Fire Line for Sprinkler
Fire Line for Sprinkler
(OP)
An existing building, that is approximately 5,000 SF, is being furnished with a fire sprinkler. NFPA 13. There is a 6" main along the roadway with an existing hydrant approximately 300 feet to the east and west.
The new line will only service the sprinkler system. I'm not sure where to begin on what calc's are needed. I've ordered the NC Fire Code and have a copy of the IPC. I've contacted the plumber to see what criteria he is going to list in the bid documents, since the actual design of the system will be done after award. I've got a call into the Fire Marshal as well.
Figured I put a question out to get some feedback on what things I should be looking for and asking for, so as to get what I need from the appropriate parties.
A representative with the utility department felt a 2" line would be sufficient. How do I confirm?
Thanks in advance.
The new line will only service the sprinkler system. I'm not sure where to begin on what calc's are needed. I've ordered the NC Fire Code and have a copy of the IPC. I've contacted the plumber to see what criteria he is going to list in the bid documents, since the actual design of the system will be done after award. I've got a call into the Fire Marshal as well.
Figured I put a question out to get some feedback on what things I should be looking for and asking for, so as to get what I need from the appropriate parties.
A representative with the utility department felt a 2" line would be sufficient. How do I confirm?
Thanks in advance.





RE: Fire Line for Sprinkler
http://www.firehydrant.org/info/ftest2.html
The tests are usually performed by the local fire dept., the local utility, or an independent contractor. This data can be used to model the existing lines flow and pressure characteristics using a pump and reservoir in either EPAnet or waterCAD.
Who ever is desinging the sprinkler system should be able to provide you with the necessary demand and pressures that will be required for the proposed sprinkler system based on code requirements.
Look at this book online for more in-depth info
http://www.haestad.com/books/pdf/awdm.pdf
RE: Fire Line for Sprinkler
I have had many jobs where the water utility says a 2" line should work and we ended up need an 8" line. Again, it all depends on what the fire sprinkler design criteria is for the building.
Travis Mack
MFP Design, LLC
www.mfpdesign.com
RE: Fire Line for Sprinkler
RE: Fire Line for Sprinkler
RE: Fire Line for Sprinkler
The FP contractor won't get going until the project is awarded. I'm supposed to have materials needed to the Architect by Wednesday.
Doesn't seem that the needed information is available at this time?
RE: Fire Line for Sprinkler
Travis Mack
MFP Design, LLC
www.mfpdesign.com
RE: Fire Line for Sprinkler
I've scanned the document, though wasn't looking for this in particular at the time. Will take another look.
RE: Fire Line for Sprinkler
But on a more serious note you could determine the likely linear footage but explain that this is best case because you don't know where the connection to the mechanical room will be located.
You could also explain that you can't determine the size until the fire protection calculations have been performed by the FP engineer. If you want to guess the size at least guess big so the projects cost will decrease instead of increase in case of changes.
That is the general rule of thumb if someone wants some impossible to obtain number prior to project design. Guess big preliminarily so construction cost will decrease not increase in the long run.
RE: Fire Line for Sprinkler
RE: Fire Line for Sprinkler
4" may or may not be enough depending on what pressures you have available. Recently did a large dry attic that required a 6" lead-in. The calc area was still 2535 sq ft.
There are other sprinklers and other options that may allow for smaller flows, but this just goes to show that the size of the building has little to do with the required flow. It is more about commodity, system type and the over-discharge of the system (dry systems have relatively high over-discharges)
Travis Mack
MFP Design, LLC
www.mfpdesign.com
RE: Fire Line for Sprinkler
A 4" pipe hits 8 ft/sec at about 350 gpm, which isn't much for a sprinkler system.
Also, your feed has to be at least the size of the riser.
RE: Fire Line for Sprinkler
RE: Fire Line for Sprinkler
Also a size smaller than 6" may be permitted if the ug line is used for nothing else and calculations prove it is sufficient.
However you should wait until your FP contractor verifies the size.