Bath pipe to Soil pipe

[cdh]

Hi

Building an extension, but need to move the bath waste pipe from the outside wall.

I intend to connect the sink waste pipe to the bath waste pipe using a T piece and then running the one pipe into the soil stack.

Do I have to use 50mm pipe to meet building regs?

Thanks

 

[wingcoax]

I'm not an expert on plumbing but i think you are not allowed to run grey water(sink & bath)into black waste(toilet)something to do with bio bugs at the sewage works.

 

[kevplumb]

news to me

 

[advancedplumber]

doing that will not be against building regs but teeing individual sanityware appliances together ie wash hand basins, baths and showers can cause syhonage of the traps. here comes the science!!! all small wastes under 2 inch (or 50mm) should go straight into the main stack as they will all then be vented. if u tee 2 together ( not including the toilet as it is already 4 inch) then as the water is running along the smaller bore pipe and meets the tee joint it can pull or syhon the water out of the trap at that piece of sanityware, causing the foul gases to come up the pipes and enter the room. thats what the trap does, traps the smell. i have seen it done and folk get away with it but i have been to loads of places where say if u empty a bath or washhand basin and theres a gurgling noise at a shower tray waste followed by the fowl smell. so be aware.