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EPA to list 'safe' CFC alternatives.

With the Montreal Protocol's international deadline for the elimination of CFCs recently moved ahead to Jan. 1, 1996, foam makers around the world are scrambling faster than ever to find alternatives. In an effort to ensure the safety of replacement blowing agents, the U.S. EPA hopes to establish a set of guidelines for their use by the end of this year.

Last fall, the agency created a preliminary policy aimed at governing the use of CFC alternatives. Labeled the Significant New Alternatives Policy (SNAP), the final version is set to go into effect this fall. Under the ruling, numerous HCFCs, HFCs and water-based blowing agents will be deemed either acceptable or unacceptable based on their ozone-depletion and global-warming potentials, flammability and chemical toxicity. Separate listings will be issued for blowing agents used in rigid and flexible polyurethane foams, PUR integral-skin foams, polystyrene extruded insulation board and sheet, phenolic foam insulation board and polyolefin foams.

For rigid polyurethane foams, the program will further break down the CFC alternatives according to application. In some cases, an alternative may be acceptable for one application but unacceptable in an application for which safer options exist, says Drusilla Hufford, chief of the EPA's substance analysis and review branch. For example, HCFC-141b is the best alternative for some applications where other blowing agents cannot provide the same performance. In other cases, different blowing agents work as well as 141b and have significantly lower ozone depletion and global warming potentials. In such cases, 141b would not be allowed under the SNAP quidelines.

PROPOSALS FOR PUR FOAMS

For rigid laminated boardstock, the EPA is considering OK'ing HCFCs 123, 141b, and 142b, as well as mixtures of HCFCs 22 and 141b, 22 and 142b, and 123 and 141b. Also expected to be approved for these applications are pentane, carbon dioxide and a new formulation, 2-chloropropane. Some industry insiders have expressed doubt over the acceptability of this newest alternative, saying its volatile organic compound (VOC) emission level may be too high for it to be deemed safe.

For rigid appliance foams, the preliminary list includes HCFCs 22, 123, 141b and 142b; mixtures of HCFCs 22/141b, 22/142b and 123/141b; various hydrocarbons such as pentane, isopentane and hexane; and C|O.sub.2~.

Commercial refrigeration, spray and sandwich panels would be allowed to use HCFCs 22, 123, 141b, 142b and a 22/142b mixture; as well as the above-mentioned hydrocarbons and C|O.sub.2~. Rigid slabstock and other rigid foams would be restricted to using HCFCs 22 and 123, with HCFC 141b being permitted only for use in insulation and flotation foams.

On the flexible urethane side, the proposed guidelines would consider HCFC-123 and C|O.sub.2~ acceptable alternatives. Methylene chloride and acetone are also being examined but may run into conflict with other regulations. Because of their VOC emission levels, use of both substances is tightly restricted under OSHA guidelines for worker safety.

Blowing agents for polyurethane integral-skin products would be restricted to HCFCs 22 and 123, hydrocarbons, methylene chloride and C|O.sub.2~. EPA has said that HCFC-141b is unacceptable for these products except for those used in automotive safety foams.

Besides these blowing agents, the EPA is also looking at the safety of HFCs 134a and 152a and several perfluorocarbons. However, the perfluorocarbons would not be acceptable in rigid appliance foams, EPA says.

After the agency publishes its final ruling later this year, it will give users of these substances 45 days to comment on its list of alternatives. To assist foam processors in understanding the implications of the program, EPA has set up a SNAP Hotline that can be reached at 1-800-296-1996.
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Title Annotation:Regulatory Update; chlorofluorocarbons
Author:Monks, Richard
Publication:Plastics Technology
Date:Feb 1, 1993
Words:611
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