Pentane and Ozone Depletion Potential

The most common pentane blowing agents used in the manufacture of PIR systems and their respective chemical formulations are N-pentane, Iso-pentane, and C-pentane. All three pentane isomers have zero Ozone Depleting Potential (ODP) and either a zero or very low Global Warming Potential (GWP) potential (less than .00044). For this reason, the EPA lists pentane, as a suitable replacement for hydro-chlorofluorocarbons (HCFC’s) which are considered harmful to the stratosphere.

HCFC-141b was a common blowing agent in use prior to January 1, 2005 and was considered to be an ozone-depleting substance since over time cells break down in the presence of strong ultraviolet (UV) radiation and release chlorine or bromine atoms, which destroy ozone molecules. In fact, one chlorine or bromine molecule can reportedly destroy 100,000 ozone molecules. Yet even HCFC-141 was a step improvement over its predecessor because it reduced the ozone depleting power by 90% (compared to the chlorofluorocarbon CFC-11).

The pentane based chemistry provides 100 percent reduction of ozone depletion. The added benefit of either zero or low global warming potential is an indirect advantage of pentane formulation.

Read More:

Ozone is a pungent, slightly bluish gas, made up of three oxygen atoms (O3). About 90 percent of Earth’s ozone actually is in the stratosphere which begins at an altitude of about 8 km at the poles (17 km at the Equator) and extends upward to about 50 km. Ozone in the stratosphere shields Earth from otherwise destructive ultraviolet radiation that can damage DNA in living systems. Stratospheric ozone is constantly being created and destroyed through natural cycles. Various ozone-depleting substances, such as CFCs and HCFCs, however, accelerate the destruction processes, resulting in lower than normal ozone levels.

The Ozone Depleting Potential ( ODP) is the ratio of the impact on ozone of a chemical compared to the impact of a similar mass of CFC-11. Thus, the ODP of CFC-11 is defined to be 1.0. Other CFCs and HCFCs have ODPs that range from 0.01 to 1.0. HFCs have zero ODP because they do not contain chlorine. The Montreal Protocol on Substances That Deplete the Ozone Layer and its amendments control the phaseout of the production and use ozone-depleting substances. Visit http://www.epa.gov/ozone/index.html for more information.