Comparing the Environmental Impacts of Foam Panel Insulation: Blowing Agents

Foam products are widely used in various industries such as construction, packaging, and refrigeration. The quality and performance of foam products depend largely on the type of blowing agent used to create the cellular structure of the foam. Blowing agents are substances that can produce gas bubbles in a liquid matrix, causing it to expand and solidify into foam.

Massachusetts law 310 CMR 7.76 prohibits the sale of XPS foam that contains certain hydrofluorocarbons (HFCs) after January 1, 2024. This law is designed to reduce greenhouse gas emissions from XPS foam. HFC-134a use as a blowing agent for XPS will be prohibited by the law.

HFC-134a replaced chlorofluorocarbons (CFCs) as a blowing agent. CFCs were found to be harmful to the ozone layer, so they were banned in the Montreal Protocol (1989). HFC-134a is a hydrofluorocarbon, which is a less harmful alternative to CFCs. However, HFC-134a is still a greenhouse gas, so it is being phased out in favor of even more environmentally friendly blowing agents.

One of the most common types of blowing agents used in foam products are hydrocarbons, such as pentane, butane, and cyclopentane. Hydrocarbons are organic compounds that consist of only hydrogen and carbon atoms. They have several advantages over other types of blowing agents, such as chlorofluorocarbons (CFCs) and hydrofluorocarbons (HFCs), which are synthetic chemicals that contain chlorine and fluorine atoms.

One of the main benefits of using hydrocarbons as blowing agents is their environmental friendliness. Unlike CFCs and HFCs, hydrocarbons do not deplete the ozone layer, which protects the Earth from harmful ultraviolet radiation. Hydrocarbons also have a very low global warming potential (GWP), which measures how much a gas contributes to the greenhouse effect that causes climate change. The GWP of a gas is calculated by comparing its heat-trapping ability and lifetime in the atmosphere to that of carbon dioxide (CO2), which has a GWP of 1.

According to the Intergovernmental Panel on Climate Change (IPCC), the GWP of pentane is 11, the GWP of butane is 4, and the GWP of cyclopentane is 11. These values are much lower than the GWP of some commonly used HFCs, such as HFC-134a, which has a GWP of 1300. This means that hydrocarbons have a much smaller impact on global warming than HFCs.

Another benefit of using hydrocarbons as blowing agents is their compatibility with various types of foam materials. Hydrocarbons can be used to produce polystyrene (PS) foam, polyurethane (PU) foam, and polyisocyanurate (PIR) foam, among others. Hydrocarbons can also be blended with other blowing agents, such as hydrofluoroolefins (HFOs), to achieve optimal properties for different applications.

Hydrocarbons are also cost-effective and readily available compared to other blowing agents. They are derived from natural gas or crude oil, which are abundant and cheap sources of energy. Hydrocarbons are also easy to handle and store, as they have low boiling points and high vapor pressures.

Hydrocarbons are an excellent choice for blowing agents for foam products, as they offer environmental, technical, and economic benefits over other alternatives. Hydrocarbons can help reduce the ozone depletion and global warming effects caused by CFCs and HFCs, while providing high-quality and versatile foam products for various industries.

When choosing XPS insulation panels you should check the technical specs carefully to assess the full environmental impact of your choice. There are newer choices for XPS blowing agents which are more environmentally sustainable than XPS manufactured with HFCs. Blowing agents with more favorable GWP profiles include: pentane, c-pentane, pentane/HFO blends, carbon dioxide, and nitrogen. In any event, XPS with HFCs will be banned for sale in Massachusetts in 2024.