Expanded Polystyrene Foam (EPS)

Expanded Polystyrene Foam (EPS) and the Vinyl Clad Portable Spa Cover

Moldy EPS Foam CoversDiscarded expanded polystyrene does not biodegrade for many hundreds of years and is resistant to photolysis. Because of this stability, very little of the EPS discarded in today’s modern, highly engineered landfill biodegrades. Because degradation of EPS creates potentially harmful liquid and gaseous by-products, American landfills are directed to minimize contact with the air and water required for degradation. By impeding the natural degradation process, EPS waste can stay buried in our landfills for up to 2000 years.

Polystyrene foam is a major component of debris in the ocean, where it becomes toxic to marine life. Foamed polystyrene blows in the wind and floats on water, and is abundant in the outdoor environment. Polystyrene foams are produced using blowing agents that form bubbles that expand the foam.

Although polystyrene can be recycled at recycling facilities most polystyrene is not. The EPA (United States Environmental Protection Agency) estimates that 25 billion polystyrene cups are tossed every year. Since polystyrene degrades very slowly – more than 500 years for a single cup – the EPA considers this a serious environmental problem. Several green leaders, from the Dutch Ministry of the Environment to Starbucks’ Green Team, advise individuals reduce their environmental impact with reusable coffee cups.

Vinyl clad, expanded polystyrene spa covers have been around for about 30 years with few questions regarding claims made of their R value. A single sheet 3” thick of 1.5 lb foam could have an R value of 11.5 in a dry test chamber. In ambient weather with moisture a common factor, that R value could be reduced by 35% to 7.4 ”. If that sheet was tapered it would be as energy efficient as the thinnest portion as energy follows the path of least resistance. A 4” to 2” tapered spa cover would have an R value of considerably less than most claim due to its conductive vinyl, gaping hinge and the 2” thick tapered edges. Further reducing insulating benefits is the conductive nature of condensation or water accumulating in the foam core from radiant energy. This natural occurance eventually leads to an unwieldy weight and an early demise of the components that comprise the cover. Mold and mildew from water permeated spa covers can promote foul odors and health problems. The typical EPS foam spa cover (7’x 7’) represents 3520 styrofoam cups. When multiplied by the number of replacement spa covers in the U.S. annually that amounts to over 6 billion cups headed to landfills with 7 billion additional being created for existing and new spas, all destined for land fill sites.