Overview
EN ISO 4142:2002 is an international standard specifying requirements for laboratory test tubes made from various types of glass. This standard, developed by ISO Technical Committee ISO/TC 48 in collaboration with CEN, defines three types of test tubes classified by their glass material: Type I (borosilicate glass), Type II (neutral glass), and Type III (soda-lime glass). The document ensures consistency in quality, dimensions, and chemical resistance, making it vital for laboratories requiring reliable glassware for experimental and analytical use.
Test tubes covered under EN ISO 4142:2002 are suitable for general laboratory applications ranging from chemical reactions to sample heating. Compliance with this standard guarantees test tubes meet minimum standards for thermal and chemical durability, dimensional accuracy, and safe handling.
Key Topics
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Classification of Test Tubes
- Type I: Made from borosilicate glass; highly resistant to chemicals and thermal shock, suitable for most lab uses including boiling.
- Type II: Made from neutral glass; chemically resistant and suitable for moderate temperature changes, ideal for pH sensitive samples.
- Type III: Made from soda-lime glass; limited chemical resistance and not suitable for direct flame exposure; used primarily for general mixing and simple tasks.
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Material Specifications
- Type I test tubes comply with ISO 3585 and ISO 4803 regarding borosilicate glass properties.
- Chemical resistance standards include ISO 719 (water resistance), ISO 695 (alkali resistance), and ISO 1776 (acid resistance).
- Each type has defined coefficients of thermal expansion to ensure suitability for temperature variations in laboratory conditions.
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Dimensional and Construction Requirements
- Precise dimensions, including length, diameter, and wall thickness are standardized across three series.
- Test tube ends must be smoothly finished perpendicular to the axis either with a rim or fire-polished for safety and usability.
- Bottoms are hemispherical with controlled wall thickness to ensure durability.
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Marking and Identification
- Type I test tubes are marked with "boro 3.3" or equivalent to indicate their borosilicate glass composition.
- Type II and III may have marking on packaging instead of individual tubes.
- Designation formatting includes the type, nominal size, and wall thickness (e.g., Test tube ISO 4142-10×75-M).
Applications
EN ISO 4142:2002 test tubes are essential for:
- Chemical Analysis: Type I borosilicate test tubes withstand harsh chemical environments and heating, making them ideal for reactions, titration, and sample boiling.
- Biochemical Assays: Neutral glass (Type II) tubes are suitable for biological samples requiring moderate heat and no pH interference.
- General Laboratory Tasks: Soda-lime glass (Type III) test tubes handle mixing, storage, and non-critical heating where cost efficiency is prioritized over chemical resistance.
- Educational Labs: Use of standardized test tubes ensures consistent experimental conditions in teaching environments.
- Quality Control: Laboratories following ISO and CEN standards can use these standardized glassware items to maintain reproducibility of tests and compliance with international protocols.
Related Standards
- ISO 3585: Specifies properties of borosilicate glass used in Type I test tubes.
- ISO 4803: Defines specifications for borosilicate glass tubing.
- ISO 719: Details water resistance testing methods for glassware.
- ISO 695: Specifies methods for determining alkali resistance of glass.
- ISO 1776: Protocol for testing acid resistance of glassware.
- CEN/CENELEC Internal Regulations: Governs adoption of European Standards including EN ISO 4142.
EN ISO 4142:2002 aligns with broader international laboratory glassware standards to ensure interoperability and safety across national and organizational boundaries.
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