ID#3006 made on
MRc4.1 - Recycled content - 10% (post-consumer + 1/2 pre-consumer)
LEED BD+C: New Construction, LEED BD+C: Schools, LEED ID+C: Commercial Interiors, LEED BD+C: Core and Shell
One of the most significant materials we have specified for this project is a wall system that is comprised of recycled polystyrene embedded in a Portland cement matrix cast into panels to provide bot...
One of the most significant materials we have specified for this project is a wall system that is comprised of recycled polystyrene embedded in a Portland cement matrix cast into panels to provide both structural support, and a high insulation value. This system (Perform Wall) has an average weight per panel (10"x15"x10') of 156 lbs. Because polystyrene is so much lighter than cement, the polystyrene within the panel only weighs 37lbs, but comprises 85% of the panel by volume. We have this information documented from the manufacturer. To calculate the percentage of recycled material based on the criteria of weight only, the polystyrene would only be 24 % of the total weight, while the manufacturer states that the polystyrene is 85% of the product volume. We believe we have followed the design intent by specifying a product with a high percentage of recycled content, and would like to be granted an exception to the calculation method and be permitted to utilize the 85% for submittal purposes. We will include the manufacturer's information in the submittal.
The LEED Version 2.0 Reference Guide (page 194) provides guidelines for calculating the recycle content of materials. The method described above uses Equation 3 (Assembly Recycled Content) methodology for the concrete-based wall system. Given this is based on weight, and since the polystyrene is a lighter material than the concrete, the equation does unfortunately reduce the assembly's overall recycled content value.
An alternative calculation methodology is to apply Equation 1 (Recycled Content Value). This would require itemizing the materials/components that make up the wall system and determining both their individual costs as well as the percentage of post-consumer and post-industrial recycle content. Calculations done this way may result in a higher recycle content value in comparison to using the other method. The manufacturer of this system should be able to provide individual costs and the respective recycled content for all the materials. Applicable Internationally.
Related Addenda (Corrections & Interpretations)