09 Feb Is your fixed foam system affected?
Foam-based fire protection systems provide an important role in the protection of life, property and business continuity for facilities manufacturing and using Class B ignitable liquids. The risks posed would not normally be managed by water alone and the scalable nature of a foam system makes it simpler and more cost-effective than alternative methods of protection. However, as chemical analysis methods have improved over the past 20 years, it has become apparent reflects Simon Barratt, Foam Product Manager, Viking, that some of the ingredients used in fluorinated AFFF-based foam concentrates can have a harmful and persistent effect on the environment and human life.
Legislation to restrict and ban the use of fluorinated surfactants is increasing globally and Europe already has legislation that affects fixed foam systems. There is a lot of chemistry behind this topic but to keep things simple we shall refer to these chemicals as PFAS (Perfluoroalkyl and Polyfluoroalkyl Substances). These manufactured chemicals are used in many industries to improve the strength, resistance and performance of products such as non-stick pans, stain resistant furniture or fire resistant clothing. In firefighting foam, PFAS is used to increase the speed of foam coverage and make the bubble structure more resistant to fire and heat. This is important for fast extinguishment but also to maintain post fire stability to prevent re-ignition.
PFOS (Perfluorooctanesulfonic acid) and PFOA (Perfluorooctanoic acid) were commonly used in past foam concentrate formulations and are sub chemicals belonging to this common group of PFAS’s. The use of PFOS has been prohibited in Europe since 2011 and now pending legislation will restrict the use of PFOA, which will have a direct impact on many fixed foam based fire protection systems. PFOA was regulated by ECHA (European Chemicals Agency) in 2020 which first restricted its use for training and risk types but from 1st January 2023, its cannot be used in firefighting foam unless system discharges can be contained. In this case, the end user has until 4th July 2025 before the PFOA based foam concentrate needs to be removed from service. Most foam concentrate manufacturers had stopped using PFOA in their formulations by 2016 so effectively any foam system installed before this time will probably need some form of remediation work to remove and dispose of the firefighting foam. Shorter chain PFAS chemicals were increasingly used from around 2012 (commonly referred to as C6) but they too are under additional pending restrictions, which will have an effect on all PFAS based firefighting foam systems in the next 5-7 years.
At this time, a way to avoid future legislative restrictions and future remediation cost is to use an SFFF (Synthetic Fluorine Free Foam) based foam system. There is no doubt that the trend towards the use of SFFF in fixed fire protection systems is gathering pace. These foams are manufactured without any intentionally added PFAS chemicals whilst still providing good levels of fire performance. However, achieving suitable performance using the same parameters as in the past can be challenging and it means that SFFF’s are often not a drop-in replacements. An example of this is with non-aspirated foam enhanced sprinklers which are commonly used for the protection of ignitable liquids in storage or when used in production processes for example.
Non-aspirated foam sprinklers
Fire protection sprinklers and sprinkler nozzles are a simple but effective form of active fire protection used in many different applications globally. They are deployed in closed head systems with a fusible element or as sprinkler nozzles in open deluge systems with the fusible element removed. These conventional fire sprinklers are not designed with foam use in mind. They are designed to efficiently distribute water in the desired manner depending on the object or risk they are protecting. They are also small, discreet and, due to the high volume used throughout the world, have a sensitive, almost commodity-based price point. Despite this, used with the correct combination of system components and foam concentrate, they can perform very well as foam-enhanced sprinkler systems.
A conventional fire sprinkler is considered a non-aspirated foam discharge device and typically gives a low expansion ratio of no more than 4:1, with fast drainage times. It is therefore important to select a foam concentrate that has been developed and then independently tested by a third party specifically for use with sprinklers. Factory Mutual (FM) and Underwriters Laboratories (UL) are considered the most relevant and challenging authorities when it comes to fixed foam system product testing. Their respective foam test standards, FM5130 FM5130 non-aspirated sprinkler fire test and UL162 include material testing, fire performance testing and follow-up manufacturing audits, which gives a higher level of consumer confidence compared to other standards commonly referenced, such as EN13565-1. Both these organisations recognise that conventional non-aspirated sprinklers are different in foam performance to other discharge devices and therefore, the traditional foam quality approach is not applicable. Instead, each sprinkler type is tested under prescribed conditions with variables such as foam concentrate type, K-Factor, application density, fuel type and installation height.
Use and availability of fixed foam systems
A fixed foam system is about its constituent components working together in a holistic way across a range of parameters such as temperature, density and discharge pressure – whilst delivering suitable fire performance. The availability of SFFF based FM or UL approved systems at the time of writing remains relatively low with only four original manufacturers offering product lines capable of providing certificated solutions. Further, only one company is offering a range of non-aspirated sprinklers tested at different heights and K factors with both hydrocarbon and polar solvent ignitable liquids. This now enables a close overlap to the situation found with fluorinated foams. This has enabled end users to start their transitioning work as an FM or UL approval is often mandatory to their AHJ’s (Authority Having Jurisdiction) and required according to NFPA design codes.
Application design standards such as NFPA11, NFPA30 or FMDS 7-29 require the use of Approved / Listed foam concentrates that have been tested on the subject fuels with the intended sprinkler manufacturer and type. This can limit choice because such testing is difficult and expensive but the user does at least have the assurance of proven fire performance.
Use of FM (Approved) or UL (Listed) foam concentrates tested with sprinklers is a sound approach to fire performance. Manufacturers using the freedom allowed under EN13565-2:2018 to justify the use of foams with non-aspirated sprinklers based on foam quality alone are not considering the full picture. This is because it is very difficult to take accurate and consistent foam qualities as non-aspirated sprinklers produce a low expansion and a very fast drain time, which is difficult to measure. In a look to the future, both these test standards are referenced in the draft revision to the European sprinkler system design standard, EN 12845-1 and a clause in the (foam) supplies section states that ‘Where fluorine free foam concentrate is to be used, automatic sprinklers and aspiration devices shall be tested in combination with the specific foam solution to protect the risk. UL 162 or FM 5130 can be used as procedures to prove the system performance.’ This is a positive move towards more robust foam system installations in Europe and gives decision makers clearer guidance on suitable product to use.
Transitioning of existing systems to SFFF
End users wanting to be compliant with the new regulations regarding the use of PFAS in firefighting foam will need to transition their systems to SFFF in the coming years. As previously mentioned, there are no drop in solutions when changing foam but some situations will be easier and cheaper than others. Proportioning equipment will normally need changing which would include a review of the storage tank and foam concentrate pipework. Then the discharge devices will need to be reviewed to check if the current densities, flows and pressures will work with the new foam. As the market moves more towards having robust certification such as FM and UL, this means that the selected concentrate should have test and accreditation data. If the existing hardware is already tested with the new SFFF foam then the transition exercise will be much easier than if none of the hardware matches the concentrate. In extreme cases, a complete new set of system components might be required. Transitioning from a fluorinated to non-fluorinated foam system is different from project to project so it is important to work with manufacturers and suppliers that can give design and product selection guidance based up tested solutions and product compatibility. For many end users, these PFAS restrictions are now looming ominously close.