Water filled systems also have a narrower temperature range. Upper end the same but lower end on AF can go 40 plus lower.
Chris -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Roland Huggins Sent: Tuesday, July 31, 2012 10:15 AM To: [email protected] Subject: Re: E x p a n s i o n T a n k s Water and Polypropylene has about the same degree of thermal expansion so I don't believe that is the reason. Although it hasn't really been discussed by the TC, the stated premise on SMALL antifreeze systems is that there is no trapped air. Conversely, we expect a lot of trapped air in a standard wet pipe system. Having said that, the corrosion driven efforts to reduce trapped air has NOT been correlated with the expansion concerns. Somewhere along the way, the two opposing efforts will bump heads. Roland On Jul 31, 2012, at 7:55 AM, Brad Casterline wrote: > the reason we do not need expansion tanks on wet systems is due to > water's low coefficient of thermal expansion, but since it is not > zero, and assumed potable, we use a 1/2" relief valve. why on grids > but not trees?, (until > 13-2013)-- because with an aux drain on the secondary main, most of > the air > (cushion) can be purged at system charge or recharge. now with the > emphasis on getting the air out, best to use a relief valve on trees > too. > this is my > understanding-- i might be mistaken. > > -----Original Message----- -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://fireball.firesprinkler.org/mailman/private/sprinklerforum/attachments/20120731/c6fadb5d/attachment.html> _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum
