Just a thought. I normally don't worry about velocities too much. However, your system is 40 years old. Can you examine the inside of the mains BEFORE you quote it? If the mains are clean & smooth, a 120 c factor (assuming wet) and high velocities probably won't skew the calcs. But if the mains are dirty & rough, I'd start thinking about being more conservative.
Thought for the day complete. Ed Kramer Littleton, CO > -----Original Message----- > From: [EMAIL PROTECTED] [mailto:sprinklerforum- > [EMAIL PROTECTED] On Behalf Of Chris Cahill > Sent: Monday, June 02, 2008 8:47 AM > To: [email protected] > Subject: High velocities > > > > A question for where there is healthy pressures. Around > here 60 is considered high. I know places with 28 static. > Got a OHII system that needs to be changed to EXII. > That's not negotiable. It's a 40 yo pipe schedule > system. That appears to be in good shape. The BL need to > be replaced for 100 sq.ft. but the main even the last 12' > of 2.5", 25' of 3" and 36' of 3.5" can fly without being > replaced. The openings are where I need them. There is a > FP with about 140 psi at the 900gpm demand. The "problem" > is the velocities in one segment of pipe are just about 40 > (last piece of 3") and about 30 in the 3.5". I quote > problem because I know 13 has no limit, this is not FM. > There is still better than 15 psi safety. > > So the question is where you have pressure do you > typically burn it up with small pipe size at the cost of > velocities getting high or do you leave a lot of safety? > Again not FM and OK per 13. > > Any thoughts on why this is a bad idea? It's easy to say > just pull the offending pipe. In reality though you all > know the competitive market and spending owners money. > > > Chris Cahill, P.E. > Fire Protection Engineer > Sentry Fire Protection, Inc. > > 763-658-4483 > 763-658-4921 fax > > Email: [EMAIL PROTECTED] > > Mail: P.O. Box 69 > Waverly, MN 55390 > > Location: 4439 Hwy 12 SW > Waverly, MN 55390 > > _______________________________________________ > Sprinklerforum mailing list > [email protected] > http://lists.firesprinkler.org/mailman/listinfo/sprinklerforum > > To Unsubscribe, send an email to:Sprinklerforum- > [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)
