Technical Resources Area
Technical Resources Area |
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The aqueous foaming agent AFFF is by its nature a surfactant. Surfactants can cause some polyolefin systems to stress crack. Plascoat PPA 665 was developed to withstand the environmental stress cracking caused by surfactants. PPA 665 and its variants have been used in fire extinguisher systems since 1987 with no lining failures.
a) ASTM D1693 (Bell Test)
The test pieces are bent over onto themselves and immersed in a 50% solution of a detergent at 50șC until 50% of the samples have cracked. PPA 665 passed more than 1000 hrs on this test whilst other standard polyolefins failed at 24 hrs.
b) AFFF Resistance
Test plates coated in PPA 665 were immersed in a 50% solution of AFFF at 50șC. After 12 weeks the coating was still in good order. In contrast, on the same test epoxy-polyester powder failed (cracked) after one week and epoxy coatings after only 3 weeks.
c) Plascoat PPA 665 has passed all the test methods outlined in EN3, the European Norm for fire extinguishers. These tests include a cycling test in AFFF.
From these accelerated tests and from long-term practical experience it can be estimated that Plascoat PPA 665 will resist a 10% solution of AFFF for a minimum of 10 to 15 years.
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Plascoat Systems Ltd. Trading Estate, Farnham, Surrey GU9 9NY, UK Tel: +44 (0) 1252 733777, Fax: +44 (0) 1252 721250 email: sales@plascoat.com |
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