Re: [EnergyPlus_Support] ASHRAE standard 90.1 building envelope

1) Yes and yes. Yes. The "Rated" R-Vales must be calculated correctly using the film values in that section if you are modelling as per Appx G. It is also sometimes required to de-rate some layers (eg. Framing/insulation layers) to account for the thermal breaks as the standard dictates.

Yes. Rated values are different as they are rated by different norms in different countries. You can and should hand calculate the rated values as per the required norm. But don't compare the rated value as per one norm to that value as calculated by another norm.

2) you already know which film values to apply and how, judging by your post. The bit in the middle is just the sum of the layer by layer R-values (R=thickness/conduction_coeffecient... if I remember correctly). The key is therefore to set the conduction coefficient(s).

I recommend the hand calculation as excersize.

Mit freundlichen GrÃ¼Ã?en- Sent from my iPhone (excuse the brevity)

i. A.

Jean Marais

b.i.g. bechtold

Tel. +49 30 6706662-23

On 03.10.2013, at 00:09, <seanking.1970@xxxxxxxxxxx> wrote:

Dear all,

I got two questions regarding ASHRAE standard 90.1 building envelope when creating baseline building model for LEED.

1. In appendix A of the standard, are surface resistances (say interior 0.11, exterior 0.04) compulsory for all 8 climate zones please? To my understanding, generally different countries use different surface resistance figures (example of difference between the UK and Germany). Please could anybody confirm this?

2. For constructions of roofs - insulation entirely above deck, do U-values from Tables 5.5-1 though 5.5-8 (in relation to different climate zone) include deck (either metal deck or concrete deck or likes) into the calculation. If yes, how to set thermal properties of the decks? If no, is definition on surface resistance right?

Thank you very much in advance.

Sean

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