8 Ill. Adm. Code 215.255
Liquid Level Gauging Devices
Section 215
Section 215.255 Liquid Level
Gauging Devices
a) Gauging devices shall be arranged so that the maximum liquid
level to which the container may be filled is readily determinable.
b) Gauging devices shall have a design working pressure at least
equal to the design pressure of the container on which they are used.
c) Tube type liquid level gauging devices on containers in excess
of 3,000 gallons shall be equipped with shutoff valves at the lower connection.