Email Enquiry
Request For Foam InfoInitial Email Enquiry – The installation described is quite a simple method of delivering foam. The foam concentrate is held in a storage tank, not pipework. The pipework is the method of distribution and is therefore a dry line when not in use. Corrosion is not a major concern in this instance providing the line is kept free and clean. As this installation is a jetty application, close to sea water, it would be wise to construct the delivery system in stainless steel ( normally 304 would be adequate for this type of application) If the line has been constructed in carbon steel the salt present in sea water will cause more corrosion in the medium term than the foam solution. The distribution lines will require periodic replacement, corrosion is inevitable. We can only guess that the storage tank is of stainless construction, if the tank is mild steel, it most definately needs to be lined to protect the carbon surface regardless of the foam type to be used. With regard to the foam product to be used for the fuel risk described, we would make the following comments:- Our recommendation in this instance would be AFFF-AR 3x3. This type of product has longevity as a natural consequence of it's formulation, upto 15 years would be expected. FILMOPOL 3 from Bio Ex, France, is a high performance foam concentrate approved to EN1568 part 3 and 4. It is not prone to detrimental effects of long term and wide ranging change in climatic temperatures. For this particular application the product should be rated as a 3% application on hydrocarbon and 3% for alcohol (polar solvents). This would be a wise recommendation given that the extinguishing process is delivered via a fixed system with little opportunity for intervention to the foam mix via the monitors or specific knowledge of the fuel type to be extinguished during the early stages of foam attack. This foam percentage will also provide an extention to the overall time for a foam application. Polymer drop-out is not a concern. Polymer drop-out only takes place when the foam concentrate has been blended into solution and is left standing. The results of this type of formulation separation can be seen taking place after three months but as I have mentioned, this will not take place in this particular application. This is more likely to be seen taling place in portable or hand held extinguishers where the alcohol resistant foam is held in solution. We would normally recommend FFF-AR. Fluoro-free foams such as ECOPOL from Bio
Ex, France. I would recommend that ECOPOL should be used when the installation requires periodic testing. This will ensure that there is no detrimetal environmental impact during servicing of the system. The installation operator should be aware that large volumes of perfluorinated foam solution discharged into the sea or river estuary could result in fish and other sea life being eliminated and at best will cause widespread contamination of sea stocks. FFFP-AR is not a product we would recommend for this particular application. Organic matter such as protein will not have a reasonable life span in the temperature conditions described. Regardless of what a manufacturer insists with their product, protein based foams are highly unlikely to be unchanged by these temperature changes beyond five years. Solids separation is an inevitable consequence of long term storage and directly impacts on the performance of the foam. This is often seen in warm climates in the form of milky coloured deposits at the bottom of storage tanks.
Author’s identities are concealed for privacy and security reasons. Further information on the information contained in this topic can be directed to the JOIFF secretariaty.
|
