Here's the last in my series of industrial photos in black and white from a closed down and abandoned car manufacturing plant.
Interestingly, the fire repression system is still live which I think is a government regulation. This pressure gauge is on one of the massive water pipes that feeds the sprinkler system in one of the plant buildings. A drop in pressure means water is leaking (in a fire it's intentionally spraying out) and that's what triggers the fire department to attend. In one of my other posts you can see the rest of this part of the fire system.
