Certain proprietary and patented building systems, structural components, and building materials are identified in this report in order to adequately specify the test specimen and the experimental procedures. In no case does such identification imply recommendation or endorsement by the National Bureau of Standards, nor does it imply that the proprietary products identified are necessarily the best available for the purpose.

This report does not account for possible variation in the performance of these proprietary products.

The contents of this report are not to be used for advertising or promotional purposes.

Library of Congress Catalog Card No. 73-602417

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