Training has always represented a considerable proportion of the average working day for the Fire Service. This may represent as much as a third of the available time. Training must be fit-for-purpose and cost-effective. It must not expose personnel, members of the public, or the environment to unnecessary risk. The key word here is “unnecessary”. As long ago as 1984 the UK Health & Safety Executive recognized that some occupations such as fire fighting are inherently hazardous and that training has to take this into account1. At the time HM Fire Services Inspectorate at the Home Office in London circulated a Dear Chief Officer Letter (DCOL 8/1987) which advised that “Drills and exercises based on all expected operational requirements should be devised and regularly practised under conditions of maximum realism”.

A balance has to be struck between avoiding unnecessary risk – note that this does not necessarily mean avoiding any risk –  and inclusion of the necessary objectives of realistic training. Risk assessment and management is quite general, with principles as laid out in the Health Safety Executive’s useful HSG65 guidance booklet (www.hse.gov.uk/pubns/indg275.pdf). Risk management does not apply exclusively to the control of risk to personnel or members of the public but also includes controlling risk to the environment, as well as exposure to financial and legal liability.

The objectives of training with firefighting foam and foam generating equipment have to be clearly identified. In certain safety critical applications where time is of the essence such as airport firefighting and rescue operations, the regulatory authorities insist on training personnel and testing equipment with foam that meets ICAO performance level B, that is the same foam under the same conditions as would be used operationally. The reasons behind this philosophy include ensuring that the equipment used is kept fully functional and that operational procedures are fine-tuned to the foam and equipment being used.

There are, however, potentially at least, environmental consequences of using standard foam on a regular basis for training and maintenance. Over time, uncontrolled run-off will lead to contamination of groundwater or water courses as was the case with Jersey Airport which featured in an ITV Channel Television report. Foam-contaminated run-off needs to be contained and then disposed of correctly. This adds considerable costs to the training budget which a municipal fire brigade may not be prepared or able to carry. Other approaches that save cost and protect the environment but also deliver the purpose of training then have to be considered.

What are the goals of foam training? What are the options?

Clearly the aim is to train firefighters to use foam generating equipment correctly under operational conditions and to be able to apply foam to a fire in the most effective manner.

This requires them to have some knowledge of the properties of both the foam used, the equipment used to generate it, and the various types of fire they will have to deal with. In particular they should be aware of the differences in behaviour and capabilities between foam for Class A carbonaceous fuels and for Class B hydrocarbon fuels, including the need for alcohol-resistant (AR) variants. How the foam is applied is also important. For example, is the finished foam aspirated or non-aspirated? Is there a requirement for low, medium or high expansion foam? Is the incident area hydrologically sensitive and does this mean that a more long-term environmentally friendly solution is desirable – for example, the use of a fluorine-free foam instead of a fluorosurfactant-containing foam such as an AFFF, FFFP or FP product or its AR variant? How do the various fuels behave in a fire and are there useful generalisations about which type of foam is most appropriate that can be taught? Training must address all of these issues.

When talking to fire officers I often use two simple initial questions to probe their awareness of some of these issues. The first – you are still a mile or two away from a mixed chemical storage site tank fire; how do you know, as officer in charge of the first attendance, which type of foam should be used? If the smoke is almost colourless the fuel is most likely highly polar, containing its own oxygen such as methanol or MEK, and you will need an AR foam; if the smoke is dense black then it is probably an oxygen-deficient hydrocarbon fire, such as gasoline or diesel, and will require a standard AFFF, FFFP, FP or fluorine-free Class B foam. And second – you arrive at a large petrochemical incident where ground monitors have been established but are still some way away; how do you know what type of foam is being used? If the monitor plume is white or near-white the foam is probably a synthetic AFFF or fluorine-free foam, if it is pink or orange-red the it almost certainly a FFFP or FP foam as the protein concentrate used in its manufacture is usually heavily contaminated with the dark red blood-pigment haemoglobin.

Because of environmental pressures, both real and imagined, and the cost of building containment facilities at fire service training grounds and subsequent specialised disposal of foam-contaminated run-off, there has been a move towards using gas-fired foam training rigs and training foams. These gas rigs can be turned on and off at will and have limited environmental impact.

However, and it is a very big however, these do not give firefighters experience in how Class B foams behave with hydrocarbon pool fires, nor indeed how the fires themselves behave. Moreover, the use of most training foams does not provide practical experience of how a fluorosurfactant-containing film-forming foam (normal or alcohol-resistant (AR) AFFF, FFFP or FP) behaves on a pool fire. There are a number of solutions developed by end-users. For example, one can use a low fluorine AFFF foam, thus reducing any environmental impact, to demonstrate film-forming on hydrocarbon fuels.

Another approach would be to use a standard EN3 tray fire with an AFFF product in combination with gas-rig training. An additional issue is whether the site being used for training is authorised or licensed to burn liquid fuels, since the production of smoke is unacceptable in many areas.

For training with alcohol-resistant (AR) foam a tray containing a polar solvent such as acetone which burns with virtually no smoke, is a viable option. The inability of AFFF, FFFP or fluoroprotein foam to extinguish a polar fuel fire can be demonstrated, as can the efficiency of a properly formulated AR product.

Standard training foams as well as the newer fluorine-free products do not contain fluorinated derivatives, being formulated from hydrocarbon surfactants. Both have the advantage of being able to be used in medium and high expansion modes, which a standard AFFF cannot, as well as being environmentally more friendly. Training foams have an added disadvantage. They cannot and should not be used to teach fire extinguishment, especially under conditions where there is any significant risk to personnel, as they do not have the performance of operational foams.

Is there an acceptable “one stop” foam concentrate solution for municipal fire brigades which covers both Class A and Class B risks? One driving force for seeking a one-stop solution is purely practical –  it simplifies training and procurement. Certainly firefighters need to be taught the difference between what is required of the finished foam in each case.
Class B foams must be able to spread and maintain a layer across a hydrocarbon surface, either by film-forming as with standard AFFF or by other mechanisms for fluorine-free products; they must form a stable foam blanket and have resistance to burn-back even at high temperatures, for example in contact with red-hot steel tank sides; drainage times must be acceptable; vapour suppression must be efficient; foam generation with both fresh and saltwater must be possible without loss of effectiveness; and AR variants must be available. Class A foams, on the other hand, are specifically formulated for optimum penetration of a carbonaceous fuel. This is brought about not only by a lowering of the surface tension –  hence the term often used for these foams, “wetting agents” –  but also by increasing capillary penetration. The requirements for a Class A and a Class B foam are to some extent contradictory.

Fluorosurfactant Class B foams do not penetrate a carbonaceous substrate nearly as effectively as optimally formulated hydrocarbon Class A foams. Class A foams do not film-form or have good burnback resistance. Suggestions that it is possible to use a standard fluororsurfactant-containing Class B foam at a lower concentration for Class A fires as a “one stop” solution are potentially environmentally irresponsible, since the use of such a foam on, for example, a large wildland fire will result in contamination of ground and surface waters with fluorinated degradation products. In addition fluorosurfactants do not penetrate carbonaceous fuels nearly as well as hydrocarbon surfactants.

Is there an acceptable one-stop, single-foam compromise that balances the requirements for Class A and Class B fuels? Probably, given the way developments in the industry seem to be going. One solution is that of using a single, Class B fluorine-free foam for everything. Fluorine-free foams have two major advantages over those containing fluorosurfactants (AFFF, FFFP and FP or their AR variants): they do not break down to give extremely persistent fluorinated degradation products; they can also can be used for producing efficiently low, medium and high expansion foam. Disadvantages include having to accept a potentially lower Class A performance, and a higher cost compared to a Class A product. On balance operational and training advantages may be felt to outweigh the disadvantages.
1. Health and Safety Executive Training for hazardous occupations a case study of the
Fire Service HSE Occupational Paper Series OP8 HMSO London (1984).

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