Connection to main soil pipe

[fiaraziqbal]

Good morning,

 

I am laying out the design for a new build connection to.a main sewer line that runs on my land.  Its 160mm uPVC and i shall be connecting with a standard 110mm soil pipe.

 

I am only applying for the building regs as opposed to carrying out the actual work.  

 

I undestand all the componenets except for one, i have been asked to place a disconnection chamber into the design near the main swere pipe yet i do not seem to ba able to locate that specific componenet.  Is that the same as an inspection chamber? or does it have a different name?

 

 

Regards

fiaraz

Edited March 8, 2021 by fiaraziqbal

[ToughButterCup]

1 hour ago, fiaraziqbal said:

...

i have been asked to place a disconnection chamber into the design near the main swere pipe yet i do not seem to ba able to locate that specific componenet.  Is that the same as an inspection chamber? or does it have a different name?

...

Quote

What Is A Disconnecting Chamber?

Every new home that has a drainage system ought to have a disconnecting chamber. The manhole sits at the boundary of a home, where the foul pipe connects to the gravity pipework (just before it flows to the main sewers along the street).

Often, the point acts as a minor septic tank, receiving and storing sewer waste from the home for several days, even weeks.

Where is it located? The answer is better understood if the purpose is clear. It's placed away from the home to prevent the entry of sewerage gas into the home drainage system, which could lead to smells and other unpleasant effects. 

The size of the manholes depends on the number of branching drains connected to it. There should be enough room to access the disconnecting trap for drain inspection and routine cleaning. Some people use entrance covers with open grating, which serves as an air inlet, and others prefer airtight covers.

If the disconnecting chamber is in an isolated position, the lid is probably cast iron with a grating that serves a means of ventilation for the sewage. Otherwise, the chamber comes with a ventilating pipe that acts as an air inlet. It rises above the ground level, where an accidental emission of gases from manholes won't become a nuisance.

https://www.easymerchant.co.uk/underground-drainage/inspection-chambers/budget-manhole-bases-risers/

accessed 08032021

[Mr Punter]

Not ever had to put one of these in.  Is it a Scottish thing?

[Temp]

Google found this. Sounds like a combined u bend and air vent ? 

 

https://chestofbooks.com/architecture/House-Construction/Ventilation-Disconnection-And-Inspection-Part-2.html

 

"A disconnecting chamber or manhole within the curtilage of the premises and as near to the public sewer as possible. is infinitely better than a simple air-inlet pipe. The size will depend largely upon the number of branch-drains connected with it, but there should be plenty of room for access to the disconnecting-trap for inspecting the drain, and for cleansing it whenever required. The entrance-cover may be provided with an open grating to serve as an air-inlet, or it may be found preferable to use an air-tight cover, constructing an air-inlet in the manner shown in the last figure. Fig. 335 shows a section of a typical disconnecting chamber. In the drainage of town buildings, especially office premises, it is difficult to provide within the curtilage a disconnecting chamber, so that this will have to be constructed under the footway, subject to the approval of the local sanitary authority, who will no doubt not only exact a payment for the easement."

 

 

[Temp]

All the drawings i can find of a "disconnecting chamber" are very old. It appears to be located at the point where your private sewer becomes public. I'm wondering if they just want a regular inspection chamber at that point these days?

 

[PeterW]

3 minutes ago, Temp said:

All the drawings i can find of a "disconnecting chamber" are very old. It appears to be located at the point where your private sewer becomes public. I'm wondering if they just want a regular inspection chamber at that point these days?

 

That’s an old clay interceptor trap ..! Haven’t seen one of those in years ..! Real pig to clear and they fail and what happens is they flow over the top of the D entry point and people pull the plugs and they never get re-installed. 

[Temp]

More googling finds "Demarcation chambers" from several companies.

https://hspipe.uk/product/hs-demarcation-control-chamber/

https://www.mjabbott.co.uk/products/hs-r-demarcation-chamber

 

 

I think you may have to ask Building Control what they want unless someone else here knows. 

 

 

 

[TonyT]

https://www.gov.scot/publications/building-standards-2017-domestic/3-environment/37-wastewater-drainage/
 

section. 3.7.4

[Temp]

11 hours ago, TonyT said:

https://www.gov.scot/publications/building-standards-2017-domestic/3-environment/37-wastewater-drainage/
 

section. 3.7.4

 

That says one is required but unfortunately not what a "Disconnecting Chamber" actually is. It says they must be constructed in accordance with BS EN 752:2008 which was updated in 2017. I found a copy of the 2017 edition and it only has a one word reference to "Disconnecting" that doesn't help. 

 

Strange that if they are required nobody appears to make them, at least not under that name. 

[HerbJ]

The house I demolished for my new build had an old interceptor chamber. It was originally the lodge house for a Victorian mansion, which had been gradually subvivided into 10 plots large plots, from 1950 thorugh 1970. It was the last chamber on the system at the time. 

 

When I was dealing with Thames Water on my new build, I was told that they were first introduced in Victorian times:  in cities to stop smells(and rats) from the main system passing back to houses -  a real problem for terrace houses and the like - see https://www.labc.co.uk/news/my-dad-told-me-about-them-drain-interceptors. 

 

Anyway, I was told it was no longer necessary and could replace it with a new inspection chamber, which was a big help as this gave me an extra 200 - 250mm or so drop in invert level and improved my foul water drainage design/layouts.

Edited March 9, 2021 by HerbJ

[fiaraziqbal]

On 08/03/2021 at 09:19, ToughButterCup said:

https://www.easymerchant.co.uk/underground-drainage/inspection-chambers/budget-manhole-bases-risers/

accessed 08032021

that makes sense,i have come across a one way valve that can be attached to an inspection preventing back flow in case of flooding or bacl flow from scottish waters side.

[PeterW]

I’d try and avoid interceptors as they create a settlement point when the flow is low and they are really suited to old flush volumes etc and now you’ve dropped to 4 litre flush volumes the flows are much lower and slower. 

[fiaraziqbal]

As an update, a disconnection chamber in scotland is a standard inspection chamber and is the point at which the responsibility for piping belongs to scottish water.