12/12/2007

ASTM and Roofing

By Richard L. Fricklas

 

Most subscribers to this newsletter have some awareness of an organization called ASTM Intl. (previously known as the American Society for Testing and Materials). Some specifiers may call for products that meet ASTM standards, without really knowing what the standards represent.

Applicability to Roofing and Waterproofing
Material standards are developed through a consensus process. For many materials, the project leadership was generally by a producer of such products. However, ASTM requires all committees to be balanced between users (building owners and roofing contractors), producers, and general interest people. Standards cannot be published which can be construed as restraint of trade or proprietary in nature. For many materials, the process may include development of new test methods where none exist; ‘round-robin’ testing of products; statistical analysis of precision, bias, and reproducibility; and establishing meaningful levels of performance.

Standards and Specifications
ASTM Committee D08 concentrates on roofing and waterproofing materials, including bituminous, modified bituminous, elastomeric and thermoplastic, and spray polyurethane foam. ASTM Committee C16 has jurisdiction over thermal insulation materials including wood fiber, perlite, glass fiber, mineral wool, glass foam, and cellular plastics such as polyurethane and polystyrene boards. C16 also is responsible for publishing test methods and recommended practices for those products.

Developing ASTM publications
Let’s examine an example of standards development: ASTM D7119, Standard Guide for Sampling Spray Polyurethane Foam and Coating in Roofing (published July 2007).

First, some background. Spray polyurethane foam (SPF) and associated coatings have been around for decades. However, they were considered specialty items, requiring precision foaming equipment and highly skilled applicators. The Fairfax, VA-based Spray Polyurethane Foam Alliance (SPFA) has identified some of the reasons why SPF has not gained more of a share of the commercial roofing market. These included variable levels of skill at the applicator level, variable quality of product from some sources, and lack of training by inspectors performing a quality assurance role.

To address these issues SPFA established training programs and accreditation for contractors, inspectors, and even for the producers of the chemical raw materials to address all these issues. However, individual producers had their own version of quality assurance, as did members of the National Roofing Contractors Association (NRCA), Rosemont, IL. Raleigh, NC-based RCI Inc. (The Institute of Roofing, Waterproofing, and Building Envelope Professionals, formerly the Roof Consultants Institute) had their opinions as well.

ASTM subcommittee D08.06 was formed to address these foam-roofing issues as well as to develop and publish material specifications and practices. Some of the most significant publications of this committee were D6705, Standard Guide for the Repair and Recoat of Sprayed Polyurethane Foam Roofing Systems; D5469, Standard Guide for Application of New Spray Applied Polyurethane Foam and Coated Roofing Systems; D6694, Standards Specification for Liquid-Applied Silicone Coating Used in Spray Polyurethane Foam Roofing; and D6083, Standard Specification for Liquid Applied Acrylic Coating Used in Roofing. The subcommittee is close to publishing a similar specification for liquid-applied polyurethane coatings as well.

The Consensus Process
For a number of years, I chaired the D08.06 task force charged with developing the SPF sampling guide, so I have chosen this to illustrate the process. At the time I was writing curricula for the Roofing Industry Educational Institute (RIEI), I discovered disagreement within the industry on how quality assurance was to be performed on spray foam (and coatings). Since I had also been associated with the SPFA accreditation program, it seemed to be easy to poll the industry, get the best numbers, and publish them.

The D08 committee, like most, only meets twice a year, so if a negative vote sets back the development of a standard, it may be 6 months before the issue is resolved. After a number of drafts, we thought all negatives had been resolved, only to find some negatives had been misplaced along the way. Several years passed, with draft after draft being rejected, but small compromises were achieved, with most of the progress reached after I had retired. Credit must be given to the dedicated leadership of Mason Knowles, who was the executive director of SPFA, and his D08 task force. I had the pleasure to discover that the D7119 standard had finally been published in July 2007. Excerpts follow.

Definitions
Core samples are cylindrical sections approximately 2 to 3 inches in diameter. They shall be cut using a round metal template or coring tool, and they shall extend from the surface down to, but not through, the substrate. (We were aware that there were a number of homemade coring devices around, so we were able to use “approximate” as a compromise.)

Slit samples are crescent-shaped samples approximately ½-inch wide, ¾-inch deep, and 2 to 3 inches long, cut with a sharp knife. Slit samples are used to examine the uppermost polyurethane foam layers and the coating system. (Approximate worked here, too.)

Significance and use. Adequate coating thickness (mil thickness) is necessary to protect polyurethane foam from the effects of ultraviolet degradation. This guide outlines general procedures for sampling and measuring the coating thickness by using slit or core samples. (We used “adequate”, realizing that this guide was for sampling, and adequacy would have to be defined by individual coating manufacturers.)

Sampling. When specified (sampling is not always required), samples shall be taken from the SPF roofing system for quality assurance. Two core samples from the first 100 squares and one additional sample for each additional 100 squares of fraction thereof. When specified, six slit samples shall be taken for every 100 squares.

Repairs of holes made by removal of core or slit samples. Holes shall be filled with polyurethane foam or a polyisocyanurate foam plug set in a compatible sealant. Density of the foam shall be equal to or slightly greater than that specified in C1029, Type III. After filling the hole, apply sufficient compatible sealant to completely cover the plug, extending onto the coated surface.

Report. A description of coating system, noting granules if present, number of base and topcoats, minimum and average thickness of base and topcoats, location of samples on roof plan, number of foam passes and average thickness of each pass, compressive strength and density of foam, comments on adhesion of components, etc.

Significance of this Standard Guide
The reader certainly will note where compromises were made. On the other hand, the persistence of leaders like Mason Knowles in this case cannot be overemphasized. Note that a specifier or building owner cannot passively call for sampling SPF following D7119, but must custom-fit the level of quality assurance desired.

Am I proposing that readers should join ASTM? Yes, why not? You don’t have to attend meetings in order to participate. Ballots are mostly collected online, and if you do have objections (negatives), the subcommittee must consider them. ASTM also holds roofing symposia every several years, with the most recent just held December 2-3, 2007. (Proceedings will be available at the ASTM website.) Membership dues for ASTM is only $75 per year, which includes free registration for roofing symposia, as well as one free volume of specifications.

Visit the ASTM online bookstore for a list of available ASTM specifications on roofing and waterproofing.

 

 
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