6.2 Failure in Warrington
This case study is based on an investigation carried out after catastrophic failure of a virtually new tank in Warrington, Cheshire. It had been installed at the premises of a small business manufacturing ‘dairy detergent’ (Paper 4). The latter is a dilute solution of caustic soda to which various other chemicals are added to aid the cleansing effect; one use is for flushing out dairy equipment on farms. The 40 per cent caustic soda was the basic raw material for the final product, and just four deliveries had been made to the factory when the failure occurred. Each delivery involved complete filling of the tank.
The failure fortunately occurred after the shift had left for the day, and was spotted by the production director, who was alone in the office above the factory floor. He heard a bang, followed by what sounded like rain, and when he looked out onto the factory floor, he saw a jet of fluid shooting across the open space (Figure 1, Paper 4). The protective wall around the tank completely failed to contain or constrict the fluid, which ran along the floor and into an adjacent unit that printed tachograph discs. Here the damage was extensive, because specialist printing equipment was attacked and wrecked. The local fire brigade were called on to contain the fluid, and prevent escape into the outer environment. Eventually, a specialist recovery company was hired to remove the fluid.