Overview
ISO 5215:2022 - "Laboratory plastic ware - Volumetric flasks" specifies construction, marking and accuracy requirements for general laboratory volumetric flasks made of plastic. It defines nominal capacities (10, 25, 50, 100, 250, 500, 1 000 ml), two accuracy classes (A and B), the reference temperature (normally 20 °C, or 27 °C where adopted), and testing and identification rules used for preparing volumetric standard solutions and routine analytical work.
Key topics and technical requirements
- Capacity and reference temperature: Capacity is the volume of water contained at the reference temperature (20 °C or 27 °C where applicable). Corrections for other temperatures follow ISO 4787.
- Classes of accuracy: Two classes - Class A (higher accuracy, used for standard solutions) and Class B (lower accuracy). Maximum permitted errors are defined in the standard (see Table A.1).
- Materials: Flasks must be made of generally non-brittle, translucent or transparent plastics with suitable chemical/thermal resistance. Typical materials noted: PFA and PMP for Class A; PP may be used for Class B.
- Construction & dimensions:
- Wall thickness must be robust and reasonably uniform.
- Body shapes allowed (pear or conical) must provide a stable base; stability tests specified (no toppling at defined inclinations).
- Neck must be approximately cylindrical, perpendicular to the base, and avoid undue variation in internal diameter.
- Internal neck diameter and distance of the graduation line from diameter changes are essential for accuracy.
- Closures and threads: Stoppers and screw caps must comply with ISO 383 (interchangeable joints) and DIN 168‑1 (knuckle threads) as applicable. Annex B describes knuckle thread dimensions.
- Graduation line & marking:
- Graduation line must be permanent, uniform and ≤ 0.4 mm thick, encircling the neck in the lower two‑thirds.
- Required markings: nominal capacity, unit (ml/cm3), reference temperature, “In” (contains), class letter (A/B) with tolerance, maker’s mark, joint/thread size and plastic material code (per ISO 1043‑1). Class A flasks for verification must carry an identification number.
- Testing and uncertainty: Capacity testing is carried out in accordance with ISO 4787; uncertainty calculations reference ISO/TR 20461, ISO/IEC Guide 98‑3, or EURAMET guidance.
Applications and users
- Laboratories preparing volumetric standard solutions and performing quantitative chemical analysis.
- Manufacturers of laboratory plastic ware and closures.
- Quality assurance, procurement, and calibration laboratories verifying volumetric capacity and traceability.
- Regulatory bodies and testing laboratories specifying equipment for compliance with good laboratory practice.
Related standards
- ISO 4787 - Volumetric instruments - Methods for testing capacity
- ISO 384:2015 - Design and construction of volumetric instruments
- ISO 383 - Interchangeable conical ground joints
- ISO 1043‑1 - Plastics symbols and abbreviations
- DIN 168‑1 - Knuckle threads
- ISO/TR 20461, ISO/IEC Guide 98‑3, EURAMET Calibration Guide No. 19 - uncertainty and calibration guidance
Keywords: ISO 5215:2022, laboratory plastic ware, volumetric flasks, class A volumetric flask, capacity testing, ISO 4787, PFA, PMP, polypropylene.