scope:

PREFACE

This publication represents a basic standard for the substantial and durable construction and acceptable performance of mechanically actuated automatic vent damper devices which are capable of being installed on existing gas-fired appliances and is predicated on the use of these devices with certified gas-fired appliances equipped with draft hoods.

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 automatic vent damper devices, 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 an automatic vent damper device depends to a great extent upon its proper application to an existing gas-fired appliance installation, and it should only be installed on a properly operating appliance by a qualified installing agency in accordance with the automatic vent damper device manufacturer's installation instructions and local codes. General criteria for gas-fired appliance installations, including venting systems, can be found in the National Fuel Gas Code, ANSI Z223.1-1984 (NFPA 54) and the Standard for Chimneys, Fireplaces, Vents and Solid Fuel Burning Appliances, ANSI/NFPA 211-1984.