CDA
Check out FM data sheet 7-98 HYDRAULIC FLUIDS, see below for an overview of the hazard. We find this hazard on a daily bases at many types of occupancies even in low combustible loading machine shops and metal bending operations. As noted below the only way to control the spray oil fire hazard is to shut down the pump for the oil. If not the fire continues to burn, a 40' torch fire is something that gets other combustibles going. Since it is a three dimensional fire the sprinkler protection does little to control the fire. I do not think most building officials understand the hazard and the IBC does not address it.
2.1.1 Ignitable Liquid Hazard Scenario
Hydraulic fluids can create spray fires when accidentally released from the equipment or piping they are contained in. These fires tend to be intense and produce significant heat release rates. A hydraulic spray fire can easily ignite combustibles and severely damage steel building elements or metal equipment if the spray impinges on them. Depending on the flow rate and the size of the leak, sprays can extend up to 40 ft (12.2 m) from the release point. Pressurized sprays producing very small diameter droplets are easily ignited at temperatures well below the normal flash point of the hydraulic fluid. In these cases, the small droplets promote complete combustion of the release and a corresponding short spray distance.
Pressurized oil in hydraulic systems presents a considerable fire hazard, particularly in processes where ignition sources are constantly present, as in plastic forming, die casting, automatic welding and melting, and heat-treating of metal. Escaping hydraulic oil has caused many severe fires, particularly where building contents or construction were combustible, interlocks to automatically shut down pumping systems were not provided, or sprinkler protection was lacking.
When hydraulic oil is released under pressure, the usual result is an atomized spray or mist of oil droplets. The oil spray is ignited readily by hot surfaces, such as heated or molten metal, electric heaters, open flames, or welding arcs. The resulting fire usually is torch-like, with a very high rate of heat release. Spray fires cannot be extinguished by automatic sprinklers, so this high heat release fire will continue until the flow of liquid
is shut down.
