ANSI Z21.93-2017/CSA 6.30-2017 PDF Download

ANSI Z21.93-2017/CSA 6.30-2017 is a standard that provides guidelines for the construction and use of excess flow valves for natural and propane gas with pressures up to 5 psig. The standard applies to valves that are made entirely of new and unused parts and materials, and are intended for use after the service meter or second stage regulator. The valves are not to exceed 2 inches (50 DN) in nominal pipe size.

The purpose of the valves covered by this standard is to automatically limit the downstream flow of gas if it reaches the valves' trip flow. This ensures the safety of the gas distribution system by preventing excessive flow in the event of a rupture or other abnormal condition.

The standard applies to valves used with a variety of gases, including natural gas, manufactured gas, mixed gases, propane gas, and LP gas-air mixtures. The valves are designed to operate at pressures not exceeding 5 psi (35 kPa) and have a minimum operating pressure of no greater than 5 inches water column (1.24 kPa).

In terms of temperature range, the valves are required to be capable of operation within an ambient temperature range of -20°F to 150°F (-29 °C to 66 °C). However, manufacturers may specify that their valves can operate at temperatures outside this range.

The standard also provides guidelines for measurement units. If a value for measurement is given in the standard and is followed by an equivalent value in other units, the first stated value is considered the specification. All references to pressure in the standard are considered gauge pressures unless otherwise specified.

Additionally, the standard includes SI (Metric) units to allow for its use in metric measurement systems. This ensures compatibility and ease of use for international applications. However, if both the measurement and corresponding value in other units are specified as a quoted marking requirement, both units must be provided.