Chlorofluorocarbon (CFC) and hydrochlorofluorocarbon (HCFC) compounds have been used for decades in applications ranging from refrigerants in air conditioning, heat pumps and refrigeration systems, to blowing agents in foam thermal insulation and other applications.

Due to their atmospheric lifetimes, CFCs and HCFCs can migrate to the stratosphere where ultraviolet sunlight decomposes the molecules, releasing chlorine. Chlorine, in turn, reacts with ozone, reducing stratospheric ozone concentrations.

The stratospheric ozone layer has a protective effect for life on earth in filtering out a portion of the sun's ultraviolet radiation (UV-B). Increased levels of UV-B at the earth's surface may affect human health (such as causing increased incidence of skin cancer) and may damage plants and cause injury to aquatic and terrestrial life.

In 1974 Molina and Rowland identified mechanisms by which stratospheric destruction of ozone occurred [Nature 6/28/1974]. This work was built on suppositions by Crutzen in 1970 that nitrogen oxides from fertilizers and supersonic aircraft might deplete the ozone layer. Scientific efforts were launched in both the public and private sectors to verify or disprove the proposed depletion theory. Investigations continued in the 1970s and early 1980s. Antarctic ozone layer thinning in the austral spring was observed for several seasons before and the observations were published in 1985. This thinning came to be called the "ozone hole."

Scientific evidence has linked the ozone hole occurrence to the presence of chlorine [and bromine] in the unique Antarctic stratosphere weather, chemistry and physics. This occurs when the sun strikes the very cold polar stratospheric clouds (PSCs) in the austral spring. These clouds contain crystals of water vapor and nitric acid, forming the reaction sites for the destruction of ozone. The ozone hole has occurred each year since first observed, varying in depth, size and duration. The overall trend has shown greater depletion each year.

Some ozone layer thinning has also been observed in the Northern Hemisphere. The depletion has been substantially less since the Arctic PSCs are not as cold as those found in the Antarctic. Canada, the United States, Australia, New Zealand, Japan and some European countries monitor and regularly report the UV intensity as part of the daily weather information.

Concentrations of ozone depleting chemicals (including the CFCs and HCFCs) in the lower atmosphere peaked in 1994 and are now slowly declining. Some evidence exists that the peak concentrations may also have been reached in the stratosphere [Nature, 12/7/2000]. The ozone layer is expected to return to pre-industrial levels by the mid-21st century.

The United Nations Environmental Program (UNEP) and the World Meteorological Organization (WMO) coordinated the Vienna Convention establishment in 1985. The Vienna Convention provided the framework for the subsequent drafting of the Montreal Protocol, which encourages intergovernmental cooperation on research, systematic ozone layer observation, CFC production monitoring and information exchange. The Montreal Protocol established different phaseout schedules for developed and developing countries. Montreal Protocol parties are committed to implementing domestic controls to ensure compliance with the international agreement.

The Montreal Protocol, adopted in 1987, initially required developed countries to reduce CFC-11 and CFC-12 consumption by 50%, among others including halons and some brominated compounds, by the year 2000. The protocol allows phaseout schedule modification as more scientific and technological information become available.

The London amendments of 1990 called for a 100% phaseout of the developed country CFC production by 2000.

The 1992 Copenhagen amendments advanced the CFC phaseout to 1996. It also set an HCFC phaseout schedule starting with a consumption cap in 1996, moving to full phaseout by 2030 with four intermediate steps (65% of the cap in 2004, 35% in 2010, 10% in 2015, and 0.5% in 2020). The cap was established as the ozone depletion potential weighted HCFC consumption and 3.1% of CFC weighted consumption, with a base year of 1989. Some additional HCFC and CFC production is allowed to supply developing country domestic needs.

In 1995, the HCFC cap was reduced. The 3.1% factor for weighting the 1989 CFC consumption was reduced to 2.8%.

The 1997 Montreal adjustments designated that HCFC consumption between 2020 and 2030 be used only for servicing equipment already in use by 2020.

The 1999 Beijing amendments (which become effective on 1/1/2001 or when 20 countries have ratified, whichever comes later) control future developing country CFC and HCFC production.

Current developing country curtailments include:

CFC consumption freeze at the 1995-97 average on 7/1/1999, and phase out of consumption and production by 1/1/2010.

Freeze HCFC consumption at 2015 levels on 1/1/2016 and phase out consumption by 1/1/2040.

The United States Congress authorized the Montreal Protocol implementation through the Clean Air Act, with U.S. Environmental Protection Agency (EPA) regulations. Today, developed country CFC production has been practically eliminated except for some special applications. The HCFC consumption cap became effective 1/1/1996 for all developed countries. The EPA is monitoring HCFC consumption quarterly and will implement allocation measures.

The Montreal Protocol treats HCFCs as a group providing each country implementation flexibility. The U.S. EPA applied separate phaseout schedules for each HCFC starting with the highest ozone depleting substance (ODS) compounds. The regulations permit newly produced HCFC-22 and HCFC-142b use in new products through 2010 and for equipment service until 2020. Similarly, the regulations permit newly produced HCFC-123 use in new products through 2020 and for equipment service until 2030. HCFC-141b may be produced and consumed through 1/1/2003.

Refrigerants and insulation affect human lives daily, from the basic necessities such as food to facilitating the manufacture and use of computers. The 20th century saw numerous advancements in the fields of medicine, microelectronics and space exploration. Many of these advancements were only made possible within a controlled environment. Those environments required refrigerants such as CFCs and, more recently, HCFCs and HFCs. CFCs, HCFCs and HFCs are widely used due to their unique characteristics of safety, performance, reliability, energy efficiency and cost effectiveness. HFCs were developed as a replacement to CFCs and HCFCs because they have zero Ozone Depletion Potential (ODP). Use of HFCs is increasing today.

4.1 Refrigeration Uses

Refrigeration systems include residential refrigerators and freezers, commercial refrigeration systems and transport refrigeration systems. Extensive use of refrigeration assures adequate food supplies at low cost and helps prevent or retard microbial, physiological and chemical changes in food that lead to spoilage. In addition, refrigeration is important in the manufacture, storage and distribution of pharmaceuticals, medical supplies, blood and tissues in the health industry. Refrigeration also plays a major role in the production of industrial and agricultural chemicals.

Most current refrigeration systems are based on vapor compression, designed to use HFC-134a, HCFC-22, hydrocarbon gases or ammonia. Ammonia is widely used in large-scale commercial food freezing and storage, industrial refrigeration and some large water chillers for air-conditioning systems.

HFC-134a is used in home refrigerators, freezers, coolers for produce and dairy storage in food stores, and distribution centers. HCFC-22 is used in medium-temperature systems and low-temperature systems. Refrigerant blends R-404a and R-507 are the current leading candidates to replace HCFC-22 in low-temperature applications.

4.2 Air-Conditioning Uses

Air conditioning has become essential in most buildings. ASHRAE has conducted extensive human comfort research, documenting air conditioning’s beneficial effects in reducing heat stress and improving health, safety and productivity. Many critical manufacturing processes involving printing, textile processing, photographic materials, electronic components, computer operations, laboratory clean spaces and telecommunications could not function without the environmental control provided by air conditioning. System sizes range from small room or central air conditioners and heat pumps to sophisticated commercial and industrial built-up systems.

Most currently installed equipment uses CFCs and HCFC-22. HFC-134a and HCFC-123 are typically used in new and retrofitted centrifugal water chillers for cooling large buildings. HCFC-22 is used in some centrifugal chillers and in positive displacement compressor water chillers, air conditioners and heat pumps generally installed in smaller buildings. Residential air conditioners and heat pumps also utilize HCFC-22. The replacements for HCFC-22 include HFC blends R-410A (new equipment) and R-407C (retrofits and new equipment).

Rigid closed-cell polyurethane foam uses HCFC-141b or HCFC-142b with HCFC-22 as a co-blowing agent and is used extensively for thermal insulation. Rigid foam produced by using HCFCs is a very efficient insulating material. Such foams are used for insulation in household refrigerators and freezers, commercial refrigeration display and storage facilities, refrigerated rail cars, delivery trucks and truck trailers, and commercial and residential buildings. The efficient insulating properties of foam insulation made with HCFCs result in good energy efficiency and low cost that may not be as readily achievable with substitute blowing agents.

Currently the most likely replacements for HCFC-141b are pentane blends. The resulting foams are 10 to 15% less efficient than the HCFC-141b foams. HFC-134a and carbon dioxide (CO₂) are the two potential replacements for HCFC-142b. Foams produced with only water as the blowing agent are thermally less efficient and are not practical in applications where the insulation thickness cannot be increased to compensate for the reduced insulating value. Foams produced using HFCs, such as HFC-134a, are expected to have thermal performance similar to those produced using HCFC-142b. Alternative technologies, such as microcellular foams and vacuum panel insulation, are under investigation but will require time to commercially replace the current technologies.

With the total phaseout of CFC production, new refrigeration and air-conditioning equipment continues to evolve using HCFCs, HFCs and ammonia as the refrigerants of choice. This process of development continues as HCFC phaseouts approach. The selection of alternative refrigerants is based on the favorable combination of characteristics such as availability, high energy efficiency, low toxicity, good heat transfer characteristics, stability, materials compatibility, safety and cost effectiveness.

To produce equipment with alternatives to CFCs and HCFCs, the heating, ventilating and air-conditioning (HVAC) industry has made major commitments to using HFC- 410A, an azeotropic blend of HFC-32 and HFC-125, to replace HCFC -22 in air-conditioning refrigeration circuits up to 20 tons. Multiple circuits will allow a wide amount of HFC-410A uses. The blend HFC-407C is being used as a replacement for existing HCFC-22 installations and several new equipment applications. HFC-134a is gaining acceptance for larger equipment such as screw and centrifugal chillers.

The use of CFC-502 in industrial refrigeration is transitioning toward HFC-404A and HFC-507. Ammonia, an efficient and zero ODP refrigerant, continues to have wide acceptance in industrial refrigeration as well as some large commercial applications.

Hydrocarbon refrigerants such as iso-butane and propane have had commercial success in northern and Western Europe for residential refrigerators and heat pumps. Safety concerns have limited their use in North America. Only a very limited number of large hydrocarbon-based systems are currently operating.

Recently, there has been significant research into CO₂ as a refrigerant. Carbon dioxide was a popular refrigerant in the late 19th century.

Alternative refrigerants developed to replace ozone-depleting substances that result in energy inefficiencies are a major concern. Modern air-conditioning equipment efficiency has continually improved, and is increasingly important with increased focus on reducing greenhouse gas (GHG) emissions. ANSI/ASHRAE/IESNA Standard 90.1-1999, "Energy Standard for Buildings Except Low-Rise Residential Buildings," provided an overall building efficiency increase over the 1989 standard.

In some low temperature applications, the alternative refrigerant energy penalties have been severe. Some of the energy penalty can be offset by the refrigeration system design such as using economizers. Heat loss through less efficient foam insulation may also increase energy usage.

To reduce refrigerant leaks from long piping runs, the supermarket industry has experimented with using secondary brine at the display cases and limiting the refrigerant piping to the mechanical room. In test cases, this has led to a significant improvement in system refrigerant containment but has imposed an additional performance penalty.

By using a central facility, the public safety concerns associated with use of ammonia can be eased and the energy and environmental advantages leveraged. Ammonia use for large healthcare and institutional applications has increased.

Energy efficiency is a key issue. The amount of CO₂ released to the atmosphere due to energy consumption during the lifetime of the equipment is often significantly greater than the global warming potential (GWP) effect from refrigerant lost to the atmosphere. This is particularly true when good refrigerant containment practices are observed.

Ozone depletion and climate change are global atmospheric issues that are not completely independent. Global warming raises the lower atmosphere temperature. This in turn lowers the upper atmospheric temperature. A colder stratosphere may lead to an increase in PSCs, which are the catalytic sites for ozone depletion chemical reactions. Global warming may lead to delayed recovery of the ozone layer and may be partially offset by ozone destruction. This, however, is a complex atmospheric interaction, the consequences of which are not fully known.

CFCs, HCFCs and HFCs are also greenhouse gases, but are relatively minor players in total greenhouse gas emissions. The principal greenhouse gases resulting from the combustion process (energy consumption) are CO₂ and water vapor. Although CO₂ has a lower global warming potential than HFCs, CO₂ is released to the atmosphere in much greater volumes. The atmospheric decay of CO₂ is not a simple exponential like many other gases. By convention, it is often referred to as having an atmospheric lifetime of 200 to 350 years. HFCs typically stay in the atmosphere less than 50 years. Since CFCs and HCFCs are included in the Montreal Protocol phaseout schedule, atmospheric concentrations are expected to decrease with time. Consequently, when the environmental impacts of HFCs are weighed against those of CO₂, energy efficiency becomes the dominant factor in climate change mitigation.

The regulatory approaches to address each issue differ as well. Under the Montreal Protocol, the approach is to phase out consumption and production of ozone-depleting substances (including CFCs and HCFCs). Under the climate change Kyoto Protocol, emissions will be reduced for targeted greenhouse gases (including HFCs). All targeted greenhouse gases are included in the same "basket." Increases in any one gas can be offset by decreases in another gas. This means the improved energy efficiency (and the associated reduction of CO₂ emissions from power generation) can offset the direct emission of the refrigerant (HFC emissions).

ASHRAE’s Position Statement and Position Paper on Climate Change provides background information on the issue and climate change’s relevance to building technologies. The document is available at the ASHRAE website.

A significant portion of the CFCs, HCFCs and HFCs produced are used for refrigeration and air conditioning. The past use of CFCs and HCFCs in refrigeration and air conditioning represents a major contributor to ozone depletion.

With ASHRAE’s position as a refrigeration and air conditioning technology leader, the Society and its 50,000 worldwide members have the opportunity to make a significant contribution to reducing environmental impacts of the HVAC and refrigeration technology.

As a standards-writing organization (accredited by the American National Standards Institute), ASHRAE currently has more than 90 published standards and guidelines and another 30 under development. Over a third of these deal specifically with refrigeration and air conditioning. Many address the testing, application and usage of refrigerants.

Refrigerants are assigned numbers and are classified by toxicity and flammability characteristics in Standard 34, "Designation and Safety Classification of Refrigerants." Standard 15, "Safety Code for Mechanical Refrigeration," provides designers and code officials with procedures on the safe use and handling of refrigerants in buildings.

ASHRAE Guideline 3, "Guideline for Reducing Emission of Fully Halogenated Chlorofluorocarbon Refrigerants," addresses refrigerant emission reduction practices in manufacturing, design, installation and servicing of equipment. Guideline 3 is being updated to a standard (Standard 147P).

Employing funds raised in the private sector, ASHRAE’s research program currently has over $12-million U.S. in projects underway. Approximately one-third of the projects are directly aimed at refrigeration and air-conditioning research. The research is conducted at universities and independent research organizations.

Providing a variety of vehicles for the broad dissemination of new and emerging technologies in a timely manner is an important ASHRAE function. These vehicles include technical presentations at Society meetings (international, regional and local levels), the printed media, electronic communications and opportunities for continuing education.

The ASHRAE Handbooks, published in four volumes, are updated on a four-year cycle, with a newly updated volume produced every year. One of the four volumes is dedicated to refrigeration. The ASHRAE Transactions document the technical and symposia papers of semi-annual Society meetings. The Society produces a quarterly International Journal of HVAC&R Research and the monthly ASHRAE Journal. Special publications include design manuals, guidance documents and user manuals for understanding complex standards.

ASHRAE supports overall environmentally balanced solutions to atmospheric concerns. Actions taken to secure low or zero ozone-depleting solutions at the expense of energy efficiency would not represent a balanced approach.

ASHRAE will take a leading role in addressing ozone depleting substance use for refrigeration and air conditioning. ASHRAE’s activities are directed to the public’s benefit are independent of proprietary interests in specific applications and products.

ASHRAE will continue to conduct research on the development and application of HFCs and other alternative refrigerants (such as carbon dioxide) and alternative technologies. This research includes methods for improving the energy efficiency of all refrigeration and air-conditioning systems.

To assist in the timely transition away from ozone depleting substances to new alternatives, ASHRAE has placed two key industry standards on a continuous maintenance status – permitting incorporation of new technical developments on an accelerated basis. The two standards closely tied to the introduction of new refrigerants into the marketplace are Standard 34, "Designation and Safety Classification of Refrigerants," and Standard 15, "Safety Code for Mechanical Refrigeration."

To help ensure the "proper application" of Standard 15, "Safety Code for Mechanical Refrigeration," ASHRAE will publish a user’s manual to assist equipment manufacturers, design professionals, contractors and maintenance staff, building owners and operators and others in the proper installation, use and care of refrigeration systems.

ASHRAE, as an international organization, will lead in providing technical information to developing countries related to the phaseout of CFCs.

ASHRAE urges the implementation of worldwide conservation measures to minimize emissions of all refrigerants employing the latest technology, guidance documents and standards.

ASHRAE urges worldwide compliance with the provisions of the Montreal Protocol including its amendments and adjustments.

ASHRAE recommends that in order not to discourage the use of viable alternatives to CFCs, the current phaseout schedules of the Montreal Protocol should not be accelerated.

ASHRAE urges code-developing organizations and local code implementing authorities to adopt promptly provisions permitting new improved technologies and products (when shown to be safe and effective and when available commercially). Since the key to the implementation of new technical advances is well-informed code officials, technical updates must be provided. ASHRAE will participate actively in these code processes.

ASHRAE will provide information and technology to support voluntary actions and the development of public policy.

Revision Date: March 8, 2001

©2001 ASHRAE. All Rights reserved.