Small hose connections supply pipe size

[coarts]

When small 1 1/2 hose connections are provided in storage occupancies, nfpa 13 states in 8.17.5 {2007} that pipe size shall comply with sizes given ie. 1 1/2 to 1 1/4 to 1" down. etc. However in 12.8 the code says that you must allow 50 gpm at most remote and up to 100 gpm multiple. Does this mean we need to hydraulically calculate the pipe size all the way to the valves themselves with this gpm and over rules the 1 1/2 sizing? These hose valves are a separate system of piping which goes back to the header and has a special prv and control valve. It runs over 1000 ft. to the most remote valve. Can't we just run 1 1/2 max. and call it a day. Thanks.

 

[TravisMack]

When I have a separate hose system for these as you describe, I just add the 100 gpm hose allowance at the base of riser for this. I believe that section 12.8 is forcing the issue that you need to include up to 100 gpm inside hose allowance when you have interior hose stations.

Sometimes, these are fed from adjacent systems. When I do this, I just plug in the 50 - 100 gpm where the hose station supply comes off the sprinkler system.

I don't believe you are required to calculate the piping in the small hose station system. There is not a minimum pressure req'd by NFPA 13 for these stations. For piping going that far, I may throw a quick calc on it to make sure I can get water out of the last hose valve while flowing the minimum 50-100 gpm. I would hate to have a situation where you can't even get the minimum flow to the valves at any pressure.

This has been a practice that has been accepted by all of the AHJs, 3rd party review firms and insurance reviewers that I have had review plans.

I hope this helps.

Travis Mack
MFP Design, LLC

 

[SprinklerDesigner2]

I agree with Travis.

Coming off an adjacent system I usually run 1 1/2" pipe for everything. I can spread hangers out, run everything thinwall except for the drop where all I need is a 1 1/2" threaded elbow at the bottom.

If a separate feed I'll run the common hose main 2" coming off with 1 1/2" for each individual hose stations.

In Georgia they don't like hose stations for occupant use. The fire department will not use them and I think we can agree in the event of a fire in a warehouse full of plastic people should leave the fire to the overhead sprinkler and professionals evacuating the building immediately. In Georgia if you insist on hose racks then all employees must receive certified training in their use. I haven't purchased a hose rack in years and years.