Tenement drains

[Windmill]

There are repeated problems caused by blockages in the external
drainpipes used on most of Edinburgh's 100-year-old tenement buildings.
Sometimes a block near ground level, sometimes a blocked vent pipe,
sometimes siphoning of water from sink traps, cause unknown.

And, nowadays at least, it seems to be allowed that people can run sink
drains into external WC drainpipes.

What's the best anti-siphoning design for a water trap? The basic S
shape seems inadequate.


--
Windmill, Til...@Nonetel.com Use t m i l l
J.R.R. Tolkien:- @ O n e t e l . c o m
All that is gold does not glister / Not all who wander are lost

[polygonum]

On Sun, 16 Oct 2011 00:59:11 +0100, Windmill
<spam-n...@onetel.net.uk.invalid> wrote:

> There are repeated problems caused by blockages in the external
> drainpipes used on most of Edinburgh's 100-year-old tenement buildings.
> Sometimes a block near ground level, sometimes a blocked vent pipe,
> sometimes siphoning of water from sink traps, cause unknown.
>
> And, nowadays at least, it seems to be allowed that people can run sink
> drains into external WC drainpipes.
>
> What's the best anti-siphoning design for a water trap? The basic S
> shape seems inadequate.
>
>

You could always try HepVo. We have three (bathroom & cloakroom). Seem to
work OK.

--
Rod

[A.Lee]

Windmill <spam-n...@Onetel.net.uk.invalid> wrote:

> There are repeated problems caused by blockages in the external
> drainpipes used on most of Edinburgh's 100-year-old tenement buildings.
> Sometimes a block near ground level, sometimes a blocked vent pipe,
> sometimes siphoning of water from sink traps, cause unknown.
>
> And, nowadays at least, it seems to be allowed that people can run sink
> drains into external WC drainpipes.
>
> What's the best anti-siphoning design for a water trap? The basic S
> shape seems inadequate.

An air admittance valve/fitting somewhere in the waste pipe, or, an
anti-siphon U bend. These let air into the sytem, but dont allow it out,
so, in theory, rather than sucking water through the U bend, it should
allow air to be sucked in instead.
Something like these:
<http://www.toolstation.com/shop/Plumbing/Air+Admittance+Valves/d20/sd31
36>


--
To reply by e-mail, change the ' + ' to 'plus'.

[PeterC]

Yup. No siphonage, no blow-back, no evaporation etc.
http://www.a-s-m.com/hepvosanitarywastevalve.html
--
Peter.
The gods will stay away
whilst religions hold sway

[Andy Dingley]

On Oct 16, 7:29 am, polygonum <rmoudndg...@vrod.co.uk> wrote:

> You could always try HepVo. We have three (bathroom & cloakroom). Seem to  
> work OK.

They're good in Northern tenements with outside pipes - no water traps
to freeze.

[Dave Plowman (News)]

In article <Lt4tA...@freebie.onetel.net.uk>,

Windmill <spam-n...@Onetel.net.uk.invalid> wrote:
> There are repeated problems caused by blockages in the external
> drainpipes used on most of Edinburgh's 100-year-old tenement buildings.
> Sometimes a block near ground level, sometimes a blocked vent pipe,
> sometimes siphoning of water from sink traps, cause unknown.

Don't whoever cleared the blockage know what caused it? Likely the usual
suspects - nappies etc. And fat.

--
*Pride is what we have. Vanity is what others have.

Dave Plowman da...@davenoise.co.uk London SW
To e-mail, change noise into sound.

[Windmill]

Andy Dingley <din...@codesmiths.com> writes:

>On Oct 16, 7:29=A0am, polygonum <rmoudndg...@vrod.co.uk> wrote:

>> You could always try HepVo. We have three (bathroom & cloakroom). Seem to=
> =A0

>> work OK.

>They're good in Northern tenements with outside pipes - no water traps
>to freeze.

Seems to be a good idea. But how long do they last?

[Windmill]

An excellent suggestion. Didn't know they existed, though it seemed
likely that there would be something of the sort.

But I'm wondering how they would function under a kitchen sink, where
you might expect the drain water to contain rice grains, carrot
peelings, congealed fat, etc. etc.

[Windmill]

Very compact. That would cure siphoning problems, but not overpressure,
I think.
And a blocked/partly blocked downpipe at street level, one or two dozen
feet below, is not uncommon.
Maybe I'll need to try both this and one of those HepVo gadgets another
poster suggested.

[Windmill]

"Dave Plowman (News)" <da...@davenoise.co.uk> writes:

>In article <Lt4tA...@freebie.onetel.net.uk>,
> Windmill <spam-n...@Onetel.net.uk.invalid> wrote:
>> There are repeated problems caused by blockages in the external
>> drainpipes used on most of Edinburgh's 100-year-old tenement buildings.
>> Sometimes a block near ground level, sometimes a blocked vent pipe,
>> sometimes siphoning of water from sink traps, cause unknown.

>Don't whoever cleared the blockage know what caused it? Likely the usual
>suspects - nappies etc. And fat.

Spot on, according to hearsay. Nappies, sanitary towels, etc.

The people who would know for certain would be the organisations the
City hires to fix the problem (because getting all the owners to agree
to fix it themselves is nearly impossible).
Having the City do it has the advantage of spreading the financial pain
when the bill is split perhaps 16 or 20 ways among all owners.
The disadvantage is that sometimes the City gets too cosy with the
plumbing companies.

[PeterC]

On Tue, 18 Oct 2011 04:55:26 GMT, Windmill wrote:

> Andy Dingley <din...@codesmiths.com> writes:
>
>>On Oct 16, 7:29=A0am, polygonum <rmoudndg...@vrod.co.uk> wrote:
>
>>> You could always try HepVo. We have three (bathroom & cloakroom). Seem to=
>> =A0
>>> work OK.
>
>>They're good in Northern tenements with outside pipes - no water traps
>>to freeze.
>
> Seems to be a good idea. But how long do they last?

I fitted one to a sink that takes a lot of crud from various breeds of
take-aways and it's given no trouble for about 10 years now.

[fred]

In article <Lt4tA...@freebie.onetel.net.uk>, Windmill

<spam-n...@Onetel.net.uk.invalid> writes

>There are repeated problems caused by blockages in the external
>drainpipes used on most of Edinburgh's 100-year-old tenement buildings.
>Sometimes a block near ground level, sometimes a blocked vent pipe,
>sometimes siphoning of water from sink traps, cause unknown.
>
>And, nowadays at least, it seems to be allowed that people can run sink
>drains into external WC drainpipes.
>
>What's the best anti-siphoning design for a water trap? The basic S
>shape seems inadequate.
>

On the blockages themselves I have had experience of these on external
stacks on Glasgow tenements which are generally 6" cast iron for soil
and 3" cast iron for waste water.

I haven't seen problems on the soil stack but have seen it on the waste
stack. Corrosion on the inside of the pipe gives a key for hair and
washed off skin/body fat which eventually builds up on the pipe. Once
this builds up to a certain thickness it appears to fall off in lumps
leading to blockages.

Our solution is to periodically clean the stack down with a strong
caustic soda solution. I make up half a kilo of caustic in a 2 gallon
bucket, pour it down the bath trap, leave it for thirty minutes, half
fill the bath with hot water then let this go at once to flush down the
stack. The idea is to repeat this at each floor, starting at the bottom
but of course this requires the cooperation of all owners/occupiers.

With this approach I've not had a problem with traps being sucked out.

I can't see any reason for the vent to get blocked on its own but could
imagine a partial blockage below the top flat making it look like the
vent was obstructed.
--
fred
FIVE TV's superbright logo - not the DOG's, it's bollocks

[Windmill]

fred <n...@for.mail> writes:

>On the blockages themselves I have had experience of these on external
>stacks on Glasgow tenements which are generally 6" cast iron for soil
>and 3" cast iron for waste water.

Similar in Edinburgh, I believe.

>I haven't seen problems on the soil stack but have seen it on the waste
>stack. Corrosion on the inside of the pipe gives a key for hair and
>washed off skin/body fat which eventually builds up on the pipe. Once
>this builds up to a certain thickness it appears to fall off in lumps
>leading to blockages.
>Our solution is to periodically clean the stack down with a strong
>caustic soda solution. I make up half a kilo of caustic in a 2 gallon
>bucket, pour it down the bath trap, leave it for thirty minutes, half
>fill the bath with hot water then let this go at once to flush down the
>stack. The idea is to repeat this at each floor, starting at the bottom
>but of course this requires the cooperation of all owners/occupiers.

Which can be difficult to arrange, especially nowadays when people work
all kinds of hours.

>With this approach I've not had a problem with traps being sucked out.
>I can't see any reason for the vent to get blocked on its own but could
>imagine a partial blockage below the top flat making it look like the
>vent was obstructed.

That could be it.

Anyway if I get more reports of smells I'll find out what the last bill
from the City was all about (it's usually drains, but I've forgotten)
and ask what their procedures are.

I'm a bit worried about the possibility of jamming in these HepVo things
when grease etc. builds up, but it seems to me that you could put one
below a standard U bend.

Belt AND braces, sort of thing.

And maybe even add an AAV below the HepVo gadget (at least one of
these seems to have been designed so that it doesn't have to be above
sink level).

Of course the smell might be drifting in from the flat below.......

[The Natural Philosopher]

Not another pensioner died and not been found for 3 months...?

[Windmill]

The Natural Philosopher <t...@invalid.invalid> writes:

>> Of course the smell might be drifting in from the flat below.......
>Not another pensioner died and not been found for 3 months...?

I never see people in tenement stairs gossiping together, yet somehow
the grapevine always knows all about everything.
So it puzzles me when no one notices someone hasn't been seen for
months.

Maybe it's just the papers following the 3 laws of journalism: make it
short/snappy/up.