Overview
ISO 4142:2002 specifies a range of laboratory test tubes suitable for general laboratory use. The standard distinguishes three material types - Type I (borosilicate), Type II (neutral glass) and Type III (soda‑lime glass) - and defines requirements for material, construction, marking and dimensions. ISO 4142:2002 helps laboratories and manufacturers ensure consistent quality, interchangeability and appropriate chemical and thermal performance for routine lab work.
Key Topics
- Classification and designation: Test tubes are classified as Type I, II or III. When designated, a tube reference includes the standard number, type, nominal dimension and wall thickness (for example:
Tube à essai ISO 4142-10×75-M).
- Materials:
- Type I: borosilicate glass (conforming to ISO 3585 and ISO 4803), coefficient of thermal expansion ~3.3×10⁻⁶ K⁻¹.
- Type II: neutral glass as specified by the manufacturer; generally ~5.0×10⁻⁶ K⁻¹.
- Type III: soda‑lime glass as specified by the manufacturer; generally ~9.1×10⁻⁶ K⁻¹.
- Chemical resistance: Minimum resistance requirements reference ISO 719 (water), ISO 695 (alkaline attack) and ISO 1776 (acid attack).
- Construction and finish: Open ends must have a smooth perpendicular finish (rim or flame polished). Bottoms are generally hemispherical with controlled wall‑thickness ratios relative to the nominal lateral wall.
- Dimensions and tolerances: Nominal lengths, diameters and wall thickness tolerances are specified in tables within the standard (Tables 2–4) for each type and series of tubes.
- Marking: Type I tubes must be marked to indicate borosilicate composition and thermal expansion (e.g., "boro 3,3"). For Types II and III, required information may be placed on packaging.
Applications
- Type I (borosilicate): Suitable for most common laboratory applications, including heating and boiling of samples; used where good thermal and chemical resistance is required.
- Type II (neutral): Appropriate for many routine procedures with moderate heating (e.g., water baths) and samples that may vary in pH; avoid rapid exposure to an open flame without preheating.
- Type III (soda‑lime): Intended for general mixing and simple laboratory tasks with limited chemical resistance and moderate heating; not suitable for open flame use.
Practical value: ISO 4142:2002 provides manufacturers and laboratory procurement teams a clear basis for selecting test tubes that meet predictable dimensional, marking and performance expectations.
Related Standards
- ISO 3585 - Borosilicate glass 3.3 - Properties
- ISO 4803 - Laboratory glassware - Tubes in borosilicate glass
- ISO 719 - Glass - Hydrolytic resistance
- ISO 695 - Glass - Resistance to alkaline attack
- ISO 1776 - Glass - Resistance to acid attack
Keywords: ISO 4142:2002, test tubes, laboratory glassware, borosilicate, neutral glass, soda-lime, dimensions, chemical resistance, marking.
