Overview
EN ISO 8655-3:2022 - "Piston-operated volumetric apparatus - Part 3: Burettes" specifies the metrological and labeling requirements for piston-operated burettes with nominal volumes up to 100 ml designed to deliver their specified volume (Ex). The standard defines how burettes are adjusted, tested and documented so users and calibration laboratories can determine and rely on the accuracy and repeatability of volumetric deliveries.
Key topics and technical requirements
- Scope & applicability: Applies to burettes (manual, electric, pneumatic or hydraulic drives) with nominal volumes ≤ 100 ml intended to deliver Ex.
- Metrological requirements: Defines procedures and criteria for stating trueness and precision of the total system (drive plus change-over units where applicable).
- Maximum permissible errors: Tables of systematic and random error limits (see Tables 1 and 2). If a selected usable volume is not tabulated, the standard provides a formula to scale errors by Vnom/Vs and caps the error at 25%. Volumes below 10% of nominal are treated specially.
- Adjustment:
- Initial adjustment at the factory.
- Subsequent adjustment allowed per manufacturer instructions and referenced measurement methods.
- Adjustment reference conditions: standard temperatures (20 °C or 27 °C options), 50% RH and 101.3 kPa using grade 3 water (ISO 3696:1987).
- Any subsequent adjustment must be visibly documented.
- User information & marking: Requirements for markings and the information manufacturers must supply to users (performance data, applicable drive/change-over combinations, calibration instructions).
- Reference measurement procedures: Gravimetric (ISO 8655-6), photometric (ISO 8655-8) and alternative procedures (ISO 8655-7) are normative for calibration and verification.
Practical applications and users
- Laboratories performing titrations and end-point determinations where delivered volume must be known precisely (analytical chemistry, pharmaceutical QC, environmental testing).
- Manufacturers of piston burettes for quality control and product declarations.
- Calibration and testing laboratories, inspection bodies and maintenance teams performing routine checks, verifications and re-adjustments.
- Educational and research labs that require documented volumetric performance for compliance and reproducibility.
Related standards
- ISO 8655-1 - Terminology, general requirements and user recommendations
- ISO 8655-6 - Gravimetric reference measurement procedure
- ISO 8655-7 - Alternative measurement procedures
- ISO 8655-8 - Photometric reference measurement procedure
- ISO 3696 - Water for analytical laboratory use
EN ISO 8655-3:2022 is essential for anyone responsible for the accuracy, calibration or procurement of piston-operated burettes and supports consistent volumetric measurement practices across laboratories and manufacturing.
