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ANSI Z21.15b-2013 / CSA 9.1b-2013: Technical Requirements for Manually Operated Gas Valves
A Detailed Review of the Supplement for Gas Valve Safety, Construction, and Performance Testing
Scope and Applicability
The standard ANSI Z21.15b-2013 / CSA 9.1b-2013 is a supplement to the base standard ANSI Z21.15-2010 (CSA 9.1-2010). It applies to manually operated gas valves used in gas appliances, connector valves, and hose end valves. These valves are intended for use with natural, manufactured, mixed gases, liquefied petroleum gases (LP-gas), and LP-gas-air mixtures in the vapor phase.
The supplement introduces modifications and clarifications to construction, performance, and marking requirements. It is part of the Z21/83 series of standards developed under the American National Standards Institute (ANSI) and the Canadian Standards Association (CSA).
Key Scope Inclusion: The standard covers valves with inlet and outlet connections from ⅛-inch to 2 inches nominal pipe size (NPS) and operating pressures up to ½ psig (3.5 kPa). Low-pressure valves used in residential, commercial, and industrial gas systems fall under its jurisdiction.
Technical Requirements
Construction and Materials
Valves must be constructed from materials that are resistant to the corrosive effects of the fuel gases and the operating environment. Material specifications include:
- Body materials: Brass, bronze, or other corrosion-resistant alloys. Non-metallic materials may be used if they meet the fire resistance and impact tests.
- Seats and seals: Must be compatible with lubricants and fuel gases. Elastomeric seals must satisfy aging and compression set requirements per ASTM D2000.
- Pressure-containing parts: Minimum wall thicknesses are defined to withstand hydrostatic pressures at 5 times the rated working pressure.
Leakage Requirements
Two types of leakage tests are defined: seat leakage and shell leakage. The allowable leakage rates are specified in the following table:
| Test Type | Test Pressure | Maximum Leakage Rate |
|---|---|---|
| Seat leakage (air) | 3 to 5 in. w.c. (0.75–1.25 kPa) | 0.01 ft³/h (0.28 L/h) per inch of nominal valve size |
| Shell leakage (air) | 5 psig (34.5 kPa) | Zero detectable leakage |
| Hydrostatic shell strength | 5 × rated pressure (min. 125 psig) | No rupture or permanent deformation |
Critical Safety Note: Leakage testing must be conducted after the valve has been cycled 6000 times at maximum rated torque to ensure long-term seal integrity under wear.
Flow Capacity and Pressure Drop
The standard specifies minimum flow coefficients (Cv) for various valve sizes. For example, a ½-inch NPS full-port valve must have a Cv of at least 12.0 when tested with air at a pressure drop of 1 psig. Valves that do not meet the flow requirement cannot be marked as “full-port.”
Marking and Instructions
Each valve must be permanently marked with:
- Manufacturer’s name or trademark
- Model or part number
- Rated pressure and temperature range
- Gas type designation (e.g., “LP” for liquefied petroleum)
- ANSI Z21.15b / CSA 9.1b compliance mark
The supplement updates the marking requirements to include a clear indication of the valve’s open/closed position using a visual indicator (e.g., on the stem or handle).
Implementation Highlights
Manufacturers seeking to certify products to ANSI Z21.15b-2013 / CSA 9.1b-2013 must adhere to the following implementation steps:
- Design review: Ensure that the valve design incorporates a positive mechanical stop in both the open and closed positions, separate from the sealing surfaces.
- Testing: Perform the required endurance, leakage, hydrostatic, and flow tests at an accredited laboratory. The standard mandates testing every production batch or periodic testing per the certification body’s requirements.
- Documentation: Maintain traceability records for all materials, including chemical composition and test reports for non-metallic parts.
- Labeling: Update product labels to include the supplement reference and the date of manufacture (month and year).
Implementation Tip: To reduce time to market, consider using pre-approved component suppliers whose seals and lubricants have already been tested for compatibility with your valve design.
Compliance and Certification Notes
Compliance with ANSI Z21.15b-2013 / CSA 9.1b-2013 is voluntary in the United States but may be mandatory in certain states or jurisdictions that adopt the standard by reference. In Canada, compliance with the equivalent CSA 9.1b-2013 is required for sale and installation of gas valves under provincial gas codes.
Certification is typically performed by nationally recognized testing laboratories (NRTLs) such as CSA Group, UL (Underwriters Laboratories), or Intertek. The certification process includes:
- Initial type testing of representative samples
- Factory inspection and follow-up audits
- Recertification when the base standard or supplement is revised
Compliance Alert: Valves that do not meet the updated marking requirements by the effective date of the supplement may be rejected during inspection. Ensure that the open/closed indicator is permanently attached and legible after 6000 cycles.
Frequently Asked Questions
Q: What is the difference between ANSI Z21.15b-2013 and the base standard ANSI Z21.15-2010?
A: The supplement “b” clarifies marking requirements, adds a specific flow capacity test for full-port valves, and updates the endurance cycling test to 6000 cycles from 2000 cycles in earlier editions. It also harmonizes certain leakage test procedures with CSA 9.1-2010.
A: The supplement “b” clarifies marking requirements, adds a specific flow capacity test for full-port valves, and updates the endurance cycling test to 6000 cycles from 2000 cycles in earlier editions. It also harmonizes certain leakage test procedures with CSA 9.1-2010.
Q: Does this standard apply to gas shut-off valves for outdoor appliances like grills?
A: Yes, the standard covers hose end valves used in outdoor gas appliances. These valves must meet the same leakage and endurance requirements, additional corrosion and weather resistance tests apply for outdoor-rated valves (refer to Annex A of the standard).
A: Yes, the standard covers hose end valves used in outdoor gas appliances. These valves must meet the same leakage and endurance requirements, additional corrosion and weather resistance tests apply for outdoor-rated valves (refer to Annex A of the standard).
Q: Can I use a single certification for both the U.S. and Canada?
A: Yes. The standard is jointly published by ANSI and CSA, and a single certification to ANSI Z21.15b-2013 / CSA 9.1b-2013 is recognized by both countries. Look for the combined mark (e.g., CSA US/Canada) on the product.
A: Yes. The standard is jointly published by ANSI and CSA, and a single certification to ANSI Z21.15b-2013 / CSA 9.1b-2013 is recognized by both countries. Look for the combined mark (e.g., CSA US/Canada) on the product.
Q: Are there any special requirements for valves used with LP-gas?
A: Yes. Valves for LP-gas must have a smaller orifice to prevent overpressurization, and all elastomeric seals must be LP-gas resistant. The marking must include “LP” and the maximum allowable pressure (usually ½ psig for low-pressure applications).
A: Yes. Valves for LP-gas must have a smaller orifice to prevent overpressurization, and all elastomeric seals must be LP-gas resistant. The marking must include “LP” and the maximum allowable pressure (usually ½ psig for low-pressure applications).