Overview
ISO 384:2015 - Laboratory glass and plastics ware - Principles of design and construction of volumetric instruments defines the design principles that make volumetric instruments (glass or plastic) reliable, convenient and accurate for laboratory use. The standard sets out requirements for material selection, dimensional design, graduation and marking, accuracy classes, calibration reference conditions and construction details to ensure consistent performance of pipettes, burettes, volumetric flasks and similar volumetric instruments.
Key topics and technical requirements
- Scope and materials: Applies to volumetric instruments manufactured from glass or suitable plastics; instruments should be free from visible defects and internal stress and be chemically and thermally appropriate for intended use.
- Reference conditions: The unit of volume is the millilitre (ml = cm3). The standard reference temperature is 20 °C (27 °C permitted where nationally adopted); temperature influences capacity and must be considered at calibration.
- Accuracy classes: Defines accuracy classes A (and AS) for higher-grade instruments and B for lower-grade instruments. Maximum permissible error (MPE) must be specified per instrument, class and application.
- Permissible error and sizing: MPE values are linked to instrument geometry - notably the internal diameter at the graduation line (D) - and are set from preferred numerical series to ensure reasonable progression with capacity. For scaled instruments, the MPE must not exceed the volume equivalent of the smallest scale division.
- Calibration and testing: Calibration and use methods reference ISO 4787; the standard promotes gravimetric volume determination (mass of water corrected for buoyancy and density). Plastic instruments typically require more frequent recalibration due to lower long‑term stability.
- Construction and features: Guidance on wall thickness, preferred circular cross‑section, stability (flat bases), delivery jets (smooth taper, finishes), stoppers and stopcocks (materials, tapers, interchangeability) and limits on inner diameter to control accuracy.
- Graduation, scales and marking: Specifies spacing, line figure sizing, visibility and marking conventions to ensure readable and reproducible volumetric readings.
Applications and users
ISO 384:2015 is essential for:
- Laboratories (analytical, clinical, educational) selecting or specifying pipettes, burettes, volumetric flasks and dispensers
- Manufacturers designing and producing laboratory glassware and plastic volumetric instruments
- Quality and calibration laboratories performing acceptance testing and routine calibration
- Procurement and regulatory professionals who need standardized specifications for traceability and compliance
Using ISO 384 helps ensure accurate liquid measurement, repeatability, safer lab practices and interoperability across suppliers.
Related standards
- ISO 4787 - Volumetric instruments: methods for testing of capacity and for use (calibration)
- ISO 383 - Interchangeable conical ground joints
- ISO/IEC Guide 99 (VIM) - Metrology vocabulary
- Related product standards referenced in the ISO 384 development: ISO 1042, ISO 648, ISO 835, ISO 385, ISO 4788
Keywords: ISO 384:2015, volumetric instruments, laboratory glassware, plastic volumetric instruments, calibration, volumetric accuracy, reference temperature, graduation lines.
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