Phos-Chek is the most concentrated Class A foam available today. Many other products contain significantly more water, up to 85%.


Water Content


A significant portion of the Class A foam specification should include water content limitations on the foam concentrate. Some suppliers add water to their foam concentrate in order to lower their costs. Typical water content necessary for concentrate production is about 45%. Some “concentrates” contain as much as 85% water!











Phos-Chek has special properties and has passed third party laboratory testing criteria not matched by any other product. Phos-Chek:


  • Passes and exceeds U.S Government Environmental, Health, Safety and Corrosion standards and require- ments by similar agencies around the world
  • Contains no EPA listed hazardous materials
  • Readily biodegrades in the environment and meets all technical requirements of the National Fire Protection Association (NFPA) Standard #1150
  • Extinguishes both Class A and B fires- passing UL Wetting Agent tests at the following use rates:


Class A fire - Ordinary combustibles; wood, paper, plastic, rubber at 0.1% or 1 gallon of concentrate per 1000 gallons of water 















Water, as it is converted into steam, has tremendous capacity to absorb and carry away heat. Unfortunately, water’s strong surface tension causes it to bead up and roll off most fuels and away from heat too fast to be able to absorb its full heat capacity.


Phos-Chek’s unique combination of surfactants significantly reduces water’s surface tension. As a result, water

containing low concentrations (0.1% to 1.0%) of Phos-Chek foam concentrate:


  • Stretches out the water droplet into a bubble and holds it that way, increasing its heat absorbing surface
  • Penetrates deep into Class A fuels
  • Has an affinity for carbon. Phos-Chek bonds with carbon like a magnet holding the water against the fuel. It grabs onto smoke greatly increasing visibility and reducing knockdown time











Class A Foam Comparison Field Testing



Recently hosting a Foam School, brands of foam were tested in an equal manner under normal conditions.  


Each foam was sprayed and monitored for consistency upon deployment and after a period of time had extended. 


See the Results for Yourself?


Another great way to compare your foam is to look at its UL Classification testing results to see what value it passed at. This provides the minimum induction percentage required for a Class A fire.


Phoschek UL Percentage is 0.1, therefore 1% is the minimum induction percentage required when attacking class A fires


Many suppliers claim that their product meets the requirements of the National Fire Protection Association (NFPA) 1150 standard “Fire-Fighting Foam Chemicals for Class A Fuels in Rural, Suburban, and Vegetated Areas”.


The NFPA 1150 specification requirements are the same as the USDA Forest Service specification. However, the USDA Forest Service conducts or oversees tests with other outside laboratories and qualifies a product that meets their requirements. NFPA 1150 is simply a standard; they do not conduct any tests to validate performance.



Underwriters Laboratory (UL) conducts fire suppression effectiveness testing for Class A (wood crib & ginned cotton) and Class B (heptane) combustibles when products are UL listed as a Wetting Agent. 

These tests will ensure that a product will extinguish a fire. Use rates required to pass these fire tests vary between different products that have been tested against this standard.


Phos-Chek WD 881 Class A foam is a UL Listed Wetting Agent at a very low use rate of 0.1%. Click on to verify a UL Wetting Agent listing. Search their on-line certifications directory by product name or “wetting agent” in search criteria.


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