Mich. Admin. Code R. 408.31065

Current through Vol. 24-18, October 15, 2024
Section R. 408.31065 - Equivalent U-Factors

Rule 1065. Section R402.1.4 and table R402.1.3 of the code are amended to read as follows:

Table R402.1.3

Equivalent U-Factorsa

Climate Zone

Fenestration U-Factor

Skylight U-Factor

Ceiling U-Factor

Frame

Wall

U-Factor

Mass wall U-Factor b

Floor U-Factor

Basement

Wall

U-Factor

Crawl

Space

Wall

U-Factor

5A

0.32

0.55

0.030

0.057

0.082

0.033

0.059

0.055

6A

0.32

0.55

0.026

0.057

0.060

0.033

0.050

0.055

7

0.32

0.55

0.026

0.057

0.057

0.028

0.050

0.055

a. Nonfenestration U-factors shall be obtained from measurement, calculation, or an approved source.

b. When more than half the insulation is on the interior, the mass wall U-factors shall be a maximum of 0.065 in zone 5 and marine 4, and 0.057 in zones 6 and 7.

R402.1.4 Total UA alternative. If the total building thermal envelope UA (sum of U-factor times assembly area) is less than or equal to the total UA resulting from using the U-factors in Table R402.1.3 (multiplied by the same assembly area as in the proposed building), the building shall be considered in compliance with Table R402.1.1. The UA calculation shall be done using a method consistent with the ASHRAE Handbook of Fundamentals and shall include the thermal bridging effects of framing materials.

Mich. Admin. Code R. 408.31065

MR 19, Eff. 2/6/2016