Vent pipe question

[jerrythemole]

Hi, I want to reorganise my bathroom, but I have a problem with a 110mm vent pipe in the corner which is boxed in. The vent pipe continues up from the soil pipe and through the roof to outside. My question is can I reduce the size of vent pipe above the highest water inlet to the soil pipe section, this would save me a lot of hassle moving stuff around.

Thank you

 

[Bahco]

can I reduce the size of vent pipe above the highest water inlet to the soil pipe section,

Yes if you don't mind the smell of sewers in your house.

Do not touch!

 

[jerrythemole]

Thanks for your answer, but could you explain to me why reducing the size of pipe would cause smells?

Thanks

 

[seco services]

as now your soil pipe vents to outside.
reducing it to inside the bathroom it won't vent to the outside anymore.

 

[gigz]

Is it not possible to put a bend on the soil to outside and vent there ? (900mm above highest window)

 

[LUNAT]

HI


no problem

 

[wiggikins]

HI


no problem

 

[waterworks]

Your post is confusing me do you mean reduce the diameter of vent pipe or the length of it?.

You can use a air admittance valve on internal vent DURGO VALVE.

 

[jerrythemole]

Hi
I don't want to reduce the length of the vent pipe I just want to reduce the diameter of it. The soil pipe would stay the same I just want to alter the vent pipe section that runs from the top of the soil pipe up through my roof to outside.

 

[waterworks]

Not a good idea, better off to re-route it keeping it the same diameter.

 

[jerrythemole]

Thanks for the advice, One last question, will it be ok to have a couple of 90 degree bends in the vent pipe?

 

[waterworks]

Yes 90 degree bends in vent part of stack will be okay.

 

[lagunaglen]

Dont see how reducing diameter will cause a problem, have seen it done a lot in Leeds area where they have reduced it to run it up under tiles in loft conversions.

 

[waterworks]

Not only is a vent pipe used to ventilate drainage system it is also used to stop self siphonage on fittings connected to it ie WC pan, it sucks air from vent rather than pan where atmospheric pressure would remove the water seal.

Old systems used to be a 2 pipe system where a smaller anti syphon pipe was connected just behind pan especially where there was more than one wc on the same stack.

 

[jerrythemole]

Thanks for your answers, I didn't know there was so much to think about with a vent pipe.