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Facts About HCFC-225 Usage Ban In 2015
November 21, 2012 |Estimated reading time: 6 minutes
Editor's Note: This article originally appeared in the September 2012 issue of SMT Magazine.In 1974, Sherwood Rowland and Mario Molina discovered that chlorofluorocarbons (CFCs) were depleting the ozone layer. In 1995, the pair received the Nobel Prize in Chemistry for this work. In response, the United Nations Environment Programme (UNEP) called an international conference to discuss the issue. Shortly thereafter, the U.S. banned all non-essential uses of CFCs as propellants in aerosols. In 1987, the Montreal Protocol on Substances That Deplete the Ozone Layer was signed by 24 countries, requiring all developed countries to begin the phase-out of CFCs by 1993 and reduce CFCs to 50% of the baseline (1989 amounts) by 1998. Since 1987, more than 190 countries have signed this treaty (United States Environmental Protection Agency Office of Air and Radiation, 2007).
A timeline for the phase-out of hydrochlorofluorocarbons (HCFCs) was created in 1997 per the Montreal Amendment. To meet the 90% total reduction requirement for all HCFCs by 2015, HCFC-225 is now being phased out (United States Environmental Protection Agency, 2010).
How is the HCFC-225 Phase-Out Defined?
The Clean Air Act addresses the phase-out of HCFC-225 in section 605(a). The first part covers the restriction of use and states, “Effective January 1, 2015, it shall be unlawful for any person to introduce into interstate commerce or use any class II substance unless such substance has been used, recovered, and recycled; is used and entirely consumed (except for trace quantities) in the production of other chemicals; or is used as a refrigerant in appliances manufactured prior to January 1, 2020.” In this case, “use” refers to the use of the controlled substance (HCFC-225) and not to finished products containing HCFC-225. Therefore, end-users may use, and continue to purchase, products containing HCFC-225 made before January 1, 2015. After that date, manufacturers of products containing HCFC-225 can only make these products if the HCFC-225 has been used, recovered, and recycled.
What is HCFC-225?
HCFC-225 is a mixture of two isomers, HCFC-225ca and HCFC-225cb. A common source of HCFC-225 is from Asahi Glass Company and known as Asahiklin AK-225, a precision cleaning solvent. AK-225 has many unique properties, including its ability to form azeotropes (mixtures that act as one chemical, with unique and constant physical characteristics), good solvency, and thermal stability (making it good for use in vapor degreasing). AK-225 is non-flammable, and VOC (volatile organic compounds, which are smog producing and highly regulated) exempt, allowing for its use in California. AK-225 also has a low acute toxicity (the exposure level of AK-225 is 100 ppm 8h TWA compared to 200 ppm for trans), low viscosity (meaning that it flows well), high density (it’s heavier than water, so it will displace water), and low surface tension (meaning that it will flow well under low stand-offs). Unfortunately, due to the ozone depleting potentials of HCFC-225ca and HCFC-225cb, 0.02 and 0.03, respectively, it is now being phased out (Daniel, et al., 2007). What are Replacements for HCFC-225?
In 1994, the EPA implemented the Significant New Alternatives Policy (SNAP) program to assist in the transition to “safer, practical, and economically feasible alternatives across multiple industrial, consumer, and military sectors.” The SNAP program either accepts or rejects potential substitutes using the following process. First, manufacturers submit information on substitutes to the EPA. The EPA then reviews these substitutes in terms of their health and environmental effects; the substitute’s ozone depleting potential, global warming potential, toxicity, and flammability are considered. After the substitute has been reviewed, the EPA issues a listing for the substitute. To date, the EPA has approved more than 300 substitutes for more than 60 different uses. Potential substitutes for HCFC-225 include DuPont Vertrel solvents, n-Propyl Bromide, Trichloroethylene, 3M HFEs, and Techspray’s Precision-V solvents (United States Environmental Protection Agency, 2010).
DuPont Vertrel Solvents
DuPont Vertrel solvents have physical characteristics very similar to HCFC-225; however, they are also much more environmentally friendly and currently have no use restrictions. Vertrel solvents have exposure limits ranging from 190 to 200 ppm, over an eight-hour time-weighted average (TWA); HCFC-225’s limit is 100 ppm over an eight-hour TWA. Vertrel solvents have a lower cleaning efficiency than AK-225; however, Vertrel/trans blends are compatible in cleaning power to AK-225. Vertrel solvents also have similar materials compatibility to HCFC-225, which has broad materials compatibility (DuPont, 2011).
Techspray offers the Precision-V line of products, containing Vertrel XF, as a replacement for products containing AK-225. Products in the Precision-V line are Precision-V Vapor-Degreaser Parts Cleaner, and Precision-V Vapor-Degreaser Flux Remover. These solvents have a lower boiling point than most vapor-degreaser solvents. This reduces heat stress on components being cleaned and reduces energy consumption for the boil sump and chiller coils.
n-Propyl Bromide (nPB)
Solvents containing nPB work well for difficult precision cleaning; however, they are not considered environmentally friendly. The acceptable exposure limit for nPB solvents is 25 ppm over an eight hour TWA (United States Environmental Protection Agency, 2010). Health hazards include damage to the reproductive system, liver, and nervous system. There is also evidence that nPB causes damage to the brain. These effects have been observed in animals with as little as 400 ppm exposure (Agency for Toxic Substances and Disease Registry, 2001).
Trichloroethylene (TCE)
From a health and environmental standpoint, TCE is not a good replacement, as it has been a suspected carcinogen for years and breathing even small amounts may produce several unpleasant side effects, including headaches, lung irritation, dizziness, poor coordination, and difficulty concentrating (Agency for Toxic Substances and Disease Registry, 2001). TCE has an OSHA permissible exposure limit (PEL) of 100 ppm TWA. ACGIH recently reduced TCE’s threshold limit value (TLV) from 25 ppm to 10 ppm due to a recent EPA study that concluded, “…TCE poses a potential human health hazard for noncancer toxicity to the central nervous system, kidney, liver, immune system, male reproductive system, and the developing fetus…The human evidence of carcinogenicity from epidemiologic studies of TCE exposure is strong for non-Hodgkin Lymphoma…” (United States Environmental Protection Agency, 2011). TCE is an aggressive cleaner; this makes it unsuitable for use with most plastics and elastomers. A positive quality of TCE is its cost, as it is much less expensive than some of the modern chemistries (DuPont).
3M’s HFEs (hydrofluoroethers)
From an environmental standpoint, 3M HFEs have been granted VOC exemption. They are described by 3M as having “no ozone-depleting components, a shorter atmospheric lifetime, and a lower global warming potential than CFCs” (3M, 2011).
What Does This Mean to the End-User?
The first section of the Clean Air Act 605(a) restricts use. In this case, “use” refers to the use of the controlled substance, HCFC-225, not to products containing HCFC-225. Products containing HCFC-225 made before January 1, 2015, may continue to be sold and used by end users indefinitely. For Techspray products, this means that all aerosol products containing HCFC-225 and all bulk blends containing HCFC-225 made prior to the cut-off may be sold after December 31, 2014. Sales and use of 1663-54G, -5G, and -G, will end on December 31, 2014. Beginning on January 1, 2015, HCFC-225 can only be used in the manufacture of cleaning products if it has been used, recovered, and recycled, per the Clean Air Act 605(a). See the table below for a quick overview of how the HCFC-225 phase-out affects Techspray products.
Exceptions
To date, the U.S. EPA has not announced any exceptions to the HCFC-225 ban. However, if history is any indicator, we can expect to see exemptions for military use, and possibly medical use, for applications in which a replacement has not been identified.
References:
1. 3M™ Novec™ Engineered Fluids, 2011. 2. Agency for Toxic Substances and Disease Registry, Toxic Substances Portal - Trichloroethylene, July, 2001. 3. Daniel, J., Velders, G., Douglass, A., Forster, P., Hauglustaine, D., Isaken, I., et al. Scientific Assessment of Ozone Depletion: 2006, Global Ozone Research and Monitoring Project, Report No. 50, Geneva, World Meteorological Organization, 2007. 4. DuPont Vertrel Product Comparison, April, 2011. 5. DuPont Vertrel Specialty Fluids, 2011. 6. Toxicological Review of Trichloroethylene, United States Environmental Protection Agency, Washington D.C., 2011. 7. Ozone Layer Protection, United States Environmental Protection Agency, Washington D. C., 2010. 8. Achievements in Stratospheric Ozone Protection, United States Environmental Protection Agency Office of Air and Radiation, Washington D.C., 2007. Lindsey Shehan is a chemist for Amarillo, Texas-based Techspray and is responsible for tracking regulations, product testing, and special projects. She has a B.A. in Chemistry from Texas A&M University and is a member of SMTA.