Page 1 of 2 12 LastLast
Results 1 to 12 of 21
Plumbing & Plumbers Forum - PB versus Pex, something not quite right
Like Tree6Likes

PB versus Pex, something not quite right

Discuss PB versus Pex, something not quite right at UK Plumbers Forums; I am converting a stone barn with 4 washrooms to fit and a remote boiler ( 3 Ph electric due to an abundance of solar power) I intended to fit ...
  1. #1
    Member
    Join Date
    Aug 2016
    Posts
    6
    Thanks
    0
    Thanked 1 Time in 1 Post

    Question PB versus Pex, something not quite right

    I am converting a stone barn with 4 washrooms to fit and a remote boiler ( 3 Ph electric due to an abundance of solar power) I intended to fit a hot water loop system, however on aquiring the required PB barrier pipe (polyplumb) i find that the application notes for this product say under no circumstances should this be used for this type of installation. So not being one to take this lying down I started digging a hole! first i spoke to polypipe to ask why? they said it was due to the oxygen content of the hot water being constantly circulated would over time strip away the barrier layer??? This sounded a little off so decided to speak to WRAS and ask if this also applied to Pex? they couldn't comment however in the course of the conversation it became apparent that WRAS approval for polypipe was originally for cold water use and that the approval for hot water had been achieved by a work around using Bs 7291 part 1 2 or 3. The WRAS approval expired in august and to date, no application has been made for re-approval, for either cold water use or for hot water use which would require a lengthy testing.
    Apart from this though, My question/concern is that my understanding is that Pex is also approved under BS7291 part 1,2 or 3 and also would not be suitable under this for use in hot water loop circuits yet many suppliers of Pex and PB are saying Pex is o/k
    WHAT IS GOING ON HERE?

  2. #2
    UK Plumbersforums Trusted Advisor.
    SimonG's Avatar
    Join Date
    Feb 2011
    Location
    in the land of make believe, in the county of durham, next best to Yorkshireland
    Posts
    16,038
    Thanks
    552
    Thanked 1,556 Times in 1,495 Posts

    Default Re: PB versus Pex, something not quite right

    Rural barn? Plastic pipes and mice dont mix.

    Secondary returns not to be done in plastic. Manufacturers say no, so do at your own risk.
    rpm and steveb like this.
    Fly Me To The Moon And Let Me Play Among Stars.............




    No I'm not cheap, but I'm happy in my work.

    Wouldn't you rather have somebody that's happy working in your house?


  3. #3
    Member
    Join Date
    Feb 2011
    Posts
    1,996
    Thanks
    1
    Thanked 242 Times in 232 Posts

    Default Re: PB versus Pex, something not quite right

    Quote Originally Posted by windycol View Post
    yet many suppliers of Pex and PB are saying Pex is o/k
    WHAT IS GOING ON HERE?
    Manufacturers test to their own standards and industry standards.
    Their own may exceed Industry.

    If a manufacturer says it's OK for recirculating, then it must be.
    Who have you found that say it can be used.?

    Speedfit
    Polypipe
    Marley
    Uponor
    Pipelife
    Wavin

    All the above are part of the Plastic Pipes Group, say not suitable.
    Last edited by snowhead; 13-09-2016 at 10:36 PM.

  4. #4
    Plumbers Arms member
    Chalked's Avatar
    Join Date
    Jan 2013
    Posts
    3,814
    Thanks
    89
    Thanked 452 Times in 440 Posts

    Default Re: PB versus Pex, something not quite right

    No pex or PB will allow circulated hot water. Only Uponor q&e is suitable.
    As above though, mice love pex and PB. Why not use copper?

  5. #5
    Member
    Join Date
    Feb 2011
    Posts
    1,996
    Thanks
    1
    Thanked 242 Times in 232 Posts

    Default Re: PB versus Pex, something not quite right

    From here;
    https://www.google.co.uk/url?sa=t&rc...x36DDQ&cad=rja

    Uponor MLC & Secondary circulation.

    Secondary circulation is classified as a system that:

     Provides potable hot water
     Maintains a temperature in excess of 65°C
     Replenishes water used in outlet with fresh water (oxygenated water) .
     Is a pumped circulation system.

    If all four of the points are covered your system is classified as a secondary circulation system (or recirculation system). Plastic pipeworks manufactured under BS-7291-1/3 2010 cannot be used in secondary circulation applications. Uponor MLC pipe can be used in secondary circulation because it is manufactured under a different standard (BS EN ISO 21003-1 2008) also because of the aluminum layer within the pipework it has a higher tolerance than a standard PEX pipe system. Although there still should be appropriate water temperature control on the system to ensure the water temperature does not exceed 70°C as stated in our guidelines.
    Last edited by snowhead; 13-09-2016 at 11:00 PM.
    Chalked and tolly like this.

  6. #6
    Member
    Join Date
    Jun 2013
    Posts
    1,743
    Thanks
    0
    Thanked 136 Times in 135 Posts

    Default Re: PB versus Pex, something not quite right

    Why is it that some of these pipe brands can be used for heating systems, circulating at the same or higher temperatures and not be a problem.

    As for Uponor pipe stating that the temperatures should not exceed 70 C, well that's barely above the temperature requirements for prevention of Legionella.

    Not sure what your regs state, but ours state, the circulation temperature should be a minimum of 65 C.

    I wouldn't use a product that gives the supplier a 'get out of gaol card' over a 5 C clause.



  7. #7
    Member
    Join Date
    Feb 2011
    Posts
    1,996
    Thanks
    1
    Thanked 242 Times in 232 Posts

    Default Re: PB versus Pex, something not quite right

    Quote Originally Posted by oz-plumber View Post
    Why is it that some of these pipe brands can be used for heating systems, circulating at the same or higher temperatures and not be a problem.

    As for Uponor pipe stating that the temperatures should not exceed 70 C, well that's barely above the temperature requirements for prevention of Legionella.
    Heating systems cycle On /Off so the pipe isn't constantly at high temperatures, even in the UK

    Uponor;

    Heating systems and fan coil installations where the water temperature does not continuously exceed 80oC, or momentarily exceed 95oC (no more than 100 hours a year), and maximum operating pressure of 10 bar. Also, the system must be installed with room and water temperature controls in accordance with the current Building Regulations Parts L1 (Energy – Dwellings) and L2 (Energy – Non Dwellings) for England and Wales, or an equivalent national standard for Scotland or Republic of Ireland.
     Hot water services installations where the water temperature
    does not continuously exceed 70oC, or momentarily exceed 95oC (no more than 100 hours a year), and maximum operating pressure of 10 bar.

  8. #8
    Plumbers Arms member

    Masood's Avatar
    Join Date
    Nov 2011
    Location
    East London / Essex border
    Posts
    4,769
    Thanks
    622
    Thanked 584 Times in 527 Posts

    Default Re: PB versus Pex, something not quite right

    Quote Originally Posted by snowhead View Post
    Heating systems cycle On /Off so the pipe isn't constantly at high temperatures, even in the UK
    Plus CH primary water will eventually de-aerate. It's oxygenated water that creates problems for plastic pipe...
    GSR? Want gas safety or boiler repair advice? We will check out that you're genuine via the gas safe website, so please don't be offended when we ask for your details. DIYers, odd job people and have a go heroes need not apply.

    Find us at:

    http://www.ifraplumbingandheating.com


  9. #9
    rpm
    rpm is offline
    Member rpm's Avatar
    Join Date
    Jan 2013
    Location
    Wherever I lay my hat
    Posts
    7,840
    Thanks
    350
    Thanked 479 Times in 464 Posts

    Default Re: PB versus Pex, something not quite right

    Having seen what small mice can do to plastic pipe I wouldn`t risk it.

  10. #10
    Member
    Join Date
    Aug 2016
    Posts
    6
    Thanks
    0
    Thanked 1 Time in 1 Post

    Default Re: PB versus Pex, something not quite right

    Cos copper doesnt come in 50metre coils at 28mm diameter that's why!

  11. #11
    UK Plumbersforums Trusted Advisor.
    SimonG's Avatar
    Join Date
    Feb 2011
    Location
    in the land of make believe, in the county of durham, next best to Yorkshireland
    Posts
    16,038
    Thanks
    552
    Thanked 1,556 Times in 1,495 Posts

    Default Re: PB versus Pex, something not quite right

    Your putting a 28mm secondary return in?
    Fly Me To The Moon And Let Me Play Among Stars.............




    No I'm not cheap, but I'm happy in my work.

    Wouldn't you rather have somebody that's happy working in your house?


  12. #12
    Member
    ShaunCorbs's Avatar
    Join Date
    May 2015
    Location
    North Wales (so hide all your sheep) :D
    Posts
    9,683
    Thanks
    136
    Thanked 686 Times in 675 Posts

    Default Re: PB versus Pex, something not quite right

    O God get a plumber in unless it's a swimming centre or a small hospital you won't need a src that big
    IMPORTANT:
    Carbon Monoxide can be produced when ANY fuel is burnt, including oil, gas, wood and coal.

    Want gas safety or boiler repair advice? :
    Please supply your Gas Safe / Oftec / Hetas Number, DIYers, odd job people and have a go heroes need not apply, and remember any fuel burning appliance can kill


Everybody loves a good deal: Deals and Discounts on Dozens of Powertools!
Everybody loves a good deal: Deals and Discounts on Dozens of Powertools!

Similar Threads

  1. Old fart versus new technology
    By mountainman in forum Gas Safe Register Forum - Public Forum
    Replies: 2
    Last Post: 18-10-2012, 08:50 PM
  2. Magnaclean versus TF1
    By mountainman in forum Central Heating Forum
    Replies: 28
    Last Post: 17-07-2012, 02:35 PM
  3. PTFE versus Loctite
    By antonm919 in forum Plumbing Forum
    Replies: 12
    Last Post: 24-04-2010, 10:14 AM
  4. Power shower versus TV
    By Plumbstar Tom in forum Bathrooms, Showers and Wetrooms
    Replies: 14
    Last Post: 11-03-2010, 05:10 PM

Visitors found this page by searching for:

Nobody landed on this page from a search engine, yet!

Tags for this Thread


Try our Talk Electrician Forum and our popular Tilers Forums for more free advice from professional tradesmen.
Tens of thousands of tradesmen and over 2 million combined posts.


Plumbers Forums is a community-driven forum shared between all members.