Disagreement about radiant barriers
You recently published "Radiant barriers" by Joan P. Crowe, an NRCA manager of technical services, in the June issue, page 64. Crowe notes NRCA does not recommend the use of radiant barriers in roof assemblies because the 2- to 5-degree Fahrenheit (1- to 3-degree Celsius) increase in roof temperature could reduce the service lives of roof assemblies.
I believe NRCA has done itself and its membership a disservice in making this notation. Crowe cites Reflective Insulation Manufacturers Association (RIMA) TB103, which notes the use of radiant barriers should not reduce the life of asphalt shingles. In fact, as also noted in the article, most major roof shingle manufacturers have confirmed their shingles are warranted when used with radiant barriers.
Radiant barriers have been used in roof assemblies for nearly two decades and installed either laminated to roof sheathing or draped over or between roof trusses (not as depicted in the illustration used in the article). Their effectiveness in reducing energy consumption has been noted and recommended by the California Energy Commission and county of Honolulu, and they are widely used throughout the Sunbelt.
If Crowe has actual data that prove radiant barriers reduce the lifespan of asphalt shingles, I would be interested in reviewing the data because I never have seen any such information. Radiant barriers have been tested by many manufacturers and third-party energy and testing centers. All reached the same conclusion as noted by RIMA. I believe NRCA should provide its membership with the facts, and the facts do not support Crowe's final comments in the article.
I recommend NCRA reconsider and change its position regarding the use of radiant barriers and print an appropriate retraction. Thank you for your attention to this matter.
Julie Cole
LP
Portland, Ore.
Following is Crowe's response:
"Thank you for your comments. NRCA stands by its position."
SPF roof system performance
NRCA Senior Director of Technical Services James R. Kirby's article "What is code-compliant?" June issue, page 36, is a recital of the current state of building codes, ASTM International standards and spray polyurethane foam (SPF) applications. But Kirby fails to adequately explain that existing SPF roof systems are performing appropriately. ASTM C1029, "Standard Specification for Spray-Applied Rigid Cellular Polyurethane Thermal Insulation," is being revised, which will allow performing SPF roof systems to comply with ASTM-based building codes.
The Spray Polyurethane Foam Association (SPFA) encourages contractors and suppliers to comply with all applicable building codes and regulatory requirements when applying SPF roof systems and insulation systems. In the case of SPF roof systems, however, building codes (with the exception of the Uniform Building Code) call for the use of SPF that rarely, if ever, existed because of a requirement to comply with ASTM C1029. This put the SPF industry in the situation of having to explain to building code officials why the foam that has been performing for the past 30 years is acceptable as a building product. Fortunately, most building code officials recognize this flaw in the code requirement and accept the use of SPF roof systems based on past performance.
Since the article was published, SPFA and NRCA have met to develop a more cooperative process to assist in the revision of ASTM C1029 in the shortest time frame possible. We hope this will be accomplished in the near future.
Mason Knowles
SPFA
Arlington, Va.
Following is Kirby's reply:
"Thank you for your comments. I stand behind the information in the article. The article did not address performance issues with SPF-based roof systems, and in no way was the article's intent to imply SPF-based roof systems are not performing."
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