Perhaps the box allows some of the hot air to escape? The bag would certainly allow radiative and convective heat into the package faster than the cardboard. If the bag was in the sun, the radiation would be allowed to directly heat the heads and elements. Add the trapped hot air and maybe it is enough...
Matt Grisé PE*, LEED AP Sales Engineer Alliance Fire Protection *Licensed in KS & MO 913.888.0647 ph 913.888.0618 f 913.927.0222 cell www. AFPsprink.com -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Greg McGahan Sent: Thursday, August 12, 2010 1:05 PM To: [email protected] Subject: Re: heads in plastic bags I heard years ago from a 30 yr man that if you put heads in a ziploc plastic bag that the heads would fuse when it is hot, but he had never seen them fuse in or out of a box otherwise. We just had 12 heads fuse in a ziploc bag with the plastic caps still in place in an enclosed building under construction. It is a mystery to me, the glass was in the bag, there are no marks on the heads, they are just fused. It is hot here - 103 ish - but not that hot. I also have never seen heads fuse in the back of a truck etc around here, but these have. Thanks On 8/12/2010 12:53 PM, Ron Greenman wrote: > Why would heat transference into and out of a plastic bag be different > than the same regarding a box except for time lag? Now if directly in > the sun you'd get more radiant impingement quicker through the plastic > bag, if clear but I doubt if it would be significant. I think people > tend to equate how they "feel" regarding their own ability to regulate > their body temperature with heat on inanimate objects. Consider the > concept of one blanket or coat being "warmer" than another or that it > is "cooler" in the shade or when sitting in front of a fan. Is it the > insulating properties of the one blanket over the other relative to > your ability to produce heat or to some inherent quality of "hotness" > in the blanket (electric blankets notwithstanding)? Or is the breeze > from the fan wicking away your sweat quicker than evaporation by > itself causing you to lose heat quicker and thereby feeling cooler? > How about in the shade? Is the ambient air cooler or are you just not > being impinged on by both convection and radiation rather then just > the former? So put heads in the direct sun, in an environment where > heat in is faster than heat out and maybe, but I gots to think it > would have to be in Death Valley or somewhere equivalent. > > On Thu, Aug 12, 2010 at 10:17 AM, Greg McGahan<[email protected]> wrote: > >> Anybody ever heard that if you put sprinklers in plastic bags that it can >> cause them to fuse when heads in boxes won't - from heat inside trucks etc? >> Thanks, >> Greg >> >> >> _______________________________________________ >> Sprinklerforum mailing list >> [email protected] >> http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum >> >> For Technical Assistance, send an email to: [email protected] >> >> To Unsubscribe, send an email to:[email protected] >> (Put the word unsubscribe in the subject field) >> >> > > > -- _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field)
