Utility Drainage 110mm - Trap?

[Spinny]

Builder has run 110mm underground  drainage pipe through footings into a new utility room to provide drainage for sinks and appliances.

 

There is a 110mm 90 degree bend on the end of the pipe to bring the drain in and up to floor level.

 

Is this ‘correct’ or should there be a 110mm water trap fitted to bring the drain in and up whilst stopping toilet/drain smells from coming up into the utility room ?

 

Also a boiler condensate and a HW cylinder tun dish will discharge into this drain.

[Iceverge]

 

Ours used these. 

 

Seem to work ok. The Trap is on the bottom of the sink/shower/whatever to stop smells. 

 

I suppose it might leak around the rubber eventually. 

 

On the plus side the lack of "U"bend will make it easier to rod if that's ever an issue. 

 

 

[kandgmitchell]

Or this

 

UGW40D_d79ddae1-9e46-4a5d-9c1c-6cd0ce090fe7.pdf

[Spinny]

Thanks. He has currently fitted the first of these.

 

I am uncomfortable with this as it doesn’t seem like a fully permanent seal. We have had an occasional blocked drain and if this happened in the future things could back-up along the drain. If it isn’t a good seal, in the worst case we could end up with toilet waste leaking out into the subfloor void hidden from view & access. So I think the second seems better.

 

Q1 But maybe the 110mm pipe should be extended up to just above floor level anyway (rather than hidden under the floor?)

 

Ofher questions are:

Q2 The smaller horizontal waste pipe is for boiler condensate. Can’t see anything to stop smells coming up that pipe ?

Q3 A UVC tundish needs an outlet which might be routed into this drain pipe - how can I tell if the soil pipe is good enough for high temp (95C) water ?

Q4 Is there a PB or PEX waste pipe fitting with a mechanical seal to comply with section 3.60 of the G3 regs ?

 

 

[dpmiller]

where is the 110 going- could you put a back-inlet trap just outside the house?

[OwenF]

23 minutes ago, dpmiller said:

where is the 110 going- could you put a back-inlet trap just outside the house?

This. I’ve just done the same for my utility (going to be taking sink, washing machine, condensate and tundish)

However, this has got me wondering if the back entry gulley forms an effective trap. The invert of incoming/outgoing is above the reservoir. I guess the little bottle insert must do the ‘trapping’

 

[OwenF]

1 hour ago, Spinny said:

Q1 But maybe the 110mm pipe should be extended up to just above floor level anyway (rather than hidden under the floor?)

 

I extended the 90 up so the ‘nut’ of the 40mm adaptor sits just above structural floor level (chipboard). This will be below a base unit, which won’t get tiled so theoretically I could get to the 110mm opening with a minor floor cut.

at worst I can rod direct at the adaptor

[Temp]

We have same 110mm coming up through floor, rubber adaptor to 40mm and a trap under the sink. Been fine since 2007.

 

[Spinny]

1 hour ago, Temp said:

We have same 110mm coming up through floor, rubber adaptor to 40mm and a trap under the sink. Been fine since 2007.

 

OK thanks but have you ever had a blocked drain ? We have every few years as neighbours drain also runs into our manhole. Most recently the builder blocked things by dropping a piece of 40mm waste down it. If it backs up and leaks it would be very costly taking up a heated floor, units, worktop, sink etc.

[Spinny]

2 minutes ago, Spinny said:

However, this has got me wondering if the back entry gulley forms an effective trap.

I don’t have a back entry gully on mine though, just straight pipe into an access point about 2m away.

[Spinny]

Anyone know about Q2/3/4 ?

[Temp]

1 hour ago, Spinny said:

OK thanks but have you ever had a blocked drain ? We have every few years as neighbours drain also runs into our manhole. Most recently the builder blocked things by dropping a piece of 40mm waste down it. If it backs up and leaks it would be very costly taking up a heated floor, units, worktop, sink etc.

 

No but the drains were pressure tested so they are air tight at least at the very low pressures of the test.

[Temp]

1 hour ago, Spinny said:

OK thanks but have you ever had a blocked drain ? We have every few years as neighbours drain also runs into our manhole. Most recently the builder blocked things by dropping a piece of 40mm waste down it. If it backs up and leaks it would be very costly taking up a heated floor, units, worktop, sink etc.

 

No but the drains were pressure tested so they are air tight at least at the very low pressures of the test.

 

Would a rigid adapter be better?..

 

https://www.plastics-express.co.uk/110mm-single-waste-adaptor-40mm-p-pte384?gad_source=1&gclid=CjwKCAiA0PuuBhBsEiwAS7fsNd5pdI_QWgEGsQK9BDJaplSn8aLIZC2QICfQYJdVtHmSE7pAMV4rqBoCWVEQAvD_BwE

 

[Dave Jones]

there wont be any smells as the stack is required to be vented at roof level. bog and sink booth have built in traps.