D2 disharge

[gingalig]

Hi, I appreciate any help here apologies if it's not the right forum.
I want to clarify that a D2 discharge can be into a 32mm polylropolene pipe with a hepvo trap/tundish with push fit. I would like to be able to fit down the outside of a building with a cage at the outlet with an air gap. If I've managed to misinterpret the regs can you put me straight.

Many thanks

 

[ShaunCorbs]

Nope you have them correct just need to clip well and use pushfit pipe

You can go into the stack aswell

 

[gingalig]

Nope you have them correct just need to clip well and use pushfit pipe

You can go into the stack aswell

Thank you Shaun. As always a well of knowledge and Information. Cheers.

 

[Last Plumber]

Will it stand the heat?

 

[ShaunCorbs]

Will it stand the heat?

Yes push fit will take the reg of 90 plus for x amount

https://www.bpfpipesgroup.com/media/20922/Discharge-from-unvented-hot-water-storage-cylinders-into-plastic-sanitary-pipework-systems.pdf

 

[gingalig]

Will it stand the heat?

I've usually done them in Copper but from my understanding of the regs your D1 has to be copper with the 300mm drop then a mcalpine hepvo trap/tundish with correctly rated polypropylene 32mm pipe discharge acceptable.

 

[ShaunCorbs]

I've usually done them in Copper but from my understanding of the regs your D1 has to be copper with the 300mm drop then a mcalpine hepvo trap/tundish with correctly rated polypropylene 32mm pipe discharge acceptable.

Depends on the length for pipe dia

 

[Last Plumber]

Does this make sense to you?

G3 Document.

3.57 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 (e.g. as specified in the relevant part of BS 7291- 1:2006 Thermostatic pipes and fittings for hot and cold water for domestic purposes and heating installations in buildings. General requirements)


BPF Pipes Group.

The BPF Pipes Group and its members strongly advise that pipes manufactured to BS 7291: 2006 (Parts 1 to 3) are not used for the downstream pipe D2.

 

[gingalig]

Does this make sense to you?

G3 Document.

3.57 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 (e.g. as specified in the relevant part of BS 7291- 1:2006 Thermostatic pipes and fittings for hot and cold water for domestic purposes and heating installations in buildings. General requirements)


BPF Pipes Group.

The BPF Pipes Group and its members strongly advise that pipes manufactured to BS 7291: 2006 (Parts 1 to 3) are not used for the downstream pipe D2.

It does, although there is an article in CIPHE that refers to the british plastic federation suggesting the use of polypropylene pipework secured at 300mm spacing and conforming to B.S EN 1451-1:2000 is suitable downstream of D2 via an approved tundish adaptor and water less trap. On condition that any connected pipework or soil stack is verifiable. My query was, as there is no access to a soil stack, was if it was ok to discharge through the polyethylene pipework providing a cage at termination with a visible air gap, as the pipework would be verifiable. Which following Shaun's comment and some further reading seems ok.

 

[Last Plumber]

It does, although there is an article in CIPHE that refers to the british plastic federation suggesting the use of polypropylene pipework secured at 300mm spacing and conforming to B.S EN 1451-1:2000 is suitable downstream of D2 via an approved tundish adaptor and water less trap. On condition that any connected pipework or soil stack is verifiable. My query was, as there is no access to a soil stack, was if it was ok to discharge through the polyethylene pipework providing a cage at termination with a visible air gap, as the pipework would be verifiable. Which following Shaun's comment and some further reading seems ok.

Yes. I would say so. I get mine off BES but there are others.
Whilst we are on this subject. Can you see anything wrong in running say a 22mm D1 to termination above ground with a cage?
In other words, no tundish. There are situations where a tundish is not visible and would be pointless. There are also situations where the run is too far to get the fall on a D2. What are your thoughts on those situations?

 

[gingalig]

I suppose it would depend on the install, my understanding is that a tundish should allow a visible indicator of any potential issues. And at worst you could probably hear if there was a large escape through prv. I was called to a unvented that had been diy,d a while back and you could hear the water running through the tundish as well as the give away of large pool of water on the floor where the d2 was not connected once it was routed behind the cylinder, the expansion had been connected via a t into the hot outlet which wasnt permissible and inlet set had been blanked off. I can see that a d1 direct to outside would do the job and take your point that some pipework is really hard to visibly see, but if remotely possible would always want to see the tundish as any issues could be ignored or not noticed. Saying all that I'm G3 but not massively familiar with unvented and mainly just try and join the dots.

 

[chris watkins]

I've usually done them in Copper but from my understanding of the regs your D1 has to be copper with the 300mm drop then a mcalpine hepvo trap/tundish with correctly rated polypropylene 32mm pipe discharge acceptable.

Good practice to do the D1 in copper but I don't think I have ever seen anything in Regs to say it must be, just the limitation of its length (Max 600mm) & minimum diameter, otherwise this could effect the through put of water & therefore the kW rating of the Temperature relief valve.
The is no requirement for a 300mm drop on the D1 before the tun-dish. The 300mm minimum is on the D2 after the tun-dish to reduce the risk of discharge water backing up & overflowing.
When using a HepVO trap connected to the tun-dish (BV1/21 kit) it will ensure that there is always the 300mm due to its total length (hep valve will act a non-return anyway).

 

[gingalig]

Good practice to do the D1 in copper but I don't think I have ever seen anything in Regs to say it must be, just the limitation of its length (Max 600mm) & minimum diameter, otherwise this could effect the through put of water & therefore the kW rating of the Temperature relief valve.
The is no requirement for a 300mm drop on the D1 before the tun-dish. The 300mm minimum is on the D2 after the tun-dish to reduce the risk of discharge water backing up & overflowing.
When using a HepVO trap connected to the tun-dish (BV1/21 kit) it will ensure that there is always the 300mm due to its total length (hep valve will act a non-return anyway).

Sorry my bad, mixing me d1s and d2s, every days a shcool day, thanks for the input, always better to understand why and how than just join the dots ;-)

 

[Stigster]

Just for info - For those that can get their D2 to the discharge point within the 9 metres minus 0.8 for any bends, I have been interested in using Tectite Flexible Metal tube. It only comes in 15 and 22mm hence restricted to the 9 metre run but looks like a useful product for the job.

It takes the required heat, is flexible with its aluminium layer and stays bent, easily routable and comes in straight lengths and coils for jointless runs.

Just a heads up but it looks useful in some installations. Pegler Yorkshire -

 

[ShaunCorbs]

I don’t believe that is suitable/ acceptable stig

 

[Stigster]

I don’t believe that is suitable/ acceptable stig

May I ask why as as far as I can tell it meets the requirements. Happy to learna nd be corrected though of course.

 

[ShaunCorbs]

May I ask why as as far as I can tell it meets the requirements. Happy to learna nd be corrected though of course.

I believe temp it’s not rated for discharge I think might be worth an email to peg

 

[Stigster]

I believe temp it’s not rated for discharge I think might be worth an email to peg

It's rated to 95 degrees stamped on it which is above discharge temperature. Pegler themselves state in a press release it does "handle temperatures of more than 100°C and working pressures up to 16 bar." but that probably doesn't count and what's actually written on the pipe does.

The regs state it must be capable of withstanding the discharge temperature and T&P relief valves discharge below that temperature.

 

[ShaunCorbs]

It's rated to 95 degrees stamped on it which is above discharge temperature. Pegler themselves state in a press release it does "handle temperatures of more than 100°C and working pressures up to 16 bar." but that probably doesn't count and what's actually written on the pipe does.

The regs state it must be capable of withstanding the discharge temperature and T&P relief valves discharge below that temperature.

That’s decent to know I would still ask peg then you have no reason not to be able to use it

 

[Stigster]

That’s decent to know I would still ask peg then you have no reason not to be able to use it

Yes confirmation from the manufacturer would be ideal. I do think I could justify using it if ever questioned but official word would remove any doubt.