At work the city requires fire extinguishers and occupant-use fire hoses to be tested and recertified, or replaced every 5 years. Recertifying is only a little bit cheaper than replacing a fire hose, so they get tossed.
I asked the fire tech if I could have the 2 hoses he was going to discard that day from our shop and he said yes.
Occupant fire hoses are 1 1/2" diameter and sit folded on a hanger ready to pull and go in the event there is a fire in the building and someone is brave/stupid enough to try and be a hero. The tech said many cities were removing the requirement for fire hoses as few people were likely to use them even if they had the need.
When I was in college many decades ago, there was a room fire and me and another resident attempted to gain access to the fire hose on that floor before realizing we would die from smoke inhalation before we could even get the hose out. Eventually the professionals showed up and took care of business.
The threads on a fire hose are NST, like machine screws, and like a common garden, fire hoses have a flat rubber gasket to seal against the supply fitting. Potable water supply lines have NPT. Pipe threads jam fit to lock and seal. Standard threads are made to be removable. So there is an adapter to mate the supply NPT to the hose NST.
That adapter is sold on eBay for $20 and a polycarbonate fog nozzle for $17. I installed a tee in the output pipe on my canal pump and screwed the NPT to NST adapter into the tee, then attached the fire hose and added the nozzle.
Step 1: Lots of Water
A fire hose nozzle does not completely shut off, so as to protect the pump on the fire truck and the hose itself from the internal pressure needed to operate the hose properly. Fire hoses kink easily, they are not made to be bent a lot when in use. They also require a fair amount of pressure to fill properly. My pump already had two manual gate valves to select the zone to water. I turned both gate valves off to direct all the water to the fire hose.
Twisting the nozzle selects between fog and stream.
The flow in a hose grows with the square of the diameter, so a 1 1/2" fire hose will pass 9 times as much water as a 1/2" garden hose. 1.5 squared/0.5 squared = 2.25/0.25