Shower rooms, STPs, anti syphon traps and AAVs

[jfb]

I have a small shower room in a small outbuilding/office with waste plumbing as in the drawing.

It goes to a sewage treatment plant and this is vented at the end of the run through the roof of a barn conversion about 25m upstream of the shower room/office.

In the interest of the toilet not sucking water out of basin/shower traps is my best option:

 

1. fit anti syphon traps to both shower and basin

2. fit an AAV - if so where should it go? can it go where I indicate on the drawing or should it be closer to the toilet (upstream of the shower and basin)

3. Fit all the above.

4. Don't bother with any of them - it will all be fine!

[Gone West]

2 hours ago, jfb said:

2. fit an AAV - if so where should it go? can it go where I indicate on the drawing or should it be closer to the toilet (upstream of the shower and basin)

I would fit one where you have indicated.

[ProDave]

I would extend the pipe up above the WC and fit the AAV there.  There is a risk of sucking the water out of the basin trap when you flush the WC.

[jfb]

16 hours ago, ProDave said:

I would extend the pipe up above the WC and fit the AAV there.  There is a risk of sucking the water out of the basin trap when you flush the WC.

 

Could I just go for a basin trap with built in AAV as I will have some issues getting an AAV behind the toilet?

I think I hadn't quite clicked that an anti syphon trap is essentially an AAV.

[Russell griffiths]

Does that toilet not go out through the wall??

if it does how about a small stack outside. 

[Mike]

Building Regs Part H would be a good place to start.