In the case of the dry system, however, they also serve the purpose (I believe) to keep water out of the drop. Once the water enters the drop, it's trapped and will eventually corrode the pipe - sometimes to the point of sealing the entire diameter.
In the case of a riser nipple on a branch line, the air in the branch line will compress enough to allow water into the line, and thus will likely enter the drops - for eternity, or until the drop is drained. Mark A. Sornsin, PE Fire Protection Engineer Ulteig Engineers, Inc. Fargo, ND 701.280.8591 [EMAIL PROTECTED] -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of A.P.Silva Sent: Thursday, May 08, 2008 8:34 AM To: [email protected] Subject: RE: Return Bends I know it doesn't seem right. But is it achieving its intent? Return bends are used to prevent scale and other sediments being trapped at the head. To some extent, at least except from the individual branchline, won't this be achieved? Tony -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Garth W. Warren Sent: May 8, 2008 5:07 AM To: [email protected] Subject: Re: Return Bends what is being proposed to you is a line on a riser nipple off of the main NOT return bends. The return bend is there for a reason and what is being proposed to you does not serve the purpose. The suggestion should be rejected. Garth ----- Original Message ----- From: "A.P.Silva" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Wednesday, May 07, 2008 11:08 PM Subject: Return Bends > I have a situation, dry system running in heated space below the attic in > part of the building. In other parts, within the attic space. Where it is > running in the heated area, sprinklers are pendent type. So the need for dry > pendents or return bends. The contractor doesn't want to install individual > return bends for each pendent head (for cost reasons). Instead he is > proposing to make the entire branchline as the return bend. The branchline > to have a riser at the connection to the main. Then from the branchline drop > down directly to each pendent head. Any problems? > > Tony > > _______________________________________________ > 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) _______________________________________________ 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)
