scope:

SCOPE & LIMITATIONS

This standard applies to pilot operated and direct acting pressure reducing, pressure relieving (back pressure), differential pressure and temperature regulators.

Selection of a leakage class is not restricted as to regulator design, but acceptable values for various commercially available designs are suggested for each class under Section 4.

The standard cannot be used as a basis for predicting leakage at conditions other than those specified.

This standard is similar to FCI 70-2, Control Valve Seat Leakage.

This standard does not apply to pressure regulators as defined in the following standards:

• ANSI Z21.18/CSA 6.3, Gas Appliance Pressure Regulators

• ANSI Z21.80/CSA 6.22, Line Pressure Regulators

• ANSI Z21.78/CSA 6.20, Combination Gas Controls for Gas Appliance

PURPOSE

This standard establishes a series of seat leakage classes for regulators and defines the production test procedures.