Technical Council for “Cool Roofs”

1. Technical Council for “Cool Roofs” Concepts, Experiences and Recommendations for Adoption in Brazil Ricardo Abrahao – Dupont Daniel Arruda e MoisesFreitas – Dow

2. The Physics Behind: Reflectivity & Emissivity Black Roof (bituminous)Reflectance ≥ 5 – 10 %Emissivity ≥ 90 % White Cool RoofReflectance ≥ 88 %Emissivity ≥ 90 % Metal RoofReflectance ≥ 90 %Emissivity ≥ 15 – 22 % Ideal Cool Roof Reflectance = 100 %Emissivity = 100 % Reflectance – ability of a surface to reflect heat radiation Emissivity – ability of a surface/body to emit heat by radiation

3. Urban Heat Islands: the reality of modern cities Surface Temperature (Day) Air Temperature (Day) Surface Temperature (Night) Air Temperature (Night) Image source: NASA/Goddard Space Flight Center Scientific Visualization Studio Image source: US Environmental Protection Agency The heat island effect

4. Reflectivity / Emissivity and Solar Radiation Almost 100% of solar energy is in the visible or near-infrared range

5. Solar Reflectance 1.0 0.8 0.6 0.4 0.2 0.0 Galvanized Steel 50 IR-Refl. Black Black Paint 40 Al Roof Coat. White Cement Coat. Temperature Rise ( °C) 30 Green Asphalt Shingle Red Clay Tile 20 White Asphalt Shingle White Paint Lt. Red Paint Lt. Green Paint Optical White 10 0 0.0 0.2 0.6 0.8 1.0 0.4 Solar Absorptance = 1 – Solar Reflectance The most effective Reflactance of Solar Radiation

6. Cool Roofs – Different forms, Shapes and Materials Image Source: American Rooftile Coating

7. Roofs are Exposed to severe Damaging Effects of... Main Challenges– 1 - How to address durability and effectiveness of the reflective surface 2 – Define Local Standards for Cool Roofs Effectivenss Sunlightand UV radiation Freeze/thawcycles Wateringress Mechanicalstrains Settlingandotherbuildingmovement

8. International Standards and Assossiations“ Cool Roofs” • Local building codes abound in the US • The Miami-Dade County Building Code is commonly referenced as a standard by many other local municipalities • Most building codes accept or specify ASTM D-6083 • CEC Title 24 • Building code that requires installation of cool roofs in new low-slope roofs or re-roofing projects in California • Coatings standards loosely based on ASTM D-6083 • ASTM D-6083 • Standard sets the bar for a high quality coating • Commonly specified by architects, specifiers, and building owners for roofing projects • Joint US Department of Energy and Environmental Protection Agency program that promotes energy-efficient products and practices • Roofing products, and roof coatings, is one of many categories included in Energy Star Government and NGOs Manufacturers Associations Rating Organizations Electric Utilities Channel Associations

9. Cool Roofs Proposal • 1 – Creation of Brazilian Consortium for Cool Roofs Rating • 2 – Definition of Cool Roofs Minimum Requirements: • Low-slopped reflective roofs – 3-year-aged Solar Reflectance of at least 0.55 and Thermal Emittance of at least 0.80. Or a three-year-aged solar reflectance index (SRI) of at least 65 • Steep-slopped reflective roofs - 3-year-aged Solar Reflectance of at least 0.35 and a three-year-aged Thermal Emittance of at least 0.80. Or a three-year-aged solar reflectance index (SRI) of at least 38 • Green Roofs • Vegetated Roof Systems that are either extensively and/or intensively vegetated, containing a minimum thickness of 2.5 inches (63.5 mm) of growing medium and covering a minimum of 75% of the roof area with durable plantings.

10. Minimal Requirements for Cool Roofs

11. 2B – Durability Standards for LAM

12. 2B – Durability Standards for LAM

13. 2B – Durability Standards for LAM

14. ASTM D 6083 - Standard Specification forLiquid Applied Acrylic Coating Used in Roofing

15. Os parâmetrostécnicosparaTelhadosFriosdevem ser comprovados e seusvaloresdefinidos com base empesquisaslocaisquecomprovem a efetividades e representatividades dos mesmospara a realidadeclimática e econômicaBrasileira. “Cool Roofs are one of the quickest and lowest cost ways we can reduce our global carbon emissions and begin the hard work of slowing climate change.” Steven Chu, United States Secretary of Energy 1997 Nobel Prize for Physics

16. Q&A Thanks Obrigado!

17. Bird’s eye view of a city Sacramento, California (≈ 1 km2) Why are cities hot? One reason: many dark surfaces. Roofs Other 14% 19% 39% 29% Vegetation Pavements Urban fabric above tree canopy

18. 1998 UHI simulation of Los Angeles Basin(cool roofs + cool pavements + trees) Changes to Los Angeles Basin (10,000 km2): 1,000 km2 residential cool roofs 250 km2 nonresidential cool roofs 1,250 km2 cool pavements 320 km2 shade trees 230 km2 non-shade trees Benefits air temp. reduction = 3°C (5°F) direct energy savings = $104M/y indirect energy savings = $71M/y smog avoidance = $360M/y direct + indirect + smog = $535M/y A.H. Rosenfeld et al. 1998. Cool communities: strategies for heat island mitigation and smog reduction. Energy and Buildings 28:51-62.

19. Potential U.S. white-roof benefits • Retrofitting 80% of U.S. air-conditioned commercial buildings (2.1B m2) would annually save • $735M • 6.2 Mt CO2 (=1.2M cars) • 9.9 kt NOx (=0.6M cars) • 26 kt SO2 • 126 kg Hg through energy conservation • Product lifetime energy savings has present value of $11B New York Times, 30 July 2009 19 19

20. * CRA = Conditioned Roof Area Source: Lawrence-Berkeley National Laboratory Economic Impact of Cool Roofs • Factors affecting energy savings in buildings: • Local climate • A building’s operating systems • A building’s internal conditions • A building’s roof surface area • A building’s roof assembly design and construction • Costs of energy supply (e.g. coal-powered electricity, natural gas, etc.)

21. ASTM D6083 • American Society of Testing Materials • Específica a qualidade do revestimento • Comumenteusadaporarquitetos, especificadores, construtores, projetistas, etc. paraprojetos de lajes e coberturas. • California Energy Commission (CEC) Title 24 • Baseadana ASTM D6083 • ContémosRequisitos de energy saving • Refletividade Solar • Emissividade • ABNT NBR 13321 • AssociaçãoBrasileira de NormasTécnicas • Específica a qualidade do revestimentoimpermeabilizante • Comumenteusadaporarquitetos, especificadores, construtores, projetistas, etc. paraprojetos de lajes e coberturas. • Energy Star • Requisitos de Refletividade Solar & Emissividade • VOC: SCAQMD rule is  50 g/L

22. 2B – Liquid Applied Membranes – Acrylic Elastomeric Reflective Roof Coating Alta refletânciacomparadaàsmembranassemrevestimento Alta emissividade Reduçãoefetivaemtemperaturasinternas – especialmenteemclimasquentes Economia de energia e redução das emissões de CO2 Proteção e resistência à exposição natural: umidade, mofo, algo, UV, Vida prolongada do telhado e do seubenefíciosustentável Fácil e rápidaaplicação (a líquido) compatível com quasetodotipo de substrato.