There is a standard fire coupling thread and it doesn't match anything plumbing related.
Fire hose connections vary from town to town because so many systems were installed 100years ago before the standard was written in the 60's. Around here, fire departments carry couplers for their own town and several adapters in case they get called to assist somewhere else.
A local fire sprinkler service company will know the answer for your area.





Reply With Quote

Bookmarks