NATIONAL FOREWORD

This Indian Standard (Part 5/Sec 20) which is identical with ISO 8791-2 : 2013 ‘ Paper and board — Determination of roughness/smoothness (air leak methods) — Part 2: Bendtsen method’ issued by the International Organization for Standardization (ISO) was adopted by the Bureau of Indian Standards on the recommendation of the Paper and Its Products Sectional Committee and approval of the Chemical Division Council.

Several test methods, using different instruments, are available to obtain a numerical value indicative of smoothness/roughness. However, as results of determinations obtained with different methods are not necessarily convertible, it is necessary to refer the results of this test in terms of specific type of method /instrument used such as Bendsten or Sheffield method, etc. Bendsten method is one of the test methods, which is included in IS 9894 ‘Method of test for smoothness/roughness of paper’, which was published in 1981. While preparing this standard, considerable assistance was derived from IS0 2494 : 1974 ‘Paper and board — Recommended procedure for determination of roughness — Constant-pressure air-flow method’.

Subsequent withdrawal of ISO 2494 and also considering the importance of following the uniform practices globally, the Committee felt that it would be more convenient to prepare this standard method by adoption of ISO 8791-2 on dual number basis. This method would be of assistance to the manufacturers for controlling the quality of their products and to the consumers for testing that they get a material of acceptable quality.

There is another Indian Standard, IS 1060 (Part 5/Sec 17)/ISO 8791-4 : 2007 ‘Determination of roughness/ smoothness (air leak methods) : Part 4 Print-surf method’, is also available.

The text of ISO Standard has been approved as suitable for publication as an Indian Standard without deviations. Certain conventions are however not identical to those used in Indian Standards. Attention is particularly drawn to the following:

a) Wherever the words ‘International Standard’ appear referring to this standard, they should be read as ‘Indian Standard’.

b) Comma (,) has been used as a decimal marker while in Indian Standards, the current practice is to use a point (.) as the decimal marker.