ISO 22241-2-2019 PDF

Full title and description

Diesel engines — NOx reduction agent AUS 32 — Part 2: Test methods. This International Standard specifies the analytical and physical test methods required to determine the quality and chemical characteristics of AUS 32 (aqueous urea solution, commonly traded as AdBlue®, DEF or ARLA) as referenced in ISO 22241‑1.

Abstract

ISO 22241‑2:2019 defines standardized laboratory and referee test procedures (including classical and instrumental methods) for measuring properties and impurities in 32 % aqueous urea solutions used in selective catalytic reduction (SCR) systems for diesel engines. The test methods enable manufacturers, laboratories and regulators to verify compliance with the quality requirements given in ISO 22241‑1.

General information

• Status: Published
• Publication date: February 2019
• Publisher: International Organization for Standardization (ISO)
• ICS / categories: 43.060.40
• Edition / version: Edition 2 (2019)
• Number of pages: 44

Metadata above follows the ISO bibliographic record for ISO 22241‑2:2019.

Scope

Specifies the test methods required to determine the chemical composition, impurities and key physical properties of AUS 32 (nominal 32 % m/m urea in demineralized water) so that conformity to the performance and purity requirements in ISO 22241‑1 can be assessed. Methods cover refractive index/urea content determination, nitrogen/urea by combustion or equivalent, determination of biuret, aldehydes, insoluble matter, alkalinity, phosphate and certain elemental impurities, plus reference procedures and precision statements where applicable.

Key topics and requirements

• Determination of refractive index and urea content (annex procedures correlating nD20 with urea mass fraction, used for routine control).
• Determination of total nitrogen/urea content by combustion / thermal conductivity (reference methods for calibration and referee testing).
• Quantification of impurities and degradation products: biuret, aldehydes (e.g., formaldehyde), insoluble matter (gravimetric), alkalinity (as NH3) and phosphate (photometric/referee methods).
• Requirements for sampling, sample containers and handling to avoid contamination or degradation prior to testing.
• Precision, repeatability and acceptance criteria referenced to the specification limits given in ISO 22241‑1 (e.g., target urea ~32.5 % m/m with a specified permissible range; specific limits for biuret, aldehydes, insolubles and selected trace elements are provided in the related quality standard).

Typical use and users

Used by DEF/AUS 32 manufacturers, independent and OEM quality laboratories, vehicle and engine manufacturers, component (SCR) suppliers, transport/fleet quality control teams and regulatory bodies to verify product conformity, investigate suspected contamination or degradation, and to support dispute resolution where referee methods are required. Typical applications include incoming raw-material checks, batch certification, shelf‑life and stability testing, and root‑cause analysis for SCR system failures.

Related standards

ISO 22241‑2 is part of the ISO 22241 series. Closely related documents include ISO 22241‑1 (Quality requirements for AUS 32) and ISO 22241‑3 (handling, transportation and storage). Earlier withdrawn editions (2006) were superseded by the 2019 revisions. Users should consult the other parts of ISO 22241 when applying test results to specification compliance.

Keywords

AUS 32, AdBlue, DEF, diesel exhaust fluid, urea solution, SCR, NOx reduction, test methods, refractive index, biuret, aldehyde, insoluble matter, phosphate, quality control.

FAQ

Q: What is this standard?

A: ISO 22241‑2:2019 is the part of the ISO 22241 series that specifies laboratory and referee test methods used to assess the chemical and physical quality of 32 % aqueous urea solutions used as NOx reduction agents in SCR systems.

Q: What does it cover?

A: It covers analytical procedures (refractive index/urea content, total nitrogen/urea by combustion, biuret, aldehydes, insolubles, alkalinity, phosphate and related sample handling and precision statements) needed to verify conformity with the quality requirements set out in ISO 22241‑1.

Q: Who typically uses it?

A: DEF/AUS 32 producers, independent test laboratories, vehicle and engine OEMs, SCR component suppliers, fleet quality teams and regulatory or inspection bodies.

Q: Is it current or superseded?

A: The 2019 edition (Edition 2) is the published current edition for ISO 22241‑2; earlier 2006 editions were withdrawn and replaced by the 2019 revision. Users should check for any amendments or revisions after 2019 before final application.

Q: Is it part of a series?

A: Yes — ISO 22241 is a multi‑part series. Part 1 covers quality requirements/specification, Part 2 provides test methods (this document), and Part 3 addresses handling, transportation and storage; other related documents and amendments may exist.

Q: What are the key keywords?

A: AUS 32, AdBlue, Diesel Exhaust Fluid (DEF), urea concentration, refractive index, biuret, aldehyde, insoluble matter, phosphate, SCR, NOx reduction.