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PREFACE

This publication represents a standard for safe operation, substantial and durable construction, and acceptable performance of draft hoods for gas appliances. It is the result of years of experience in the utilization of gas, supplemented by extensive research.

Nothing in this standard is to be considered in any way as indicating a measure of quality beyond compliance with the provisions it contains. It is designed to allow compliance of draft hoods for gas appliances, the construction and performance of which may exceed the various provisions specified herein. In its preparation, full recognition has been given to possibilities of improvement through ingenuity of design. As progress takes place, revisions may become necessary. When they are believed desirable, recommendations should be forwarded to the Chairman of Accredited Standards Committee Z21,8501 East Pleasant Valley Road, Cleveland, Ohio 44131.

Safe and satisfactory operation of a draft hood depends to a great extent upon its proper application to a gas-fired appliance installation, and it should only be installed on a properly operating appliance in accordance with the draft hood manufacturer's installation instructions and local codes. General criteria for gas-fired appliance installations, including draft hoods, can be found in the National Fuel Gas Code, ANSI Z223.1, (NFPA 54), the Standard for Chimneys, Fireplaces, Vents and Solid Fuel Burning Appliances, ANSI/NFPA 211, and the Standard for Installation of Domestic Gas Conversion Burners, ANSI Z21.8.