Expanded polystyrene foam, or EPS, is typically white and composed of expanded beads of polystyrene. Its most familiar uses are packing peanuts and moulded styrofoam-like pieces that come in boxes protecting and keeping your new television or computer in place securely.
To others, it's the material that is used for the insulating board component of Exterior Insulation Finishing Systems.
EPS vs. XPS
Expanded polystyrene foam differs from extruded polystyrene foam, or XPS, because XPS is far less dense and contains more spaces for air to circulate. EPS, on the other hand, is perfect for insulating and sound-proofing. XPS is also commonly known as Styrofoam.
Styrofoam products often get a bad reputation with regards to their environmental impact. For XPS, this reputation is deserved. You might have always been warned you shouldn't break Styrofoam because you'll release dangerous chlorofluorocarbons, or CFCs, into the air, which are harmful to the atmosphere and ozone layer. These CFC's are what is put into the Styrofoam applications to expand the beads. EPS, however, might surprise you:
- EPS is not made using CFCs.
- The manufacturing of EPS uses less resources and energy than alternative materials, such as paper-based ones.
- EPS is completely recyclable and is also safe to use in landfills as a stabilizing material.
- XPS is manufactured with CFCs or HCFCs, hydrofluorocarbons, which are still detrimental to the ozone layer.
- Many fast-food restaurants caught a lot of flack for using the non-environmentally friendly and wasteful XPS-based containers for their food, and have since switched over to paper and cardboard.
- XPS is rarely, if ever, recycled.
One of the key manufacturing differences between the two foams is that gas is added to XPS when it's manufactured, whereas EPS is manufactured by expanding beads already containing the gas. Both foams are available for EIFS applications, but EPS is the most environmentally-sound choice.
EPS is lightweight, being the lightest packing material available, and therefore the fuel used in transportation is significantly reduced. EPS is also used in making sports safety equipment like ski and bicycling helmets due to its high shock-absorption capabilities, as well as having a closed-cell structure that makes it optimal for insulation purposes. It also is resistant to humidity and has a low water absorption rate, and it is also of no nutritional value to moulds, fungi, parasites or insects and is no interest of them with regards to infestation potential like organic materials, such as wood, would be.
Studies and Potential
An American-based company recently did an Eco-Efficiency Analysis with regards to the environmental impact of different kinds of wall cladding systems, including brick, stucco and EIFS. Among the criteria analyzed for each were the amount of resources used up in the manufacturing process, the risk of illness of injury to those who work with them, whether they are toxic or give off any toxic emissions, and their energy consumption in manufacturing. EIFS came out on top, having the smallest environmental impact in every category.
The insulating foam is what gives EIFS its energy-efficient properties and its recommendation as a "green" insulation. This is why EIFS qualifies for the Government of Canada's and the Government of Ontario's eco-friendly renovation programs, where homeowners can receive grants and rebates for making improvements to their homes that increase their home's energy efficiency. Installing EIFS is on the list of eligible improvements.
EIFS is also leading the way for LEED certification for Canadian buildings. LEED, or Leadership in Energy and Environmental Design Certification, is given to buildings that are energy-efficient and use environmentally friendly and sustainable materials, among other criteria. The LEED program exists to provide recognition for green building efforts, allow for a building's qualification for government incentives and contribute to green building knowledge. The Canadian LEED certification was adapted from the one in the United States, but altered to compensate for Canadian climates and laws by the Canadian Green Building Council.
A tight and insulating building envelope is necessary for an energy-efficient building, and it's not costly to have installed. Any money spent will quickly be realized as a returnable investment when heating and cooling bills are noticeably lower.