Okay Engine Experts, Can we talk?
I've been doing research for the last several years about High-Fire operations for smaller departments like mine (That's a relative term mind you, we have about 220 on duty each day. I mean small compared to FDNY, HFD, CFD and the other bohemeths)
I noticed while I was doing my research that Storz couplings started showing up on our FDC's (Fire Department Connections i.e. Standpipe connections) on buildings of all heights. We currently carry 4" line with Storz couplings for supply line. Our code division thought it would be helpful and make for a simpler connection. Nice thought on their part but I realized a problem. Stamped on the hose was "NFPA 1963 Supply Line."
You may say at this point, "so what?"
Well that configuration of hose and coupling (LDH hose with Storz couplings) is only to be operated at 180 psi and tested at 200 psi. Still saying so what? Let me continue.
Several of our buildings are tall enough to require pressures greater then 200 psi to supply the heighest pressure needed and some over 300 psi. Do you know see my concern?
At first I was being told that it was because we bought cheap hose, which very well could have been the case but then I ran into the "hose" guy. He told me the weakness stemmed from the Storz couplings and not necessarily the hose. I was intriqued! He went on to explain to me that the locking ears on the coupling are the weak link in chain. This made sense to me because of my background in rope rescue. Yes, I said rope rescue, just follow me.
Anyone who has sat through many rope classes has been told that if an aluminum caribiner is dropped from a significant height, the caribiner may have developed micro-cracks and may be unsafe to use. So with that information lets look back to our aluminum Strorz couplings that get "dropped" out of hose beds over the years and who has ever heard the clanging of a Storz being drug up the street when the hose is being loaded?
When hose and couplings are new they are tested to a certain pressure before it passes and gets the NFPA stamp. These pressures are much greater then the normal use pressure the hose and couplings will operate at in the field to allow for the abuse the hose and couplings will take over the years. This margin of "abuse" keeps us from blowing hoses as frequently. Now, with that being said, how many of us have experienced hose failures at the normal operating and test pressures?
My point to writing all of that is to emphasis to the reader that we should not pressure hose higher then the recommended levels.
So let me finally get to the discussion points:
Do you have Storz FDC's on buildings that could require pressures higher then 180 psi?
If you do, have you researched the problem I have posed here? If so, what did you find out?