Vertical drop on 32mm waste

[DaveyH]

Hi,

Just I the process of replumbing our bathroom for new bath, sink and shower. I am moving the sink to a different wall.

Is it ok to have vertical drop in a 32mm waste pipe? The vertical bit is 45cm long. Inside the house the 32mm pipe is 1 meter long and has a fall of approx 1 in 20.

I have already made up the pipe work, it all just needs solvent welding together.

Here is a photograph of it, with various pipes labelled.

Untitled

• DaveyH
• 22 Feb 2014
• 1

The vertical bit is 32mm and goes into a 32-40mm converter, it then joins the waste from the shower.

Inside the house the 40mm pipe to the shower is about 1m long and has a fall of approx 1 in 30.

I have also added 2 rodding access points.

Also is what I've done ok as far as building regs are concerned.

PS. In our area all rainwater and all waste all ends up going down the same underground drains. I believe on new housing estates they are kept separate.

Thanks in advance.

 

[GavThePlumber]

It is your house , do what ever you like.

It will most likely need a anti vacuum trap, like
http://www.screwfix.com/p/anti-vac-bottle-trap-32mm/15739

 

[GavThePlumber]

Also, use a 135 bend if you can or at the minimum a 92.5

 

[DaveyH]

Thanks for replying.

I wasn't sure if having vertical bit of pipe would cause a similar effect to turning an open bottle of water upside down, ie the water inside the pipe would go glug glug glug and not flow as good as it would, when you tilt the bottle. If that makes sense, it’s really hard to find the right words sometimes.

Where the 32mm pipe exits the house I have used a 92.5 degree swept T with a rodding access point solvent welded into the top.

 

[GavThePlumber]

Thanks for replying.

I wasn't sure if having vertical bit of pipe would cause a similar effect to turning an open bottle of water upside down, ie the water inside the pipe would go glug glug glug and not flow as goof as it would, when you tilt the bottle.

It is called induced siphonage.

If you put normal p/s traps in this install, it will suck them dry and thus you will have a smelly sewer gas filled room

 

[DaveyH]

Thanks for replying.

I wasn't sure if having vertical bit of pipe would cause a similar effect to turning an open bottle of water upside down, ie the water inside the pipe would go glug glug glug and not flow as goof as it would, when you tilt the bottle.

It is called induced siphonage.

If you put normal p/s traps in this install, it will suck them dry and thus you will have a smelly sewer gas filled room

Cheers.

I totally understand what you mean, but on our setup I'm not sure if traps really do much, because outside the house, our bath, sink and shower wastes all join with rainwater via a big funnel thing (I think it’s called a hopper). You can see it in the right hand side of the photo on my first post. Do we have an unusual setup or is this quite common?

Also, the soil pipe is total separate (above ground), but I know for a fact underground the soil and wastes(+rainwater) all feed into the same drains.

 

[GavThePlumber]

I totally understand what you mean, but on our setup I'm not sure if traps really do much, because outside the house, our bath, sink and shower wastes all join with rainwater via a big funnel thing

Google what i said, it doesn't matter if you are open/vent/hopper/mace

This pipe work is not to the correct standard, if you want it to work you need vac traps, i am not after a debate on this, so good luck.

 

[DaveyH]

Google what i said, it doesn't matter if you are open/vent/hopper/mace

This pipe work is not to the correct standard, if you want it to work you need vac traps, i am not after a debate on this, so good luck.

Sorry. I didn't mean to offend, your help is greatly appreciated.

So. What would I need to change on this, to make it to the correct standard, ie eliminate the possibility of siphonage. At the end of the day I just want it all to work correctly.

Would something like this have been better (see the red lines)?

Untitled

• DaveyH
• 22 Feb 2014
• 1

Because I can easily change it at moment, as nothing has been solvent welded yet and I've got some pipe left to play with.

Thanks

 

[DaveyH]

Would a completely separate pipe be even better still, maybe something like this?

Untitled

• DaveyH
• 23 Feb 2014
• 1

 

[chantelle]

Just tilt the external elbow to 45 degrees then take it across on that angle then drop at the lowest point to join the main pipe to your hopper or do as your second foto.

 

[DaveyH]

Just tilt the external elbow to 45 degrees then take it across on that angle then drop at the lowest point to join the main pipe to your hopper or do as your second foto.

Thanks for your reply.

I think I will probably go for photo 2 and keep the pipes completely separate.

Thanks for the help chaps.

 

[Nige F]

[
I think I will probably go for photo 2 and keep the pipes completely separate.

Thanks for the help chaps.

that`s better but you`ll still need an anti vac trap on the basin

 

[DaveyH]

[
I think I will probably go for photo 2 and keep the pipes completely separate.

Thanks for the help chaps.

that`s better but you`ll still need an anti vac trap on the basin

Really? What do I actually need to do to then, to eliminate completely the possibility of induced siphonage or is it just going to be impossible on this kind of setup?

 

[Nige F]

a.v trap or a tee where the pipe goes outside ( like a cleaning tee ) reduce the end to overflow pipe size and have a short length of overflow vertically up the wall - that`s an old fashioned " puff pipe "

 

[MJGas]

Maximum run on 32mm waste is 1.7m