ISO 304-1985 PDF

Full title and description

Surface active agents — Determination of surface tension by drawing up liquid films. This International Standard describes a laboratory method for measuring surface tension by measuring the maximum vertical force required to detach a stirrup, ring or edged plate from the surface or to draw up a liquid film from a measuring cup.

Abstract

The method measures the maximum force needed to act vertically on a stirrup or ring in contact with the liquid surface (or on a plate with an edge) to separate it from the surface or to draw up the film formed. The procedure is applicable to pure liquids and to solutions (including surface-active agents).

General information

• Status: Published; confirmed as current following a systematic review in 2019.
• Publication date: 1985-12 (December 1985).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 71.100.40 (Surface active agents).
• Edition / version: Edition 2 (1985).
• Number of pages: 10.

Scope

Specifies a technique for determining surface tension by drawing up liquid films using a ring, stirrup or edged plate and measuring the maximum vertical force required. The method is intended for pure liquids and for solutions containing surface-active agents; it covers apparatus, procedure, calculations and reporting of results.

Key topics and requirements

• Principle: measurement of the maximum vertical force to detach a ring/stirrup or to draw up a film from a liquid surface.
• Apparatus: specified measuring cup, stirrup/ring or edged plate, force-measuring device and means for controlled immersion/withdrawal.
• Procedure: standardised positioning, immersion and withdrawal rates, and measurement of peak force followed by calculation of surface tension.
• Applicability: suitable for pure liquids and for solutions of surface-active agents; includes notes on reproducibility and limits of the method.
• Calibration, reporting and corrections: requires calibrated force measurement and clear reporting of test conditions (temperature, sample, apparatus details); a technical corrigendum was published to correct the edition.

Typical use and users

Used by analytical and quality-control laboratories, chemical and surfactant manufacturers, materials researchers and academic laboratories for routine surface-tension determination, product formulation, comparative testing and R&D investigations into wetting and interfacial properties.

Related standards

ISO 304:1978 — the original 1978 edition (withdrawn and superseded by the 1985 edition). ISO 304:1985/Cor 1:1998 — Technical Corrigendum 1, which applies to the 1985 edition. The standard is maintained by ISO/TC 91 (surface-active agents).

Keywords

surface tension, surface active agents, surfactant, liquid film, ring method, stirrup method, interfacial properties, force measurement, ISO 304

FAQ

Q: What is this standard?

A: ISO 304:1985 is an International Standard that specifies a laboratory method for determining surface tension by drawing up liquid films using a ring, stirrup or edged plate and measuring the maximum vertical force involved.

Q: What does it cover?

A: It covers the principle, required apparatus, test procedure, calculation of surface tension from the measured force, and reporting of results for pure liquids and solutions containing surface-active agents.

Q: Who typically uses it?

A: Analytical and QC laboratories, surfactant and chemical manufacturers, materials scientists, and academic researchers working on interfacial and wetting properties commonly use this method.

Q: Is it current or superseded?

A: The 1985 edition (Edition 2) remains published and was last reviewed and confirmed as current in 2019; a technical corrigendum (ISO 304:1985/Cor 1:1998) also applies. ISO records indicate the standard may enter revision under ISO/CD 304 in future work.

Q: Is it part of a series?

A: ISO 304 is a stand-alone method for surface-tension measurement under the ISO document series for surface-active agents; it is maintained under ISO/TC 91 (surface-active agents) and has an earlier withdrawn 1978 edition.

Q: What are the key keywords?

A: surface tension; surface-active agents; surfactant; liquid film method; ring/stirrup method; force measurement; interfacial properties.