Applies to pressboard and presspaper for electrical purposes.The series does not apply to laminated material.This part specifies the test methods to be used in testing pressboard and presspaper for electrical purposes to meet the requirements prescribed in the specification sheets of Part 3.NOTE In this standard, reference is made in several places to ISO standards accompanied by a short description of the method used. It is to be understood that this short description is meant for identification purposes only and that all details should be taken from the ISO standard itself.The main changes with respect to the previous edition are listed below:The following test methods have been cancelled:- Flexibility- Conductivity of the organic extract- Contamination of liquid dielectricsThe following test methods have been rewritten:- Compressibility- Conductivity of the aqueous extract- Cohesion between pliesThe following test method has introduced:- Determination of metallic particles with X-ray.