As foam concentrate technology marches forward toward more environmentally friendly products, more and more discussions are taking place involving what to expect from an equipment and foam perspective related to changing over to new foams. While there are changes coming to improve our environmental responsibility, manufacturers are working hard to ensure that the best products are put in the hands of industry emergency response personnel worldwide. When we say “best products,” we mean systems that include both the foam concentrate AND the equipment components to mix the foam with the water and then add the air and agitation necessary to generate foam qualities suitable for extinguishment.

Because foams are changing, we naturally expect metering settings and proportioner orifices to change. This is because of viscosity differences in the foams. This is an expected requirement when changing any system to a new foam type—C8 to C6 to fluorine-free foam (FFF). Along with the metering adjustments, there are cleaning and flushing requirements necessary to ensure piping, tanks, and systems are made ready for a new foam. Depending on the foam you choose, minor additional changes associated with materials compatibility and nozzle types may be necessary.

Not to worry: Major equipment replacements or modifications are not necessary. Don’t panic!

The following information will hopefully be helpful in preparing your truck and equipment for your new environmentally friendly foam concentrate of choice.

Foam Concentrate Mixing Compatibility

The category of foam concentrate mixing compatibility spans all types of foams—C8, C6, and fluorine-free versions. The rule of thumb is, if it’s a different foam concentrate type or manufacturer, do not mix in storage containers, tanks, or piping. It may, and likely will, cause immediate changes in viscosity and fluid structure. If you are consuming foam concentrate while discharging foam solution, switching from one foam type or manufacturer to another through a proportioning system, eductor, pump, or nozzle is not a problem. It is recommended that the system be flushed with water for a short time after foam solution pumping. This will ensure that the piping is free of any mixture or old foam before filling the foam system with the fresh concentrate. Foam solutions and expanded foams of different types will work together and not degrade one another so long as they are being used properly and on the fire they were intended for. 

Mixing compatibility concerning C8, C6, and new FFFs is largely unchanged. As usual, different foam concentrates are not recommended to be mixed because of chemical reactions that can be triggered, resulting in loss of firefighting effectiveness, thickening, or separation in the foam. This is true for mixing different manufacturers’ foams as well as mixing foams of different types from the same manufacturer.

There is usually no problem adding new foam of the same brand and product name to existing foam in your tank. The user should call the foam concentrate manufacturer with the product name