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Article: Winds of environmental change. (preventing ozone layer depletion by discarding chlorofluorocarbons, and hydrochlorofluorocarbons)
- Article from:
- Doors and Hardware
- Article date:
- March 1, 1993
- Author:
CopyrightCOPYRIGHT 1993 Door and Hardware Institute. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
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Many of the best heavy-duty flush doors being made today have cores of polyurethane foam. This foam provides excellent thermal insulation. If it is foamed-in-place, adhering to everything inside the door, it adds greatly to impact resistance, structural integrity and flexural strength. It is really tough material, and it doesn't weigh much. Since less force is needed for opening and closing these doors, the attached hardware works better and lasts longer. Doors built this way are eliminating entrance problems in many industrial, institutional and commercial settings.
Making polyurethane foam requires the use of a blowing agent. Over thc past 30 years or more, the ...