Fighting pressure fires
History shows from time to time incidents happen in tank farms, plants and refineries. Each fire teaches people to improve systems and create new standards and processes.
No fire is like any other, so fire fighting equipment needs to be specialised. One example of the particular risk in the oil and chemical industry is a 3D or jet fire. This occurs when burning liquid is under pressure. These 3D fires can be caused by an external explosion, radiant heat or mechanical damage at tanks, pipelines or piperacks. Pressure fires can be found at bottom flanges of tanks, valves, pump stations, pipelines racks, ships, vents and broken or burned seals. Weak valves can brake or a ignited spill can burn some pipe sealings away.
When the sealing at the bottom flange or the pipe to that flange is destroyed, there is no possibility of stopping the fuel escaping from the tank. This causes a significant amount of pollution and can trigger other fires.
The right agent to attack the 3D fires is dry chemicals, but these are difficult to apply. In nearly all incidents the area surrounding a pressure fire is filled with burning fuel which can be extinguished with foam. But for safety reasons fire fighters are not allowed into this area.
Texas-based Williams Fire & Hazard Control has developed a new technology which can apply dry chemicals from the same distance as standard dry chemical technology, but with a lesser application rate.
Williams combines a tunnel shaped water foam stream with the dry chemical agent, which is placed in the centre of the tunnel.
