Section #: 13- 607.1.A.5, 13-607.2.A.3.6, Table 13-6C-18 - 20 Text of Modification [additions underlined; deletions stricken]: 607.`1.A.5 WhiteCool Roof Credit. House for which a whitecool roof credit shall have an installed roof that meets the following criteria.
Roof type may only be metal, concrete, tile or single ply membrane for residential construction.
Roof must be white…
Roof much have a tested solar reflectance of greater than 4% when evaluated in accordance with ASTM Standard E-903. Testing of a qualifying sample of the roofing material shall be performed by an approved independent laboratory with these results provided by the manufacturer.
607.2.A.3.6 White Cool Roofs Cooling multiplier may be taken for whitecool roofs where a whitecool roof is installed of an approved configuration and solar reflectance and solar reflectance. Cooling credit shall be taken against the ceiling load by multiplying the summer point multiplier for the ceiling configuration and insulation level chosen on Form 600-A-97 by a credit multiplier according to the tested reflectance: of 0.55. CM = 1.155 – 0.935 (Reflectance) Where: Reflectance = fractional (0-1) Note that where a tested reflectance is not available the assumed roof reflectance will be 4% and a a CM value of 1.118 will be used for those which are untested. This is also true for those roofs that do not use the Cool Roof Credit. 608.2.A.4 White Cool Roofs A heating multiplier will be taken for whitecool roofs where a whitecool roof is installed of an approved configuration and solar reflectance and solar reflectance. Heating credit shall be taken against the ceiling load by multiplying the winter point multiplier for the ceiling configuration and insulation level chosen on Form 600-A-97 by a credit multiplier according to the tested reflectance: of 0.55. HM = 0.987 + 0.088 (Reflectance) Note that where a tested reflectance is not available the assumed roof reflectance will be 4% and a a HM value of 0.987 will be used for those which are untested. This is also true for those roofs that do not use the Cool Roof Credit.
Table 13- 6C-18 – 13-6C-20, Duct Multipliers Change column names Attic w WhiteCool Roof Calculation of WDM and SDM for Cool Roofs WDM, cool roof = (WDM, white roof – WDM, unconditioned) * Reflectance/.65 +WDM, unconditioned SDM, cool roof = (SDM, unconditioned– SDM, white roof) *
Reflectance/0.65 +SDM, white roof Where:
Reflectance = fractional Fiscal Impact Statement[Provide documentation of the costs and benefits of the proposed modifications to the code for each of the following entities. Cost data should be accompanied by a list of assumptions and supporting documentation. Explain expected benefits.]: A. Impact to local entity relative to enforcement of code: Products would be tested according to ASTM E-903 to determine product reflectance. All products are rated and tested would be eligible for a cool roof credit. Those not tested would not be eligible for the credit.
Impact to building and property owners relative to cost of compliance with code:
Typically choosing a lighter, more reflective color within a roofing system is a no or very low cost option. Thus, the proposal would be cost neutral.
Impact to industry relative to cost of compliance with code:
Typically choosing a lighter, more reflective color within a roofing system is a no or very low cost option. Thus, the proposal would be cost neutral.
Rationale [Provide an explanation of why you would like this Proposed Modification to the Florida Building Code.]:
Current White Roof Credit only allows for very white roofing to obtain a credit
Very dark roofing does not get a negative within the analysis and code process as would be appropriate
Providing the arithmetic within the existing code to make the change would be very simple since analysis shows the impact to be linear.
Data on the impact of small changes in roof reflectance is borne out by extensive monitoring at FSEC and in studies for Florida utilities
Providing incremental improvements would spur innovation ("cool colors") within the roofing industry and encourage publication of reflectance data for available roofing systems
Default roof absorptance in lieu of data would be 0.96 (very dark shingles)-- even obtaining small improvements in reflectance would be made explicit in the code
Please explain how the proposed modification meets the following requirements:
1. Has a reasonable and substantial connection with the health, safety, and welfare of the general public: Provides improvement to health, safety and welfare of the public. Cooler roofing products on new homes would reduce interior temperatures inside homes in the event of power interruption such as after hurricanes. 2. Strengthens or improves the code, and provides equivalent or better products, methods, or systems of construction: Provides more flexibility for locating more reflective roofing products within various roofing types for designers and builders. 3. Does not discriminate against materials, products, methods, or systems of construction of demonstrated capabilities:
The current white roof credit biases against certain roofing systems, such as shingles which could obtain credit for lighter colors with the revised system. The new proposal would help reduce discrimination against products and systems of construction.
4. Does not degrade the effectiveness of the code: Effectiveness of the code would be increased by builders and homebuyers having more cool roofing choices with more taking credit for improvements.
While white is often not an aesthetic choice, use of an incremental scale would encourage consumers to choose more reflective colors and pigments
The new approach would have approval from the Florida utilities which would see the changes to the building stock as positive within their service territories to reduce summer peak load