Cal-Code Sight Glass is no longer required for Externally Pressurized Expansion Tanks in California

Subchapter 2. Boiler and Fired Pressure Vessel Safety Orders
Article 4. Installation
§763. Low-Pressure Boilers.

(g) All hot water heating systems shall be equipped with a suitable expansion tank that will be consistent with the volume, temperature, pressure, and capacity of the system as required by the Code. All such expansion tanks shall have an allowable working pressure at least equal to the maximum allowable working pressure of the boiler with which they are used, and the maximum allowable working pressure shall be stamped on a nameplate visible after installation.

All expansion tanks connected into systems having boilers designed for more than 30 psi working pressure shall be constructed, inspected, and stamped according to the Code, Section VIII, unless it can be proven to the satisfaction of the Division that the design and construction will provide equivalent safety. Expansion tanks connected into systems having boilers designed for 30 psi or less shall be designed, constructed, and stamped according to the Code, Section VIII, or according to good engineering practices with a factor of safety of at least 4.

All expansion tanks shall be fitted with either: (1) a water gage glass or other means for indicating visually the water level in the tank, or (2) a bladder-type expansion tank provided the tank is fitted with an airtight bladder inside the tank and it is provided with a means of determining the presence of air cushion in the tank. The hot water heating system shall be installed, inspected, and equipped with the required safety relief and shut-off devices in accordance with the Uniform Mechanical Code, Chapter 10, February 1997 Edition.

Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.


The above information is provided free of charge by the Department of Industrial Relations from its web site at http://www.dir.ca.gov/.