The CRR (corrosion resistance ratio) is solely based on wall thickness: CRR = (X / Y)^3
Where: X is the thickness of the pipe in question at the first exposed thread OR THINNEST WALL SECTION FOR UNTHREADED PIPE. And Y is the thickness of schedule 40 pipe under the first exposed thread. So if you are roll-grooving the pipe, schedule 10 or even schedule 7 can have a CRR of 1 or greater. You aren’t trying to thread 10” pipe, are you? CRR is simply a mathematical formula that has absolutely nothing to do with the chemical makeup of the pipe. While galvanizing or MIC-coating might help the pipe resist corrosion, it does not affect the CRR. -Kyle M From: Sprinklerforum [mailto:[email protected]] On Behalf Of Richard Carr Sent: Friday, August 11, 2017 6:22 AM To: [email protected] Subject: RE: [EXTERNAL] RE: 10" pipe with 1.0 CRR I thought that as a manufacturing standard all steel pipe regardless of schedule had to have a CRR of 1 or greater. Richard Carr, SET Branch Manager Cox Fire Protection, Inc 6555 Grace Lane. Jacksonville, Fl. 32205 [email protected]<mailto:[email protected]> 904-781-8227 From: Sprinklerforum [mailto:[email protected]] On Behalf Of Mark.Phelps Sent: Friday, August 11, 2017 9:00 AM To: [email protected]<mailto:[email protected]> Subject: Re: [EXTERNAL] RE: 10" pipe with 1.0 CRR Isn't the CRR based on the actual remaining wall thickness at the root of the first exposed thread outside of a fitting? So if you're not threading it, it should theoretically have a CRR greater than 1.0. Also, I believe the term Standard wall pipe in 10" diameter refers to schedule 30. Mark at Aero 602 820-7894 Sent from my iPad On Aug 11, 2017, at 5:49 AM, Mike Stossel <[email protected]<mailto:[email protected]>> wrote: It has always been my understanding that the corrosion resistance ratio benchmark of (1) is based on threaded schedule 40 steel, so I believe any other pipe type would have a better or worse ratio, but not the same. Mike Stossel SET <image002.png> 36 Barren Road East Stroudsburg, PA 18302 Office: 973-670-2627 [email protected]<mailto:[email protected]> From: Sprinklerforum [mailto:[email protected]] On Behalf Of Dewayne Martinez Sent: Friday, August 11, 2017 8:39 AM To: [email protected]<mailto:[email protected]> Cc: [email protected]<mailto:[email protected]> Subject: 10" pipe with 1.0 CRR Anyone know of 10in non-sch40 pipe that has a CRR of 1? Have a project where the EOR is insisting on this. They also have a 100lb maximum point load per hanger…..but that is a conversation for another day! Thanks, Dewayne Martinez Fire Protection Design Manager TOTAL Mechanical Building Integrity W234 N2830 Paul Rd. Pewaukee, WI 53072 [email protected]<mailto:[email protected]> Ph: 262-522-7110 Cell: 414-406-5208 http://www.total-mechanical.com/ <image004.jpg> _______________________________________________ Sprinklerforum mailing list [email protected]<mailto:[email protected]> http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
_______________________________________________ Sprinklerforum mailing list [email protected] http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org
