scope:

PREFACE

This publication represents a standard for safe operation, substantial and durable construction, and acceptable performance of circulating tank, instantaneous and large automatic storage gas water heaters. It is the result of years of experience in the manufacture, testing, installation, maintenance, inspection and research on water heaters designed for the utilization of gas. There are risks of injury to persons inherent in some appliances that, if completely eliminated, would defeat the utility of the appliance. The provisions in this standard are intended to reduce such risks while retaining the normal function of the appliance.

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 storage, with input ratings above 75,000 Btu per hour, circulating and instantaneous water heaters, 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 storage water heater, with input ratings above 75,000 Btu per hour, a circulating water heater or an instantaneous water heater depends to a great extent upon its proper installation, and it should be installed, as applicable, in accordance with the National Fuel Gas Code, ANSI Z223.1; manufacturers' installation instructions and local municipal codes.

Users of this American National Standard are advised that the Devices/products/activities within its scope may be subject to regulation at the Federal state or local level. Users are strongly urged to investigate this possibility through appropriate channels In the event of a conflict with this standard, the Federal, state or local regulation should be followed.