Life cycle assessment could set new standard for green building, expert says

Posted June 3, 2010, 8:16am EDT

Source: Daily Commercial News, June 2, 2010

Today’s rating systems for green buildings ignore some of wood’s intrinsic and unique features, such as thermal mass and acoustic values, Helen Goodland, LEED AP told delegates at the Architect Institute of B.C.’s recent annual conference.

As a result, it doesn’t earn many credits in construction.

Using a Life Cycle Assessment (LCA) analysis would be more beneficial, said Goodland, executive director for the Light House Sustainable Building Centre.

Green rating systems now in place, whether sourcing certified wood from forests or using it in construction, come with information gaps and often a lack of enforcement for the use of those standards.

“There is even a lack of common LCA protocol,” she explained.

LCA analysis tracks the environmental impact of a given product throughout its life-span, not when it lands at the construction site.

Such on-site rating systems simply use content credits aimed at reducing transportation emissions.

She advocates using the International Organization for Standards (ISO) 14040 protocol for LCA as there is an ability to “capture the whole embodied energy footprint” of the product.

ISO has derived protocols for developing frameworks, validating and measuring the life-cycle of products.

However, more work is needed to bring LCA analysis into green building rating systems used in the construction industry today, she said.

Standards for wood from certified forests have also varied and the Canadian Standards Association (CSA) is moving into the gap, she said, pointing to the CSA forest certification program.

The program looks at performance and chain-of-custody.

She said it is important that such programs be consistent and enforceable to ensure their integrity and credibility with the end user.

Goodland completed a study in 2009 for Forest Innovation Investment that looked at different green rating and certification systems to better understand what opportunities existed for green building products.

A total of 11 national and international rating systems were surveyed for a total of 18 applications.

They were the U.K. system BREEAM; Built Green Canada; CASBEE; Green Globes; Green Star; LEED; Living Building Challenge; NAHB Model Green Home Buildings Guidelines and SB Tool.

In commercial buildings, Goodland’s research indicated that the system LEED CI (commercial interiors) offered the highest credits for wood use, but it was only 18 per cent of the total, while SB Tool provided just eight per cent of the credits.

Credits earned on green rating systems for multi-family residential found that Built Green Canada offered the highest rate at about 28 per cent, while Green Star offered only 10 per cent.

Of the total applications, 12 (including LEED NC Canada, LEED CI, LEED for Homes, plus the Built Green systems) offered no recognition for the LCA benefits of wood.

Green Globes gave points for LCA, but not specific methodology.

SB Tool did offer points for LCA methods that examined embodied energy, lifecycle GHGs and lifecycle costs.

In looking at the various rating systems, Goodland found that wood lost points in indoor environmental quality.

Credit was given to installing natural or low-VOC carpet, but wood floors were not rewarded.

Goodland identified “rating system gaps” in sound abatement strategies that use wood panel and fibre product; a lack of recognition for new products such as wood fibre insulation; wood’s thermal mass and passive design features were not credited, and wood’s material efficiency in combining a number of features such as insulation, light-weight, structural integrity and weather resiliency are also ignored.