They wouldn't even have to be in a bucket to be creeping, although I see the clue to other improper handling procedures in general before/during installation. But even with best intentions, are the Fed Ex trucks bringing us the heads air conditioned? L O N G supply chain...
glc -----Original Message----- From: sprinklerforum-boun...@firesprinkler.org [mailto:sprinklerforum-boun...@firesprinkler.org] On Behalf Of craig.pr...@ch2m.com Sent: Wednesday, February 17, 2010 4:04 PM To: sprinklerforum@firesprinkler.org Subject: RE: Accidental Fusing/unintended operation We think of the installation conditions contributing to things like solder creep due to heat exposure but what about the fitter with a bucket of heads in the back of his truck on a hot August day parked in the shop where it's over 100F? Some failures could be the result of poor handling before installation. Craig L. Prahl, CET Fire Protection Specialist Mechanical Department CH2MHILL Lockwood Greene 1500 International Drive PO Box 491, Spartanburg, SC 29304-0491 Direct - 864.599.4102 Fax - 864.599.8439 craig.pr...@ch2m.com http://www.ch2m.com -----Original Message----- From: sprinklerforum-boun...@firesprinkler.org [mailto:sprinklerforum-boun...@firesprinkler.org] On Behalf Of jhoff...@kcp.com Sent: Wednesday, February 17, 2010 3:35 PM To: sprinklerforum@firesprinkler.org; bcasterl...@fsc-inc.com Subject: Re: Accidental Fusing/unintended operation I think we are over-analyzing the incident. Heads do fail occasionally. Not frequently but sometimes. This has happened here twice. One was a Grinnell Duraspeed back in 1997. There was no heat source nearby that was an obvious culprit. It was installed in the factory area (25 feet ceilings) along with hundreds of others. The plant is air conditioned so the ambient is less than 100 degrees F. It was a 1968 brass head, 165 degree F issue C Duraspeed. We sent it to our lab (yes, we have our own lab). the scanning electron microscope analysis showed elongation of the grains of metal in the solder bond indicating creep. However, they also saw some porosity in the solder, which may have resulted in a less-than-standard ability to resist the forces exerted on the link. So the manufacturing process may not always be perfect. We then sent the parts to Grinnell for their analysis. They determined that the link separated due to creeping apart of the solder bond. Their microscopic viewing of the solder bond indicated that the surface texture was similar in appearance to those that were known to be over-heated. Over-heat is defined as an ambient over 100 degrees F. There could have been steam pipes in the area of the failed sprinkler at one time which may have exposed this head to over-heat, but there were no steam pipes in the area at the time of the failure. We sent them several other heads that were adjacent to the failed one and they did strength tests on the link and they all tested normal. For a 212 degree F sprinkler an overheat condition would be over 150 degrees, which an attic area in Kansas may or may not reach at one time or another. Our experience was that the sprinkler failed in the middle of the day, years after any heat exposure, if there ever was heat exposure, for no apparent reason. Things fail sometimes. Do lab analysis, send parts off to the manufacturer but eventually you have to replace the head and move on. John Hoffman P.E. | Fire Protection Engineer | Facility Engineering Services, KCP, LLC - Burns & McDonnell Engineering | National Nuclear Security Administration's Kansas City Plant | Operated by Honeywell FM&T | 2000 E. 95th St | Kansas City, MO 64131 | ph 816-997-7213 sprinklerforum-boun...@firesprinkler.org wrote on 02/17/2010 02:03:49 PM: > [image removed] > > Accidental Fusing > > Brad > > to: > > sprinklerforum > > 02/17/2010 02:04 PM > > Sent by: > > sprinklerforum-boun...@firesprinkler.org > > Please respond to sprinklerforum, bcasterline > > -The change in pressure is half the density times the velocity > squared.- > > > > I have been asking myself these questions--- > > 1-why had the head been through 6 summers without fusing- without a > manufacturing or installation defect showing up? > > 2-why had the head fused at 6:30 AM, not 9 hours earlier? > > If it was due to "heat", the only answer could be a dynamic scenario where > the different conditions became "right"- > > an increase in THIS here, a decrease in THAT there. differences--- as > far as > "heat" goes, there is one between > > TEMPERATURE and QUANTITY. Quantity varies as the mass, Temperature as > the kinetic energy. I knew the only way > > for the Quantity to change is if the head gained or lost mass (the > higher velocity of the air at the head, the lower the pressure, > > the faster the solder vaporizes. maybe the old guy in the art room at > MU did > see that sprinkler vaporize). Kinetic energy is > > half the mass times the velocity squared. For Temperature > measurements, the > AVERAGE velocity is theorized. When I think of > > an increase in the quantity of the air passing the head, I think of an > increase in the probability of "fresh quantities of heat"- > > quantities with higher than average kinetic energies, which Would > raise the > temperature- (a bad example would be draining > > and charging wet systems frequently- introducing "fresh air"). > > I have always been amazed at sprinklers-the fine line between going > off when > they are supposed to, but not until. > > > > > > > > > > > > _______________________________________________ > Sprinklerforum mailing list > Sprinklerforum@firesprinkler.org > http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum > > For Technical Assistance, send an email to: supp...@firesprinkler.org > > To Unsubscribe, send an email > to:sprinklerforum-requ...@firesprinkler.org > (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list Sprinklerforum@firesprinkler.org http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: supp...@firesprinkler.org To Unsubscribe, send an email to:sprinklerforum-requ...@firesprinkler.org (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list Sprinklerforum@firesprinkler.org http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: supp...@firesprinkler.org To Unsubscribe, send an email to:sprinklerforum-requ...@firesprinkler.org (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list Sprinklerforum@firesprinkler.org http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: supp...@firesprinkler.org To Unsubscribe, send an email to:sprinklerforum-requ...@firesprinkler.org (Put the word unsubscribe in the subject field)
