Turning the tide on climate change

Description | Indicators | Scoring Criteria | Definitions | Issues

Use phase and end of life global warming gas emissions : The goal of this credit is minimization of global warming gas emissions over the entire life cycle from cradle-to-cradle,. The current Pharos scoring indicators are based only on a cradle-to-gate analysis. For the vast majority of products, most of if not all of the emissions are generally in the cradle-to-gate phase of the product life cycle We recognize, however, that there are certain categories of products that either directly use energy during use (such as appliances, HVAC systems or light bulbs) or have a significant effect on the energy usage of the building (for example insulation, through changing the performance of the thermal envelope). Furthermore the efficiency of the end of life recovery system, if any, will affect climate change impacts of the end of life phase. In some cases, these effects will be sufficient to significantly affect the overall global warming gas emissions in the life cycle. Incorporation of these issues into a building material scoring system such as Pharos is difficult due to the building specific nature of these effects - e.g., the difference between use phase global warming emissions of two different roof membrane systems with different reflectivity, will vary depending upon the local climate and the rest of the roof assembly design and can only be calculated with very building specific modeling.

We welcome identification of products that may fall into this category, studies that help assess the relative importance of use and end of life phase global warming gas emissions and most importantly ideas on how best to incorporate analysis of use and end of life phase global warming gas emissions into the Pharos framework and scoring system.

Functional units: The standard unit of product for a given product class used for these comparisons is related only to physical size - square foot, linear foot, etc. It does not include all of the parameters typically included in "functional units" as defined for life cycle analyses, such as performance characteristics or time. Definition of functional units and how they will be used in this tool is a task for future versions. We welcome suggestions.

Boundaries: Insuring common boundaries in the calculation of global warming gas emissions is a big challenge.

GWPs: We anticipate developing a table of 100 year global warming potentials for common gas emissions from building manufacture processes for Version 2.

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