This procedure provides for non-rated site-built skylights, and alterations to fenestration (i.e., repairs or replacement of glass), with an option to comply with the Energy Standards. The Center of Glass (COG) values are required to be used in Equation NA6-1, NA6-2 and NA6-3 and shall be determined by the manufacturers in accordance with NFRC procedures. A copy of the manufacturer cut sheets or data sheet shall be provided identifying the COG values as an attachment with the Fenestration Certificate of Compliance.

1. NONRESIDENTIAL AND MULTIFAMILY BUILDINGS FOUR STORIES OR GREATER
   For Nonresidential cases, the Alternative Default Fenestration Procedure option is available for up to 200 ft2 of site-built skylight area, and alterations to vertical fenestration. The manufacturer cut sheet or data sheet shall be used to identify the COG values for the U-factor, Solar Heat Gain Coefficient (SHGCC) and Visible Transmittance (VTC). If unable to determine center of glass information, the alternative Energy Commissions Default Tables in Section 110.6 of the Energy Standards must be used to determine the appropriate fenestration default values. The values listed in Table 110.6-A for U-factors and TABLE 110.6-B for SHGC values are whole fenestration product values. Since there is no default Visible Transmittance value available, the alternative is VTC =1.0; this will be used to determine the total fenestration product, VTT, which includes the glass and frame of the fenestration.
   For Nonresidential, the altered fenestration (other than a repair) shall meet the values listed in Table 141.0-A unless the altered glass area meets the Exception to Section 141.0(b)2A in the Energy Standards. If the altered fenestration or glass alone is not rated by NFRC then the Alternate Default Fenestration Procedure can be used.
2. RESIDENTIAL AND MULTIFAMILY BUILDINGS THREE STORIES OR LESS
   For Residential cases, the Alternate Default Fenestration Procedure option is available only when nonrated site-built fenestration is being installed in a residential dwelling. For Residential site-built fenestration up to 250 ft² in area or 5% times the conditioned floor area (CFA), whichever is greater shall meet Sections §110.6(a)2. and §110.6(a)3.
   The Alternate Default Fenestration calculated values are typically less efficient than those listed in the Prescriptive Approach in Table 150.1-A and Table 150.1-B of the Energy Standards. The Visible Transmittance (VT) value is not required to meet residential energy compliance. If unable to acquire center of glass (COG) thermal performance values from the manufacturer, then the Energy Commissions Default Tables shall be used; Table 110.6-A for U-factors and TABLE 110.6-B for SHGC values and documented on the on a self-produced manufactured default label. The default label shall be attached to the unrated fenestration product. An example of the label can be found in the Residential Compliance Manual.
3. DOCUMENTATION
   1. The Energy Commission's Fenestration Label Certificate form for nonresidential application shall be used to document the Alternate Default Fenestration calculated values for each non-rated site-built fenestration unit; or
   2. For residential, a manufactured Default Label attached to each non-rated site-built fenestration unit.

The equations listed below are to be used for only for unrated site-built fenestration that meets the requirements in either item 1 or 2 above.