What has happened to our firefighting foam agent?

14 Nov What has happened to our firefighting foam agent?

Andy Hall, founder of Hall Fire & Safety Consultants has been asking himself this question for several years. With over 25 years in fire and safety globally, and a primary interest in foam and foam systems Andy has now chosen to share his thoughts with FME readers.

Since early 2000 when the leading manufacturer of AFFF, 3M Inc. voluntarily withdrew from the firefighting foam market, the development of new firefighting foams has principally been driven by environmental legislation. For 3M, it was the determination by the US EPA that PFOS (Perfluorooctane Sulphate) the fluorosurfactant that was a key chemical ingredient in their foam agent was harmful to the environment. PFOS has a PBT profile (Persistent, Bio-accumulative and Toxic) which led the chemical to be listed as a Substance of Very High Concern under REACH and then to be identified under the Stockholm Convention as a Persistent Organic Pollutant.

Many per- and polyfluoroalkyl substances (PFASs), also commonly referred to as perfluorinated chemicals (PFCs) are found worldwide in the environment, wildlife and humans.

Other major manufacturers of foam agent used alternative fluorosurfactants including another PFAS  known as PFOA (Perfluorooctanoic acid). Investigations by the US EPA concluded that PFOA, similar to PFOS, is also persistent in the environment, is found at low levels in the environment and in the blood of the general US population, and causes developmental and other adverse effects in laboratory animals. Accordingly, the EPA took steps in cooperation with eight leading companies manufacturing per- and polyfluoroalkyl substances, to join in a global stewardship programme with the ultimate goal of eliminating these chemicals from emissions and products by the end of 2015.

With regard to firefighting foam a result of this stewardship programme was the development of new fluorosurfactants with fewer than eight carbon atoms. The impact on the manufacturers of AFFF, FFFP etc. was the need to reformulate and relist their foam agents based on the so called C6 (short chain PFASs). These short-chain PFAS chemicals are generally less toxic and less bio-accumulative in wildlife and humans but are still persistent and have the potential for Long Range Transport (LRT). The first of these solely C6 based AFFF’s appeared on the market around 5 years ago and now in 2017 all the major foam manufacturers are offering these short-chained based foam agents.

The demise of PFOS also saw new research and development work into Fluorine Free Foams (FFFs). As many writers have pointed out in the past FFFs are not new technology and actually the first FFFs were available before AFFF, but at the end of the 1990’s and early 2000’s FFF was mainly confined to multipurpose, high expansion and Class A foam types. Renewed efforts to formulate high performance Class B foam agents without fluorine chemicals led to a number of companies launching new FFF agents onto the market with claimed comparative fire performance to good AFFF’s

Today whilst it may not be true to say that we are looking at “new technology” foam agents we are certainly looking at purchasing “new formulations”. Based on all the claims and counter claims we have seen at conferences, in magazine articles and “fact sheets” circulated in public domain these new C6 and FFF formulations don’t perform to the same performance levels as the older formulations! That seems a contradictory comment based on the fact that in the same public domains we hear and read of more products achieving QPL with their Mil Spec AFFF products, or achieving a IA rating according to EN 1568 Part 3, or achieving an ICAO Level C rating.

There are also reports and comments of companies carrying out their own fire test performance tests and having these new formulations not achieving extinguishment or providing very limited burnback protection.

Some of these may of course be due to the test criteria or techniques applied, but worth mention is the fact that the LASTFIRE Group through their programme coordinator have stated at a number of foam forums in recent years that performance of new formulation foam agents has
not been as they tested previously with the older formulations. Noting that the LASTFIRE test protocol is a batch test rather than a listing or approval, it is certainly used by its member companies and the POG sector in general as an indication of foam performance. It should also be recognised that the foam manufacturers are constantly developing and refining formulations, so past performance whether good or bad might  not be a true indication of the formulations offered to the market today!

So clearly environmentally driven legislation has changed the chemicals that are used in currently available foam formulations, and these new formulations may not have the same operational performance as the foam formulations we were using 5 years ago.

As a user are you going to be faced with a change out situation similar to Halon 1211 and 1301?

In many countries and generally this relates to those countries that are signatories to the Stockholm Convention on Persistent Organic Pollutants you will have already had to dispose of your PFOS based foam agent in accordance with the local regulations.

At the time of writing I am aware of one local authority having jurisdiction that has implemented a policy that provides a time frame for the use of the older long-chain PFAS based foam agents to be changed out. Other countries have not implemented any legislation at this time requiring the removal or extended the restriction of use regulations relating to the use of these foam agents. In fact even the recent EU Commission Regulation 2017/1000 dated 13th June 2017 concerning the Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) as regards perfluorooctanoic acid (PFOA), its salts and PFOA related substances not only allows for older longer-chain foam agent already in systems or designated for firefighting on a site to continue to be used after the implementation date of the Regulation, but also allows for the manufacture and supply of these older longer chain foam agents to continue to be supplied until 4th July 2020 !

At the other end of the scale is the Policy and Regulations that apply in the Australian State of Queensland. The Queensland Department of Environment and Heritage Protection introduced its Management of Firefighting Foam Policy in July 2016, following nearly 3 years of investigations and consultations.

Within the Policy under section 6.2 Fluorinated firefighting foams the following regulations are stated

6.2.1 foams containing pfos

Use of foams that contain the fluorinated organic compound PFOS as well as its salts or any compound that degrades or converts to PFOS at a concentration greater than that listed in Table 6.2.2 A in a foam concentrate must no longer be used and must be withdrawn from service as soon as possible, including legacy stock.

6.2.2 foams containing pfoa & pfoa precursors to be withdrawn

Firefighting foams that contain PFOA, PFOA precursor compounds or their higher homologues, where the total organic fluorine content equivalent to PFOA and higher homologues exceeds that listed in Table 6.2.2 A in foam concentrate must be withdrawn from service as soon as practicable and any held stocks (and other related wastes) must be secured pending disposal. These materials are to be managed and disposed of as regulated waste.

Table 6.2.2 A – Fluorinated organic compounds limits in concentrations

6.2.4 foams containing short-chain fluorotelomers

Foams containing short-chain fluorotelomers (C6 or shorter perfluorinated moieties) can be used if it is found to be the only viable option, after firefighting effectiveness, health and safety risks, environmental protection and property protection characteristics have all been appropriately considered, however, the following requirements must be met:

• The foam must be C6 purity compliant foam

• No releases directly to the environment (e.g. to unsealed ground, soakage pits, waterways or uncontrolled drains)

• All releases must be fully contained on site

• Containment measures such as bunds and ponds must be controlled, impervious and must not allow firewater, wastewater, runoff and other wastes to be released to the environment (e.g. to soils, groundwater, waterways,
stormwater etc.)

• All firewater, wastewater, runoff and other wastes must be disposed of as regulated waste to a facility authorised to accept such wastes.

Whilst the Queensland position on the older long-chain (PFAS) foams is one which is very different to the EU position, what is also worth highlighting is their position on the new formulations with short-chain fluorosurfactants. Manufacturers of these fluorosurfactants and firefighting foam manufacturers have all devoted many years and much expense developing these new short-chain foam agents. Yet within the extensive Explanatory Notes that Queensland DEHP has published to accompany the Policy Document they detail their precautionary principle towards the foams containing short-chain fluorotelomers and reference a number of scientific studies. From their evaluation of all the information (and within the explanatory notes they reference over 100 papers / studies etc.) they concluded that “If new generation shorter-chain C6-based fluorinated foam products are to be used there needs to be careful control of in terms of purity and management as the information on their properties and effects is very limited with significant indications that the per- and poly-fluorinated compounds with various functional groups (as well as fluoropolymers) share properties and effects with the fluorinated organic compounds already of serious concern.”

The future is fluorine free?

Accepting that fluorine free foam agents do, in common with all firefighting foam agents, have short-term adverse environmental impacts, the fact is that these foam agents do not contain the persistent toxic (PFASs) compounds that are causing concern and driving environmental regulations to be devised for the control and restriction in production and use of these chemicals. It is quite conceivable that a fluorine free foam agent could have long-term adverse environmental impact from the inclusion of other persistent compounds or persistent breakdown products which maybe toxic, and proper assessment is required.

Many of the leading manufacturers of PFAS based foam agents are now also offering fluorine free foam agents. In much the same ways as there are better performing AFFF’s the same is true for FFF. As stated earlier there are FFF products on the market today that have fire performance with ratings that are the same as good AFFF’s under the same test conditions. There are issues with FFF however, not least the fact that most are non-Newtonian liquids with high viscosities. Accordingly changing a system that was using an AFFF to a FFF is not necessarily a “drop-in” replacement. The proportioning devices and transfer systems from the foam concentrate storage to the proportioner will need to be evaluated, and may need to be changed.

Manufacturers in testing the FFF agents are well aware of the importance of good bubble structure in relation to the fire performance of a FFF. Emergency responders from the POG and Chemical sector have expressed reservations on how a FFF agent would perform when discharged through high volume monitors with non-aspirated nozzles. It is argued that the small-scale fire tests that are used to provide foam agents with performance ratings do not replicate, even in a scaled version, the conditions faced with a full surface hydrocarbon fuel tank fire for example. I am aware that the LASTFIRE Group is currently running some larger scale fire tests with a representative number of FFF foams and at least one C6 foam. Hopefully when this testing is completed we may have a better idea about how those tested FFF perform with direct application and low expansion ratios. Noting additionally that one of the stated objectives of this series of fire performance tests is also to revalidate the LASTFIRE test protocol to determine if it is still relevant for these new formulations (whether C6 or FFF)

Opportunities for new technologies

The changes in environmental legislation have already led to changes in the formulation of foam agents, and through testing we may find that we have to update our plans in terms of minimum rates of application, delivery devices etc. The need for containment, treatment and possible disposal as regulated waste add to the overall position that we need where we need to use firefighting foam to minimise the quantities used.

Whilst driving performance of the foam agent itself this should also lead to looking at new technologies. An example of this is CAF (compressed air foam). Here the foam solution is mixed under controlled conditions with nitrogen or compressed air to create the finished foam. Although not a new idea there are now two manufacturers who have FM approval on their CAF systems and the rates of application approved by FM for use are more than 50% less than for a normally aspirated foam system. There are limitations for the use of CAF but still an example of a technology that could significantly reduce the potential environmental impact without impacting the firefighting capabilities of the system or the foam agent used!

Final thoughts

If you were purchasing an AFFF in 1999 there is a good chance that you would have purchased a PFOS based product from 3M with the expectation that this foam agent would still be available for use today. If you are specifying or purchasing firefighting foam agent today there are a number of factors that need to be assessed beyond the firefighting performance, and perhaps these legislation driven changes are allowing the industry to take a step towards developing a total life (cradle to grave) approach to their firefighting foam usage.

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