Images courtesy of www.naturallywood.com.

Placing special emphasis on the use of local materials is a popular approach to reducing the environmental impacts of construction projects. Sourcing materials within 500 miles of the site is a fairly straightforward way to earn one to two points under the Regional Materials credit in the LEED rating system (see sidebar). However, the reality may be more complex, and it may not be safe to assume that the pursuit of this credit will reduce the environmental impact of your project.

The primary impacts of transportation are the fossil fuels used in conveyance and the associated GHG emissions. But it is simplistic to consider these impacts independently from what is being transported and why.

The interplay of all the environmental impacts of materials needs to be considered in totality and objectively assessed. Unlike in Europe, there are no regulations in Canada which require accountability from product manufacturers for the environmental impacts of raw-material extraction, production, transportation, etc. The magnitude of these impacts can be significant and building materials are particularly problematic. Large amounts of energy are required for the manufacture of most common construction materials such as steel, glass and concrete.

While it may seem somewhat counterintuitive, transportation impacts are not necessarily a function of distance. Mode of transportation matters a lot. A product travelling a long distance in a highly efficient mode may have a smaller environmental footprint than a product with fewer miles to travel in an inefficient carrier. LEED sets out transportation efficiencies as follows: shipping by truck (2,127 kJ/ton-km) is more than six times worse than rail (373 kJ/ton-km) and more than 15 times worse than ship (138 kJ/ton-km). So, shipping 1 ton of wood from Vancouver to Asia is roughly the same energy-wise as driving 1 ton of steel from Vancouver to Calgary (973 km) in a truck.

A report by Forintek on Japan’s Woodmiles system corroborates the same principle, maintaining that “1 kilometer of truck travel is equivalent to 31.9 kilometers of ocean travel on a bulk carrier.” The report, which is concerned with the transport of lumber from Canada to Japan, states that instead of doubling Japan’s self-sufficiency in logs, a faster way to attain the same carbon dioxide reduction would be to shift some of Japan’s imports from Canadian logs to Canadian sawn lumber, which is less dense and lighter to transport.

The UK is the first to have a Publicly Available Specification — PAS 2050 — for assessing carbon footprint of individual products. This methodology brings together all carbon impacts (transportation, raw material extraction, manufacture, etc). “Carbon Footprint of Four Canadian Wood Products Delivered to the UK as per PAS 2050 Methodology,” a study prepared by the Athena Institute and FP Innovations (available at www.naturallywood.com) assessed four British Columbia wood products of interest to the UK market. Despite being transported more than approximately 16,000 km, all four Canadian products represent a net carbon sink upon delivery in the UK.

Using transportation as a metric of environmental impact is clearly limited. The solution is for buildings to be assessed using a life-cycle impact assessment methodology. This process analyzes total environmental impacts of all materials and energy flows, either as input or output, over the life of a product from raw material to end-of-life disposal or rebirth as a new product.

Increasingly, some companies (such as Interface), industries (such as the BC Forestry industry) and countries (such as France), are looking to life-cycle analysis (LCA) as a standard method (defined by ISO 14040) with which to assess and report environmental impacts. Under Loi Grenelle 2, France now requires environmental product declarations (EPDs) to be in place for a host of product categories.

Tools such as BEES provide quick, graphical comparisons of products (free download or online from www.nist.gov/el/economics/BEESSoftware.cfm).

Athena’s spreadsheet-based application, EcoCalculator, comes preloaded with a wide range of envelope and structural assemblies for a series of North American climate zones and urban centers. It is easy to use and free to download (available at www.athenasmi.ca). Athena’s Impact Estimator can assess whole buildings with data input from drawings and/or bills of quantity. All of these systems will enable the full range of impacts to be considered, not just transportation.

Clearly, mainstream adoption of LCA will only happen when building owners are motivated either by regulations or by market demand for this information. However, with so many accessible tools available, LCA thinking can start today and can inform designs from schematic stage forward. You may be surprised by what you find out.