam-water sprinkler system, please consult the Foam Water Sprinkler section under the Fire Protection division (Figure 6).

Figure 6: Foam water sprinkler listings for Ansul foam concentrates.

How does this relate to the inspection, testing, and maintenance (ITM) of foam systems?

It is important to note the foam concentrate and equipment are listed together as a foam system.  One cannot simply change out the foam concentrate if it fails the periodical foam quality tests without considering the equipment as well.  It is possible that a foam concentrate switch may also require some equipment being switched as well.


Furthermore, it is possible that such a scenario may have already occurred.  If you are on site completing the flow testing to ensure the proportioning equipment is working as designed and you are having trouble getting the required percent concentration of foam in the foam-water solution, it could be that the equipment is not designed for use with the foam concentrate on site.

If you have any questions regarding this article or have a question that you would like to see addressed in a future article, please contact Dyne Fire Protection Labs at or (800) 632-2304.

©Dyne Fire Protection Labs 2019