The design of unit skylights rated for performance grade for both positive and negative design pressures shall be based on the following equations:
| Fgi ≤ PGPo | (Equation 24-14) |
| Fgo≤ PGNe | (Equation 24-15) |
where:
| PGPos | = | Performance grade rating of the skylight under positive design pressure; |
| PGNeg | = | Performance grade rating of the skylight under negative design pressure; and |
Fgi and Fgo are determined in accordance with the following:
For Wo ≥ D,
where:
| Wo | = | Outward wind force, psf (kN/m2) as calculated in Section 1609. |
| D | = | The dead weight of the glazing, psf (kN/m2) as determined in Section 2404.2 for glass, or by the weight of the plastic, psf (kN/m2) for plastic glazing. |
| Fgi | = | Maximum load on the skylight determined from Equations 24-3 and 24-4 in Section 2404.2. |
| Fgo | = | Maximum load on the skylight determined from Equation 24-2. |
For Wo < D,
where:
| Wo | = | Is the outward wind force, psf (kN/m2) as calculated in Section 1609. |
| D | = | The dead weight of the glazing, psf (kN/m2) as determined in Section 2404.2 for glass, or by the weight of the plastic for plastic glazing. |
| Fgi | = | Maximum load on the skylight determined from Equations 24-2 through 24-4 in Section 2404.2. |
| Fgo | = | 0. |