ISO 8655-3:2022

Overview

ISO 8655-3:2022 - "Piston-operated volumetric apparatus - Part 3: Burettes" defines metrological and usability requirements for piston-operated burettes with nominal volumes up to 100 ml. The standard specifies maximum permissible errors, requirements for marking, information to be supplied to users, and procedures for adjustment and performance testing of burettes designed to deliver their specified volume (Ex). It is part of the ISO 8655 series addressing piston-operated volumetric apparatus.

Key topics and technical requirements

• Scope and applicability: Applies to piston-operated burettes (manual, motorised, pneumatic or hydraulic drive) designed to deliver specified volume (Ex) up to 100 ml.
• Metrological requirements: Defines how to declare and determine systematic and random errors for the complete system (controller plus any interchangeable piston/cylinder units).
• Maximum permissible errors: Provided in tables for motor-driven and manual burettes (see Table 1 and Table 2). Errors depend on nominal volume and distribution volume; methods are given to calculate permissible errors for volumes not listed.
• Error scaling formula: When required, the tolerated error at a selected volume Vs is obtained by scaling the nominal-volume error:
  e(Vs) = (Vnom / Vs) × e(Vnom), with a cap of 25% where applicable.
• Adjustment conditions: Initial and reference adjustments are to be performed under defined environmental conditions (reference temperatures used by countries: 20 °C or 27 °C, 50% relative humidity, 101.3 kPa) using laboratory-grade water (ISO 3696, grade 3).
• Marking and user information: Burettes must be permanently marked with nominal volume, unit of measure, manufacturer/brand, type, serial number, and the “Ex” abbreviation. Manufacturer documentation must include adjustment basis, usable volume range, minimum selectable volume meeting performance limits, maintenance and cleaning instructions, and guidance for bubble-free filling.
• Adjustment records and traceability: If a burette is readjusted after initial factory setup, the change must be clearly indicated and recorded.

Applications and who uses it

• Calibration and testing laboratories performing gravimetric, photometric or alternative volume determination (ISO 8655-6/7/8).
• Laboratory instrument manufacturers for product design, quality control and technical documentation.
• Quality assurance teams and lab managers establishing acceptance criteria, routine checks and maintenance protocols for volumetric dispensing.
• Procurement specialists assessing compliance and performance claims for burettes used in analytical chemistry, titration, pharmaceuticals and research labs.

Related standards

• ISO 8655-1 (definitions, general requirements)
• ISO 8655-6, -7, -8 (reference and alternative volume measurement procedures)
• ISO 3696 (laboratory water quality)

Keywords: ISO 8655-3:2022, burettes, piston-operated volumetric apparatus, metrological requirements, maximum permissible errors, calibration, laboratory burettes, marking, Ex.