Section 402. Building Envelope Requirements
402.1 to 402.2 {As in IECC-C}
402.3 Roof solar reflectance and thermal emittance.
Low-sloped roofs directly above cooled conditioned spaces in Climate Zones 1, 2 and 3 shall have a minimum 3-year-aged solar reflective index of 78, as determined by the Cool Roof Rating Council.
Exceptions: The following roofs and portions of roofs are exempt from the requirements of this subsection:
1. Portions of the roof that include or are covered by the following:
1.1. Photovoltaic systems or components.
1.2. Solar air or water-heating systems or components.
1.3. Roof gardens or landscaped roofs.
1.4. Above-roof decks or walkways.
1.5. Skylights.
1.6. HVAC systems and components, and other opaque objects mounted above the roof.
2. Portions of the roof shaded during the peak sun angle on the summer solstice by permanent features of the building or by permanent features of adjacent buildings.
3. Portions of roofs that are ballasted with a minimum stone ballast of 17 psf (74 kg/m2) or 23 psf (117 kg/m2) pavers.
4. Roofs where not less than 75 percent of the roof area complies with one or more of the exceptions to this section.
402.3.1 Aged roof solar reflectance.
Where an aged solar reflectance required by Section 402.3 is not available, it shall be determined in accordance with Equation 4-3.
Raged = [0.2 + 0.7(Rinitial - 0.2)] (Equation 4-3)
where:
Raged = The aged solar reflectance.
Rinitial = The initial solar reflectance determined in accordance with CRRC-S100.
402.4 {As in IECC-C}
402.5 Air leakage – thermal envelope. {As in IECC-C}
402.5.1 Air barriers. {As in IECC-C}
402.5.1.1 Air barrier construction. {As in IECC-C}
402.5.1.2 Building test.
402.5.1.2.1 General.
The completed building must be tested as follows:
1. Tests must be accomplished using either (a) both pressurization and depressurization or (b) pressurization alone, but not depressurization alone. The test results must be plotted against the corrected P in accordance with § 9.4 of ASTM E779.
2. The test pressure range must be from 25 Pa to 80 Pa per § 8.10 of ASTM E779, but the upper limit may not be less than 50 Pa, and the difference between the upper and lower limit may not be less than 25 Pa.
3. If the pressure exponent is less than 0.45 or greater than 0.85 per § 9.6.4 of ASTM E779, the test must be rerun with additional readings over a longer time interval.
402.5.1.2.2 Air leakage rate.
The air leakage rate of the building envelope may not exceed 0.40 cfm/ft2 at a pressure differential of 0.3 inches water gauge (2.0 L/s • m2 at 75 Pa) at the upper 95% confidence interval in accordance with ASTM E779 or an equivalent method approved by the Code Official.
402.5.1.2.3 Testing failures.
a. Visual inspection to seal leaks.
If the tested rate exceeds 0.25 cfm/ft2 but does not exceed 0.40 cfm/ft2 , a visual inspection of the air barrier must be conducted, and any leaks noted must be sealed to the extent practicable. Any further requirement to meet the leakage air rate is waived.
b. Corrective action and retesting.
If the tested rate exceeds 0.40 cfm/ft2, corrective actions must be made, and the test completed again. A test above 0.40 cfm/ft2 will not be accepted.
402.5.1.2.4 Reporting.
a. General.
A report that includes the tested surface area, floor area, air by volume, stories above grade, and leakage rates must be submitted to the building owner and the Code Official.
b. Corrective actions.
An additional report identifying the corrective actions taken to seal air leaks must be submitted to the building owner and the Code Official.
402.5.2 to 402.5.8 {As in IECC-C}
(Ord. 23-252.)
