1312.1 Standard Procedure for Determination of Glazing and
Door U-Factors: U-Factors for glazing and doors shall be
determined, certified and labeled in accordance with Standard
RS-31 by a certified independent agency licensed by the
National Fenestration Rating Council (NFRC). Compliance shall
be based on the Residential or the Nonresidential Model Size.
Product samples used for U-factor determinations shall be
production line units or representative of units as purchased
by the consumer or contractor. Unlabeled glazing and doors
shall be assigned the default U-factor in Table 10-6.
1312.2 Solar Heat Gain Coefficient and Shading Coefficient:
Solar Heat Gain Coefficient (SHGC), shall be determined,
certified and labelled in accordance with the National
Fenestration Rating Council (NFRC) Standard by a certified,
independent agency, licensed by the NFRC.
EXCEPTION:
Shading coefficients (SC) shall be an acceptable alternate for compliance with solar heat gain coefficient requirements. Shading coefficients for glazing shall be taken from Chapter 31 of RS-1 or from the manufacturer's test data.