Sorry, C=80 I believe
> On Aug 29, 2014, at 4:46 PM, Brad Casterline <[email protected]> wrote: > > At one time 13 said for 50 year old underground C=100. I do not see it in the > '07, just that the AHJ is permitted to consider other C values. > >> On Aug 29, 2014, at 4:31 PM, Travis Mack <[email protected]> wrote: >> >> This was not brought up in project specs or plans. Nor was it brought up in >> plan review. This was a project that had an existing 4" ductile supply >> line. It is supplying some paint booths and some exhaust ducts in an >> otherwise unsprinklered building. When the guys did the forward flow test >> of the new backflow preventer, there was an issue that they weren't getting >> as much water as they thought it should have. So, the EOR for the project >> comes back and says something about the calcs. According to my customer, >> the EOR says per a "chart" the C-Factor should have been 60 instead of 140. >> For 3 of the 4 paint booths, it is not a problem. They are small and plenty >> of margin. For the 4th, we end up with a problem. But, if there is nothing >> in the specs or criteria to cause the modification of that pipe, I am not >> sure where it will go. The good thing is that we still have a margin on the >> system, but it is less than the 10% required. >> >> I have just never heard of having to do this modification. I wanted to make >> sure it was something I have not been missing. >> >> Travis Mack, SET >> MFP Design, LLC >> 2508 E Lodgepole Drive >> Gilbert, AZ 85298 >> 480-505-9271 >> fax: 866-430-6107 >> email:[email protected] >> >>> On 8/29/2014 2:20 PM, Mark A. Sornsin, P.E. wrote: >>> Travis, >>> >>> Off-hand I can offer no help. >>> >>> But I am curious to see the responses. Had the engineer denoted the >>> requirement in the project drawings or specs, I'd definitely side with >>> them. If not, then I want to know if he has a leg to stand on (i.e. code >>> reference). >>> >>> This CAN be a significant issue and is another example of a potentially >>> serious 'miss' by engineers who don't do their jobs with regards to >>> sprinkler system drawings/specs. E.g., take a 200 ft. run of existing 6 in. >>> pipe - 50 years old. They tell you to use it to modify the existing pipe >>> schedule sprinkler system to meet the new occupancy. Most often, a >>> contractor can get away with simply assuming it is 6" ductile with a >>> c-factor of 140. But what if in reality it is unlined cast iron? What >>> C-factor are you to use? >>> >>> FM taught me that it depended on the water corrosiveness. Who determines >>> that? I don't know if the FM data is acquired from anything that could be >>> cited by code. Their tables say 50 yr old cast iron in mildly corrosive >>> ware should have a C-factor of 75; if corrosiveness is severe, it should be >>> 40. At an extra Hazard, Group I demand of 750 gpm, the friction though 100 >>> feet of pipe can vary from 1.5 psi at C=140; to 4.6 psi at C=75; to 14.9 >>> psi at C=40. Pretty significant variance and not something that should be >>> blown off by the engineer or designer. >>> >>> Ideally you'd do a water test THOUGH that pipe to verify actual friction >>> losses - but that is almost never a viable option. Then again, if you were >>> able to do so, you may be able to get a change order when you prove that >>> the engineer overlooked a serious issue. >>> >>> Mark A. Sornsin, P.E. | Karges-Faulconbridge, Inc. | Fire Protection >>> Engineer | Fargo, ND | direct: 701.552.9905 | mobile: 701.371.5759 | >>> http://www.kfiengineers.com >>> >>> -----Original Message----- >>> From: Sprinklerforum >>> [mailto:[email protected]] On Behalf Of Travis >>> Mack >>> Sent: Friday, August 29, 2014 3:52 PM >>> To: [email protected] >>> Subject: Modifications to C-Factor due to age of pipe >>> >>> Does anyone know if there is any requirement in NFPA or Uniform Facilities >>> Criteria to modify the C-Factor of existing underground piping based on the >>> age of the pipe? If so, do you have a section reference so I can look it >>> up. An engineer is requiring us to do it, but won't provide the reference. >>> Yeah..It is one of those days. >>> >>> -- >>> Travis Mack, SET >>> MFP Design, LLC >>> 2508 E Lodgepole Drive >>> Gilbert, AZ 85298 >>> 480-505-9271 >>> fax: 866-430-6107 >>> email:[email protected] >>> >>> _______________________________________________ >>> Sprinklerforum mailing list >>> [email protected] >>> http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org >>> >>> ______________________________________________________________________ >>> This email has been scanned by the Symantec Email Security.cloud service. >>> For more information please visit http://www.symanteccloud.com >>> ______________________________________________________________________ >>> >>> ______________________________________________________________________ >>> This email has been scanned by the Symantec Email Security.cloud service. >>> For more information please visit http://www.symanteccloud.com >>> ______________________________________________________________________ >>> _______________________________________________ >>> Sprinklerforum mailing list >>> [email protected] >>> http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org >> >> _______________________________________________ >> Sprinklerforum mailing list >> [email protected] >> http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
