Pressure Testing Newly installed system

[paulandfrodo]

Hi,

I've got a terrace that has been refurbished. As part of the refurbishment new plumbing through out.

It's not vented, but has a dergo at the top of the SVP.

I've used a pressure test kit and inflatable plugs and all the underground stuff is fine - sticks at 100, ok, drops to 90 after 5 mins.

The rest of the system....

If I block all of the soil pipes off (at manhole) and then try the normal test...

Either, the pressure increases and I get air bubbles coming through the toilet highest in the system. Or I get bubbles (not the monkey) coming through shallow traps (Bath).

This has all been in place for 3 months and I've got no leaks, no smells ect.

BUT I've got my building reg's sign off on Friday and need to prove it's air tight...

I would appreciate your comments.

Paul.

p.s. I'm in Winchester area. Why is it that ONLY toolstation sell inflatable plugs ? Tried Williams, PTS, BSS, Plumb Centre !!

 

[muggles]

Good luck getting that signed off. What pressure are you testing your stack to? If you have fitted shallow bath traps you need to change them as they do not comply with regs when connected to a soil stack. The minimum acceptable trap seal on a bath or shower is 50mm depth, if yours are less then you must change them. The correct test for internal waste pipework is 38mm for 3 minutes, with all traps maintaining a minimum 25mm seal

 

[paulandfrodo]

BC are happy with the use of Dergo - which incidentally is off 3" at the top of the stack - due to falls and running between joists. BC are happy with the use of the 3" too.

The bath is a shallow trap and not a P-Trap. This is due to the distance between the bottom of the bath and the floor, your pretty limited in what you can get in without hacking the floor away, which I was attempting to avoid, not through the work, just for keeping the floor intact.

All of my sinks are dip tube traps, so should be fine - as are my two showers.

My washing machine (not attached) has a fanny trap - but that's fine.

 

[paulandfrodo]

Mmm... Just been reading R.D Treloar 2nd Edition.

Yep, looks like my bottle traps are fine. Shower traps are fine - under adverse pressure - the water just pushes up but no bubbles.

So, it's the bath that might continue to be the issue. I presume the shallow traps are in place for refurbs - which is how BC are viewing this work.

I've just thought. As the bath water runs into the SVP at a location I can get to, I could put a P-Trap in before I go into the SVP. this would save having to remove the tiles from the bath. As the sink and shower also discharge into this same pipe I could do all three in one !! Even though the other two are fine...

Paul.

 

[muggles]

I'm afraid BC will not look kindly upon your excuse of wanting to keep the floor intact, rules is rules and if you have non-compliant traps installed you'll be well advised to change them before BC turn up to inspect, otherwise you'll end up getting charged for a revisit when they fail you and make you change them. You don't need a P-trap, just a bath trap with the correct seal depth, and yes you may well need to cut the floor out, which will be much more difficult to do now the bath is installed.

You never mentioned the 3" in your first post so I find your mentioning it now a little puzzling, but yes you can use 3" for the dry portion of the stack with no issues.

Incidentally, going back to your first post, the correct test for underground drainage is to raise it to 110mm for five minutes prior to testing, after which it should be able to hold 100mm for 7 mins, not 5.

 

[paulandfrodo]

Muggles,

Don't get me wrong. I would not leave the trap in place and use excuses of the floor for no doing the right thing. This my own house not a job for a client (as I am not a jobbing plumber but have done my NVQ's some time ago).

I have no problems doing the right thing and have no problem removing tiles - A hatch for access has been left so it's not big problem. I do this as a matter of course on anything I might need to get to later (Plumbing or Electrics). Cutting the floor won't be a problem with a Fein Multimaster - great machines.

Sorry for mentioning the 3" didn't mean to throw the cat amongst the proverbial pigeons. You can use 3" for wet as well as dry - as long as you've only got a single WC going down it, but it 's not ideal - it's a design compromise.

In relation to the underground pressure test, I was just going by manufactures instructions. I am happy to run for 7 mins.

Thank you for your reply.

Just so you can see part of what I've done. This is a before and after of one room

After. Please note all panels removable - with bevel (looks nice that square) and 6mm gap around edges


Before (top of SVP is incoming from bath) Yes, all heating runs come in here too


After Geberit Frame installed, because I only wanted to loose 250mm into the Utility room

 

[tamz]

If you are struggling to get the correct seal trap in use a hepV0.

All traps on a single stack system should be 75mm seals

I presume the shallow traps are in place for refurbs

One pipe fully vented. (totally different system)

 

[paulandfrodo]

Ah, yes, what is commonly know (sorry it's course) as a fa**y trap ! I've used one to resolve a problem due to space restrictions available to the trap. All the other traps are 75mm bottle. Bottle as they are cheaper.

 

[muggles]

All traps on a single stack system should be 75mm seals

Since when? Just re-checked building regs and it definitely says 50mm for baths and showers, 75mm for basins and sinks

 

[tamz]

My mistake it is 50mm for baths/showers and 75mm the rest. Type too fast for the brain to follow

 

[morrissey86]

Good luck getting that signed off. What pressure are you testing your stack to? If you have fitted shallow bath traps you need to change them as they do not comply with regs when connected to a soil stack. The minimum acceptable trap seal on a bath or shower is 50mm depth, if yours are less then you must change them. The correct test for internal waste pipework is 38mm for 3 minutes, with all traps maintaining a minimum 25mm seal

sound advice!

 

[paulandfrodo]

Well, after a little checking (tile removal) I did have a 50mm bath trap on.

The air loss turned out to be from 38mm to 28mm over 3 mins. The place had no wet patches, had been done (plastered and painted) for 3 months.

The place does now have access panels on ALL 90 deg bends for EVERYTHING.

signed off.. done.. next time, I will do it a little difference and test at EVERY stage prior to coving up.