I just had some more information from "the other guys" (NFSA). I was told that NFPA references the lowest one day mean temperature. This is found in A10.5.1. Using this gets me pretty close to where the AHJ had agreed to go with information on the project in question.
I think that I will just use this diagram in the future until there is more clarification on the issue from NFPA 13 officials. This will really impact those of you in the northern part of the country with respect to AF systems >40 gallons. The viscosities get way out of hand real quick at those lower temps. -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Travis Mack, SET Sent: Friday, September 19, 2008 10:28 AM To: [email protected] Subject: RE: viscosities Ed: Yeah, we were able to make the system work at viscosities for 0F. According to one of the gov't websites, the temperature was only below 0 for 20 days in something like the last 20 years. So, it was deemed reasonable to go with the viscosities for 0F. I believe it works out to about 99.8% of the time, the temps will be above 0F. If the global warming boys are right, then it may be even less :-) I would love to see more guidance for the temperatures to be used for the DW calcs. It can make huge swings in the requirements. -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Ed Kramer Sent: Friday, September 19, 2008 10:11 AM To: [email protected] Subject: RE: viscosities Thanks, Travis. Seems more complicated than it has to be, but I guess thats how you get around software limitations. Concerning your original question: I noticed on a different forum you & the AHJ agreed to use a temp that is subceeded (if thats a word) only about once per year. Seems reasonable. Roland: It wouldn't hurt my feelings if the DW requirement was tossed. Barring that, there certainly should be more guidance for temperature selection. I envision a lot of layout techs (myself included) fumbling big time. Getting input from the AHJ is a great idea, but they also need guidance. Using Travis' project as an example, how's a contractor supposed to bid something like that? Ed Kramer Littleton, CO > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:sprinklerforum- > [EMAIL PROTECTED] On Behalf Of Travis Mack, SET > Sent: Thursday, September 18, 2008 4:10 PM > To: [email protected] > Subject: RE: viscosities > > Ed: > > This system is entirely in the attic. The riser is the only portion > that is in the heated space. > > I do these calculations in 2 parts. I calculate the system back to > the interface of anti-freeze solution / water and get a pressure & > flow demand at that point utilizing the DW calcs. I then do a second > calculation using HW that is from the city supply to the interface > point. > > It is basically how we used to do rack systems calculations. You calc > the rack system and get a k-factor with pressure/flow demands. Plug > that into the overhead system and there you go. > > In several people that I have talked to today about this, I am getting > about 50/50 of saying to use each temp. It is pretty funny. I am > still waiting on the AHJ. Hopefully, I can get a pretty decent > concensus soon. > > > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Ed > Kramer > Sent: Thursday, September 18, 2008 2:43 PM > To: [email protected] > Subject: RE: viscosities > > Travis, > > This doesnt address your question, but I'm curious if the entire AF > system is subject to outdoor temps (or just part of it). > > I ask, because if a significant part of the system is in a heated > area, then it further complicates selecting an appropriate viscosity. > My limited understanding of HydraCalc is that a single viscosity and a > single density is entered for the entire calc (if I'm wrong, someone > please correct me). > Do you use the high viscosity (extreme min temp), the medium viscosity > (average min temp) or the low viscosity (room temp)? Obviously the > room temp viscosity wouldn't be appropriate, but how's a designer to choose? > As > in your example, the selected viscosity can make a whale of a > difference in system costs. > > I've yet to calc an AF system using Darcy-Weisbach, so I'm hoping > someone can enlighten me. > > Ed Kramer > Littleton, CO > > > > > Ok..another viscosity question. > > > > When using HydraCalc to calculate antifreeze systems using the Darcy > > method, it asks for viscosities of solutions. I have a data sheet > > with the viscosities at various concentrations and various > > temperatures. My question is, do you use the average daily minimum > > temperature for an area, or the extreme daily minimum for an area? > > For this particular project, the difference is 40°F in the 2 > > temperatures. With the average daily minimum temperature, the > > system > works with the available pressure. > > With the extreme daily minimum, the city supply is not even close. > > There is a 100+ psi swing in the demands. > > > > So, do we go with average minimums, or extreme minimums? > > > > There is always the option to go to a dry system, but the increased > > design areas and reduced c factor will also force a pump on this > > project. An anti-freeze system at average daily minimum works > > without a fire pump. > > However, we don't want to design/install an inadequate system. > > > > > > Please feel free to call if you have any questions or comments. > > > > Travis Mack, SET > > MFP Design, LLC > > 2508 E Lodgepole Dr > > Gilbert, AZ 85298 > > 480-505-9271 > > [EMAIL PROTECTED] > > > > _______________________________________________ > Sprinklerforum mailing list > http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum > For Technical Assistance, send an email to: > [EMAIL PROTECTED] > > To Unsubscribe, send an email to:Sprinklerforum- > [EMAIL PROTECTED] (Put the word unsubscribe in the subject > field) > > __________ NOD32 3453 (20080918) Information __________ > > This message was checked by NOD32 antivirus system. > http://www.eset.com > > > _______________________________________________ > Sprinklerforum mailing list > http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum > For Technical Assistance, send an email to: > [EMAIL PROTECTED] > > To Unsubscribe, send an email to:Sprinklerforum- > [EMAIL PROTECTED] (Put the word unsubscribe in the subject > field) _______________________________________________ Sprinklerforum mailing list http://lists.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) __________ NOD32 3456 (20080919) Information __________ This message was checked by NOD32 antivirus system. http://www.eset.com _______________________________________________ Sprinklerforum mailing list http://lists.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) __________ NOD32 3456 (20080919) Information __________ This message was checked by NOD32 antivirus system. http://www.eset.com _______________________________________________ Sprinklerforum mailing list http://lists.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)
