Frames for glass doors and windows need to be designed to be both thermally insulating and structurally strong, and there are computer programs which accurately determine the required properties. However, these programs are complex and expensive to use and are not useful for initial design work. By identifying the structural and insulating roles of the various layers within the frames we obtain simple results for the thermal transmittance and structural properties of frames. These results can be used for design guidance. More accurate (but still simple) results were obtained and coded in Excel for easy processing.
References R. J. Roark ``Formulas for stress and strain'' McGraw-Hill (1965), 4th ed. ``Thermal performance of windows, doors and sharing devices–-Detailed Calculations''. iso 15099:2003(E) ``Thermal performance of windows, doors and shutters–-Calculation of thermal transmittance–-Part 2 Numerical Method for Frames''. bs eniso 10077-2-2003 ``Thermal performance of windows, doors and sharing devices–-Part 1 General''. bs en 10077-1:200
