This standard specifies a method, based on the stretching of liquid films, for the determination of the surface tension of aqueous or organic solutions, of surfactants, or of mixtures containing one or more surfactants. The method described in this standard is also applicable to the determination of the surface tension of pure liquids or solutions that do not contain surfactants. NOTE- Among the numerous methods established to determine surface tension, the one based on the stretching of liquid films has great advantages, due to the simplicity of its operating procedure and the existence, in commerce, of highly automated devices.