ROUGHNESS – Bendtsen
Purpose of the test
This test is performed to determine the roughness of paper, solid board or folding board.
Procedure
Operate the instrument in accordance with ISO 8791-2 and the manufacturer’s instructions.
Leave the samples exposed for 24 h to 23°C and 50% R.H., according to ISO 187.
Make a measurement in the middle of each test piece (pressure 1.47 kPa, manostat 150) with the side marked with red lines turned towards the air flow (upwards).
Report 10 measures in ml/min, their mean and standard deviation calculated to 3 significant figures.
ISO 8791-2
Nr. of samples
12 test pieces per level
Special size A4
Levels
Level 1: 40.0÷70.0 ml/min
Level 2: 150÷250 ml/min
Level 3: 650÷850 ml/min
Level 4: 1200÷1700 ml/min
Reporting
Report 10 valid results of measurements in ml/min, their mean and their standard deviation. All to three significant digits.