Building envelope values and fenestration areas determined in accordance with Equation 4-2 shall be permitted in lieu of compliance with the U-, F- and C-factors in Tables C402.1.3 and C402.1.4 and the maximum allowable fenestration areas in Section C402.4.1.
|A||=||Sum of the (UA Dif) values for each distinct assembly |
type of the building thermal envelope, other than slabson grade and below-grade walls.
|UA Dif||=||UA Proposed - UA Table.|
|UA Proposed||=||Proposed U-value • Area.|
|UA Table||=||(U-factor from Table C402.1.3 or Table C402.1.4) • Area.|
|B||=||Sum of the (FL Dif) values for each distinct slab-on-|
grade perimeter condition of the building thermalenvelope.
|FL Dif||=||FL Proposed - FL Table.|
|FL Proposed||=||Proposed F-value • Perimeter length.|
|FL Table||=||(F-factor specified in Table C402.1.4) • Perimeter length.|
|C||=||Sum of the (CA Dif) values for each distinct below-|
grade wall assembly type of the building thermalenvelope.
|CA Dif||=||CA Proposed - CA Table.|
|CA Proposed||=||Proposed C-value • Area.|
|CA Table||=||(Maximum allowable C-factor specified in Table C402.1.4) • Area.|
Where the proposed vertical glazing area is less than or equal to the maximum vertical glazing area allowed by Section C402.4.1, the value of D (Excess Vertical Glazing Value) shall be zero. Otherwise:
|D||=||(DA • UV) - (DA • U Wall), but not less than zero.|
|DA||=||(Proposed Vertical Glazing Area) - (Vertical Glazing Area allowed by Section C402.4.1).|
|UA Wall||=||Sum of the (UA Proposed) values for each opaque assembly of the exterior wall.|
|U Wall||=||Area-weighted average U-value of all above-grade wall assemblies.|
|UAV||=||Sum of the (UA Proposed) values for each vertical glazing assembly.|
|UV||=||UAV/total vertical glazing area.|
Where the proposed skylight area is less than or equal to the skylight area allowed by Section C402.4.1, the value of E (Excess Skylight Value) shall be zero. Otherwise:
|E||=||(EA • US) - (EA • U Roof), but not less than zero.|
|EA||=||(Proposed Skylight Area) - (Allowable Skylight Area as specified in Section C402.4.1).|
|U Roof||=||Area-weighted average U-value of all roof assemblies.|
|UAS||=||Sum of the (UA Proposed) values for each skylight assembly.|
|US||=||UAS/total skylight area.|