ISO 187 Paper - Paperboard and Pulp - Standard Atmosphere for Conditioning and Testing

EUROLAB, with its state-of-the-art accredited laboratories and expert team, offers precise and rapid testing services within the scope of ISO 187 testing. This standard specifies standard atmospheres, conditioning procedure, and procedures for measuring temperature and relative humidity for the conditioning and testing of pulp, paper, and board.

The physical properties of paper are affected by its moisture content, which in turn depends on the relative humidity (RH) and history of the surrounding atmosphere. In order to perform tests on paper in a certain physical state, it is brought into equilibrium in an atmosphere of standard temperature and relative humidity.

The moisture content of a given paper in equilibrium with a given atmosphere varies depending on whether equilibrium is reached by moisture absorption or desorption and how far the moisture content is from the equilibrium value. This hysteresis affects physical properties that vary with moisture content. Preconditioning the paper from low relative humidity and then bringing it to standard atmosphere will prevent most of the hysteresis effect. Typically the change in moisture content of a given sample is less than 50% when the sample is subsequently conditioned to 23% relative humidity and 0,15°C. Unless otherwise stated, the equilibrium condition must be maintained at low relative humidity.

For experiments in which hysteresis of the equilibrium moisture content could lead to significant errors, the sample should be preconditioned for 10 hours in air at a relative humidity between 35% and 40% and a temperature not exceeding 24°C prior to conditioning.

Samples should be kept in such a way that conditioning air has free access to all surfaces so that their moisture content reaches a state of equilibrium with atmospheric water vapor. This equilibrium is considered to be reached if the difference between two consecutive weighings of sample samples (Mn and Mn+1) at least 1 hour apart is equal to or less than 0,25% of the mass of Mn. For higher weight papers the interval between weighings needs to be longer and the degree of agreement expected between successive weighings must take into account the known cycling characteristics of the test chamber.

EUROLAB assists manufacturers with ISO 187 test compliance. Our test experts, with their professional working mission and principles, provide you, our manufacturers and suppliers, the best service and controlled testing process in our laboratories. Thanks to these services, businesses receive more effective, high-performance and quality testing services and provide safe, fast and uninterrupted service to their customers.