Toilet waste and buchan traps question

[billy_smith]

Hi,

I've had a plumber at my house as I'm doing a loft conversion,Now I require a new 4" soil pipe installed and the plumber came today and said that he could branch into an existing drain above ground to run the new 4",However on another quote I got the other plumber said that I could not branch into that existing 4" drain as there is a buchan trap there and it will choke with the toilet waste,He reccomended digging up to expose the drain,cutting in a branch after the buchan trap and running a new section of drain from there ?!

This is a combined drainage system according to both plumbers !!

What option sounds correct as I have no idea ??

 

[Nige F]

Do they know what the buchan heal they are on about . I had to google it it`s better known down here as an interceptor trap..and it goes in the last manhole before the main sewer/ cess pool . It`s supposed to have solids flowing through it - though they do often block. Can you post some pics. Or we`re likely to be talking @ cross purposes

 

[billy_smith]

Hi thanks for the reply,

Yep I just googled it also,It is also known as interceptor trap,So it would be perfectly acceptable to connect my 4" soil into this trap then ??

 

[seco services]

only one man that'll tell you what his happy with and thats the bc.

 

[billy_smith]

I've drawing from the architect and they are as clear as mud,All it shows is my new 4" stack connected into drainage out the back !!

As you say though,BC will be quick enough to pick any problems.

 

[Nige F]

The interceptor will be right at the end of the drain run I still don`t see what the 2 plumbers are on about --were they Gas Fitters

 

[Hugh Jaleak]

Where does the existing W.C. go to? The interceptor is usually fitted just before the boundary before the sewer exits the property to join the main. Any existing W.C. plus all other drainage from the house (inc rainwater on a combined system) will go through the interceptor.

I cannot see any reason why the new stack cannot be connected to the drain at the nearest convenient point, may require a new manhole, but BCO will make that decision on site.

 

[billy_smith]

This interceptor is just before the manhole at the back of my property,My rainwater,bathwater and kitchen sink run into it,My WC waste must be branched after the interceptor as when the pan is flushed there is no movement in the interceptor but when I run the bath there is movement in the interceptor.

I managed to get hold of a local council plumber that stays a few doors down from me and he says running the WC waste into the existing drain and using the interceptor isn't a problem ! He says there designed to work with waste products from th WC ?!

 

[Nige F]

Just what I said- " it`s supposed to have solids through it"- Though it`s strange that your WC doesnt go through it . Any combined systems down here have trapped gullies under the rainwater downpipes . That seals the RW from the sewer. Sounds like you have a system where the RW and -for convenience- sink etc. are separated by the interceptor, Must be common in your town , But if you then put a WC before it - you are in effect letting the WC vent it`s smells tthrough the rainwater pipes . So it`s me and the Council guy that are right I`ll Bet the Building officer won`t let you go into drain before the buchan - but not for the reason your plumber said

 

[sooey]

Are you sure he said "that buchan trap"?