push fitting of storm rain water pipe - dislodging

[moideen]

The storm rain water system in our 10-year-old, 5-story building is experiencing a persistent issue with water leakage. Specifically, during rainfall, the PVC push fitting on the mezzanine floor (which houses offices and a shared lobby) becomes loose. This fitting connects the header, which spans and links all drainage pipes from the various risers.
The movement and shaking of the pipe header during rain cause the Y or bend fitting to dislodge, resulting in water falling to the floor. Unfortunately, this problem has occurred consistently since the building opened, causing damage to equipment on the mezzanine floor, including a lift.
The branch pipe size in the risers is 110 mm, while the headers on the mezzanine floor measure 160 mm. The current support system consists of 10 mm threaded rods for both the header and branches.
To address this issue, there is a proposed plan to install new pipe supports using a C-channel bracket support measuring 100*50*40 mm. Before undertaking this potentially costly job, I would appreciate your insights and comments on the viability and effectiveness of this solution.


The problem with the world is that intelligent people are full of doubts, while stupid ones are full of confidence.
-Charles Bukowski-

 

[1503-44]

Please post a picture or describe the type of pipe and joint system.?

Might be better to address the pullout problem directly by holding the joints together.
Pull-push joints often can be supplied with a mechanical joint lock to keep them from pulling out.

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[TugboatEng]

This may be more costly than brackets. You mention 5 stories. If there is head pressure due to insufficient pipe diameter you may need to replace all of the piping with larger diameter.

 

[1503-44]

The joint locks will hold higher pressures, thereby allowing a higher max flow, but yes, a bigger D, could also help.

The floor drains are larger due to the flat pipe slopes. If they are filling and causing the back pressure, it will be a really big job.

A reanalysis of the system to determine the cause of the apparent system pressure increase due to the rainwater flow and what needs to change to solve it should be the first order of business.


--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[PEDARRIN2]

Plumbing Codes typically do not allow push type joints in a building.

They also typically require some type of lateral support at changes in direction when the pipe is in the size range being discussed. Typically would use something like

https://www.eaton.com/content/dam/e...eismic-bracing/fig-4l-il309015en-instrsht.pdf

Also, PVC pipe is usually solvent welded. Before you do other costly methods, try to fix the faulty joint.

 

[r6155]

Are you sure there is no blockage in the piping?

Regards

 

[LittleInch]

That was my thought- is this really a push fit fitting or a glued fitting with no glue?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[r6155]

Try a borescope inspection.
Regards

 

[moideen]

@ 1503-44 - These are PVC pipes with push fittings. There are no visible mechanical joints. I'll attach the images. As you mentioned, the slope needs to be rechecked. If the slope is incorrect, static pressure inside the header may build by while water filling the riser.
@ TugboatEng- Appointed a team to study the total number of drain outlets and recheck the pipe size.
@PEDARRIN2- As far as I am aware from the site, the technician applies adhesive to the same fitting.
@N r6155-Not sure, it is to be checked.


The problem with the world is that intelligent people are full of doubts, while stupid ones are full of confidence.
-Charles Bukowski-

 

[moideen]

the lay out

The problem with the world is that intelligent people are full of doubts, while stupid ones are full of confidence.
-Charles Bukowski-

 

[1503-44]

Have to invent a glued collar, or something, or just replace the problem joints with thermowelds joints of some kind. Time to get creative?

--Einstein gave the same test to students every year. When asked why he would do something like that, "Because the answers had changed."

 

[LittleInch]

Not easy to see what's going on there, but I think someone just cut a length of the pipe too short or installed it in the wrong sequence and then couldn't get it to fit. You need to build pushfit from the bottom up otherwise you have real fun getting it it fit together.

Maybe the picture isn't great, but the pipe looks like it isn't cut square?

Which bit is leaking exactly?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[TugboatEng]

U-Bolt clamps do not restrain axially, in fact there is supposed to be a small gap between the U-bolt and pipe which is why they come with double nuts.

We can see the the pipe is shifting in the clamp by the white colored markings in the picture. Do consider replacing the clamp with one that offers axial restraint.

 

[r6155]

Option: inject air and check for leaks, if possible.

Regards

 

[LittleInch]

Agree about the U bolts for sure.

Push fit systems need to be restrained axially in line otherwise they move and detach.

If that lower line was held in place then you wouldn't have the issue. Looking at the marks it seems the main line is able to move a lot to the left hand side.

That's what you need to solve.

We can't see what's tot eh left. Can you sketch this up or add more photos?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.