Basic Foam Operations - Part 2

There are a variety of foam concentrates available to the fire service. Some are more specialized than others and some are more common. In order to give company members a working knowledge, we’ll give a brief overview of the different types of foam...

Given today’s incidents that the typical municipal fire department responds to, it is critical that the department has the ability to adapt to a host of situations. The multitude of chemicals that are a part of our everyday lifestyle also means problems for the first responders. As such, a foam concentrate that is good on both hydrocarbon and polar solvent spills and fires would increase any department’s capability. Concentrates such as AR-AFFF are one type of foam that would offer this advantage.

Today’s foam concentrates are designed to be mixed in certain ratios with water. In the past, 3% and 6% were common settings. The directions on a typical 3% x 6% five-gallon pail of AR-AFFF foam concentrate, for example, directed that for hydrocarbon fuels, the mixture of concentrate to water was 3% (in other words 97 gallons of water and 3 gallons of foam concentrate), while for polar solvent spills the ratio was to be set at 6% (6 gallons of concentrate and 94 gallons of water).

Newer concentrates can be as low as 1% mixtures of concentrate to water. Take a look at some of the products available from the different foam manufacturers. Each of their product guides goes in-depth as to the ratio as well as application rates for different types of fuels and spills.

Today’s common foam concentrates can be mixed with both fresh water as well as saltwater. This further increases our advantages. The fire service responds to many different types of incidents and a shore-based community could very well find itself relying on out-of-the-ordinary water supplies for any number of reasons. A response attributed to a manmade disaster or a natural disaster could render the municipal infrastructure and water supply useless. Such a situation calls for out-of-the-box thinking and knowing that saltwater could be a key ingredient in making our strategy work would pay dividends.

During the application of foam, concentrates of the same family, such as AFFF, can be mixed together just prior to eduction, but to batch mix the concentrates of different manufacturers for extended periods of time could become problematic. Also batch mixing for extended periods of times with other types of concentrates can be problematic. Always check with the manufacturer to determine the limitations of your foam concentrate.

Foam is also mildly corrosive and after application it is important that all elements of the foam system (i.e., nozzles, eductors, appliances, etc.) be flushed for at least several minutes.

The shelf life of foam concentrate is another advantage. Most concentrates have lengthy shelf lives of 5 to 25 years, but depending on the manufacturer, type of concentrate, and the storage conditions (such as temperature and exposure to direct sunlight) can all affect the lifespan of the concentrate.

There are many types of concentrates on the market and there are many sources of accurate information readily available. Take a look at some of these additional sources starting with the foam you presently have. Know your equipment before the incident occurs!

The next article in this series will take our studies further into the topic of foam firefighting and how it relates to the typical engine company.

ARMAND F. GUZZI JR. has been a member of the fire service since 1987.  He is a career fire lieutenant with the City of Long Branch, NJ, Fire Department and is the deputy director of the Monmouth County, NJ, Fire Academy where he has taught for over 20 years.  He has a masters degree in management and undergraduate degrees in fire science, education, and business administration. View all of Armand's articles here. He can be reached via e-mail at or