The Environmentally Responsible Construction and Renovation Handbook
Chapter 2 - Selecting Products and Material
When choosing construction materials, it is important to recognize that a product's environmental impact is the sum of a number of factors, many of which may not be obvious. Determining which products are best from an environmental point of view may seem like a confusing task, however the utilization of internationally recognized criteria can simplify this task. Selecting materials that provide reduced environmental impacts requires a shift in mind set. This section is intended to introduce portfolio and asset managers, project managers and building professionals, leasing agents, accommodation users and property managers, to the environmental issues that are pertinent with respect to product selection.
A product life cycle assessment is a framework that can be used to identify environmental inputs, outputs and impacts within the life of a product. The framework considers materials types, water and energy use. The manufacturing processes or activities are inventoried for the assessment. The life cycle assessment framework used for this text is based upon the Canadian Standards Association guideline CS Z760-94. The product life cycle can be grouped in four stages:
Phase 1- Raw Material Acquisition
This section addresses all of the activities required to gather or obtain a raw material or energy source. It also includes the transportation of the raw materials to the point of manufacture.
This phase can be subdivided as follows:
- Material Manufacture - the activities required to process a raw material into a form that can be used to fabricate the product.
- Product Fabrication - the process steps that use raw materials to fabricate the product.
- Filling/Packaging/Distribution - processes that prepare the final products for distribution.
Phase 3 - Use/Reuse/Maintenance
This phase begins after the distribution of products for intended use and includes any activity in which the product may be reconditioned, maintained or serviced to extend its useful life.
Phase 4 - Recycle/ Waste Management
This phase begins after the product has served its intended purpose and is scheduled for disposal into the waste stream either through recycling or via a waste management system.
Renewable resources have potentially infinite availability while non-renewable resources cannot be regenerated and are available in limited quantities. Non-renewable resources such as petroleum and old growth or tropical rain forests are created over such extended periods of time that replenishment is not measurable. Renewable resources are produced during shorter periods of time and can be managed and replenished.
Numerous organizations and programs have either finalized, or are in the process of developing certification programs that ensure resources are harvested or extracted in a manner that secures the renewal of the natural resource. Perhaps the best known of these systems is the one developed by the forestry industry. Product manufacturers and construction contractors are now able to purchase wood products that display certification stating the wood was harvested in a sustainable manner that ensured the planting of sufficient seedlings to replenish the harvested trees.
Products should be avoided that are listed on the Convention in Trade in Endangered Species (CITIES) List. Products are considered renewable when it can be verified through a certification mechanism that they are constructed with materials harvested under controlled conditions, providing for resource regeneration or when their supply is so abundant that non-regeneration provides minimal environmental impacts.
This is a quantitative figure that can be supplied by manufacturers. Industry Canada's Principles and Guidelines for Environmental Labeling and Advertising contain a well established and acknowledged definition of recycled content. Recycled content is defined as "the portion of a product's weight composed of reprocessed post-use materials." The materials may be reclaimed from either a post-consumer source, which is material that has served its intended purpose and is generated as waste, or waste created or left over from an industrial process. Recycled content is usually calculated as an averaged percentage. Manufacturers can be asked to provide the percentage of post consumer and/or postproduction waste included in the product and a total percentage of recycled content.
Remanufactured products reduce the necessity to extract and process raw materials, thereby reducing the environmental impacts of the product. A product or system is considered remanufactured if it has been diverted from the waste stream and is refabricated in a manner that has permitted a complete upgrading by either the original manufacturer or a second party. See also Remanufacturing under Section 2.3.3; Use, Reuse and Maintenance
Sustainable development provides for the needs of the present without compromising the ability of future generations to meet their needs. Sustainability holistically examines a products needs, manufacture, use, disposal and indirect impacts. The level to which a material does not negatively impact long term planning best determines sustainability. For example, non-renewable resources need not be evaluated any further as their use is unsustainable. However, a renewable resource may appear to be sustainable until further scrutiny identifies subtle long-term impacts.
The issues that are related to sustainable development are far reaching and incorporate all criteria addressed in this text. The specification of building materials that provide lowered environmental impacts will contribute towards sustainable development.
The toxicity of a product can result in health hazards and environmental problems, therefore the first approach should always be to reduce or eliminate the use of toxic material, where other options are available or viable. Solvents are often highly volatile and unstable before the curing process. Particulates produced from toxic materials during construction practices can have an adverse effect on both tradespeople and building occupants. Materials that have been fabricated or treated with toxic substances often have limited disposal options. The proper disposal of leftover toxic products requires shipment to facilities designed to handle hazardous waste. The introduction of toxic materials into landfill sites contributes to land, water and air pollution. The manufacturing processes for toxic materials tend to generate greater amounts of water and air pollution than for lower toxicity materials.
Workplace Hazardous Materials Information System (WHMIS) sheets must contain details concerning the inclusion of hazardous materials in a product. However, the lack of hazardous materials on a product's WHMIS sheet should not in itself be viewed an opportunity to make an environmental claim. Numerous international eco-labeling programs such as Canada's Environmental ChoiceM Program have established acceptable toxicity levels as part of their product guidelines.
Global Warming is a complex issue. However, it is commonly accepted that the release of greenhouse gases contributes to this problem. Two of the most significant greenhouse gases are carbon dioxide and methane. Carbon dioxide and methane are produced through natural processes, but humankind has contributed significantly to their production. There is some uncertainty as to the ultimate impacts of atmospheric change, but global warming is considered to be an essentially irreversible process. Our actions can be directly responsible for changes to the earth's atmosphere. If the changes continue to occur at the present rate, the effects on agriculture, forestry and weather patterns may be irreparable.
The burning of fossil fuels such as coal, oil and natural gas generates carbon dioxide. Reducing our energy requirement through the use of energy efficient products can reduce the generation of carbon dioxide.
Methane gas is released naturally from rotting plant materials, but landfill sites produce 30% of the methane gas produced by artificial sources. Diverting waste from landfill sites will reduce the generation of methane gas.
The contribution to global warming for most products occurs from the release of greenhouse gases during either the production or disposal stage of the product's life cycle. These are process-orientated steps and are difficult to control or qualify within the context of a single product. Global warming is therefore considered a non-quantifiable criterion.
It is believed that cloroflorucarbons (CFCs) and other ozone depleting substances are responsible for the thinning of the ozone layer that shields the earth from the sun's harmful ultraviolet rays. Many ozone depleting substances (ODS) contribute to global warming. These gases linger in the atmosphere for 60 to 100 years. CFCs are manufactured substances that are commonly contained in some refrigerants and blowing agents when producing building products and materials.
In 1987 thirty-two countries signed the Montreal Protocol on Substances that Deplete the Ozone Layer, which calls for a halt to CFC use by the year 2000. The first step towards attaining this goal came on January 1, 1996, when the production of CFCs was banned by signatories of the Protocol. A second generation of CFCs, hydrocloroflorucarbons (HCFCs), will be banned from production in the year 2025. HCFCs are currently being used as an interim solution for mechanical systems and cooling appliances that have operated on CFC based refrigerants.
Ozone depleting substances used during the manufacturing process can be quantified. CFC use and production can be eliminated through the specification of building materials that use alternative refrigerants and blowing agents.
Operational energy is the amount of energy that is consumed by a product during its use. Embodied energy is the term used to describe the amount of energy that is used to produce a product. It includes the amount of energy required to extract or harvest raw materials, transport the raw materials to a processing site, process the feedstock, package and ship the fabricated product and finally install or consume the product.
It also includes the energy to heat the plant where the product was manufactured. Organizations like the American Institute of Architects (AIA) provide general figures for the embodied energy of many products. These figures provide a degree of reference, but cannot be used for a quantitative assessment, as each application or site requires its own individual assessment.
This criterion describes the reduction of energy use or the presence of energy savings as a direct result of behavioral changes rather than technological intervention. The implementation of energy conservation practices has the same benefit to the environment as those obtained from minimizing operational energy use through products and materials. However, the success of the measures is dependent upon proper implementation and communication and is therefore not quantifiable.
Although this category is a qualitative issue, utility companies regularly promote energy conservation procedures as a recognizable means of reducing energy demands. Electrical and gas utilities are able to provide information for both residential and commercial applications. Commonly recommended energy conservation practices include turning off lights in empty rooms or the installation and use of operable windows that allows for natural cooling and ventilation.
Energy efficient systems or products give equivalent results for less energy. Energy efficient products enable consumers to consume less energy while maintaining present behaviors.
Acceptable energy consumption rates, such as those published by The Canadian Standards Association (CSA), have been established for most products. Efficient energy consumption is established on a comparative basis. However, at present a generally accepted baseline does not exist. Current energy efficiency standards are product and program specific. Standards have developed based upon on data gathered by organizations such as The New Building Energy Code, the American Society of Heating, Refrigeration and Air-Conditioning Engineers (ASHRAE), the Canadian Standards Association (CSA), Ontario Power Generation, the National Research Council of Canada (NRC), the Canada Mortgage and Housing Corporation (CMHC), The Ontario Ministry of Environment (MOE), Natural Resources Canada (NRCan) and BC Hydro Power Smart Program.
Technological advances are continually increasing the efficiency of the energy consumption of appliances and fixtures. Internationally recognized eco-labelling organizations such as the Canadian Environmental Choice Program and the American Green Seal have developed energy consumption guidelines for products and provide quantifiable energy efficiency standards that are technologically attainable. The specification of products that are considered energy efficient provides reduced environmental impacts by curtailing the environmental costs that are associated with the generation of electricity. These include carbon dioxide production from the burning of fossil fuels or the flooding of lands for the building of hydro-electrical dams.
This criterion identifies materials and products that improve energy use through their intended application and that do not consume energy, such as thermal insulation. This category applies to equipment that provides effective energy use through the regulation of electricity consumption cycles and to products that offer improved illumination from energy consumed for lighting purposes. Products that allow for regulation and utilization of solar heat gain may also be covered under this criterion. While standards exist for many construction products, in most cases these ratings are performance orientated and do not provide information regarding the potential energy savings.
Most energy utilities provide literature supporting the reduction of energy loss through the use of these non-energy-consuming products. The quantitative evaluation of this criterion can be accomplished based upon this information. Many of the eco-labelling programs address building materials that provide energy savings, but the guidelines for these products concentrate on other environmental issues such as recycled content or emission rates. However, proper application of these products undeniably reduces energy loss.
Reduced Water Consumption
The specification and use of appliances that are rated as 'low water consumption' reduces environmental impacts by reducing the necessity for water treatment. Water pollution combined with a rapid rate of water consumption can result in damage to hydrological systems. The treatment of wastewater requires the use of hazardous compounds that impact upon ecosystems. Reducing the consumption rate of water diminishes the necessity for wastewater treatment. Appliances, fixtures and systems that have been specifically designed to fulfill their intended functions while providing reduced water consumption rates, result in a lowered environmental impact.
Eco-labeling programs have established criteria that relate to the performance of specific products and the Canadian Standards Association (CSA) has developed specific tests that determine the flow rate of water consuming products. The CSA has also established flow rates for some products that define product specific low water consumption. This criterion is based upon the same principles as energy efficiency, it uses improved performance percentage against an established baseline for evaluation.
Indoor Air Quality (IAQ)
Indoor air quality refers to the chemical, physical and biological characteristics of indoor air in interior spaces. Indoor air quality is of importance for the health and well being of the occupants. Indoor air, as well as temperature, light and sound conditions must be of a quality that sustains the health of the occupants, especially in Canada where we spend a large part of our lives indoors.
Indoor air quality can be adversely effected by chemical emissions from building materials or products. Illnesses due to inferior IAQ can be broadly divided into those that occur shortly after exposure and those that do not show up until years later. Many organizations are conducting research and testing on IAQ, however few standards have been established for individual product emission rates. Indoor air pollutants can be classified as volatile organic compounds (VOCs), formaldehyde, microbe and particulate. At the present time target objectives and action objectives are recognized for ambient air within a building. Public Works and Government Services Canada (PWGSC), Health Canada, the Canada Mortgage and Housing Corporation (CMHC), The National Research Council (NRC) and Labour Canada have all indicated that reducing emission rates from building products provides a beneficial effect on indoor air quality. At the present time there are many testing facilities that can provide documentation of specific product emission rates.
Research in this field has identified ways of establishing or reducing the emission rates of recognized volatile organic compounds (VOC's), formaldehyde and microbial matter. Therefore, each of these items has been addressed as a separate criterion.
Particulate emissions are generally controlled by the mechanical systems in a building through the use of filters and proper ventilation. The reduction of particulates is best addressed through the proper design, operation and maintenance of the HVAC components that are related to particulate control.
Reduced Volatile Organic Compounds (VOCs)
The term 'volatile organic compounds' represents all chemicals containing carbon and hydrogen that have a boiling point between 50-250° C. Symptoms of VOC exposure include fatigue, headaches, drowsiness, dizziness, weakness, joint pains, peripheral numbness or tingling, euphoria, tightness in the chest, unsteadiness, blurred vision and skin and eye irritations.
Office workers are exposed to a broad spectrum of contaminants at low concentrations for periods of 40 hours or longer per week. Hypersensitive persons may have severe reactions to a variety of VOCs at very low concentrations. These VOCs can be released by building materials, carpets and numerous consumer products including plastics and fabric dyes. These reactions can occur following exposure to a single sensitizing dose, or small series of exposures. Chronic exposure to low doses can also cause reactions. Symptoms are usually non-specific and may be insufficient to permit identification of the offending compounds.
Exposure threshold levels have not been established, as the available information on toxicology and sensory effects of VOCs are incomplete. However, product emission comparisons are an acceptable method of determining a superior product. Facilities currently exist that are able to test a product's emission rates and manufacturers can be asked to provide test results for comparison purposes. Tests should be conducted on products in their average deliverable state. As a general rule, reduction of VOCs is a desirable element to creating healthier building environments.
Formaldehyde is a colourless gas that has been associated with human health impacts. The American Conference of Government Industrial Hygienists (ACGIH) has identified formaldehyde as a "suspected human carcinogen." Exposure symptoms include dry or sore throats, nosebleeds, headaches, fatigue, memory and concentration problems, nausea, dizziness, breathlessness and burning or stinging of the eyes. Formaldehyde is present when vapours off-gas from building materials such as adhesives, particleboard, fabrics and cleaning fluids. Interior formaldehyde concentrations are dependent upon the age of the source, building ventilation rate, indoor and outdoor temperatures and humidity.
Formaldehyde is found in many resins that are used in the manufacture of building products, such as particleboard, interior grade plywood and installation adhesives. Formaldehyde can be minimized in indoor air through both source reduction and ventilation methods. As formaldehyde is present in many building products, the specification of products that have been manufactured without formaldehyde will have a beneficial effect on indoor air quality. Alternative products can be specified that have been manufactured with phenol formaldehyde. This substance contains a more stable molecular structure than urea-formaldehyde and does not react to fluctuations in interior conditions. Another solution is to specify the encapsulation of all substrate materials that contain formaldehyde.
Anti-Microbial and Fungicide Treatments
Microbial and fungal contamination in indoor air is a concern as it can affect human health and comfort. Although few species can directly cause disease, chronic exposure to most fungi can induce allergic or asthmatic reactions.
Microbial elevations of indoor air became a concern in the 1950's when secondary infections of patients became a major concern in many hospitals. Since that time, manufacturers of products such as carpets and wallcoverings began to produce products that were treated to reduce microbial growth. Fungicides are a common component of paints, premixed drywall compounds and other moist products that require and extended shelf life. However, controlling microbial growth within a building can create a catch-22 situation as many fungicides and anti-microbial treatments contain chemicals which can elevate the VOC emission rates.
Although microbial and fungal problems within a building are usually associated with the mechanical components of a building, product specification can reduce the availability of suitable growth mediums and the addition of chemicals within a building. Products can be designed in a manner that naturally deters the growth of microbial matter without adding chemicals to interior environments. Paint can be specially ordered without fungicides and project specifications can call for the use of mixed-on-site drywall compound. Products manufactured from natural fibres naturally adjust to fluctuating humidity levels and often do not require topical applications of anti-microbial treatments.
Many products are reusable by consumers. Most consumers are aware of this fact, however it is important to identify new reuse opportunities that may not be readily apparent.
Industry Canada has developed a document entitled Principles and Guidelines for Environmental Labeling and Advertising. This document provides a guideline for the term reusable. For a product to be deemed reusable an application must exist that allows the end user to directly reuse the product. Where the option is not obvious, the claim must explain how the product can be reused without extensive cleaning or restoration processes. This criterion may also be used to assess the packaging materials that are associated with a product. For example, furniture can often be shipped in reusable blankets rather than in resource intensive corrugated containers.
Refurbishable products can be reused, however they usually require cleaning or restoration to attain an as-new appearance or function. During the refurbishing procedure, the product remains the property of the consumer and the expense of the refurbishing process is the responsibility of the consumer.
The refurbishing procedure may be offered either in-house by the original manufacturer or may be a procedure easily accessible through outside sources. Information regarding refurbishing processes must be readily available to the consumer. The refurbishing of a product may require the utilization of additional energy and additional waste generation. However, the environmental impacts are considerably lower than first-time fabrication in almost all cases.
This criterion differs from refurbishing in that the ownership of the product becomes the original manufacturers or a second party that provides the restoration services. Products recognized under this criterion are designed in a manner that allows for complete upgrading, where products can be inspected and disassembled to their individual elements and damaged pieces can be repaired or replaced. The product is therefore restored to an as-new condition for resale by the fabricator.
Durability provides reduced environmental impact by minimizing the maintenance or replacement requirements of a product. This provides an efficient use of natural resources and a diversion of material form landfill.
At present, durability is generally measured by manufacturer's warranties that are often too vague to be used as a baseline for the development of a criteria definition. Standard testing procedures and reporting requirements are currently being developed that will provide a reliable mechanism for environmental evaluation. However until this framework is developed and accepted, building practitioners can only qualitatively access a product's durability.
Maintenance requirements should be assessed to ensure that a product will maintain its aesthetic and functional value and manufacturer's warranties can be used to provide a marginal measure of a products durability. Product testimonials are another source of information by which to verify durability claims. Although this issue is marginally quantifiable, a mechanism for reliable quantitative analysis is not yet available.
The use of recyclable products provides efficient and effective use of natural resources. The benefits are achieved by diverting the products from the waste stream and directing them to a recycling facility.
A product that is recyclable can be returned for reprocessing into new material, however a product is not considered recyclable simply because the material is technically recyclable or there are anticipated developments in the future. Recycling programs and facilities are regionally variable and a product can only be considered and recyclable when these programs and facilities exist.
In situations where products are fabricated from numerous materials, the product design should facilitate recycling options by easy disassembly and identification of material types. For example plastic components should contain plastic sorting codes. Instructions explaining disassembly and sorting requirements for inclusion in recycling systems should also be included with products.
Source reduction is the use of less material at source to produce a product in the first place. Source reduction has significant environmental benefits. These benefits are achieved through resource savings, reduced energy expenditures during collection and processing, disposal and landfill issues.
The benefits of source reduction are difficult to measure. Unless the data are available prior to the implementation of source reduction initiatives, this principle is very difficult to quantify as it can be applied in a number of ways and no standards or reporting mechanisms exist at this time. Source reduction should be viewed as superior to most other criteria, yet not quantifiable for evaluation.
However, source reduction can be incorporated into construction projects. Building architects and designers can reduce construction waste by setting floor plans to fit the dimensions of standard construction materials. Suppliers can be required to minimize packaging. Products such as paint, joint compound and caulking can be purchased in bulk. Builders can easily reuse scrap lumber for bracing and to stake concrete forms. Careful demolition can allow the reuse of doors, windows, bathrooms and systems decorative moldings. Interior furnishing can often be restored to extend their life beyond first use. Unlike many other criteria source reduction eliminates waste and other environmental impacts rather than minimizing them.
Degradable materials break down into materials that have less environmental impacts. Degradation may occur in air, land or water and usually occurs either through biodegradation or photodegradation.
While many materials will eventually degrade, standard disposal, at a landfill site, inhibits this process. The proper management of degradable materials through appropriate facilities reduces environmental impact by diverting waste from landfill sites. Commercial composting facilities are able to accept some building materials and interior finishes for disposal. A claim that a product is degradable should be supported by reliable scientific evidence that the entire product will break down or decompose following appropriate management methods.
Waste is an output that is released into air, water or land and that has no beneficial use or perceived market value. An intrinsic characteristic of waste is that it eventually requires disposal.
The construction industry generates waste at all levels of production, use and disposal. While waste from some products can be minimized through source reduction practices, other products generate waste in areas that are less obvious to consumers and practitioners.
Waste generated at the manufacturing level is difficult to attribute to a product or material. While current legislation aims to reduce waste generation, a standardized framework has not yet been accepted that documents procedures that exceed legislated standards. However, some manufacturers have implemented procedures that provide for reduced waste generation. Where possible construction practitioners should review the procedures used during the manufacturing processes. The specification of products that have been manufactured with minimal waste generation will encourage the industry to strive to exceed legislated standards.
Packaging materials are also waste. Many building materials are shipped with minimal packaging on pallets or skids, that are reusable. Other products, such as lighting fixtures and other interior products are often over-packaged. Packaging waste generation can be reduced by requesting that manufactures reclaim packaging of products that are shipped to the construction site. Requesting a manufacturer to accept responsibility for the packaging they use encourages the minimization and reuse of packaging. The implementation of capture procedures at the site can often divert many materials from landfill. For example, skids and pallets can be diverted for reuse and corrugated cardboard can be shipped to recycling facilities.