Polyurethane foam is a plastic polymer foam frequently used in insulation and moulded foam products. Although the environmental impacts of polyurethane foam are relatively mild and more favourable than other polymer foams, environmentally responsible construction requires that you be aware of all potential impacts and act accordingly to avoid or minimise any potential risks.
Fossil Fuel Use
As a plastic polymer, polyurethane foam is made principally from petroleum and its manufacture and transportation can require additional fossil fuel use. Of course, the fossil fuel used to manufacture insulation foam should be considered in light of the fossil fuel savings obtained through insulation and reduced energy usage in heating and cooling, but more environmentally friendly options should be considered by responsible builders and contractors. Several bio-based plastics, using vegetable oils instead of fossil fuels, are available and can reduce the environmental impact of insulation.
Disposal and Burning
Improper disposal or burning of polyurethane foam can release a number of dangerous toxins into the air. Among the most dangerous toxins released are carbon monoxide, hydrogen cyanide and dioxins, all damaging for the environment and human health. As with all environmental impact assessments, determining the impact of polyurethane foam requires a full analysis of the product's life-cycle and a responsible strategy for replacement and final disposal.
Global Warming and Blowing Agents
Polyurethane foam is produced with hydrofluorocarbon (HFC) blowing agents that act as potent heat-trapping greenhouse gasses. Once again, foam manufacturers argue that the overall greenhouse gas impact of insulation foam is positive because of the reduced energy use of insulated buildings and that HFC use is a vast improvement over the previous use of clourofluorocarbon (CFC) blowing agents with demonstrated negative effects on the ozone layer, but greenhouse gas use in the manufacture of insulation foam reduces the overall positive impact of insulation. Alternative blowing agents are available and are even required in the European Union, but North American polyurethane foam still relies primarily on HFC blowing agents.
Application and Safety
At normal temperatures, polyurethane foam is chemically inert and non-carcinogenic. Dangers of off-gassing are rare with professional installation, but polyurethane foam does use halogenated flame retardants that can be harmful to human and animal health. All proper safety precautions should be taken by installation professionals and structures should be allowed to vent and be properly inspected before occupation in order to avoid any environmental impacts in occupational safety or indoor air quality.