Unvented cylinder discharge pipe

[Gromit]

Hello all

I am currently having a system boiler and unvented indirect cylinder fitted. The access to the outside for the discharge pipe is difficult and involves lifting chipboard floors so the engineer wants to connect it to a soil stack (I think it's called) - the big pipe that the toilet is connected to. Is this ok?

Many thanks and advice is much appreciated.

 

[GrahamM]

From a safety point of view, lift the boards and have the discharge outside where it is visible. It would need to be almost impossible to run the discharge outside to justify doing it any other way.
Having the discharge in a visible location may be the only way you know a very important safety device showing you something is wrong.

 

[kirkgas]

From a safety point of view, lift the boards and have the discharge outside where it is visible. It would need to be almost impossible to run the discharge outside to justify doing it any other way.
Having the discharge in a visible location may be the only way you know a very important safety device showing you something is wrong.

i dont really agree with what you are saying, properly connected to the soil stack with the right connection is acceptable as per MI so why would it be unsafe, having near boiling water outside isnt inherently safe, and if it does discharge down into the stack due to temp/pressure relief valve opening i'm sure you will hear it all over the house

 

[GrahamM]

As far as I am aware kirkgas the MI's for most cylinders and my own training state to comply with building reg. G3:
"ensure the discharge from any safety device is conveyed to where it is visible"

Ideally but not the only option is discharging between 70-100mm from ground into a drain.

Only if there is no other reasonable option alternative arrangements may be carried out for the discharge termination. In my opinion lifting a few boards would not be classed as a reason not to comply with the above.

 

[justlead1]

Hi. There are a few issues. The continuos fall required will be compromised with a trap, which will dry out providing the unit is behaving its self. The temp of discharge from temp relief valve (could be super heated steam)is hot enough to deform soil pipe if upvc. Unless changes to regs have taken place discharge pipe must be metal. The Mi. may not address uk buildig regs but European?

 

[kirkgas]

As far as I am aware kirkgas the MI's for most cylinders and my own training state to comply with building reg. G3:
"ensure the discharge from any safety device is conveyed to where it is visible"

Ideally but not the only option is discharging between 70-100mm from ground into a drain.

Only if there is no other reasonable option alternative arrangements may be carried out for the discharge termination. In my opinion lifting a few boards would not be classed as a reason not to comply with the above.

this is where i have an issue with how we all get trained and updated, you are right depending on when you were trained, i am right as i am using the current version of the training material, when you get re-assessed after the 5 yr period you will be given the version i have now and will see that you could have been using the HEP2O fitting to safely discharge to a soil stack, i'm not having a go as you are using what you were given, but you arent keeping yourself up to date with legislative changes, and depending on where you work someone isnt doing their duty by updating you (if you are an employee the firm has this job, if you are SE it is your job) the new unvented training/assessment material is a couple of months old now, so in theory you could be 4.5yrs away from getting the update, its the same with gas, how do you get updated? also you mention the MI you have, this will have been printed based on old info, download the new version of your cylinder to see if it mentions the new way to fit the D2 pipe

 

[tamz]

Perfectly acceptable to run to a stack
Have a read of this.

http://www.nhbc.co.uk/NHBCPublicati...ical/StandardsExtra/filedownload,34921,en.pdf
and this
http://content.wavin.com/__C12574CC0048F5D9.nsf/0/8D995E73907FFC85C12574CD0036249F/$FILE/HepvO_PG_032010.pdf

 

[justlead1]

Hi. Thanks for the up date

 

[GrahamM]

I like to think I keep upto date with current changes in procedure/regs as much as I can and it was only 4 months ago I done my unvented.
Why does it state in the latest Building Regulations Part G (April 2010) paragraph G3(3)(b)
"ensure that any discharge from safety devices is safely conveyed to where it is visible but will not cause a danger to persons in or about the building"?

This is the MI for the cylinder installations from the Heatrae Sadia and Ariston website they do not mention anything about terminating into a soil stack as far as I can see and appear to state following the regulation quoted above.
http://www.heatraesadia.com/docs/Megaflo_systemfit_-_Issue_5_-_36005882.pdf

http://www.ariston.co.uk/uploads/doc4ac4ac5b7dc27.pdf

If i am wrong I do not mind being told so and would just like to sort this out. Are the building regs and my recent teachings wrong ?

 

[Gromit]

Thank you all. In the event the joists went the right way and they have put the discharge externally without too much trouble. My brother in law works for the NHBC and one of his top guys didn't know the up to date rule about discharge pipes into stacks so it is clearly a complex subject.

 

[ocentric]

The key is to have the tundish so the discharge can be seen...

 

[GrahamM]

Not if it is in back of a cupboard. Are you going to have the tenant check the tundish on a regular basis on the off chance it may be passing?
That is why I was told the preferred option is to have the termination at ground level outside if possible. More chance of being noticed. Does not appear to be the case for others.

 

[Toddyplumb]

There is a self build estate near us and I am told on good authority ( although I have never seen it) That on one house the tundish was at the back of a cupboard and the only way building control would pass it was if it had a camera with a monitor in a visable place ? A lot of trouble I would have thought but you never Know

 

[tamz]

The preferred method will always be to outside but building methods and practices sometimes make this impractical.
Say in a multi storey building there may be over 100 flats. Now you could have 100 discharge pipes of various sizes, all labeled with the house number for easy identification or as would normally be the case there would be a few central discharge pipes feeding from many properties.
Either way it would not be easy to identify where the discharge was coming from and more than one could be discharging at the same time.

Things had to evolve to suit building practices and the HepVo filled that purpose.
High temperature plastics have always been available so when the correct materials are used there is no problem.

GrahamM

G3 3.56 states
The discharge pipe (D2) should be made of:
a. metal; or
b. other material that has been demonstrated to be capable of safely withstanding temperatures of the water discharged and is clearly and permanently marked to identify the product and performance standard (eg as specified in the relevant part of BS 7291) ie polypropylene

The tundish should be fitted in a visible position.

Bit of history lesson for anyone who may be interested.

When the regulations were first written sometime in 1987 (but were not due to be on the statute until late 1988) it was still standard practice in the uk for hot water to be storage fed. At the time no one really envisaged a time when all water in new build and most replacements would be potable. Combis, although they had been available since the 70's were rarely seen.
I did my unvented over the weekend of 16th to 18th October 1987 (i remember it as it was the weekend of the great storm when Sevenoaks became one oak). Before there was any unvented fitted anywhere in Britain. I left the course thinking this is the way to go.
I built a house in early 88 and fitted an unvented (3 bar polystel, state of the art?? looked like a big butane bottle) and had to delay moving in until July as the water board would not give me a supply because it did not comply with water regulations! I had to apply to the Secretary of State for Scotland for a class relaxation which, much to the annoyance of the water officer was given.
How things changed in such a short time and my small claim to fame, 1st domestic unvented cylinder fitted legit in Scotland

 

[buryboy]

GrahamM has a point. If no-one knows that the regs have changed or altered and even the Cylinder MI does not include the fact that you can now dishcharge into a soil stack. Something is massively wrong with our training/systems etc etc.
Must admit I didn't know that you can now discharge UV into a soil stack with HEP2o stuff. Now I know why I must have lost a job a couple of weeks ago. You live and learn!