Drains advice

[ScottishGasMan]

Again, on the subject of fitting new en-suit, I will be renewing the internal drains, which are currently sited as below (the thick pipe on the right being the 110mm foul drain for the toilet.

No Vent

• ScottishGasMan
• 15 Jun 2015

Am I correct in saying that this method is wrong, and where all feeds to the drain are trapped then there should be either a vent pipe or an air admittance valve at least to ensure correct drainage? as drawn below?

Vent

• ScottishGasMan
• 15 Jun 2015

And should the shower wastes be 40mm or should the whole lot be on 50mm pipe? And if so can you get a 50mm tee into a 110 soil pipe connection?

Thanks all

 

[Madrab]

Ideally for than number you would have a secondary/branch vent, to minimise the risk of syphoning/backflow on any of the traps.

Depending on whether the sink (basin ) and showers would be used at the same time, if so then I would also recommend 50mm on the branch run too.

Yes, you can run 50mm into a boss fitted onto the 110mm soil stack.

 

[ScottishGasMan]

Thanks, The sink and one shower are in the bathroom so they will never be used at once, theres actually another sink on top of that not shown in pic for the ensuit although flow from that will be tiny as will the boiler condensate, so the showers or a combination of one shower and sink could be used at same time, and there both powerful mixer ones run off of an unvented cylinder so might see about getting the 50mm for the main pipe then.

Ideally they would both be on seperate drains upto the soil pipe, but there simply is no room to have two seperate drains the way its been built.

thanks

 

[mogget]

Seems even Bathstore are calling them sinks now, English evolves I suppose as it always has done.