Letters

PIMA disagrees with LTTR criticism

I read with interest NRCA Associate Executive Director of Technical Services Mark Graham's article "Testing LTTR," January issue, page 30.

The Polyisocyanurate Insulation Manufacturers Association (PIMA) has had a collegial relationship with NRCA working together on issues important to the roofing industry. In addition, since 2003, PIMA has been a strong proponent of the long-term thermal-resistance (LTTR) concept. Our members were the first—and currently are the only—foam insulation manufacturers to embrace a scientifically supported method for depicting long-term thermal performance. Therefore, it was disappointing and baffling that PIMA and its members never were offered the opportunity to participate in the "study" Graham describes.

The article also fails to educate readers about two important programs under way at ASTM International that are exploring even better understanding and refinement of LTTR value methods. The first program, which is looking at the bias of LTTR, began three years ago and will be completed in 2008. The second program, under the leadership of Oak Ridge National Laboratory, Oak Ridge, Tenn., is developing a prescriptive version of ASTM C1303, "Standard Test Method for Estimating the Long-Term Change in the Thermal Resistance of Unfaced Rigid Closed Cell Plastic Foams by Slicing and Scaling Under Controlled Laboratory Conditions," which will result in an ASTM International LTTR value method. Finally, ASTM International's C1303 Task Group has prepared a well-defined study that will include polyisocyanurate and extruded polystyrene and should begin in the near future.

It is important to note the polyisocyanurate industry uses LTTR values while the extruded polystyrene industry continues to use ozone-depleting blowing agents and is clinging to old technology of six-month R-values. The large number of articles NRCA has published criticizing six-month R-values should be well-known to Professional Roofing readers.

With respect to specific LTTR values, FM Global is the administrator of the PIMA Quality Mark,^CM a voluntary program that enables polyisocyanurate manufacturers to obtain third-party certification for the LTTR values of the permeable-faced polyisocyanurate roof insulation they produce. Samples submitted for testing under this program are selected by an independent third party and tested by an independent third-party laboratory with test results reviewed by FM Global to ensure accurate reporting. This is the only third-party certification program of its kind for foam roof insulation products. For third-party R-value assurance, designers and contractors should specify or use polyisocyanurate labeled with the PIMA Quality Mark.

Although we look forward to presentation of the data at the upcoming ASTM International Task Group meetings, we question the real motivation of this "study" that was sponsored, in part, by the Extruded Polystyrene Foam Alliance (XPSA), especially because ASTM International has been addressing this issue for the past three years. PIMA will continue to participate in the consensus process. We hope NRCA, XPSA and the Canadian Roofing Contractors Association (CRCA) will, too.

Jared O. Blum
PIMA
Alexandria, Va.

Following is Graham's reply to the letter:

As Blum indicates, NRCA and PIMA have a cooperative working relationship on a number of issues affecting the roofing industry, including advocacy and government relations. However, as I am sure regular readers of Professional Roofing realize, NRCA and PIMA do not agree on a number of technical issues.

It is important to note the limited testing program NRCA participated in is not about polyisocyanurate insulation, PIMA or the PIMA Quality Mark program. Instead, the testing is intended to investigate some researchers' claims of a bias in the LTTR methodology. The work group believed it was important not to identify the product types tested so as not to leave an impression this is a product-specific issue. In fact, polyisocyanurate and polystyrene insulation samples were used in the testing and reported.

Before conducting the test, NRCA spoke with several polyisocyanurate insulation manufacturers and PIMA representatives regarding the researchers' reports of a bias. The responses indicated if there were a bias in the LTTR methodology, it would be relatively insignificant.

Upon viewing the results of the work group's testing, a positive bias in the LTTR methodology becomes apparent—that is, the LTTR methodology appears to overstate a product's actual R-value at five years of relative aging. Furthermore, the magnitude of the bias—up to about 10 percent for some samples tested—is of concern. NRCA believes it is important for roofing professionals to be aware of the apparent positive bias in the LTTR methodology.

NRCA remains actively involved in ASTM Committee C16 on Thermal Insulation and a number of other ASTM International committees, subcommittees and task forces. Also, NRCA anxiously awaits the completion of the work that is under way at ASTM International relating to improving the LTTR methodology.

I have shared Blum's letter with CRCA and XPSA, the other members of the work group, and their responses follow.

Following is CRCA's response to the letter:

With regard to Blum's letter, we wish to assure PIMA CRCA intends to continue to participate in the consensus process to resolve this issue. We are pleased to see PIMA has been working diligently through ASTM International during the past three years to "refine" the LTTR test method and hope its efforts will, ultimately, address the concerns regarding bias and overprediction expressed in the article.

The Underwriters' Laboratories of Canada (ULC) Thermal Insulation Committee also has recognized the limitations of the current test method and reconvened a task group to address the issue of bias in the next set of revisions. We hope the work being carried out concurrently in ULC and ASTM International will address the identified shortcomings of the current test method.

Peter Kalinger
CRCA
Ottawa, Ontario

Following is XPSA's response to the letter:

Blum begins by stating polyisocyanurate manufacturers are the "... only foam insulation manufacturers to embrace a scientifically supported method for depicting long-term thermal performance."

On behalf of the extruded polystyrene (XPS) foam insulation industry, I must strongly disagree. The XPS industry has long maintained that LTTR reporting is the proper method of reporting thermal performance, as is stated on XPSA's Web site. In 1999, we supported the use of ASTM C1303 as the vehicle during an advanced proposed rulemaking of the Federal Trade Commission (FTC); prepared and presented a white paper about the subject that was delivered to an ASTM International insulation symposium in 2002; recommended and reported long-term R-value in the marketplace (and continue to do so); and participated in ASTM International and Canadian standards-development activities to develop the best scientific test method that accurately can predict LTTR performance. In short, XPSA embraces the concept of LTTR as long as the test methodology accurately predicts thermal performance of a given product. Our concern lies in the current test method's ability to do this as it compares with actual aged-samples data. It is for this reason we engaged in the study.

The samples were drawn by NRCA and CRCA representatives and tested by a third-party testing laboratory. It was done this way so the results would be above reproach. PIMA's participation would not have changed any results because the samples were drawn from products already in the marketplace. Blum appears to take exception to the testing results as if he believed all the samples tested were polyisocyanurate. Perhaps he knows more than he is letting on because Graham does not identify the samples in the article.

The article, which included the test results, was published to educate the building owner community about the fact that the Canadian test standard appears to have a positive overreporting bias that yields higher R-values than what consumers can expect to have at five years. This goes to the heart of whether the test is indeed scientifically valid. The industry wanted to confirm or refute CAN/ULC-S770, "Standard for Determination of Long-Term Thermal Resistance of Closed-Cell Thermal Insulating Foams," laboratory results by comparing them to actual aged samples. It should be noted some polyisocyanurate insulation manufacturers had taken the position (without substantiating that position with data) that the bias was specific to XPS products.

As a responsible industry, we were compelled to further investigate to determine whether there was or is any truth to this position. The XPS industry would have preferred that the polyisocyanurate industry shared its data seeing as it had many opportunities to do so, but our requests went unfulfilled. The data were collected to compare predicted thermal performance results as measured by CAN/ULC-S770 with actual data.

The bottom line is the study substantiates bias in CAN/ULC-S770 exists. This issue officially is put to bed, and the best use of everyone's time now is to determine how best to "fix" the test method to correct for the proven bias.

As an aside, this test method also overpredicts the long-term R-value of XPS products, but the marketplace has been placed in the uncomfortable position of competing on the basis of an unfair comparison. Insulation products compete first on the basis of thermal performance. If thermal performance is equal, other attributes—physical properties and cost—then are considered. For this reason, it is important consumers understand the results obtained from various test methods relating to LTTR so products may be compared properly. At present, this is not the case because the polyisocyanurate industry continues to use CAN/ULC-S770, which by its own text admits there may be a positive bias.

XPSA continues to be clear about its LTTR position for purposes of choosing design values for XPS products—a position fully substantiated with actual data from field performance. XPSA does not promote or recommend the use of LTTR values generated per the CAN/ULC-S770 thin-slicing method. XPSA recommends retaining the use of an aged R-value of 5 per inch for all design purposes.

The article's intent was to educate specifiers about the Canadian test method to make them aware of the bias that overstates actual product performance. This overstatement applies regardless of which type of foam plastic insulation is tested. The polyisocyanurate industry uses this test method as its basis to make R-value marketing claims. Furthermore, ASTM International's polyisocyanurate material standard incorporates a "former version" (not the current version) of CAN/ULC-S770. We believe this can result in misleading specifiers or purchasers to base buying decisions on information known to be inaccurate. It is important to note the study confirms this bias because all 20 samples (both XPS and polyisocyanurate) were less than five years old and 17 of them were showing R-values less than the published LTTR values if they used CAN/ULC-S770 as their basis. In fact, four samples were less than a year old and already were less than the five-year value.

Regarding the use of ozone-depleting blowing agents, it is important to note the polyisocyanurate industry used these agents until the Montreal Protocol regulatory framework banned their use on Jan. 1, 2003; the same regulations allow for continued use of these agents by the XPS industry until 2010. The reasons for this are many, including that the XPS industry made a larger leap in technology in 1993 to achieve greater ozone-depletion savings than did the polyisocyanurate industry, which took a shorter time-frame approach. The XPS industry is in complete compliance with the Environmental Protection Agency and Montreal Protocol regulations for use of its blowing agents.

Regarding PIMA's third-party certification program: No one is questioning the third-party certification program that PIMA uses confirms the method used produces the LTTR results as published. That is the wrong question to ask ... the correct question is whether the method is scientifically based and, as such, accurate in its ability to predict long-term thermal performance. On this count, the data speak for themselves.

It also should be noted FM Global's third-party certification program was designed and implemented by the polyisocyanurate industry. Therefore, though the polyisocyanurate industry has a third-party certification program that confirms LTTR values generated were based on the procedure in their standard, it does not confirm the values reflect the boards' actual performance. The third-party certification program also does not include the requirement in the second edition of CAN/ULC-S770 to add the warning statement: "The bias of this test method has not been determined. Some preliminary data reported by the industry are showing that in certain cases, the bias could be an overprediction." In contrast, XPSA includes this statement on its Web site.

In closing, the XPS industry believes time spent on this issue would be much better used by cooperating in the ongoing standards-development activities and encouraging the industry to do what FTC demands in the residential market: reports on the basis of 180-day actual performance until a consensus-based LTTR standard can be further developed in a scientific way that ensures accurate prediction. Until then, we applaud the courage of NRCA and CRCA to take on this issue with a scientific and unbiased approach. One easily can question motives, but motives aside, the data speak for themselves.

Susan Herrenbruck
XPSA
Woodbridge, Va.

Reader says contractors deserve litigation

I want to compliment you and your staff for the continued excellence of Professional Roofing magazine. I read every issue. Sometimes, I don't get the chance to read it when it arrives, but Professional Roofing does not leave my desk until I have reviewed the articles. I am sitting here on a cruise ship off the coast of Mexico catching up on Professional Roofing magazine. Hence, my late response to the October 2005 article "Lost in the wild," page 22.

There certainly is no question contractors are lost in a wilderness of litigation as the article aptly states. There is a main cause of all this litigation: poor workmanship! Roofing contractors and their staffs should be advised to learn the trade.

When I testify as an expert witness in construction failures for or against roofing contractors, the legal action usually is caused by poor workmanship. Material failure also is a problem, but this usually is caused by improper application or the wrong materials. (Contractors often say things like, "My supplier said this should work"; "We had this left over from another job, and I didn't want to waste it"; and "I was too busy on another job.")

It is difficult to defend roofing contractors.

To be successful and avoid litigation, contractors must know roofing materials and related installation procedures. Most roof system manufacturers have training programs for contractors for the proper application of their materials to meet warranty requirements. There are few manufacturers that will sell products to those who have not been trained.

Contractors and their employees should attend the International Roofing Expo each year and learn what roofing contractors do. There, they will meet peers and discuss common issues, attend seminars, meet manufacturers' technical representatives, and acquire the necessary essential skills to do acceptable work and avoid self-induced litigation.

There is a way for contractors to prevent costly claims: Have on hand NRCA's, other associations' and manufacturers' manuals, and read them. In addition, educating foremen and roofing workers is important to minimize exposure to rising liability.

There is no question the article is correct. Roofing contractors have worked diligently to earn the litigation. They should be active in the National Roofing Legal Resource Center and clean up their acts.

Robert Cox
Cox & Associates
Pollock Pines, Calif.