The other pic 2

[ContractorDave]

I see I can only put one file at a time to a post. I should have merged the pics but here is the other one for the post on leaking sprinklers.

Thx
Dave

 

[cdafd]

sounds like maybe send a sample in for testing??


does this building have a fire pump??? if so what is normal system pressure??

 

[FFP1]

The bulb looks like it is not centered on the orifice.

I would think manufacture's defect first (especially if there are several which have similar appearance). If not, I would investigate the possibility of excessive pressure during previous years. If this system has large air pockets and there is a possibility that the building temperatures have decreased and increased; the system might have experienced pressures well above 95 psi. I realize sprinkler heads are rated for 175 pis; however, my experience suggests system presssures above 250-300 psi can/will cause problems. Sometimes the heads burst, sometimes they leak and sometimes they become deformed (as in the attached picture). If the system does not have a properly located ITC (attached near the end of the system and fed from the highest portion of the system), the system probably has trapped air pockets. This is one reason why I think the provision of the ITC at the sprinkler riser (located 1-2 ft. downstream of the flow switch) is a bad idea/design. I realize this system was installed prior to the code change which allowed the ITC at the riser; however, I figured it is worth a quick mention for other systems which have large air pockets due to this approach.

Good Luck

 

[ContractorDave]

cdafd
I may do that. No fire pump. City pressures are unlikely to reach much higher than the 100psi currently seen at the riser in the basement, though of course there are always anomolies.

FFP1
I noticed the bulb wasn't centered precisely also, but the bulb I removed from the sprinkler who's seal washer and bell plug are shown in the initial post pic seemed fine. The common denominators seem to be location and what appears to be a plastic or somesuch coating coming away from the seal washer. So I would tend to think as you say that it may be a manufacturers defect.
As mentioned to cdafd, the pressures here are rarely excessive, though I can't confirm if there has been any instances of the local FD connecting a pumper to the system and pressuring up during a test run or false alarm, though this would seem imprudent.
As to the idea of an inspectors test being installed at the highest point being a solution to excessive trapped air, in a system such as this where there's two levels of "mall" and then an additional 4 stories of hotel that does not cover the whole of the mall, large volumes of trapped air is inevitable? I would respectively suggest that there could never be a system wholly devoid of trapped air though a good designer will try and mitigate this inherent problem with a good design. I've always wondered why air reliefs were never incorporated into sprinkler systems.

Thanks both for your response

Regards
Dave

 

[FFP1]

I tend to agree with the need for 175 psi relief valves on all systems (rather than just gridded systems).

If you have two seperate areas (one 2 story and one four story) with no easy way of discharging the air from both sections, you probably have a significant trapped air problem. The "excessive" pressure problem probably occurred in the spring or fall (when temperature changes between night and day are more extreme). The damage could have occurred several years ago, but the heads are just now beginning to leak. I have seen MANY systems which have 200-300 psi during Spring and Fall months while the same systems have normal system pressure during Summer and/or Winter months.

Look into the manufacturer defect possibility, but do not discount the trapped air pressure theory. Ask the customer if they have ever had false alarm problems. If the false alarms occurred during early summer or late fall and usually at night or during the early morning hours, I would bet $ this is the source of your problem!

Good Luck