Corrosivity of long-term fire retardant Fire Trol® 931 and Fire Foam® 103 on aluminium alloys and steel

Fire retardants and foams are rapidly gaining acceptance as effective and efficient tools by fire management agencies. There is a lack of study about the corrosive effect of fire retardants despite they might produce a corrosion phenomena on various equipments during extinction operations and storage. Moreover, some aluminium components present a blue layer on the surface after use of some of the fire retardants which alarmed the fire operators. The aim of this paper is to evaluate the corrosion behaviour of aluminium and steel alloys in contact with Fire Trol® 931 and Fire Foam® 103 using electrochemical measures. Complementary results about morphology are obtained with microscopy before and after corrosion tests. Structure and composition of the corrosion products on the electrode surface are also analysed. In these solutions the corrosion rate of aluminium is low, whereas steel alloy shows a moderate corrosion. The anodic reaction of corrosion phenomenon favours the deposit of a Prussian blue layer on the metallic samples surface. This layer reduces the corrosion phenomenon on both aluminium and steel alloys.