Just back from a trip to the friends *grand design* house in Suffolk.

Lots and lots of glass but the thing which caught my eye was long waste
runs.

I have some vague idea that anything over 4m is likely to empty water
traps.

Have I got this wrong?

regards
--
Tim Lamb

On 19/08/2012 10:07, Tim Lamb wrote:
Just back from a trip to the friends *grand design* house in Suffolk.

Lots and lots of glass but the thing which caught my eye was long waste
runs.

I have some vague idea that anything over 4m is likely to empty water
traps.

Have I got this wrong?

That depends upon the bore and flow rate. In one of my factories,
building control insisted that I used 50mm waste pipe, instead of the
more usual 32mm, for hand basins with a long run and, just to be sure,
fit a running trap just before it entered the soil stack.

Colin Bignell

[Default] On Sun, 19 Aug 2012 10:07:47 +0100, a certain chimpanzee,
Tim Lamb , randomly hit the keyboard and
wrote:

Lots and lots of glass but the thing which caught my eye was long waste
runs.

I have some vague idea that anything over 4m is likely to empty water
traps.

Have I got this wrong?

That's the theory. Approved Document H gives limits on diameters of
pipes; = 1.7m for 32mm, =3m for 40mm & =4m for 50mm. If it's over
this you can install an anti-vac trap (*).

(* There are other ways involving lots of ventilating pipes which I've
never seen outside of institutional buildings more than 50 years old.)
--
Hugo Nebula
"If no-one on the internet wants a piece of this,
just how far from the pack have I strayed"?

Tim Lamb wrote:

Just back from a trip to the friends *grand design* house in Suffolk.

Lots and lots of glass but the thing which caught my eye was long waste
runs.

I have some vague idea that anything over 4m is likely to empty water
traps.

Have I got this wrong?

regards
I have over 5m on the minimum slope - it does not empty traps - in fact,
opening up a rodding point (cap on top) shows even an emptying bath to only
fill the pipe 1/2 way, leaving an air break over the top.



--
Tim Watts

Tim Watts wrote:

Tim Lamb wrote:

Just back from a trip to the friends *grand design* house in Suffolk.

Lots and lots of glass but the thing which caught my eye was long waste
runs.

I have some vague idea that anything over 4m is likely to empty water
traps.

Have I got this wrong?

regards
I have over 5m on the minimum slope - it does not empty traps - in fact,
opening up a rodding point (cap on top) shows even an emptying bath to
only fill the pipe 1/2 way, leaving an air break over the top.


I should add that is in 50mm. It did exceed the building regs guides, but it
works in practice.
--
Tim Watts

On Sun, 19 Aug 2012 13:33:17 +0100, Tim Watts wrote:

Tim Lamb wrote:

Just back from a trip to the friends *grand design* house in Suffolk.

Lots and lots of glass but the thing which caught my eye was long waste
runs.

I have some vague idea that anything over 4m is likely to empty water
traps.

Have I got this wrong?

regards
I have over 5m on the minimum slope - it does not empty traps - in fact,
opening up a rodding point (cap on top) shows even an emptying bath to only
fill the pipe 1/2 way, leaving an air break over the top.

I suppose if the outlet from the basin etc. was sufficiently restricted the
pipe wouldn't fill up.
I noticed a few years ago that modern outlets had as low as, at a guess, 25%
open area - my 60 yo outlets must be 80% and do fill the pipes.
Of course, a HepvO has no such limit.
--
Peter.
The gods will stay away
whilst religions hold sway