[Bldg-sim] U-Factor/R-Value Formula [correction to previous response]

[Cramer Silkworth]

 Matthew & All,

I did a bit of research on the ASTM tests...seems I was wrong about them including radiant and convective effects, they seem to be purely conduction tests. Check out http://www.sprayfoam.org/R-values%20of%20SPF.pdf for a description of some of the testing procedures.

-Cramer

-----Original Message-----
From: bldg-sim-bounces at lists.onebuilding.org [mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Matthew Higgins
Sent: Monday, February 04, 2008 9:46 PM
To: bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] U-Factor/R-Value Formula

Does anyone have a formula to calculate either U-Factor or R-Value using the eQuest material properties of the following?

Conductivity = (Btu/h-ft-°F)

Density =  (lb/ft^3 )

Specific Heat = (Btu/lb-°F)

And thickness.

--
Matthew Higgins, LEED AP
Technical Specialist
Environmental Dynamics, Inc.
Architecture and Sustainability Consulting Services
505.242.2851


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