ANSI Z21.79-1997 (R2021)/CGA 6.21-M97 (R2021)

Preface This publication represents a basic standard for safe operation, substantial and durable construction, and acceptable performance of a gas appliance sediment trap. It is the result of years of experience in the manufacture, testing, installation, maintenance, inspection and research on gas appliance sediment traps designed for utilization of gas. There are risks of injury to persons inherent in appliances that, if completely eliminated, would defeat the utility of the appliance. The provisions in this standard are intended to help reduce such risks while retaining the normal operation 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 gas appliance sediment traps, the safety construction and performance of which may exceed the various provisions specified herein. In its preparation, 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 or suggestions should be forwarded to the Chairman of Accredited Standards Committee Z21, 8501 East Pleasant Valley Road, Cleveland, Ohio 44131, or the Chairman of the Canadian Gas Association Standards Steering Committee on Gas Burning Appliances and Related Accessories, 243 Consumers Road, Suite 1200, North York, Ontario, Canada M2J 5E3. Safe and satisfactory operation of gas appliance sediment traps depends to a great extent upon its proper installation, use and maintenance. It should be installed, as applicable, in accordance with the National Fuel Gas Code, ANSI Z223.1; the Natural Gas Installation Code, CAN/CGA-B149.1; the Propane Installation Code, CAN/CGA-B149.2. Users of this American National Standard/Canadian Gas Association Standard are advised that the devices, products and activities within its scope may be subject to regulation at the Federal, Territorial, Provincial, 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, Territorial, Provincial, state or local regulation should be followed. Scope 1.1.1 This standard applies to newly produced gas appliance sediment traps hereinafter referred to as traps (see Part IV, Definitions), constructed entirely of new, unused parts and materials. Compliance of a trap with this standard does not imply that the trap is acceptable for use on a gas appliance without supplemental tests with the trap applied to the particular appliance design. 1.1.2 This standard applies to traps having maximum operating gas pressure ratings of 1/2 psi (3.5 kPa). 1.1.3 This standard applies to traps which are mounted in accordance with the manufacturer's installation instructions (see 2.1.2). 1.1.4 Traps complying with the provisions of this standard shall be considered as having an operating temperature range of 32°F to 125°F (0°C to 51.5°C). They may be capable of operating at a higher temperature, lower temperature, or both when so specified by the manufacturer. 1.1.5 If a value for measurement as given in this standard is followed by an equivalent value in other units, the first stated value is to be regarded as the specification. 1.1.6 Exhibit A contains a list of standards specifically referenced in this standard, and sources from which these reference standards may be obtained. 1.1.7 Exhibit B is a list of materials needed and a detailed step-by-step procedure for conducting the sediment trap testing outlined under 2.6. 1.1.8 Exhibit C contains provisions that are unique to Canada. 1.1.9 All references to psi throughout this standard are to be considered gauge pressures unless otherwise specified.