ISO 8655-5:2022

Overview

ISO 8655-5:2022 - "Piston-operated volumetric apparatus - Part 5: Dispensers" specifies the metrological requirements, maximum permissible errors, marking and user information for piston-operated dispensers. It applies to dispensers with nominal volumes from 1 μl to 200 ml, designed to deliver their preset volume (Ex). This second edition updates the first (2002), adds ISO 8655‑7 and ISO 8655‑8 as normative references, refines dispenser-tip requirements and revises the performance tables.

Key Topics

• Scope & types: Covers single‑stroke and multiple‑delivery (ratchet) dispensers, manual or powered drive mechanisms, and systems with separable change‑over units.
• Adjustment: Requires an initial adjustment and procedures for subsequent adjustment. Reference conditions are specified (20 °C or 27 °C options, 50% RH, 101.3 kPa using ISO 3696 grade 3 water).
• Metrological performance: Defines how to determine systematic (trueness) and random (precision) errors using reference methods (ISO 8655‑6 gravimetric, ISO 8655‑8 photometric, or ISO 8655‑7 alternative procedures).
• Maximum permissible errors: Tables for single‑stroke and multiple‑delivery dispensers give allowable systematic and random errors by nominal volume and selected volume. A provided formula scales errors for volumes not explicitly listed (not applied below 10% of nominal volume); a 25% cap applies when calculated values exceed that limit.
• Dispenser tips & tubing: The standard mandates testing of the complete system (dispenser + tip/tubing). Sterilisation procedures recommended by manufacturers must not degrade metrological characteristics (shape, seal, wettability).
• User information & marking: Manufacturers must supply basis of adjustment, nominal volume identification, deliverable minimum volume, error limits at specified volumes, correct use, maintenance, storage, bubble‑free filling advice, and routine test recommendations.

Applications

ISO 8655-5:2022 is practical for:

• Manufacturers - design validation, production quality control, and accurate specification of dispenser performance.
• Calibration laboratories and test houses - performance verification and routine calibration against normative methods (gravimetric/photometric).
• Laboratory users and QA/validation teams in pharmaceuticals, clinical diagnostics, biotechnology and research - selecting dispensers, establishing QC protocols, and ensuring traceable volumetric accuracy.
• Regulatory and procurement - defining acceptance criteria and supplier performance claims.

Related Standards (applicable)

• 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

Keywords: ISO 8655-5:2022, piston-operated volumetric apparatus, dispensers, metrological requirements, maximum permissible errors, dispenser tips, calibration, gravimetric, photometric, laboratory equipment.