Positioning of the Diffuser in the Foam Cylinder for ASTM D892 and D6082 Foam Test
The physical orientation of the diffuser will affect bubble size and therefore the results of the test. Thus, it is very important to be sure that the air-inlet tube is in the center of the cylinder and perfectly straight all the way down to the bottom. This is not an easy task. The Appendix of the method (Section 6.1 and Appendix X2.2.2) allows the use of a centering washer. Although this is currently not part of the main method, the ASTM Subcommittee is working on including this device in their next interlaboratory study.
Lawler Manufacturing offers several types of foam baths and varying levels of automation, including air foam, liquid bath, sequencer, and more.