Green Building Decision Matrix
I – ISSUES RELATED TO MATERIAL SELECTION BACKGROUND
1. Do we need it at all?
The most important question that can be asked is whether the material, product or component is actually needed at all. By reducing material usage, we reduce the cost of the project including labour (and design) but as well we reduce the extraction, manufacturing, distribution, and disposal of the product, the costs which are largely not included in the price of the product. Thus, reducing material use not unlike conserving energy is the easiest and most cost-effective means of achieving environmental and economic savings.
2. Is it toxic?
Most of us would suggest that a product that will release toxic substances into the environment should not be used. But today, we are literally surrounded by toxic substances. And contrary to what some people may suggest, this is not the way it’s been. A full 60,000 new chemicals are now in our environment that didn’t exist in 1960. Our environment is increasingly saturated with toxins so much so that an alarming 30% of Canadians now have allergies or chemical sensitivities.
However, it is often difficult for the purchaser to assess whether a product is toxic. The problem has many roots. Today and in the past, corporations have only been obligated to indicate a product’s ingredients and abide by toxic chemical legislation set out by the various governments. The onus was on the government and ultimately the public to show that it is toxic. Unfortunately, in most cases, only chemicals that had immediate and traceable effects would be investigated. In many cases, hard scientific data could take years before proof without a doubt. This amount of time was required for 1 chemical in one reaction never mind the extremely difficult case of identifying the synergistic effects of multiple chemicals reacting together. A release and let’s watch rather than a cautionary approach was and is being taken. Furthermore, it is apparent by the success of tobacco companies in keeping their toxic chemicals in their products, that there is little hope in this system of corporations taking any responsibility for the impacts of their products. And finally, for many of us, we just don’t have the background and education to comprehend chemical labels or for see the potential effects of using these products (many would suggest ascorbic acid (Vitamin C) is probably toxic).
Thus, education is definitely required. Place the onus on the manufacturer to prove that the product is safe. Ask the manufacture for a Material Safety Data Sheet (MSDS). Research the product using one of the many websites or publications that list environmental construction products. One rule of thumb is to select the product with the least amount of constituents that do not naturally occur in nature. Take the cautionary approach and avoid the product if it is not necessary and substitute a less toxic alternative.
3. What is the life cycle cost?
Life cycle cost or price takes into account the entire cost of employing the product. There are two levels of life cycle analysis (LCA): life cycle cost to the purchaser of the product, and entire life cycle cost to the global environment. The first approach is largely just an economic analysis. For example, when selecting exterior siding for a building, the builder would consider not only the unit and total cost of the product, but the added costs of transporting the product to the site (local market or across the continent), labour costs to install, additional costs (electricity, water consumption), maintenance costs (annual paint and repair), and disposal costs (some building products contain toxic chemicals which may introduce disposal fees). This approach clearly identifies the broader costs of employing a product and the economic costs directly to the user.
However, a more thorough approach can be taken to life cycle costing and include the costs that are not included in the purchase price (i.e. environmental impacts of extraction, manufacture etc.). With this more thorough LCA, other costs are taken into account besides economic, and impacts on other parties are identified and assessed. For example, when selecting exterior siding, the builder would consider where the product originated. If it was wood, was it harvested sustainably? Does the local industry support the sustainability of the community? How far did the wood have to be transported (since transportation is the main component of pollution in the process to create lumber)?
LCA is not a perfect science. Moreover, results are largely dependent on local and individual analysis as all variables change. Any form of LCA employed in decision-making is better than none. Making operating staff more aware of the broader issues and costs of materials is always beneficial.
4. Does it contain recycled content? Post-consumer or post-industrial?
A characteristic that many of us are now aware of and understand is recycled content. Fortunately, it is a very simple concept that can be easily identified on a product and understood by the consumer. The designer/builder should select building products in the same manner as it selects paper products for the office – the higher the recycled content the better (and recycle products at the end of their life). The only principle to be aware of is that post-consumer recycled content is preferable to post-industrial recycled content. Post-consumer content is material that is being diverted from the landfill. Post-industrial content is materials that would likely be reused anyway although still beneficial when post-consumer content isn’t available.
5. How will the product ultimately be disposed of? Can it be recycled whole or in part? Do facilities exist locally?
The two biggest problems with society today are: 1. the rate of consumption of resources and, 2. the production of waste. With this in mind, building materials should be selected with decommissioning and disposal in mind. Select products that can be returned, reclaimed, reused, recycled, or returned to the Earth as biodegradable material. If it is recyclable, do facilities exist nearby that can recycle it. Can the product be recycled or just downcycled? For example, plastic companies are notorious for indicating recyclability but have no interest in indicating to the consumer that facilities don’t actually exist to facilitate recycling of the product. Furthermore, many types of plastic can only be downcycled into products like parking stops (ultimately creating waste). Avoid products that contain toxins that ultimately will be released into the environment.
6. Is it biodegradable? Does it break down into natural constituents?
If a product is biodegradable than concerns about disposal are diminished. Be aware however, that there does not exist any legislation on product labelling with respect to the word biodegradable. For example, many conventional cleaning products have constituents that biodegrade but the resulting by-products are toxic in the environment. Seek advice and guidance from labelling programs such as Environmental Choice logos.
7. Is the product over packaged? Can the packaging be reclaimed by manufacturer?
An easy means of reducing environmental impacts is to select products that have minimal packaging or recyclable packaging. Educate the manufacturer and distributors when excess packaging is used and place the onus and cost on them to reduce and reclaim the packaging rather than the builder buying material that is then discarded.
8. Are there any social impacts to extracting, manufacturing, distributing, using, and disposing of this product?
Attempt to assess the non-economic impacts of using the product. Some are more obvious than others. For example, wood from the virgin rainforests should probably be avoided. A great deal of judgement is required in this case, and research and guidance from reliable sources is valuable.
9. Is the product durable?
What is the expected lifespan of the product? Is the expected lifespan based on the conditions that the product will be used? A general rule is to select products with the longest lifespan. Often this means increased initial cost where life cycle costing (see above) becomes important.
10. Is the product low maintenance?
Maintenance is one component of life cycle cost. In most cases, designers and builders only consider the construction cost, even though the operating expense and in some cases disposal costs can be far more significant. Attempt to select products that require no maintenance. For example, stainless steel finishes, concrete pavers vs concrete pads.
11. Are green house gases produced to extract, manufacture, distribute, use, and dispose of this product? Are the total GHG less than other products?
An issue that we are all aware of is our impacts on the global climate due to our collective release of green
12. Are ozone depleting substances produced to extract, manufacture, distribute, use, and dispose of this product? Are the total ozone depleters less than other products?
13. What is the embodied energy of the product? Is it less than the alternatives?
14. Is the product from local or regional sources?
II – PRIORITIZATION
The environmental issues mentioned above are all important. In many cases, it is difficult to decide which issue is more important when two issues are in opposition or two products with different issues are compared. This is the dilemma for the designer and operator.
To date, significant work has gone into trying to prioritize the issues. However, since each issue is not universal in nature but rather dependent on multiple factors (i.e. distance to extraction and manufacturing, climate, disposal facilities, etc.) the decisions in many cases are site dependent.
Thus, the designer and operator must therefore become involved in the decision process and this is where judgement and values are involved. For example, using steel might replace using wood treated with toxic preservatives within the park, BUT what about the emissions from the steel manufacturing down the road?
The first step for any designer/owner or organization is to identify what are the local and regional environmental threats. By identifying and documenting these threats, decisions as to which issue is more important will become easier. Some of the issues include:
§ Global Warming
§ Ozone Layer deterioration
§ Water pollution
§ Air pollution
§ Petroleum spills
§ Automobile pollution
§ Persistent Organic Pollutants
§ Logging of Old-Growth forests
§ Habitat destruction
§ Local unemployment
§ Maintenance costs and budget cuts
§ Labour costs
§ Durability and climatic factors
§ Urban sprawl
Below is the decision path that we are recommending. This line of questioning should be done for each product introduced into the project. When comparing products, in many cases it will be the product that makes it the furthest down the list. Others can be discarded.
– Is the product or material needed at all?
– Is there an alternative product or material that has less of an environmental impact over its life-cycle?
– Does it displace a product or material that has a greater environmental impact (i.e. finger-jointed lumber)?
– Is it a natural or synthetic material? Natural materials tend to have less environmental impacts.
– Does it contain potentially harmful chemicals or constituents? 1
– Is it biodegradable into natural constituents (i.e. DDT is also biodegradable)? Is this product destinied for the landfill? 2
– Is it recyclable? Is it being used in a way that allows it to be recycled (i.e. glued or screwed)?
– Does it contain recycled content?
– Does it contain or use (manufacture/use/maintenance) ozone depleting substances? 3
– How does its life-cycle environmental impacts compare with alternatives?
– How does its embodied energy (and thus in general greenhouse gas emissions) compare with alternatives?
– Is there a local product or alternative that is comparable that will reduce the impacts of transportation?1 More than 60,000 new chemicals have been invented since WW2 and less than 5% of them have been tested for human health impacts. None of them have been tested in combinations of two or more, nevermind 10,000 as in the case of a building.
2 Generally, biodegradable means into organic constituents (Hydrogen, Oxygen, Carbon, and Nitrogen).
3 Ozone depleting substances include CFCs, HCFCs, and Halons.