CSA/ANSI Z21.21-23/CSA 6.5-2023: Automatic Valves

Manual valve of fuel gas filter systems in power plant with automatic valves adhering to CSA/ANSI Z21.21-23/CSA 6.5-2023.

Keeping the flow of oil and gas in pipelines is a monumental task, requiring reliable equipment like gas valves. Without gas valves, the oil and gas industry could not assure that crude oil, refined gas, natural gas, and other materials get to their destination. CSA/ANSI Z21.21-23/CSA 6.5-2023: Automatic Valves For Gas Appliances details specifications for individual automatic valves or valves utilized as parts of automatic gas ignition system.

Valve Actuation Mechanisms

A valve is a component in a piping system that is used to control the flow of media through a system. This control is achieved by the manipulation of some type of obstructer within the valve. Actuated valves use mechanical devices called “actuators” to operate. An actuated valve operates by either manual, electrical, pneumatic, hydraulic, self-actuated, or spring force. A valve actuator provides the force needed to operate control valves and regulate fluid flow through a piping system or industrial process.

Automated valves do not require manual efforts for their operation. Instead, they possess an actuator and control system that automatically performs the opening, closing, and regulation of the valve. The benefits of this system include increase in efficiency and operator safety as well as more precision and consistent flow control using actuated control valves that respond to parameters like pipe pressure, temperature, and flow rate. CSA/ANSI Z21.21-23/CSA 6.5-2023 details requirements for such valves applicable in a gas system. The scope of this standard defines automatic valves as “a device consisting essentially of a valve and operator that controls the gas supply to the burner(s) during operations of an appliance. The operator can be actuated by the application of gas pressure on a flexible diaphragm, by electrical means, by mechanical, or by other means.”

The following are some types of automatic valves:

  • Diaphragm Type Automatic
  • Electric Type Automatic
  • Safety shutoff
  • Semi-automatic
  • Thermally actuated
  • Thermostatic valve

What Is CSA/ANSI Z21.21-23/CSA 6.5-2023?

CSA/ANSI Z21.21-23/CSA 6.5-2023 applies to newly produced automatic valves constructed entirely of new, unused parts and materials. These valves can be individual automatic valves or valves utilized as parts of automatic gas ignition systems for use with one or more of the following fuel gases: natural and propane gases. This American National Standard applies to automatic valves having maximum operating gas pressure ratings from 1/2 psi (3.5 kPa) up to and including 60 psi (413.7 kPa) and commercial/industrial safety shutoff valves (C/I valves) having maximum operating gas pressure ratings of 1/2 psi (3.5 kPa) or greater.

This standard does not apply to self-contained water heater, cooking appliance, or room heater thermostats or self-contained automatic gas shutoff valves for hot water supply systems. Additionally, compliance of an automatic valve with CSA/ANSI Z21.21-23/CSA 6.5-2023 does not imply that the automatic valve is acceptable for use on gas appliances without supplemental tests with the automatic valve applied to the particular appliance design.

What Is A Gas Valve?

A gas valve is a device used to regulate the flow of oil and gas. It controls the flow of gas into a furnace based on the signals it receives from the thermostat, assuring the right amount of gas is being delivered for the desired heat. Opening or closing an aperture controls the amount of liquids and gases allowed through pipes. The valve itself controls the flow of fluids by stopping and starting, adjusting the amounts, controlling the direction, regulating pressure, or relieving pressure.

All environments vary as some are highly corrosive and others function under constant high pressure. Due to these variants, many different types of valves (e.g., gate, glove, check, butterfly, plug, ball, and slam-shut valves) have been developed over the decades to be used within the gas and oil industry.

CSA/ANSI Z21.21-23/CSA 6.5-2023: Automatic Valves For Gas Appliances is available on the ANSI Webstore.

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