Challenging the Simplified Life-Cycle Analysis

Challenging the Simplified Life-Cycle Analysis

I recently was provided with the January 1997 issue of EBN (Vol. 6, No. 1) and found the information

of considerable interest. However, I would like to offer a few comments on “Material Selection” and the use of a simplified life-cycle analysis (LCA).

I can relate to the statement regarding the limited accuracy: “a simplified, generic LCA can never be as accurate as a detailed product LCA.” However, when you continue: “the streamlined material information can still provide a very good starting point for comparing materials,” I question the use of the term “very good,” as I am aware of the often questionable assumptions used in the development of the generic data.

For example:

On page 13, the table refers to oriented-strand board (OSB) as an example of the use of a simplified, generic LCA. However, under item #2—Occupant Health, you suggest: ”Specify OSB with MDI Binder.”

Oriented-Strand Board with an MDI binder component represents approximately 30% of the OSB produced in North America.

Over 99% of the OSB manufactured with MDI binder uses MDI in the core or center of the panel, while the face strands use phenol formaldehyde (PF) binder in either liquid or powder form. The balance of the OSB produced uses all PF binders. In all cases, the PF binder is cured during the pressing process. Regular tests of OSB panels leaving the mill by Forintek Canada Corp. indicate no measurable formaldehyde release from these panels.

Finally, neither the specifier nor the user has any way of identifying which OSB products are a mix of MDI and PF or 100% PF.

Under item #4—Hazardous By-Products, you suggest: “Determine that plant is meeting or exceeding air emission standards.”

All OSB plants are permitted by the state and federal environmental protection agencies, and emissions are regularly monitored by state authorities. In practice, it is impossible for a specifier to specify OSB from a particular mill and even difficult to specify OSB from a particular manufacturer.

Under item #7—Resource Extraction, you suggest: “Determine that wood is from a well-managed forest.”

At present there are no systems in place to certify that a forest is well managed. In the U.S., however, the American Forest & Paper Association has a membership program for sustainable forest management practices, and Canada has recently produced a Standard for Sustainable Forest Management.

OSB is manufactured from aspen or poplar in Northern North America and managed southern yellow pine tree farms or plantations in the South. When poplar is harvested, the root system remains in place for continued stability of the slope. During the first year after harvesting, the root system sends up suckers which quickly develop into growing trees, further stabilizing the slopes.

These examples show the pitfalls of using the present simplified system.

Unfortunately much of the spectrum of information on product emissions, LCA, and energy requirements is based at present on incomplete science. This leads to perceptions about products that may be unfair, and specifiers should use a great deal of caution when applying this information in their decision-making process.

John D. Lowood, President

Structural Board Association

Willowdale, Ontario, Canada

Editors’ response:Thank you for your comments. We agree wholeheartedly with your closing statement. Nothing can take the place of good information about the products and processes, and your letter is helpful in that regard. However, in light of the fact that specifiers are going to be making decisions anyway, we think it useful to have a framework for the decision-making process. And we do take issue with some of your specific points:

While formaldehyde emissions from panels made with PF binder are quite low, they are still problematic for some individuals. In addition to preferring MDI binder, which is more toxic during the manufacturing process but more stable after curing, we could have suggested sealing the OSB out of the occupied space or using an alternative (non-engineered-wood) product. To the extent that specifiers cannot determine which binders are used to make a particular product, that is a shortcoming in the industry that will only be addressed if users demand the information.

While it may not be possible to specify OSB from a particular mill, specifiers can ask their distributors to avoid products from companies that are persistently out of compliance with environmental regulations and from those that actively seek to weaken those regulations.

Companies participating in forest certification under the guidelines of the Forest Stewardship Council would certainly contest your claim that “there are no systems in place to certify that a forest is well managed.” Even the AF&PA standards, which rely on self-reporting, have caused some companies to leave the organization rather than meet the requirements, so membership in that organization is useful as a minimum guideline.