Relay control

[Darkwood]

Think we lost the OP here ... maybe he's realised the safety implications of adapting a fire suppression system and the responsibility that it comes with this but always nice to have our advice acknowledged or not in this case

 

[Knobhead]

I just hope he’s realised just how dangerous their system of work is.

 

[Robotstar5]

The systems I’ve worked on the diesel pumps would have fired up at this point.

I think they covered all the bases when they built the "new" Metro plant at Longbridge in the late 70's. The sprinkler system was run by 2 electric pumps (main & standby) which kicked in when a pressure drop was detected, if the power went out a diesel pump took over but if all failed there were 2 big "header" tanks on a hill next to the building that would gravity feed the system!

 

[Knobhead]

Don’t worry, we had plenty of water to spare. Our own canal and two feeder reservoirs. Plus a 300,000 gallon header tank in the roof of the main shop. The main shop was 120' high.
Believe it or not, you need a lot of water to make iron. Loss of water could result in a major explosion.

One of the tricky jobs I got lumbered with was emptying and refilling the header tank. Three times in one shutdown! The water is treated so you can’t just dump it back in the canal.
You try loosing 900,000 gallons of water. 600,000 gallons went in various settling ponds and clarifiers, 300,000 gallons of untreated water disappeared mysteriously over several nights.

Anyone who thinks being a “maintenance electrician” has anything to do with that weird electrictrickery stuff is deluded.

I loved every moment of it, no two days were the same. If I could I’d be back in the fray tomorrow.

 

[davesparks]

I think they covered all the bases when they built the "new" Metro plant at Longbridge in the late 70's. The sprinkler system was run by 2 electric pumps (main & standby) which kicked in when a pressure drop was detected, if the power went out a diesel pump took over but if all failed there were 2 big "header" tanks on a hill next to the building that would gravity feed the system!

Would it not have made sense to start with the gravity system? What with gravity being the least likely power source to fail

 

[Robotstar5]

Would it not have made sense to start with the gravity system? What with gravity being the least likely power source to fail

The gravity system was designed to run the sprinklers long enough for the building to be evacuated so only a few minutes after which a fire would damage property/plant. The sequence of pumps was designed to keep the sprinklers going as long as possible.

In the early days, contractors would use the fire hoses as coolant on the concrete core drilling machines but the system pressure drop would be detected in the fire station and a fire engine (internal) would turn up, they soon got fed up and contractors were banned from using the hoses.