Is a pressure switch, mounted at the compressor, that starts and stops the air compressor at pre-designated low and high pressures considered an "air maintenance device", in compliance with NFPA 13 (2013) 18.104.22.168.1?
More than likley not, unless listed for fire sprinkler system use.
The air maintenance device is supposed to be listed for sprinkler systems.
The problem with utilizing pressure switches only is that you have no control over the air volume that is being piped into the system. If the air volume is too high, the compressor may overcome a single sprinkler fusing and cause the sprinkler system to not function properly.
The air maintenance device uses pressure switches to start/stop the compressor but also regulates the air volume.
I would use the AMD...
This set up is on an old system - we are replacing the compressor and plan to put in an AMD with the new compressor. I'm trying to determine why it was done the way it was in 1989, and if it was code compliant at that time. Seems NFPA 13 had language saying that any device used for automatic maintenance of air pressure shall be of a type specifically approved for such service and capable of maintaining the required air pressure... The pressure switch is listed and apparently came with the compressor.
Any idea of the history of the requirements?
I have the 1994 NFPA 13
And it required a "listed" air maintenance device.
A few things, is this building in a city that does inspections??
If so, may have been accepted set up for that ahj, but may have not been to NFPA 13 standard.
I think we've got it figured out. Thanks for all the information.
Dry valves back in the 80's required higher pressures to keep the clappers shut...the AMD wasn't really needed...today's valves require much less pressure/air volume do to the clapper's differential port design..
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