Take a look at NFPA-13 2002 8.14.20 -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Todd Williams - work Sent: Friday, April 20, 2007 10:09 AM To: [email protected] Subject: Re: Underground Dry Pipe
Methinks you speak from some experience. You kind of eluded to t in your P.S., but there are different grades of SS. The stuff they would make 4" pipe out of is most likely a lesser grade than they would use in medical equipment and would probably start decaying a lot sooner. My guess is that it would be cheaper to build a new amphitheater than have 4" pipe and fittings made of surgical grade SS. At 09:23 AM 4/20/2007, you wrote: >Stainless steel does rust, and corrode. Anyone who has owned a sailboat >can attest to that statement. Stainless steel works because the >chromium in the alloy combined with presence of oxygen in the air forms >a passivation layer of chromium (III) oxide. This layer is too thin to >be visible, which accounts for the nice shiny appearance of stainless. >Anything that disrupts that layer, or shields the stainless from direct >contact with oxygen (buried underground) disrupts that reaction. This >accounts for the rust stains that seep out from under stainless steel >cleats, and the corrosion in a nice shiny new stainless steel >turnbuckle that has spent a year or so tightly wrapped in rigging tape. >Stainless steel pipe would probably last a lot longer than either black >steel or galvanized pipe in this application, but not forever. > >Actually in the environment described, polyethylene sleeved, cement >lined ductile iron would last the longest. No exposed metal to rust on >the inside and no exposed metal to corrode on the outside. The only >question I would have since I haven't looked into it is the sealing >properties of the gaskets under air verses water pressure. > >.Just random thoughts brought on from following this thread. > >Richard L. Mote >Designer >Rowe Sprinkler Systems, Inc > >P.S. Nickel, molybdenum and vanadium also contribute to passivation and >may be present in varying quantities some grades of stainless steel. > > >_______________________________________________ >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) Todd G. Williams, PE Fire Protection Design/Consulting Stonington, Connecticut 860-535-2080 www.fpdc.com _______________________________________________ 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)
