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)
