A presentation on the radiant above sheathing ventilation in cool roof assemblies

1. Radiant-ASV Ventilated Cool Roof Batten System Presented by Pete Bussell Founder of Cool Roof Investments (CRI) & Inventor of COOL ROOF BATTEN System

5. Why Solar Reflectance (‘Albedo’) of Light Colored Roofing Reduces Roof Surface Temperatures? The albedo of an object is a measure of how strongly it reflects light from light sources such as the Sun . Albedos of typical materials in visible light range from up to 0.9 for fresh snow, to about 0.04 for charcoal, one of the darkest substances. Albedo is measured between 0-1 0.80–0.90 Fresh snow 0.5–0.7 Ocean Ice 0.55 New concrete 0.40 Desert sand 0.25 Green grass 0.17 Bare soil 0.15 to 0.18 Decidious Trees 0.08, 0.09 to 0.15 Conifer forest (Summer) 0.12 Worn asphalt 0.04 Fresh asphalt Typical Albedo Sample Surfaces

8. Basic Principles of ASV Ventilation A Common Application for Above Sheathing Ventilation ( ASV) is the ventilation used for Cathedral Ceilings and Livable Attic Space. ASV creates a sub-tile ventilation channel which functions as a thermal bridge to reduce radiant heat transfer into the building envelope Attic Ventilation used in conjunction with ASV ventilation significantly enhances the Thermal Efficiency of a Roof System. Images courtesy of cornell corporation.com

11. Radiant Barriers - Recognized Methods of Installation Radiant barrier material is attached directly to the underside of the roof deck. Slide Courtesy of www.ornl.gov Radiant barrier is draped over the rafters or trusses in a way that allows the product to droop 1-1/2 to 3 inches between each rafter adding rafter ventilation NEW ROOF RETROFIT Radiant barrier is attached to either the faces or bottoms of the rafters or top chords of the roof trusses. Radiant barrier is laid out on the attic floor over the top of existing attic insulation and susceptible to dust accumulation.

12. The Importance of Air Space When Installing Air Barriers Slides Courtesy of www.radiantguard.com

14. Basic Principles of ‘Radiant-ASV’ Ventilation When you install either Radiant Barriers or Radiant Insulation adjacent to an airspace within a ASV (Above Sheathing Ventilation) system, … the s ynergistic benefits of ASV are harnessed with the energy saving attributes of Radiant Barriers . This combined application of both systems in an ASV roof assembly is referred to as ‘Radiant-ASV’

15. ORNL’s Radical New ‘R-ASV’ Roof Design Design Improvements Made in the Second Generation ORNL Roof Assembly (2007) During the week of July 16th 2007, a second generation PCM test roof assembly was constructed. The new roof assembly featured an improved above-sheathing ventilation system which included two separate air channels to remove heat from the PCM storage. Summertime heat transfer penetrating the roof deck of a comparison asphalt shingle roof reached a peak of about 23 Btu per hr per square foot of roof deck . The conventional asphalt shingle roof had a radiant barrier attached to the underside of the sheathing (facing into attic) and was used for comparison of how effective a radiant barrier facing into the attic would be as compared to a conventional shingle roof- and the roof with above-sheathing ventilation. By comparison, the second generation ORNL PCM roof dropped the heat flux to less than 5 Btu per hr per square foot of roof deck in field testing at ORNL where outdoor temperatures exceeded 95°F.

21. Features of Upper Riser & Mounting Assembly The Upper Batten Riser and Mounting Assembly can be installed directly to the roof deck , or applied to a Batten, Truss or Rafter. The assembly provides unrestricted drainage & ventilation of the roof deck assembly. When applied directly to trusses or rafters, the Upper Batten Riser and Mounting Assembly can optionally support flexible radiant membranes in suspension between adjacent riser assemblies mounted on rafters. This configuration forms our patent pending radiant rafter ventilation channel with variable height and ventilation flow rate options. The adjacent upper batten riser and mounting assemblies and trusses or rafters form the peripheral walls of the sub-tile ventilation channels.

22. Applications for Upper Riser & Mounting Assembly Rafter Application Deck Application

24. 3. The Lower Drip Channel Assembly The Lower Drip Channel Assembly is an optional base support assembly for the Upper Batten Riser Assembly . Using the upper and lower mounting assemblies in conjunction with each other, facilitates the installation of suspended radiant vapor barriers and rigid radiant insulation with patent pending ‘low perforation’ barrier attachment technology . Typically hundreds of perforations are required for mechanical attachment of traditional vapor and radiant barrier membranes to a roof deck system. Mechanical attachment points are elevated above the roof deck & sandwiched between the upper and lower batten riser assemblies – resulting in limited perforation of the radiant vapor barrier and roof deck, dramatically improving the long term vapor resistance of the roof deck assembly. This unique functionality facilitates the formation of a partitioned Thermally Sealed Lower Air Barrier Layer and an Upper Radiant Ventilation Layer within an ASV assembly.

25. Applications for Lower Drip Channel Assembly Flexible Radiant ASV System Rigid Radiant ASV System

26. 4. Cool Roof Batten Assembly Components

27. 5. Integrated Cool Roof Batten Assembly