Going Fluorine Free
The transition to fluorine free foams is currently not very easy. It would be totally irresponsible to suggest otherwise.
The diligent engineer will be concerned that there is very little actual test data on which to base foam system designs for F3 foams. For reasons explained here. it is very risky to extrapolate from our experience with AFFF’s, FFPF’s and fluoroprotein foams. We will lose a lot in the transition, not the least of which is 50 years of experience with fluorine containing foams. Test data, not experience, is needed to make the transition in a properly engineered manner.
Test data is the basis for design rules incorporated in the various design standards used for foam systems, such as AS 1940, NFPA 11 and NFPA 406. Currently these standards have no fluorine free options. There are good reasons for this…. there is no test data available to prove fluorine free technology for various specific applications. When test data is available the technical committees evaluate it and determine the design application rates that should be used. Until his step is taken there are very few applications that are suitable for fluorine free foams. Fire protection engineers should understand their liability risks if they design or certify foam system using fluorine free foams in the absence of design standards.
Some F3 applications can be transitioned from fluorinated foams relatively easily, some can require minimal changes to the existing systems, but a careful analysis is needed to determine what needs to change and whether an F3 foam is suitable for the application.
Relatively straight forward applications include:-
- Some F3 foams are quite capable of being used through existing foam sprinkler systems, but only when there is specific test data for that product.
- Polar solvent risks, these always required gentle application and do not rely on the aqueous film so transition is possible, but using aspirated foam only. See here…
- Application rates for various polar solvents are determined from small scale fire testing, so this application is possible now, though some large scale test data would be comforting.
- Airport and municipal fire fighting. F3 foams now have considerable history in this area and for smaller fires they have proven adequate. Some products have ICAO B certification.
In the case of Queensland, Australia, foam system owners are being forced to transition well ahead of the availability of the required F3 technologies and test data. This puts fire protection engineers in a very difficult position. Despite the legislative requirements, we are not released from our engineering obligations and as suppliers we are not released from the legal requirement to supply products and systems that are fit for purpose and to comply with the relevant standards. It is the immediate purpose for these web pages to collect available data and provide guidance for people who need to make the transition.
Some other considerations for the change to F3 foams that need to be considered are:-
- Cleaning fluorinated product from existing systems. This may be difficult in some cases. The 3M products had very high levels of perfluorinated C8 surfactants, simple cleaning will probably not remove enough residue to comply with the new legislation. Replacing your AFFF with F3 foam without effective cleaning will result in extra costs next time your foam is tested. Reservoirs of foam concentrate in crevices in pumps, valves and pipe joints will probably be enough to contaminate your new foam. Some tank materials, (GRP & polyethylene, & possibly steel) probably can’t be cleaned adequately. Bladder tanks will need new bladders. With non 3M products this may be less of an issue. Testing should be done to determine the level of C8 surfactants in the products before deciding on a change out strategy.
- F3 foams are often high viscosity products (pseudoplastic). Their flow characteristics will all be different and if replacing AFFF they will be very different. Proper engineering is required. A number F3 foams have a viscosity higher than any other high viscosity foam (by a factor of nearly 5) and almost certainly will need some system changes to work properly. Care is required and the foam concentrate suppliers should provide either shear rate Vv viscosity data or friction loss charts. See more information here..
- Some systems may need converting from non-aspirated nozzles to aspirated nozzles (hangars, helipads & jetties). See more information here..
- The design application rates for F3 foams will not necessarily be the same as for the fluorinated products they are replacing. If some F3 products can be used for tank fires, for monitor applications or in non aspirated applications, as examples, the application rates may need to be considerably higher. The foam system designer needs to be given clear guidance by the foam concentrate supplier on the design application rate for the application, if this is not provided it is the system designer who is taking full responsibility for the fitness for purpose of the foam concentrate. This data is normally available in the design standards such as NFPA 11, NFPA 406 and AS 1940, however, no F3 foam is allowed by these standards at this time.
Orion has the experience and knowledge to assist with all of these issues.