I'm not sure about the meaning of a test I did. First, let me explain that
my grey/rain water
all empties into a gully on the side of my house. I think it empties into a
salt-glazed sewer pipe.
The sewer pipe is buried under a concrete ledge running along the side of my
house.

After about 8 feet horizontally a soil pipe from the upstairs loo enters the
same concrete ledge, and joins the same sewer pipe, i.e. my sewage and
rainwater all empty into the same pipe. Just before the sewer pipe reaches
the road there is an inspection chamber, and whilst looking in there for a
completely separate reason, I rashly decided to do a leak test.

I bunged up the sewer pipe in the inspection pit, then went to the gully and
ran water into it until it
filled up the ceramic pipe draining the gully to the lip. The water level
then dropped two inches in some 40 seconds or so, then dropped much more
slowly. I repeated the test and listened for what I could hear along the
route of the sewer pipe, and distinctly heard water gurging for 40 seconds
where the soil pipe enters the concrete ledge.

Sorry to bang on in such detail, but my question is, would you folks expect
the ( unseen ) join between a soil pipe and a sewer pipe to be airtight, or
is it arranged so that flowing water coming down the soil pipe negotiates
the join ok, but standing water being pushed back up a few inches
above that join will leak out?

Do I have a problem, or am I meddling with stuff I don't understand? :-)

Andy.

In an earlier contribution to this discussion,
andrewpreece wrote:

I'm not sure about the meaning of a test I did. First, let me explain
that my grey/rain water
all empties into a gully on the side of my house. I think it empties
into a salt-glazed sewer pipe.
The sewer pipe is buried under a concrete ledge running along the
side of my house.

After about 8 feet horizontally a soil pipe from the upstairs loo
enters the same concrete ledge, and joins the same sewer pipe, i.e.
my sewage and rainwater all empty into the same pipe. Just before the
sewer pipe reaches the road there is an inspection chamber, and
whilst looking in there for a completely separate reason, I rashly
decided to do a leak test.

I bunged up the sewer pipe in the inspection pit, then went to the
gully and ran water into it until it
filled up the ceramic pipe draining the gully to the lip. The water
level then dropped two inches in some 40 seconds or so, then dropped
much more slowly. I repeated the test and listened for what I could
hear along the route of the sewer pipe, and distinctly heard water
gurging for 40 seconds where the soil pipe enters the concrete ledge.

Sorry to bang on in such detail, but my question is, would you folks
expect the ( unseen ) join between a soil pipe and a sewer pipe to be
airtight, or is it arranged so that flowing water coming down the
soil pipe negotiates the join ok, but standing water being pushed
back up a few inches
above that join will leak out?

Do I have a problem, or am I meddling with stuff I don't understand?
:-)

Andy.


Is it possible that you trapped some air in the pipe - which subsequently
gurgled out, causing the water level to fall? If so, you may not have a leak
at all.

Although I'm not by any means an expert, my impression is that leak tests
are normally performed by bunging up *both* ends of a pipe and then
pressurising it with air - and measuring the pressure drop over a specified
time.
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.

"Set Square" wrote in message
...
In an earlier contribution to this discussion,
andrewpreece wrote:

I'm not sure about the meaning of a test I did. First, let me explain
that my grey/rain water
all empties into a gully on the side of my house. I think it empties
into a salt-glazed sewer pipe.
The sewer pipe is buried under a concrete ledge running along the
side of my house.

After about 8 feet horizontally a soil pipe from the upstairs loo
enters the same concrete ledge, and joins the same sewer pipe, i.e.
my sewage and rainwater all empty into the same pipe. Just before the
sewer pipe reaches the road there is an inspection chamber, and
whilst looking in there for a completely separate reason, I rashly
decided to do a leak test.

I bunged up the sewer pipe in the inspection pit, then went to the
gully and ran water into it until it
filled up the ceramic pipe draining the gully to the lip. The water
level then dropped two inches in some 40 seconds or so, then dropped
much more slowly. I repeated the test and listened for what I could
hear along the route of the sewer pipe, and distinctly heard water
gurging for 40 seconds where the soil pipe enters the concrete ledge.

Sorry to bang on in such detail, but my question is, would you folks
expect the ( unseen ) join between a soil pipe and a sewer pipe to be
airtight, or is it arranged so that flowing water coming down the
soil pipe negotiates the join ok, but standing water being pushed
back up a few inches
above that join will leak out?

Do I have a problem, or am I meddling with stuff I don't understand?
:-)

Andy.


Is it possible that you trapped some air in the pipe - which subsequently
gurgled out, causing the water level to fall? If so, you may not have a
leak
at all.

Although I'm not by any means an expert, my impression is that leak tests
are normally performed by bunging up *both* ends of a pipe and then
pressurising it with air - and measuring the pressure drop over a
specified
time.
--
Cheers,
Set Square

It is possible some air was trapped I suppose, but the sound I heard was
trickling,
definitely water on the go. At any rate, no air would have been trapped in
the soil pipe,
as of course it opens to the air at the eaves via the stench pipe.

Also, I repeated the test three times, with identical trickling noises, and
a fall of the free
surface of the water by about 2" over about 40 seconds, whereupon it slowed
to less
than an inch over 5 minutes.

I cannot perform an air pressure test without much ado, but if you say that
a sewer pipe
should be able to pass an air leak ( when stopped up at the ends ) then I
reckon I've
definitely got a problem. I wasn't sure if a metal soil pipe-to-glazed sewer
pipe connection
had to be air tight or merely be able to take a vertical fall of water
without leaking ( in the
same way a roof is waterproof but not watertight ).

thanks,

Andy.

There should be a trap between the gully and the junction.
After that it should be airtight.

In an earlier contribution to this discussion,
andrewpreece wrote:


I cannot perform an air pressure test without much ado, but if you
say that a sewer pipe
should be able to pass an air leak ( when stopped up at the ends )
then I reckon I've
definitely got a problem. I wasn't sure if a metal soil
pipe-to-glazed sewer pipe connection
had to be air tight or merely be able to take a vertical fall of water
without leaking ( in the
same way a roof is waterproof but not watertight ).


Whilst again not claiming to be an expert, I believe that it needs to be
air/water-tight so that leakage doesn't occur into the surrounding soil if
the pipe ever gets blocked further down, and backs up.
--
Cheers,
Set Square
______
Please reply to newsgroup. Reply address is invalid.

On Thu, 28 Jul 2005 11:07:55 +0100, "Set Square"
wrote:

In an earlier contribution to this discussion,
andrewpreece wrote:


I cannot perform an air pressure test without much ado, but if you
say that a sewer pipe
should be able to pass an air leak ( when stopped up at the ends )
then I reckon I've
definitely got a problem. I wasn't sure if a metal soil
pipe-to-glazed sewer pipe connection
had to be air tight or merely be able to take a vertical fall of water
without leaking ( in the
same way a roof is waterproof but not watertight ).


Whilst again not claiming to be an expert, I believe that it needs to be
air/water-tight so that leakage doesn't occur into the surrounding soil if
the pipe ever gets blocked further down, and backs up.


When you put a new pipe in, its necessary to preasure test it in the
way being done here, to ensure there are no leaks.

I assume the desire is to stop groundwater contamination, and
unplesant odor.

Rick

"O.B." wrote in message
oups.com...
There should be a trap between the gully and the junction.
After that it should be airtight.

There is a trap leading off from the gully. It was whilst cleaning sediment
from the trap ( yuk! ) that I
decided to do a leak test.

I've decided to bash away the concrete cube that was cast around the bottom
of the soil pipe where
it enters the concrete ledge on the side of my house and have a look. I will
try and post what I find in case anyone is interested, as the leak test I
performed is quite easy for anyone ( with the same plumbing ) to do.

Andy.

Well, as in the previous thread of the same name I have now smashed open
the concrete surrounding the joint between the cast iron soil downpipe and
the saltglaze sewer pipe where I fancied I had a leak and found a cavity
about a cubic foot in size and a badly cracked 135 degree salt-glazed pipe
which connects into the rainwater drain from the gully, via a teeing-in
pipe.

The teeing-in pipe has cracked flanges too, though it doesn't visibly drip
water like the
cracked soil pipe connection: that lost half a cup of water each time I
flushed the loo.

Questions:_

Is it best to replace like with like, or can I use plastic sewer pipe?

Do I have to take up two sections of sewer pipe at the same time, in order
to be able to fit them together?

Is it easy to separate salt-glazed sewer pipes that have been cemented
together at the join without running the risk of fracturing the good pipe?

If there are hairline cracks on glazed pipes, can I just coat them with
something
( I dunno, like bitumen ) an bury them back in concrete?

cheers,

Andy.

andrewpreece wrote:
Well, as in the previous thread of the same name I have now smashed open
the concrete surrounding the joint between the cast iron soil downpipe and
the saltglaze sewer pipe where I fancied I had a leak and found a cavity
about a cubic foot in size and a badly cracked 135 degree salt-glazed pipe
which connects into the rainwater drain from the gully, via a teeing-in
pipe.

The teeing-in pipe has cracked flanges too, though it doesn't visibly drip
water like the
cracked soil pipe connection: that lost half a cup of water each time I
flushed the loo.

Questions:_

Is it best to replace like with like, or can I use plastic sewer pipe?

Plastic is fine, you'll need connectors, though, and the pipe should
be encased in concrete.


Do I have to take up two sections of sewer pipe at the same time, in order
to be able to fit them together?

Depends on your connectors...


Is it easy to separate salt-glazed sewer pipes that have been cemented
together at the join without running the risk of fracturing the good pipe?

No, it's difficult. You *might* be able to do it by
stitch-drilling into the mortar in the socket, but
you're likely to break the socket anyway.


If there are hairline cracks on glazed pipes, can I just coat them with
something
( I dunno, like bitumen ) an bury them back in concrete?

Replace or encase in concrete.