My understanding is that the 120 and 100 values for wet and dry pipes respectively accounted for an average age deterioration. The concept being that although the new pipe being calculated had an actual C-factor of 140 it would become rougher over a 50 year expected lifespan, whether altered or not, and the reduced C was to factor that in. Obviously some pipe will degrade more than others (I've seen 100 plus year old pipe that looks like it was manufactured yesterday and I've seen two year old pipe that needed to be replaced. Since none of us can guess at what will happen, nor can we determine a C-factor by eyeballing a piece of pipe we have these built-in averages in the calculations to use. Remember that these numbers we use for any of this stuff are not absolutes nor were they on that third tablet Mel Brooks dropped.
On Tue, Apr 20, 2010 at 3:57 PM, Reed Roisum <[email protected]> wrote: > Table 9 in my FM Global Hydraulics Tables has Age Factors for public and fire > pro mains and Table 6 has coefficients for underground piping based on age of > pipe and water corrosiveness. Probably not what you are looking for though?? > > > Reed A. Roisum, CET > > Engineering Technician > > > > Direct: (701)280-8580 > Cell: (701)212-8810 > > > > > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of A.P.Silva > Sent: Tuesday, April 20, 2010 5:37 PM > To: [email protected] > Subject: RE: C-Factor > > I remember FM used to have a requirement for old piping. Not sure if it is > still there. > > Tony > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Steve Leyton > Sent: April 20, 2010 4:34 PM > To: [email protected] > Subject: RE: C-Factor > > Table 22.4.4.7 for C-factor values; I'm not aware of any code or > standard-based requirement for using a certain C-value on older systems, but > the reason that a C-100 value is used for dry systems is to account for the > fact that the interior piping surface is subject to more > aggressive deterioration than in a wet-pipe system. I wonder if anyone > else has experience with calculation of VOP (very old piping) ... > > Steve Leyton > Protection Design & Consulting > San Diego, CA > > > > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of > [email protected] > Sent: Tuesday, April 20, 2010 3:13 PM > To: [email protected] > Subject: C-Factor > > Can someone tell me were in NFPA-13 dose it talk about the C-Factor for > pipe. I am doing a calc. on an old system and I know I have to change the > C-Factor but I can not find it in the code book. I found it somewere elese > and it says in old pipe i must change the C-Factor like new black pipe for > wet systems will be 120 C-Factor but if its 50 years old I must chage it to > 90. Can someone tell me were to find this info. > Thank You > > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > > For Technical Assistance, send an email to: [email protected] > > To Unsubscribe, send an email > to:[email protected] > (Put the word unsubscribe in the subject field) > > > __________ Information from ESET NOD32 Antivirus, version of virus signature > database 4946 (20100315) __________ > > The message was checked by ESET NOD32 Antivirus. > > http://www.eset.com > > > > __________ Information from ESET NOD32 Antivirus, version of virus signature > database 4946 (20100315) __________ > > The message was checked by ESET NOD32 Antivirus. > > http://www.eset.com > > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > > For Technical Assistance, send an email to: [email protected] > > To Unsubscribe, send an email to:[email protected] > (Put the word unsubscribe in the subject field) > > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > > For Technical Assistance, send an email to: [email protected] > > To Unsubscribe, send an email to:[email protected] > (Put the word unsubscribe in the subject field) > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > > For Technical Assistance, send an email to: [email protected] > > To Unsubscribe, send an email to:[email protected] > (Put the word unsubscribe in the subject field) > -- Ron Greenman Instructor Fire Protection Engineering Bates Technical College Tacoma, WA Member: SFPE, ASCET, NFPA, AFSA, NFSA AFAA, NIBS, WSAFM, WFC _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field)
