History and Development

Firefighting foams have come a long way since they were first developed in the 1960s. Originally made from hydrocarbon surfactants and water, early foams struggled to effectively smother fires. Through years of research and testing, manufacturers began incorporating fluoroprotein and fluorosurfactant compounds into foam formulations in the 1970s. These “aqueous film forming foams” or AFFFs could transform into a thin, heat-resistant film when applied to a fuel source. The new generation of foams provided vastly improved fire suppression capabilities compared to previous iterations. Further advances led to the creation of “alcohol resistant aqueous film forming foams” or AR-AFFFs that could also extinguish fires involving hydrocarbons like alcohols. By the 1980s, modern fluoroprotein foam concentrates had become the global standard for high-risk firefighting applications.

Types of Firefighting Foam and Their Uses

There are several main categories of Firefighting Foam types used today:

AFFF - As mentioned, AFFF foam is very effective on Class B hydrocarbon fuel fires involving materials like oil, gasoline, diesel, jet fuel, etc. It is stored and used in airports, marine terminals, chemical plants, and refineries.

AR-AFFF - When alcohols are involved in a fire in addition to hydrocarbons, AR-AFFF foam is needed due to its resistance to alcohol fuels. Common applications include breweries, distilleries, and fuel ethanol production facilities.

Fluorine-Free Foam - Also called “F3,” this type of foam contains no PFCs or PFAS compounds which have come under environmental scrutiny in recent decades. Though less effective than legacy foams, F3 is suitable for training purposes and some exterior fires.

Protein Foam - Generated from animal or vegetable proteins, this foam was frequently used before modern fluorinated varieties. It remains effective for Class A combustible solids like wood, paper, and trash fires.

Wetting Agent - Not a true foam, this liquid solution is applied before or during firefighting to help prevent ignition and spread of Class A fuels across structures.

How Firefighting Foam Works to Suppress Fires

When sprayed onto a fire through fixed suppression systems or handlines, modern firefighting foam utilizes three key mechanisms to effectively smother flames:

1. The foam solution rapidly forms an air-excluding vapor seal over the fuel surface, both cooling it and suffocating the fire's oxygen supply.

2. As the vapor seal expands it also helps separate and isolate combustible vapors from air above the liquid fuel layer.

3. The heat-resistant fluoroprotein film prevents reignition of extinguished fuel even after the initial foam layer is burned away. This provides durable protection lasting 15-30 minutes.

Importance of Proper Storage and Handling

For firefighting foam concentrates to perform as designed, facilities must carefully follow concentration manufacturer guidelines on storage, maintenance, and operation. Concentrates require storage within a specific temperature range, preferably in original packaging, to avoid breaking down. Regular testing verifies concentrate complies with UL-listed specifications before use. Proper class and type of foam must then be selected based on expected fuels and mixed with the correct proportion of water by inductors or balance pressure tanks. Making sure all vehicles, systems, and personnel are fully trained in operations helps ensure the most effective fire suppression.

Environmental Issues and Regulatory Actions

Concerns have grown in recent decades over PFAS compounds contained in older AFFF formulations and their impact on the environment and public health. These per- and polyfluoroalkyl substances are highly persistent in soil and water supplies, with some research linking long-term exposure to various illnesses. In response, many fire departments have transitioned to newer fluorine-free foams for training purposes and to prevent further PFAS releases.

The U.S. EPA has taken action to address both legacy AFFF stockpiles and future use. A stewardship program launched in 2019 to track and dispose of older concentrates. New Toxic Substances Control Act (TSCA) rules now require notification within 30 days of any AFFF discharge and mandate use of fluorine-free foam as of October 2020 for most situations. Significant research continues into newer foams that can achieve fire protection without harmful long-term chemistry.

properly applied and maintained firefighting foam technology forms a vital line of defense against hazardous liquid fuel and petrochemical blazes worldwide. Advances in foam chemistry coupled with responsible handling ensure ongoing ability for rapid fire control in high-risk industrial scenarios. Further innovations also promise a more sustainable solution for emergency responders in the years ahead.

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