Almost a disaster ..............................

[VernB]

I just spent 2 weeks moonlighting as a safety inspector at a nearby power plant during their annual maintenance shutdown. As the electrical expert on the team, I got to see plenty of dumb manouvers, but one in particular sticks in my mind.

One of my colleagues shut down an air compressor that was pumping CO into the plant because of the way it was positioned. Nobody he could contact right upto the control room level had any clue that this compressor was supplying air to the dry sprinkler system. As soon as the pressure leaked off, the system fired, dousing among other things, the plant's "hi yard" 13.5KV to 35KV transformers and equipment, not 15 minutes after technicians had finished working on it. They were so lucky the hi yard was dead during the maintenance, but I shudder to think about what the result would have been if it had been live.

A week later, we nearly had a misfire of the dry system in the old mill due to the disconnection of the air compressor.

I never thought about the accidental firing of sprinklers in proximity to electrical work as a hazard, but after seeing this happen twice in a row, I know I'll be paying attention to it just as much as arc flash or shock.

Vern

 

[realolman]

....One of my colleagues shut down an air compressor that was pumping CO into the plant because of the way it was positioned. Nobody he could contact right upto the control room level had any clue that this compressor was supplying air to the dry sprinkler system. As soon as the pressure leaked off, the system fired,....

Vern

I don't understand. Why would an air compressor have to run, pumping CO, to keep a sprinkler system from sprinkling... A blown fuse sets off the sprinklers?

 

[stickboy1375]

Its a dry system, I've never seen one use CO, just plain air usually...

 

[don_resqcapt19]

I don't understand. In a dry system the air pressure is provided by a source and held in the sprinker piping system by the sprinker heads. The dry valve has a larger surface area on the dry side than on the wet side so that less air pressure is needed to keep the water from flowing. Even when the air is lost there should be no release of water on a dry system...you have to open a head to get the water to flow. I know that there are dulgue systems where all of the heads are normally open and they all flow water when something tiggers the system, but I don't know how you make that work with a dry valve, unless they are using some air powered detection system.
Don

 

[iwire]

I agree with Don, you might flood the dry systems piping with with some water but you won't have water spraying out of sprinkler heads unless one is broken.

 

[pfalcon]

Vern should clarify but I believe he is saying the exhaust from the compressor was pumping CO. Not the compressed air using CO.

 

[Sarge7]

dry sprinkler system

dry sprinkler system

You are correct in regards to a dry sprinkler system should not have sprayed water unless the heads are broken or set off. The system would have never held air if a head was busted or its fusible link was broken. It would have been active untill teh water is shut down. At that point the system would have had to be drained and repaired befor it could be pressured up.

The type of system that was present was a deluge system. In this sytem all the heads are open and when water is released it sprays water through all the heads. The air compressor was used to maintain the air pressure in the air piping that runs along the deluge piping that has heads on it that have a fuseible link. When the link melts then the air is lost and the deluge system pays off.

In order for the system pay off when they shut the air compressor down they have an air leak in the system that should be fixed to prevent the lost of air in the event of a power failure.

 

[realolman]

What is the advantage of that over a water pressurized system with glass links that break with heat and just spray where the heat is?

 

[LawnGuyLandSparky]

Sometimes a water pressurized system is inappropriate in freezing temperatures.

 

[FNCnca]

We use the dry system because of freezing temps. I know of no other advantage to it.

 

[realolman]

Sometimes a water pressurized system is inappropriate in freezing temperatures.

OOOKaaaay... never thought of that. thanks