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    • CommentAuthorswindler
    • CommentTimeMar 8th 2017 edited
    I want renew (similar problem but other building ) topic
    ( http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12788&page=1#Item_0 ).
    I can't download any attachments from this link and without 2 examples for me is too difficult to understand BS EN ISO 10211 C.5.1 or C.5.2.

    I must calculate the psi value of the detail with a suspended floor (in the basement is no air change). I want to understand whether it is worthwhile more to deepen external insulation to the ground.

    Attachment (calculation R values; detail.dxf; detail.thm, THERM 7.5)

    1. is the THERM file (model) good prepared ?
    2. i understood that PSI value can be calculated in two ways?
    3. i think EN ISO 10211 C.11 formula is the easiest way
    PSI=0,1248*6,210-2,55*0,12-0,5* 7,41 * 0,16= - 0,124 , this is good calculation?
    but in another way with coupling coefficients i must get the same result..but how?

    Attachments: https://app.box.com/s/2vk77xortl5sorlpyxzelie7k53yvlko

    This forum is my last hope :confused:
    • CommentAuthorSigaldry
    • CommentTimeMar 8th 2017
    Download a copy of BR497 for starters (and BR IP 1/06).

    A suspended floor is one of the harder ones to try for your first go at thermal modeling - I'd start with corners or a jamb junction if you're wanting to learn.

    If a beam and block floor, then you'll need 3D software for the perpendicular floor junction (but 2D will do for the parallel).

    There are various training courses available - For an introduction try http://www.carbonlitetraining.co.uk/

    For more in-depth, The ACD Certification/STROMA training course was good: https://www.stroma.com/certification/training/thermal-modelling

    I also note that Elmhurst are starting to offer training http://www.elmhurstenergy.co.uk/Psi-%CF%88-Value-Competency-Scheme/29-03-2017

    The requirement under the regulations and energy assessment conventions is that any psi values come from a person with suitable expertise and experience following the guidance set out in BR 497 (and BR IP 1/06) - although the various appropriate British Standards certainly help too.

    It is very easy to make a mistake with thermal modeling or to misunderstand something (and there are even a few mistakes in BR497) that can mean you can get a result that seems reasonable, but that is wrong. Proper training and a lot of practice is needed.

    From having modeled an awful lot of details, anything that increases the heat path from inside to outside will in general help the psi value, so continuity or overlap of insulation (a good overlap between the floor and wall insulation); low conductivity materials wherever they can be used without compromising anything else (lightweight aerated blocks instead of dense); perimeter upstand insulation where appropriate; Internal insulation lining, all can help.
    • CommentAuthorswindler
    • CommentTimeMar 8th 2017
    I have to inform you that I'm not related to England.. And make calculations according only European standards (but It is not very important) ..
    I not think, that will start from the qualification (me: https://www.linkedin.com/in/tomas-kazlauskas-b2a392aa/ )
    With a simple thermal bridges have been working for several years. I have heard several similar training courses, but very disappointed (i think this problem only in my country). None of the training analyze the suspended floor, only introduces the standards, software and get up simple examples... :sad:

    I think is better with colleges now resolve this example, than try luck in any of such training's and hope to hear about suspended floor psi calculations..

    so again asking for help .
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