Overview
ISO 4803:2021 - "Laboratory glassware - Borosilicate glass tubing" specifies requirements for borosilicate 3.3 glass tubing used in laboratory apparatus. The standard covers tubing with an outer diameter range from 4 mm to 300 mm, and defines requirements for dimensions, material, denomination, designation, inspection methods and tolerances. It updates the earlier edition with clarified dimensions and measurement methods to ensure uniform quality of lab glass tubing.
Key topics and technical requirements
- Material: Tubing must be made of borosilicate glass conforming to ISO 3585 (3.3 glass) and be free from harmful tensions and defects that impair usability.
- Hydrolytic resistance: Limits on alkali extraction are specified (tested per ISO 719) to ensure chemical stability for laboratory use.
- Thermal expansion: The glass shall have a mean linear thermal expansion coefficient of (3.3 ± 0.1) × 10⁻⁶ K⁻¹ over 20 °C to 300 °C, ensuring good thermal shock resistance.
- Designation: Tubing designation includes type of glass, outer diameter, wall thickness (three categories: light, medium, heavy) and manufacturer name.
- Dimensions & tolerances: Detailed tables define nominal outer diameters, wall thicknesses and associated tolerances across the full 4–300 mm range.
- Wall thickness difference (siding): Maximum difference per cross-section is limited to 12% of the specified wall thickness (without exceeding tolerance).
- Straightness & length: Measurement procedures and straightness tolerances are given (different methods for small and larger diameters), with length supply guidance in Table 3.
- Ovality (circularity): Tolerances per measuring plane: up to 48 mm OD = 0.7%, 50–300 mm OD = 1.0%, measured by rotating the tube and recording max/min diameters.
Applications and users
ISO 4803:2021 is primarily used by:
- Laboratory glassware manufacturers producing borosilicate tubing for chemistry, pharmaceutical and food-industry labs.
- Quality control and inspection teams validating dimensional, material and chemical performance.
- Procurement and specification writers who need standardized tube descriptions (type, OD, wall thickness, manufacturer).
- Laboratory designers and equipment OEMs selecting tubing for condensers, columns, reactors, and custom glass apparatus where thermal and chemical resistance are critical.
This standard ensures compatibility, interchangeability and reliable performance of borosilicate glass tubing in demanding laboratory and technical applications.
Related standards
- ISO 3585 - Borosilicate glass 3.3 - Properties
- ISO 719 - Hydrolytic resistance test method and classification
- ISO 1101 - Geometrical tolerancing (form & circularity)
- ISO 12775 - Types of glass and test methods
Keywords: ISO 4803:2021, borosilicate glass tubing, laboratory glassware, ISO 3585, dimensions and tolerances, hydrolytic resistance, thermal expansion, wall thickness, straightness, ovality.
