My experience is all in mining and foundries where hydraulics are a necessary evil. Ultimately if you want to avoid the problem completely go with a water hydraulic system.such as OEM. That’s what tire plants do on their curing presses because the machine has to be hot to begin with. A step down is to use an emulsified vegetable oil in standard equipment. It does not sustain a flame. The alternative is a phosphate ester like Fyrquel. This sort of works. The ignition temperature is much higher but once it does ignite it burns extremely fast. It looks like black powder in a cartoon. It is also very toxic.
But by far the biggest thing you can do is maintenance. I see basically two practices. In some shops they wear nitrile gloves, liberal amounts of degreaser inside and out, and treat maintenance like surgery. Any spot where oil leaks out also means dirt is getting in. The gaps internally are mils at most so a grain of sand might as well be a boulder. Moisture corrodes then erodes all the machines surfaces. And the only way to catch it on fire is to light up a hose. The other version uses catch basins and oil dry “berms” to contain the mess. I’ve seen operators make a “dirt funnel” to add oil which to them is just like adding fuel, a routine thing. Reliability is a joke. In that condition I have seen a single spark burn up two systems in 60 seconds.
Realistically the only fire suppression systems that stand a snowballs chance are foam deluge systems and intergen gas systems and even then I’m dubious. I mean they go up in seconds. You can’t realistically expect to do anything. Your pump shuts off when fire engulfs the motor and destroys it and the wiring.
This is not fear mongering. This is experience based on actual plant videos and the work Factory Mutual has done on pool fires and similar cases. Trust me foundries are really good at catching anything on fire. It’s like working in a plant filled with a bunch of pyromaniacs. There is nothing you can realistically do to suppress or minimize hydraulic fires with standard hydraulic fluid. So first you practice isolating the units from each other with 2 hour fire walls, containment dikes, and from everything else that can be a source. Alternatively you switch to something other than conventional hydraulic fluid if you can’t minimize the risk due to the process. Anything else is a feel good bandaid. Sprinklers are a terrible idea. What happens if you dump water on oil? It floats and goes everywhere. But that’s what NFPA pushes as a solution to all situations. And no matter the fire/smoke detector that’s just an alarm to get people away/towards it. I’m dubious at best on fire suppression because I’ve seen how fast these things burn and what the fire systems do. If you can’t put it out in a couple seconds don’t bother. Hence foam deluge, dumping multiple bottles of Intergen, that’s about the only way to stop it.
