Anyone who reads the newspaper on a regular basis is familiar with the above headline. Why should building owners be concerned with depletion of the earth's ozone layer? Because most buildings have large air conditioning units (usually referred to as "chillers"), the majority of which use chlorofluorocarbon (CFC) refrigerants. When CFCs are released into the atmosphere, they contribute to depletion of the ozone layer. There are a number of current and proposed US EPA regulations which will affect use of CFC refrigerants.

When CFCs are released into the earth's atmosphere, they gradually rise into the stratosphere (upper atmosphere) and are then bombarded by the sun's ultraviolet radiation; this breaks CFCs into their chemical components. The freed chlorine (Cl) atoms form compounds with the ozone molecule, destroying it, which of course depletes the earth's ozone layer. It takes only one chlorine atom to destroy over 100,000 ozone molecules.

The value of the earth's ozone layer is that it absorbs harmful ultraviolet radiation. Theoretically, if the amount of ultraviolet radiation reaching the earth's surface were to greatly increase, there would be a consequent increase in the incidence of skin cancer among humans, decrease in production of certain crops, and the annihilation of some aquatic organisms.

Some basic EPA regulations regarding CFCs which building owners should be aware of are:

• Venting - As of July 1, 1992, it is not allowable to deliberately vent CFCs into the atmosphere during equipment service, maintenance and disposal.

• Phase-Out - Amendments to the EPA Clean Air Act establish both a final phase-out date for CFC production and dates for a series of interim reductions in CFC/HCFC (hydrochlorofluorocarbon) production levels. The final phase-out date was December 31, 1995, for CFC production, and the year 2030 for HCFC production (although HCFCs are not considered to be as harmful to the ozone layer as CFCs, they do contain chlorine and are believed to deplete the ozone layer).

• Lowest Achievable Emissions - EPA regulations which set forth requirements for refrigerant leak detection and repair practices which do not release refrigerants into the atmosphere were published in 1994.

Building owners whose chillers use CFC refrigerants should consider their options when dealing with current and future CFC regulations. There are three basic options:

1. Maintain the existing chillers which use CFCs. Use preservation and reclamation techniques to preserve the current CFC supply.
   
2. Convert existing CFC chillers so that they can use alternative (non-CFC) refrigerants.
   
3. Replace existing CFC chillers with equipment that uses alternative refrigerants or with CFC chillers which can be easily converted.

When considering the above options, it is important to remember that the final phase-out date for HCFC production is not until the year 2030 (some environmental groups are trying to accelerate the phase out date). A newly installed chiller is expected to have a useful life of 30 years; therefore, installing a chiller which uses HCFC may be feasible, but is not recommended from an environmental standpoint. Current chillers using a CFC could be converted to an HCFC, especially if the chillers are not scheduled for replacement for a number of years.

HFCs (hydrofluorocarbons), although currently more expensive than HCFCs, should also be considered. HFCs contain no chlorine and do not damage the ozone layer. There is no scheduled phase out for HFC production.

Building owners face both environmental and economic issues when dealing with CFC regulations. Those who use chillers containing CFCs may find it useful to develop a chiller maintenance/conversion/replacement plan.