scope:

This standard covers gas utilization equipment in boilers having inputs over 400,000 Btu per hour per combustion chamber except water-tube boilers having outputs of 10,000 pounds of steam per hour (approximately 12,500,000 Btu per hour input) or more.*

This standard does not apply to gas utilization equipment in boilers:

a. covered by American National Standard Installation of Gas Appliances and Gas Piping, Z21.30-1964,

b. covered by American National Standard installation of Domestic Gas Conversion Burners, Z21.8-1965, and Addenda, Z21.8a-1967 and Z21.8b-1969,

c. complying with American National Standard for Gas-Fired Single Firebox Boilers, Z21.52-1967, and Addenda, Z21.52a-1968, and Z21.52b-1971,

d. complying with American National Standard for Gas-Fired Steam and Hot Water Boilers, Z21.13-1967, and Addenda, Z21.13a- 1968, and Z21.13b-1971.

All gas-fired boilers, burners and their accessories shall be approved. Approved shall mean acceptable to the authority having jurisdiction.

In determing acceptability, the authority having jurisdiction would normally base acceptance on compliance with the appropriate Boiler Code and this standard. The authority having jurisdiction may also refer to the listings or labeling practices of nationally recognized testing laboratories**, i.e., laboratories qualified and equipped to conduct the necessary tests, in a position to determine compliance with appropriate standards for the current production of listed items, and the satisfactory performance of such equipment or materials in actual usage; or the recommendations of a nationally recognized engineering agency specializing in the field of safety to life and property.***

Reference should be made to Section 2 - Sizing of Gas Piping Systems and to Section 4 - Installation of Gas Piping Systems, of American National Standard Installation of Gas Piping and Gas Equipment on Industrial Premises and Certain Other Premises, Z83.1-1968, and Addenda, Z83.la-1969, for the sizing and installation of piping systems for equipment covered in this standard.