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  1. #1
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    comparison of tarfelt with polythene sheet as vapour barrier



    How does one compare tarfelt with 0.5 mm thick polythene sheet when the intention is to use both as vapour barriers ?

    Here we are talking of a case for a cold storage where the decision has to be taken as to which is a better option, so a technical comparison has to be made. It will be the lowermost layer, below the PUF insulation.

    Does anybody know any source of information for this ?



  2. #2
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    Re: comparison of tarfelt with polythene sheet as vapour barrier

    Quote Originally Posted by sharshal View Post
    How does one compare tarfelt with 0.5 mm thick polythene sheet when the intention is to use both as vapour barriers ?
    I usually use PE (polyethylene) sheet, 2 x 6mils = total of 12 mils thk (300microns) in rolls of 48" or 60" (1.2M or 1.5M) Width x 50M L for the floor slab vapor barrier of cold rooms with or without floor insulation.

    I use tarfelt - 3" (75mm) Width rolls - for polystyrene (PS) pipe insulation as vapor barrier.

    PE sheet is easy to install in large cold rooms.
    Tarfelt for PS pipe insulation.

    As a vapor barrier in floor of cold rooms, PE sheet would be enough and it serves the purpose - vapor barrier.

    May i ask?

    Can you find in your place a Tarfelt 1.5M W x 50M L?
    Is the material cost of no concern?


    Does anybody know any source of information for this ?
    What information do you need?

    - Porosity pr permeability of PE sheet against the tarfelt?

    - It is the only question i can think of in comparing the two materials.
    Hope somebody have the answer or info on the porosity or permeability of Tarfelt vs. PE sheet.

    Hope to have helped.

  3. #3
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    Re: comparison of tarfelt with polythene sheet as vapour barrier

    Yes, I had the same requirement, i.e. porosity and permeability for comparison purpose.

    Cost, somehow, is not an issue here. I myself do know that PE sheet is good as a vapour barrier, but the client need documentary proof.

    Thanks for your mail !

    Quote Originally Posted by winfred.dela View Post
    I usually use PE (polyethylene) sheet, 2 x 6mils = total of 12 mils thk (300microns) in rolls of 48" or 60" (1.2M or 1.5M) Width x 50M L for the floor slab vapor barrier of cold rooms with or without floor insulation.

    I use tarfelt - 3" (75mm) Width rolls - for polystyrene (PS) pipe insulation as vapor barrier.

    PE sheet is easy to install in large cold rooms.
    Tarfelt for PS pipe insulation.

    As a vapor barrier in floor of cold rooms, PE sheet would be enough and it serves the purpose - vapor barrier.

    May i ask?

    Can you find in your place a Tarfelt 1.5M W x 50M L?
    Is the material cost of no concern?




    What information do you need?

    - Porosity pr permeability of PE sheet against the tarfelt?

    - It is the only question i can think of in comparing the two materials.
    Hope somebody have the answer or info on the porosity or permeability of Tarfelt vs. PE sheet.

    Hope to have helped.

  4. #4
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    Re: comparison of tarfelt with polythene sheet as vapour barrier

    Quote Originally Posted by sharshal View Post
    I myself do know that PE sheet is good as a vapour barrier, but the client need documentary proof.
    I believe you are a consulting engineer.
    When you're hired by a customer there will be no need for a documentary proof.
    Your customer must have 100% belief in you or else your project will suffer as you need to find documents before something is considered.

    Anyway, please find attached proof (small though, limit is 100kb).

    This is a part of page 17 of Cold Storage Code of Practice, Part-1 Enclosure Construction published by The Institute of Refrigeration,Kevin House.

    Hope this helps.

    vaporseal.bmp

  5. #5
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    Re: comparison of tarfelt with polythene sheet as vapour barrier

    Hi guys,

    Here is some information that may be helpful on the discussion you have been having.

    http://www.uaf.edu/ces/publications/.../EEM-00259.pdf


    sharshal, if the client is hiring you to find this information and then specify the correct material then it becomes your responsibility to do the correct specification. One thing to be careful of is to make sure you have a contract before you hand over research. Otherwise, you are doing work for free and that's not good.

    PS. Here is another source that may be helpful.
    http://www.ces.purdue.edu/extmedia/AE/AE-95.html
    Last edited by US Iceman; 31-10-2006 at 12:40 AM. Reason: added post script

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    Re: comparison of tarfelt with polythene sheet as vapour barrier

    Thanks a lot US Iceman.

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    Re: comparison of tarfelt with polythene sheet as vapour barrier

    Hey Winfred & Iceman !

    I know this is way too late, but I had not visited this particular link after the initial posts.

    Just wanted to say thanks !

    btw, Winfred, here in India .. its a funny situation we face as consultants, especially in government projects .. this case of documentary proof comes up in just about any issue !! its odd .. but you have to live with it !

    Thanks once again !

    Sharshal
    secondly, how do I go 'directly' to my posts if I wanted to ? is there such a possibility in this site ?

  8. #8
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    Re: comparison of tarfelt with polythene sheet as vapour barrier

    We use Al imprignated Polythene sheets. They are just wonderful. Never get cracked up , last forever. We just dismantled a cold store ( -20 degc) after 10 years & that vap barrier was totally intact.

    I shall try & post the site details of that company- coming from Germany.

    Tarfelt sheets tend to get teared off during laying process.

  9. #9
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    Re: comparison of tarfelt with polythene sheet as vapour barrier

    http://www.cosella-dorken.com/bvf/ca...kte/reflex.php

    Check out these details

    In order to check our own postings, you go to NEW TO RE forum. In the end you shall find the persons who are logged in. Clieck on yur own name. That menu shall have all the postings/ all the threads link

  10. #10
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    Re: comparison of tarfelt with polythene sheet as vapour barrier

    Thanks a lot smpsmp45 !!

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