Calculating Spandrel U-Value

[Justin Kohan]

I'm calculating the u-value of the spandrel condition I have according to Section 8.22 in the NFRC Simulation Manual. For the head and sill conditions, the portion of the glazing and spacer above/below the manual shows those being removed and replaced with this orange block. The material/conductivity of that block isn't outlined. Does anyone know what to assign it? I added an image depicting what I'm referring to. 

[Zugur Rakhmanov]

Hi Justin,
It depends on what you plan to use as an attachment profile there.
Most suppliers offer such PVC profiles (see image). But there are rigid foamed polyurethane or polyethylene profiles.
For uncomplicated calculation you can дleave that rectangle section and set the 'Urethane - Thermal Break' material.

Kind regards,

Zugur

On Thu, Aug 14, 2025 at 8:35 PM Justin Kohan <jfko...@gmail.com> wrote:

I'm calculating the u-value of the spandrel condition I have according to Section 8.22 in the NFRC Simulation Manual. For the head and sill conditions, the portion of the glazing and spacer above/below the manual shows those being removed and replaced with this orange block. The material/conductivity of that block isn't outlined. Does anyone know what to assign it? I added an image depicting what I'm referring to. 

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[Jonathan Spencer]

In the context of NFRC simulations, that block is the generic softwood material in appendix A of NFRC 101, k = 0.14W/mK. You can read more about it on the first page of section 8.9 of the Sim Manual.

[Justin Kohan]

Hi Zugur,

Thanks for getting back to me. If there will be vision glazing above and below the spandrel, should I model the beginning of that glass unit with the spacers until they reach the bottom part of the frame for the sill and opposite condition for the head? I added an image to show what I mean.

Thanks,

Justin

[Zugur Rakhmanov]

Hi Justin,
If there will be vision glazing above and below your details will look like the picture shown

Kind regards,
Zugur