Also be aware.., a lot of Dry Pendants have differing K factors the longer they get. So technically, you would be replacing sprinklers with a different K factor, thereby requiring the calc as well.
R/ Matt Matthew J. Willis Living Water Fire Protection, LLC. 1160 McKenzie Rd. PO Box 877 Cantonment, FL. 32533 850-937-1850 Voice 850-937-1852 Facsimile [EMAIL PROTECTED] ----- >-----Original Message----- ----- >From: [EMAIL PROTECTED] ----- >[mailto:[EMAIL PROTECTED] On ----- >Behalf Of Todd Williams - FPDC ----- >Sent: Friday, June 06, 2008 5:30 AM ----- >To: [email protected] ----- >Subject: Re: calcs with pipe replacement ----- > ----- >The job spec calls for replacing the existing 3" sch 10 ----- >black with 3" ----- >sch 40 galvanized. As I said in a previous post, to do ----- >this job correctly and bring the system up to Code will ----- >require more than just replacing pipe. The mains are ----- >essentially flat and the the outlets are off the side of ----- >the main. The mains run out 200-250 ft from the feed, so ----- >you are looking at 5-6" of pitch; now most of the dry ----- >pendents for the second floor will be too short. That ----- >wasn't figured in the spec (prepared by the maintenance ----- >staff). Also, there are no drawings for this place, so ----- >it would be a full survey job, which would take a lot of ----- >time and money. Given the economic conditions up here, ----- >someone will probably come in a bid it bottom dollar to ----- >just replace the pipe and say the heck with the pitch, ----- >so more than likely, we won't get it. But, I've got to ----- >give my client a quote. ----- > ----- >Interestingly, this is the second job that I have been ----- >asked to look at in a couple of weeks with 17 year old ----- >+/- 3" sch 10 that has rotted out. Both are within 5 ----- >miles of my house. I believe they were installed by ----- >different contractors. ----- > ----- >This job has its own issues, but it did bring up the ----- >point about replacing existing pipe with something ----- >different with similar flow characteristics and the need ----- >for calcs. ----- > ----- > ----- > ----- >At 09:00 PM 6/5/2008, you wrote: ----- >>Todd, based on the fact that this is a repair, as ----- >mentioned, AND the ----- >>fact that you're replacing pipe that *should* have been ----- >calculated with ----- >>a hazen-williams c-factor of 100 (black steel) with ----- >piping that has a ----- >>c-factor of 120 (galvanized) - I would say you're ----- >probably going to be ----- >>alright - but better safe than sorry - so why not run calcs? ----- >> ----- >>-B- ----- >> ----- >> ----- >> ----- >>On 6/5/08, Todd Williams - FPDC <[EMAIL PROTECTED]> wrote: ----- >> > ----- >> > To do this job correctly (operative word) will ----- >require a lot more ----- >> > than just pipe replacement and thus will need to be ----- >recalculated. As ----- >> > an example, to properly pitch the pipe will require ----- >replacement of ----- >> > most of the ----- >> dry pendents ----- >> > feeding the floor below. The additional 30% increase ----- >and a few other ----- >> > things have already been mentioned to the ----- >contractor. However, the ----- >> > job spec treats this as a repair and doesn't really ----- >try to solve the ----- >> > problem of water trapped in mains (except they want ----- >an add for an ----- >> > air dryer in the quote) ----- >> > ----- >> > My question was more academic in that if you replace ----- >one pipe with a ----- >> > different type of pipe with a similar loss per foot ----- >and make no ----- >> > other changes, would it necessarily have to be ----- >recalculated. When ----- >> > does repair become modification? ----- >> > ----- >> > ----- >> > ----- >> > At 12:31 AM 6/5/2008, you wrote: ----- >> > ----- >> >> If I had high confidence of all the following, I ----- >wouldn't see the ----- >> >> need for new calcs: ----- >> >> - Strictly pipe replacement (no added ----- >offsets, elbows, ----- >> >> riser nipples, etc) ----- >> >> - The original calcs were accurate (done ----- >properly and ----- >> >> reflect 'as built' conditions) ----- >> >> - Water supply hasn't deteriorated. ----- >> >> ----- >> >> A bit of a side note - if the attic has a roof with ----- >slope greater ----- >> >> than 2/12, the design area very likely didn't include a 30% ----- >> >> increase for the slope. ----- >> >> That requirement didn't appear in 13 until 1996. ----- >But since the ----- >> >> pipe replacement is legitimately a repair, you ----- >probably don't need ----- >> >> to meet any standard other than what was in effect ----- >17 years ago. ----- >> >> ----- >> >> Ed Kramer ----- >> >> Littleton, CO ----- >> >> ----- >> >> ----- >> >> > I walked through an attic this afternoon where all of the ----- >> >> > existing mains need to be replaced. The piping is ----- >3" schedule 10 ----- >> >> > black steel, that is developing leaks after 17 ----- >years (we found ----- >> >> > another one on our tour). The proposal is out ----- >there to replace the existing with 3" ----- >> >> > schedule 40 galvanized (and provide proper ----- >pitch). I did a couple ----- >> >> > of quick calculations and at 250 gpm, the ----- >friction loss per foot ----- >> >> > for the two pipes is very close to the same. ----- >(.077 for the sch 10 black v. ----- >> >> > .075 for the sch 40 galv). My guess is that the ----- >difference in ----- >> >> > pressure would be about 0.75 psi. The calc has ----- >about 12 psi ----- >> >> > remaining. If this was strictly a pipe ----- >replacement (no other ----- >> >> > modifications), would you recommend new hydraulic ----- >calculations? ----- >> >> > ----- >> >> > Todd G. Williams, PE ----- >> >> > Fire Protection Design/Consulting Stonington, Connecticut ----- >> >> > www.fpdc.com 860.535.2080 ----- >> >> ----- >> >> _______________________________________________ ----- >> >> Sprinklerforum mailing list ----- >> >> [email protected] ----- >> >> ----- >http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum ----- >> >> ----- >> >> To Unsubscribe, send an email ----- >> ----- >to:[EMAIL PROTECTED]<to%3ASprinkle ----- >rforum-reques ----- >> [EMAIL PROTECTED]> ----- >> >> (Put the word unsubscribe in the subject field) ----- >> >> ----- >> > ----- >> > Todd G. Williams, PE ----- >> > Fire Protection Design/Consulting ----- >> > Stonington, Connecticut ----- >> > www.fpdc.com ----- >> > 860.535.2080 _______________________________________________ ----- >> > Sprinklerforum mailing list ----- >> > [email protected] ----- >> > ----- >http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum ----- >> > ----- >> > To Unsubscribe, send an email ----- >> ----- >to:[EMAIL PROTECTED]<to%3ASprinkle ----- >rforum-reques ----- >> [EMAIL PROTECTED]> ----- >> > (Put the word unsubscribe in the subject field) ----- >> > ----- >>_______________________________________________ ----- >>Sprinklerforum mailing list ----- >>[email protected] ----- >>http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum ----- >> ----- >>To Unsubscribe, send an email ----- >>to:[EMAIL PROTECTED] ----- >>(Put the word unsubscribe in the subject field) ----- > ----- >Todd G. Williams, PE ----- >Fire Protection Design/Consulting ----- >Stonington, Connecticut ----- >www.fpdc.com ----- >860.535.2080 ----- >_______________________________________________ ----- >Sprinklerforum mailing list ----- >[email protected] ----- >http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum ----- > ----- >To Unsubscribe, send an email ----- >to:[EMAIL PROTECTED] ----- >(Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum To Unsubscribe, send an email to:[EMAIL PROTECTED] (Put the word unsubscribe in the subject field)
