fire sprinkler return bend

[cda]

nfpa 13 does not seem to say anything on the length a drop can be after the return bend

just wonder if any thoughts about that.

this is on a pre action system any thing in the code about having to drain each drop after a trip??

any other thoughts about return bends???

 

[Coug Dad]

Return bends make tenant changes easier since you do not have to drain the entire zone to relocate or add sprinklers. Draining the drops would be needed if it is an area subject to freezing. If it is a heated area and the preaction is provided for some other reason, you would not need to drain the drops. Return bends are also good if the water can have a lot of contaminent like sediment. The return bend helps prevent clogging of the sprinkler.

 

[FM William Burns]

Watch out for freezing (if applicable) even if design calls for insulation over the piping (seen it and refuse it). I have always seen residual water remain in the drops but as CD mentions, if the area where they are applied is heated the drainage won't be an issue. If the area is heated you may want to make note on acceptance test inspection that "in areas where return bends are installed we (insert dept.) recommend inspection/drainage annually during the facility's NFPA 25 inspection proccess" since you never know.........

 

[cda]

just seemed strange for a certain reason, to see these long drops on a pre action, when they are trying to keep the water off of stuff, and there is no requirement in nfpa to drain them.

Oh well this job would not be interesting if we did not see the stange and unusual every day

 

[Insurance Engineer]

The reason a return bend is required is to reduce junk from getting into the pipe and clogging the orifice, not water in the pipe. The return bend requirement is also for dry pipe systems in heated areas. I see more of a problem when return bends were not required, I think prior to 1994 edition of 13. The junk in the pipe would fill the drop, harded, and no water would come out of the head. With the return bend the junk has less chance of getting into the drop and clogging the orifice.

When I do not see a return bend I ask them to take a few drops apart to see if they are clogged. If clogged I make them install return bends or a dry pendent sprinklers.

FM Burns not sure why you want annual inspection of the of return bend drops? Can you provide more detail?

 

[FM William Burns]

InsEng:

As noted just a CYA recommendation since it’s covered but hard to enforce and it is an area in the system’s piping where corrosion can occur if not checked/inspected and thus creates the potentials for pipe/system ineffectual operation regardless of 5.2.2.3 and as mentioned…..you never know. I do however understand the rationale you provided but witnessed a loss in a assisted living center five or so years ago related to the insulation example mentioned.

NFPA 25

5.2.2* Pipe and Fittings.Sprinkler pipe and fittings shall be inspected annually from the floor level.

A.5.2.2 The conditions described in 5.2.2 can have a detrimental effect on the performance and life of pipe by affecting corrosion rates or pipe integrity or otherwise rendering the pipe ineffectual.

5.2.2.1 Pipe and fittings shall be in good condition and free of mechanical damage, leakage, and corrosion.

 

[Gene Boecker]

InsEng:As noted just a CYA recommendation since it’s covered but hard to enforce and it is an area in the system’s piping where corrosion can occur if not checked/inspected and thus creates the potentials for pipe/system ineffectual operation regardless of 5.2.2.3 and as mentioned…..you never know. I do however understand the rationale you provided but witnessed a loss in a assisted living center five or so years ago related to the insulation example mentioned.

NFPA 25

5.2.2* Pipe and Fittings.Sprinkler pipe and fittings shall be inspected annually from the floor level.

A.5.2.2 The conditions described in 5.2.2 can have a detrimental effect on the performance and life of pipe by affecting corrosion rates or pipe integrity or otherwise rendering the pipe ineffectual.

5.2.2.1 Pipe and fittings shall be in good condition and free of mechanical damage, leakage, and corrosion.

I'm back on the soapbox again.

Get a corrosion protection system for the sprinkler system so that there isn't junk that can harden and clog the lines. This also reduces the potential for leaks and extends the life of the system.

NFPA 25: 5.2.2.1 almost begs for a corrosion protection system.

 

[FM William Burns]

You know, I too like that brand of soap.