Include Hose Connections at Stage in Hydr. Calcs?

8/13/2020

We are working on a new addition to an existing high school. Part of the addition is a new auditorium with a full stage. The stage will be the highest hazard and our calculation area, Ordinary 2. The stage will also have (2) 1-1/2" hose stations with fog nozzles, one on each end, north and south, to protect the stage. They will be supplied from the same fire sprinkler system protecting the stage.

Do we need to include the hose station(s) discharge in the hydraulic calculations?

If so, what would be the flow criteria from those hose connections, and is that separate from the outside hose allowance or part of it?

Thanks all for your input.

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6 Comments

8/13/2020 11:34:35 am

This is a timely question for me, as I am dealing with a lot of these lately, so I’m really looking forward to additional input or corrections. There are a couple “it depends” factors including which code the requirement is derived from. IBC 905.3.4 requires stages greater than 1,000 sg. ft. to be equipped with a Class III wet standpipe system with 1-1/2” and 2-1/2” hose connections on each side of the stage. However the exception below it allows a 1-1/2” connection per NFPA #13 (can someone confirm if this implying ONLY one is required?), or in accordance with NFPA #14 for Class II or III standpipes. (The Standpipe chapter of NFPA #101 has similar language.) I believe it would be an added inside hose stream standpipe allowance, OR, if using the NFPA #13 option (which is more likely), it would be 50 gpm for each of the two hose stations flowing at the available supply pressure. I assume added to the applicable sprinkler demand, but perhaps someone can confirm this. I have had the local AHJ on specific projects modify these requirements, such as not wanting a valve with reducing cap, but no hose. Over the years there have been NFSA informal interpretations related to the topic. I am guessing these are in the new MeyerFire NFSA EOD book.

8/13/2020 11:58:48 am

Regarding my observation above under the exception that hose stations per NFPA #13 may be utilized in a sprinklered building, and whether or not it is implying only ONE hose station is required - Per the 905.3.4 commentary in the IFC (2015):
"The exception recognizes the benefit of the building
or area being sprinklered. If so, then only a single
1-1/2 inch (38 mm) connection is required. This hose
connection is intended to be used by the fire department
and apply less water from the hose due to the
suppression activity of the sprinkler system."

Jonathan Joseph

8/13/2020 11:45:36 am

NFPA 14 2016 7.8.1 A minimum residual pressure for 1 1/2 hose connection shall be 65 psi
7.10.2.1.1 Class 2 minimum flow at 100 gpm
7.10.2.1.2 Additional flow requirements shall not be required where more than one hose connection is provided

Ivonn

8/13/2020 01:00:32 pm

If the hose connections are conected to the sprinkler system, that connections are considered a part of the fire sprinkler system, not a standpipe system. These hose connections are frequently called “standby hose” connections in my opinion or interpretation, these hose stations are not a standpipe so don't need comply with the requirements of NFPA 14 for standpipe systems,
NFPA 13 (in Chaps. 11 and 12) requires that 50 gpm be added to the sprinkler system hydraulic calculations at the two most remote connections to the hose stations. There is not requirement for the hose station to operate at any specific pressure. The idea is to provide 100 gpm total of “inside hose stream demand” for these situations.

100 gpm for inside hose and the rest for outside because the Table 11.2.3.1.2 require 250 gpm total combinated

That is my interpretantion of NFPA, maybe the local AHJ have other requirement.

Jonathan Joseph

8/13/2020 04:17:51 pm

Thanks for clearing that up Ivonn!
If the Fire Department can only use these stations, wouldn't it be supplied by the FDC and acting like a combination manual standpipe?

sean

8/17/2020 08:55:49 am

hose stations per NFPA 13 require the allowance to be added in the sprinkler calculation.

Standpipe hose valves require a dedicated calculation.

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