AS NZS ISO 33405-2024 PDF

Full title and description

AS/NZS ISO 33405:2024 — Reference materials — Approaches for characterization and assessment of homogeneity and stability. This document provides guidance and approaches for the production, characterization and assessment of reference materials (RMs), with a focus on homogeneity and stability studies, value assignment and associated uncertainty and traceability considerations.

Abstract

This standard explains concepts and gives practical approaches for: assessment of homogeneity; assessment of stability (including risk management for stability issues); characterization and value assignment of RM properties; evaluation of uncertainty for certified values; and establishment of metrological traceability of certified values. It supports the implementation of ISO 17034 and replaces/updates guidance previously given in ISO Guide 35.

General information

• Status: Published (adoption as an AS/NZS identical adoption of ISO 33405:2024).
• Publication date: ISO original published May 2024; AS/NZS adoption listed as published 30 August 2024.
• Publisher: Standards Australia / Standards New Zealand (identical adoption of the International Standard prepared by ISO/TC 334).
• ICS / categories: 71.040.30 (Chemical reagents; reference materials and related activities).
• Edition / version: Edition 1 (ISO 33405:2024).
• Number of pages: Publication length varies by publisher format (ISO main edition listed as 98 pages; AS/NZS published copy listed with local pagination of 118 pages).

Scope

Provides guidance on experimental designs and analytical approaches to demonstrate homogeneity and stability of reference materials, guidance on accelerated stability testing and post‑certification monitoring, approaches to characterization and value assignment (including uncertainty evaluation) and establishing metrological traceability for certified values. The document is applicable to a wide range of RMs but does not cover multivariate quantities such as spectral data and gives limited detail for qualitative properties (with further guidance available in related parts of the series).

Key topics and requirements

• Principles and experimental designs for homogeneity assessment (between‑unit and within‑unit considerations).
• Stability assessment approaches, including accelerated stability studies and risk management for property degradation.
• Characterization and value assignment methods for RM properties, plus evaluation of associated uncertainties.
• Establishment and documentation of metrological traceability for certified values.
• Guidance on post‑certification monitoring, end‑user storage considerations and repeated sampling from single units.
• Brief guidance on commutability assessment and introductory notes on qualitative property characterization (with pointers to companion documents for more detail).

Typical use and users

Producers of reference materials, national metrology institutes, testing and calibration laboratories, accreditation bodies, quality managers and technical staff responsible for RM production and certification, and organizations implementing ISO 17034 requirements will use this standard to design studies, document evidence of homogeneity/stability and assign values with defensible uncertainties.

Related standards

Part of the ISO 33400-series (successors/replacements to guidance in ISO Guide 35). Relevant related AS/NZS/ISO documents include AS/NZS ISO 33401:2024 (contents of RM certificates/labels/documentation), AS/NZS ISO 33403:2024 (requirements and recommendations for use), AS/NZS ISO 33406:2024 (production of RMs with qualitative properties) and other ISO 17034 conformity guidance.

Keywords

reference material, RM, homogeneity, stability, value assignment, uncertainty, metrological traceability, ISO 17034, characterization, commutability, post‑certification monitoring

FAQ

Q: What is this standard?

A: An international (and adopted AS/NZS) standard that provides approaches for characterizing reference materials and assessing their homogeneity and stability to support reliable value assignment and traceability.

Q: What does it cover?

A: Experimental designs and statistical approaches for homogeneity testing, stability testing (including accelerated studies), guidance on characterization and value assignment with uncertainty evaluation, traceability, and considerations for post‑certification monitoring and end‑user storage. It offers limited technical detail for qualitative properties and excludes multivariate quantities like spectral data.

Q: Who typically uses it?

A: RM producers, metrology institutes, calibration and testing laboratories, accreditation bodies and quality/technical managers involved in RM production, certification and use.

Q: Is it current or superseded?

A: Current — ISO 33405:2024 is the first edition (published in 2024) and replaces guidance previously provided in ISO Guide 35:2017. The AS/NZS adoption was published in 2024.

Q: Is it part of a series?

A: Yes — it is part of a suite of new/updated ISO/AS‑NZS documents addressing reference materials and their documentation, characterization and production (other numbered parts address certificates, qualitative RMs, guidance for specific RM types, etc.).

Q: What are the key keywords?

A: reference material, homogeneity, stability, characterization, value assignment, uncertainty, traceability, ISO 17034, commutability.