blue wrote:
Hi there,

I'm sorry if this is a bit long, but I'm hoping that I'm making myself
reasonable clear.

I'm trying to recover my 3rd bedroom (back bedroom), which is currently
the bathroom/wc
(victorian end-of-terrace 3 up/3down)

Don't particularly want to revert to the original design of outside wc
and a tin bath in the kitchen, although I guess that would be 'real
restoration'

Anyhow, I figure that by jiggering around with the layout of the
'middle' bedroom and the corridor from stairs to 'back' bedroom I can
actually get 1 'ensuite' bathroom/wc for the main 'front' bedroom
(about 1900*1400 mm) and 1 'family' bathroom/wc (about 2500*140 mm)

I reckon that the longest conceivable run of foulwater pipework would
be 8800 mm (8.8 metre)
in a straight line to the outside of the back wall, with 90degree turn
and further 2000mm (2 metre)
run to the soil stack.

The back bedroom floor is 150 mm lower than the rest of the house

looking at the bldg reg approved document 'H' seems I would need
for bath/shower 40 mm pipe
for washbasin 32 mm pipe
for WC 100 mm pipe

as far as I can tell I need to allow 18mm fall per metre length for all
3 items
so for the (worst case) 8.8 metre run I would need to allow a drop of
159 mm

Now, I plan to raise the level of the back bedroom floor to the same
level as the corridor, So I *think* I can generate a big enough fall.
(possibly, perhaps, maybe hedge hedge caveat caveat)

But then further on in the 'document H' section H1 diagram 3 it seems
to suggest the following
max run for 32 mm pipe = 1.7 metre
max run for 40 mm pipe = 3.0 metre
max run for 100 mm pipe = 6.0 metre for a single WC (but in table 2
above the diagram it suggests that I could have a 15metre run if more
than 1 WC discharging into same pipe)

So at this point I get confused. Seems like the 'cleanish' foulwater
has to be generated closer to the soil stack than the 'nasty'
foulwater.

What am I reading rong please!

Cheers & thanks for listening

Che

The maximums are how far you can run that size pipe without an air
admittance, so if you connect the small wastes into the soil pipe under
the bathroom, you can run everything 6m. If you use HepVO valves
instead of traps for the basin bath and shower, that will give you air
admittance into the system, so the 8.8m should be fine.

A