Overview
EN ISO 8655-5:2022 / ISO 8655-5:2022 specifies metrological and user requirements for piston-operated volumetric apparatus - dispensers. It applies to dispensers with nominal volumes from 1 µl to 200 ml, designed to deliver their preset volume (Ex). The standard is part of the ISO 8655 series adopted by CEN and supersedes the 2002 edition.
Keywords: piston-operated volumetric apparatus, dispensers standard, ISO 8655-5, volumetric accuracy, laboratory dispenser calibration.
Key topics and technical requirements
- Scope of requirements
- Metrological requirements and maximum permissible errors for dispensers.
- Marking and user information that manufacturers must provide.
- Device types and operation
- Single-stroke and multiple-delivery (ratchet) dispensers.
- Drive mechanisms: manual, electric, pneumatic or hydraulic.
- Change-over units (interchangeable pistons/cylinders) and importance of including them in performance assessment.
- Adjustment
- Dispensers must have an initial adjustment at manufacture.
- Subsequent adjustment allowed per manufacturer instructions; any adjustment must be recorded and visibly indicated.
- Reference environmental conditions: standard reference temperature either 20 °C or 27 °C, relative humidity 50%, barometric pressure 101.3 kPa, using ISO 3696 grade 3 water.
- Metrological performance
- Total-system testing must include drive, change-over unit, aspiration and delivery tubing.
- Determination of systematic (trueness) and random (precision) errors using reference methods.
- Reference measurement procedures: gravimetric (ISO 8655-6), photometric (ISO 8655-8), or alternative methods (ISO 8655-7).
- Dispenser tips and tubing: specific metrological requirements and manufacturer guidance on compatible tubing to meet specifications.
- Documentation & marking
- Manufacturers must supply clear marking and user information (operation, adjustment, calibration instructions, compatibility of change-over units and tips).
Applications and who uses this standard
- Manufacturers - design, quality control, and conformity claims for laboratory dispensers.
- Calibration laboratories and test houses - procedures and acceptance criteria for calibration and verification.
- Laboratory users - selection, correct operation, maintenance, and routine checks to ensure volumetric accuracy in analytical workflows (pharmaceutical, clinical, research, environmental testing).
- Regulatory and procurement teams - specification of equipment that meets defined metrological performance.
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 8655-5:2022 helps ensure dispenser accuracy, repeatability and traceability - essential for reliable volumetric delivery in laboratory settings.
