Influence of wall friction on settling behavior of loose-fill cellulose insulation material dependent on different surface roughness

As a preliminary test regarding the expected influence of wall friction on the settling behavior of loose-fill cellulose insulation (LFCI), a settling test was performed according to the draft ISO CD 18393, B. Two test boxes with different cavity depth were used with acrylic glass and soft board as two plank materials of different surface roughness. The wall elements were filled with LFCI and strained by drop off impacts. After 13 and 20 impacts, settling was measured and documented. Results of all four test variations show a clearly lower settling on the rougher surface consisting of soft board compared with the smooth acrylic glass. Concerning the different cavity depth, no obvious influence on wall friction is visible. Based on these results, a wall friction test with LFCI according to the Jenike test method was performed on three types of wood based panels with different roughness and acrylic glass as reference. Results show only little difference between the two rough surfaces. Under low normal stress, the three wood based surfaces are almost similar. Only acrylic glass as the smoothest surface of the test differs significantly from the others. On acrylic glass and oriented strand board, the coefficient of wall friction is rising with decreasing normal stress.