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Double glazing units - safety glass marks. And is there a front and back?

Discussion in 'Windows and Doors' started by DIYNotIan, 26 Nov 2020.

  1. DIYNotIan

    DIYNotIan

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    Hi

    I've had a few double glazing units replaced in my windows today. I noticed a couple of things this evening that I just wanted to check...

    1. If a window needs safety glass and the window has two units, should both units be marked as safety glass or just one?

    2. Do the units have a front and back or are they the same both ways? I was looking at the writing you get on the spacer bars and noticed it is the right way up on some units and upside down on others. Is this normal or should it always point the same way?

    Cheers
     
    Last edited: 8 Dec 2020
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  3. ronniecabers

    ronniecabers

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    1/ if safety glass is required on both panes then both panes should be marked. ( eg door glass, glass below 800mm from finished floor , glass within 12 inches of door ) . Potentially if only one pane is marked then only the marked pane side of the sealed unit is required to be be tough ( usually windows where internally is closer to the floor than outside or vice versa) but on saying that it is unusual and best practice would be to have both panes toughened

    2/ for each individual pane no, the only thing that would determine which way round the pane of glass should be would be within the sealed unit would be a ' coating ' such as ' low e ' ( Pilkington k or Planitherm) or a self-cleaning coating. Again once in a sealed unit , the side that has the ' coating ' determines how it how it goes in the frame , a label would have been attached to the sealed unit to specify this if it included a coating
     
  4. DIYNotIan

    DIYNotIan

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    Hi

    Many thanks for the response. I think maybe I have used the term "pane" incorrectly. When I say pane, I really mean a glass panel/unit. I've amended the tile and OP accordingly.

    1. So with regards to this point, I meant only one glass panel/unit is marked. The window has two glass panels/units which are side by side like this (that's not my actual window):

    aOnLwDNU-780x520.jpeg


    The unit on the left has a safety glass mark, but the unit on the right doesn't. Does that sound ok? Should both be marked, or is it enough to just have one mark for the whole window? Sorry I wasn't clear int he first post.

    2. I can't remember now if we opted for a coating or not. I'll go check.


    Thanks again for the help

    EDIT: Just had a look... There were two options for the replacement units - Standard and A-rated. We opted for the A-rated. No mention though as to whether these are coated.
     
    Last edited: 8 Dec 2020
  5. ronniecabers

    ronniecabers

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    Quite possible to have one tough and one not in that window. Providing the glass in the one that hasn't got a mark on is over 800mm from the finished floor/ground, inside and out , then that is ok.

    Having A rated you will indeed have a coating, the glass should be Diamant ( 'low iron ') , warm edge spacer, argon gas filled and Planitherm ( possibly Pilkington K ) low e glass. There should have been a label to indicate which way round the unit should go
     
  6. DIYNotIan

    DIYNotIan

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    No, they are more or less the same height as each other. Definitely both under 800mm.

    So should each individual unit have the mark? If the unit on the right has no mark, does that mean it is not safety glass? ***head slap emoji***

    I didn't see the glass panels before they were fitted, so no idea of they had stickers. All I know is that with some panels the spacer bar writing is one way (facing inward) and on others it is t'other (facing outward). Hopefully that just means that they stick 'em in any old how at the factory. And I'm fine with that. So long as the panels themselves have not been put in the wrong way around, then I'm happy. Is there any other way to tell whether they are the correct way around?

    Thanks for your help
     
  7. ronniecabers

    ronniecabers

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    If they are the actual glass is below 800mm ( not the frame ) , then yes , both should be toughened.

    Very unlikely fitter has put in incorrectly, majority of sealed units are manufactured on automated lines these days and won't differentiate the way the printing on the bar is facing, so I suspect all is well
     
  8. DIYNotIan

    DIYNotIan

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    BAD! 0-1

    GOOD! 1-1

    So, a score draw I guess :)
     
  9. DIYNotIan

    DIYNotIan

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    Hi again

    Just wanted to come back to this to ask... Is there any way to tell whether a unit is standard, a-rated, or whatever? I seem to remember once seeing an installer use a gizmo to check the u-Value of our old windows. He held it up there for a couple of seconds or so and got a reading. But I can't find a tool like this and if such a thing does exist I can't imagine it would be cheap??

    Any other ways to tell?

    One thing I have noticed is that on a couple of mornings since the new units were installed, some have condensation on the outside, which from what I've read means they are working efficiently. Does that point toward them being A-Rated or can that happen with any new units?

    Many thanks
     
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  11. ronniecabers

    ronniecabers

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    They aren't allowed to fit below a c rated in new frames anyway so there's a start.
    If the glass is condensating on the outside then you have , at the minimum c rated units . The following is a breakdown of your std types

    C rated - aluminium spacer bar, argon gas and Low e Glass ( Pilkington K or Planitherm)

    B Rated - as C rated by ' warm edge Spacer bar ' - normally black , white or grey and is effectively a plastic bar

    A rated - as B rated but with diamant Glass ( Low Iron Glass , optically clear, no marginally green tint.

    Now you can test for a low e glass using a ' low emissity tester ' , these usually light up or beep
    You can test for Argon Gas using a ' spark tester ' , now these we £600/700 10 years ago so dread to think what they are now.
    No known test for Diamant glass exists in a sealed unit as far as I'm aware. Just when its all stacked up in a pile you get no green tint.

    As goes for testing the u value of a sealed unit in situ, never heard of it being done , as the overall rating of the window is based on the frame and the glass
     
  12. DIYNotIan

    DIYNotIan

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    Thanks @ronniecabers - much appreciated.

    These were replacement units only. So old frames, not new.

    Hmm, I can't see anything there that will help me distinguish whether mine are C, B or A. The spacer bar is black on my units. Would a photo of the spacer bar and/or a photo of anything else help? Would the BSEN number help, or is that the same regardless of efficiency?

    Cheers
     
  13. ronniecabers

    ronniecabers

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    The BSEN number will be the type of glass eg , toughened , laminate etc it won't identify the make up of the unit .
    If you have a photo of the spacer bar then I should be able to determine whether its ali or warm edge.
     
  14. DIYNotIan

    DIYNotIan

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    Thank you so much. They're not the easiest thing to photo, so I've taken three. Let me know if you need me to take more/take the differently. Thanks again.


    IMG_20201208_142936582.jpg IMG_20201208_143012325.jpg IMG_20201208_143022391.jpg
     
  15. ronniecabers

    ronniecabers

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    Thats a warm edge spacer. I suspect you have the 'a' rated version as its unusual to see B rated used.

    Please note though that the sealed unit on its on is not energy rated and if old upvc it is highly unlikely you have an A rated frame, what you have is an untested frame with a sealed unit with a u value of 1.1 , but considering the frames are older, without going to a lot of expense, its the best you will get
     
  16. DIYNotIan

    DIYNotIan

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    Yes, that's fair enough and understood. I was aware of that before we had the units replaced, so no surprises there. I appreciate you pointing it out and explaining though. For the record, the windows themselves were installed in 2002.

    Great news if the units themselves are A rated as you suspect :)
     
    Last edited: 8 Dec 2020
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