To me this sounds like classic Solder creep. The solder softens furring warm conditions, and after many many (years) of hot days, you start to have heads pop as the solder has finally given in to the pressure it has been holding back. I think your correction on this would be glass bulb sprinklers. Jamie Seidl
On Thu, Sep 13, 2018 at 5:20 PM Larry Block, Property Manager < [email protected]> wrote: > Hi to all! > > > > I manage a number of most warehousing industrial parks around Los Angeles > and only 1 of them has a problem with heads popping off for no apparent > reason. We really need some help here in identifying the cause and its > correction. Many have said to just replace them but who is to say that this > will not happen again soon, if not later. The facts: > > > > 1. Concrete tilt up bldg from 1967 with its roof at 20’ H. > > 2. Heads are Reliable model C with the fusible link > > 3. Heads will get the 50 year UL testing in 4 years (though I assume the > 165degF rating is not relevant here) > > 4. We have lost 7 heads over 15 years, with 3 in the last 4 months! > > 5. The link assemblies are never found but the remaining “rings” show no > issues. The bronze seats > > of the head’s water port are always in perfect condition. > > 6. We see that the head’s “knuckle” that is opposite the fusible link is > usually perfectly aligned, > > but a few of them are offset up to a 1/16” and it appears > that when they move like that, > > they are rotating in an arc from the pivot points . > > 7. The water utility swears that at the time of these events, there are no > pressure surges. > > 8. No more than one head has ever gone off at a time and are not just at > one location or riser. > > 9. A nearby similar bldg of ours from 1968 with the same heads has never > had one such event. > > > > We have entertained the possibility of water pressure, birds, > electrolysis, dezincification, vibration and are at a loss. > > > > Any helpful thoughts? > > > > Thanks, > > > > Larry Block, Property Manager > > > > > <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient&utm_term=icon> > Virus-free. > www.avast.com > <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient&utm_term=link> > <#m_1665363590207642229_DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> > _______________________________________________ > Sprinklerforum mailing list > [email protected] > > http://lists.firesprinkler.org/listinfo.cgi/sprinklerforum-firesprinkler.org > -- \ \ (o> -- If life were easy... \ \_/ /) It'd be called your mom... \_/_) _|_
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