ISO 6509-2:2017

Overview

ISO 6509-2:2017 defines assessment criteria and guidance for dezincification resistance of copper‑zinc alloys (brasses) with a zinc mass fraction > 15%, when exposed to fresh water, saline water or drinking water. The criteria are based on exposure tests specified in ISO 6509‑1 (test method) and apply to semi‑finished or finished products such as bars, fittings and valves. ISO 6509‑2:2017 is not intended for complex components (e.g., flow meters, pump parts) and does not validate failures in service.

Key topics and requirements

• Scope: Assessment criteria for dezincification in copper alloys with >15% zinc exposed to potable/fresh/saline waters.
• Test basis: Acceptance limits rely on dezincification depth measurements obtained using the ISO 6509‑1 exposure/test method.
• Minimum requirement: An alloy is classified as dezincification resistant only if both the average and maximum dezincification depths are below the limits in Table 1 (or applicable national limits).
• Numeric acceptance criteria (Table 1):
  • Final forgings and castings after machining (including continuously cast bars): Average ≤ 100 µm, Maximum ≤ 200 µm
  • Extruded bars/profiles for machining - longitudinal direction: Average ≤ 300 µm, Maximum ≤ 400 µm
  • Extruded bars/profiles - transverse direction: Average ≤ 100 µm, Maximum ≤ 200 µm
• Limitations: Not applicable to complex products; other material properties (mechanical, microbiological, lead content, etc.) may also be required for specific applications. Local water chemistry, flow rate and system management affect dezincification risk and may require stricter limits.

Applications

• Selection and specification of dezincification‑resistant brasses for:
  • Sanitary installations and plumbing fittings
  • Valves and machined components used in drinking water systems
  • Manufacturers’ quality control and material acceptance testing
• Useful for corrosion engineers, materials engineers, water utilities and procurement teams assessing alloy suitability for potable and saline water environments.

Who should use this standard

• Material suppliers and alloy producers
• OEMs producing fittings, valves and machined copper alloy parts
• Test laboratories performing ISO 6509‑1 exposure tests and reporting compliance to ISO 6509‑2
• Specification writers, QA/QC engineers and regulators for water systems

Related standards

• ISO 6509‑1 (Test method for dezincification resistance)
• ISO 8044 (Corrosion terms and definitions)
• Relevant national/product standards: JIS H 3250, EN 12288, NSF/ANSI 14; EN 12163–12168, EN 12420, EN 1982 (for complementary material/product requirements).

Keywords: ISO 6509-2, dezincification, dezincification resistance, copper alloys, brass corrosion, corrosion resistance, drinking water fittings, ISO 6509-1.