Drainage testing

[jamieled]

A couple of questions for those who have done this.

 

1) What does a drainage test (witnessed by BC) involve? How much, if any, internal foul drainage pipework is required? Does it include the treatment plant?

 

2) Are inspection chambers and rodding points supposed to be airtight? If not, how are they dealt with in a pressure test?

[ProDave]

Our BC officer witnessed the pressure test on the external drains early on in the build.  For that the internal pipes were plugged.  the risers and lids of the inspection chambers all had O ring seals and they held pressure.

 

Later when I connected the treatment plant BC were unable to attend so just noted it as done.

 

Likewise even later when testing the internal pipework they were unable to attend. In case they want to see it, I videod where the tester was connected and then a boring 2 minute video of it holding pressure.

[jamieled]

Cheers.  Reason for asking is I have a metal ic cover (Due to location) with no seal and I can't see it being airtight. Same with rodding points. Trying to figure out whether I have the wrong bits or whether they don't need to seal.

[ProDave]

They will probably just make you test each run individually. Having sealed IC's just meant the whole lot could be done in one test.

[Mr Punter]

Often have to put a bung in either end of the run. Sometimes with external runs you put a bung at the far end and fill the whole underground runs with water.

[CC45]

bung in the outflow pipe of our last chamber, filled up the system to the top of the chamber.  Waited 10 mins - no drop for us so onto the final test. Remove bung (nearly lost the bugger down the pipe due to the force of the water) and look at how quick the water flowed.

 

I worried a lot about this but all went well.

[Redoctober]

Yes we had two drainage tests - One once the drains had been fitted and BEFORE they were buried and the second one was once the plumber had installed the sanitary ware.

With us the BC asked for the drainage runs to be blocked up using rubber type bungs either end and then they were pressure tested with a bike pump type instrument [ excuse the terminology but thats what it looked like]. Our builder mentioned that some BCO's have a golf ball which they roll along the pipework to ensure there is sufficient run on them!