By tuftythesquirrel - November 26th, 2022, 1:42 pm
- November 26th, 2022, 1:42 pm
#9577
Hi, I have an issue regarding the discharge pipe from the hot water cylinder temperature and pressure relief valve from the fitted by the tank manufacturer and where it is terminated.
Particularly in a passive house, where a fully ventilated soil stack would appear to be undesirable.
Our general layout of the house soil pipes, we have a main pipe that traverses the length of the house, then 5 off 110mm spurs that go to each point of use e.g. bathrooms, bedrooms, kitchen etc. At the end of each spur there is an air admittance valve to prevent siphoning. So no soil stack as such.
Note my references below apply to the Welsh versions of the building regulations. Also before anyone points out that I need a G3 qualification to do this, my arrangement with my heating engineer is that I will do all the donkey work e.g. fitting the supporting unistrut, tanks, pipework and he will do all the clever stuff, gas work, testing and commissioning to sign it off.
Normally, the discharge would go via a 15mm copper pipe into a waterless tundish, then via a 22mm copper pipe to the outside world. So not great for a passive house. There is a section and diagram in the Building Regs. Approved Document (G3.50), describing the general D1/D2 arrangement and pipe lengths etc. However, it seems to be the trend to use a dry tundish that has a 32mm outlet that allows the fitting of an appropriate plastic waste pipe (as made by Hotun/McAlpine etc.). This can also be terminated on the soil stack, via a separate pipe, again permitted in the building regulations in G3.60.
My question is, am I OK to terminate my 32/40mm soil pipe onto the 110mm soil stack, when it is not fully ventilated and only has the AAV’s.
I always try to read and understand the regulations for each aspect of the build and that is why I am asking. I read the regulations and though I was OK. However, I then read the Part G FAQ’s (link below) in relation to G3.60 which says that the stack must be fully ventilated. If I hadn’t read it I would be blissfully ignorant.
https://assets.publishing.service.gov.u ... _G_FAQ.pdf
I also read a few other articles, the first below by the CIBSE and the second from the NHBC standards. One mentions the fully vented requirement, the other doesn’t.
https://www.cibsejournal.com/technical/ ... k-systems/
https://www.nhbc.co.uk/binaries/content ... stems-.pdf
Our BCO’s are fairly laid back and don’t seem to want me to jump through too many hoops, so I might be lucky. By the way my heating engineer says it conforms to the regulations.
Any assistance would be appreciated.
Particularly in a passive house, where a fully ventilated soil stack would appear to be undesirable.
Our general layout of the house soil pipes, we have a main pipe that traverses the length of the house, then 5 off 110mm spurs that go to each point of use e.g. bathrooms, bedrooms, kitchen etc. At the end of each spur there is an air admittance valve to prevent siphoning. So no soil stack as such.
Note my references below apply to the Welsh versions of the building regulations. Also before anyone points out that I need a G3 qualification to do this, my arrangement with my heating engineer is that I will do all the donkey work e.g. fitting the supporting unistrut, tanks, pipework and he will do all the clever stuff, gas work, testing and commissioning to sign it off.
Normally, the discharge would go via a 15mm copper pipe into a waterless tundish, then via a 22mm copper pipe to the outside world. So not great for a passive house. There is a section and diagram in the Building Regs. Approved Document (G3.50), describing the general D1/D2 arrangement and pipe lengths etc. However, it seems to be the trend to use a dry tundish that has a 32mm outlet that allows the fitting of an appropriate plastic waste pipe (as made by Hotun/McAlpine etc.). This can also be terminated on the soil stack, via a separate pipe, again permitted in the building regulations in G3.60.
My question is, am I OK to terminate my 32/40mm soil pipe onto the 110mm soil stack, when it is not fully ventilated and only has the AAV’s.
I always try to read and understand the regulations for each aspect of the build and that is why I am asking. I read the regulations and though I was OK. However, I then read the Part G FAQ’s (link below) in relation to G3.60 which says that the stack must be fully ventilated. If I hadn’t read it I would be blissfully ignorant.
https://assets.publishing.service.gov.u ... _G_FAQ.pdf
I also read a few other articles, the first below by the CIBSE and the second from the NHBC standards. One mentions the fully vented requirement, the other doesn’t.
https://www.cibsejournal.com/technical/ ... k-systems/
https://www.nhbc.co.uk/binaries/content ... stems-.pdf
Our BCO’s are fairly laid back and don’t seem to want me to jump through too many hoops, so I might be lucky. By the way my heating engineer says it conforms to the regulations.
Any assistance would be appreciated.
- By Handyman14