Improve Your Product Quality
Contact us now to discover how the testing and lab facilities at Bergad Specialty Foams & Composites can improve your product quality.
Quality is priority one, both with custom and stock formulations as well as fabrication of the final product. Our polyurethane foam lab and physical testing laboratories assure the finest quality products.
How is Air-Flow Measured?
Air-Flow tests are done in accordance with ASTM D2574 G. The air-flow test measures the ease with which air passes through a cellular structure. Air-flow values may be used as an indirect measurement of certain cell structure characteristics. The test consists of placing a foam core specimen in a cavity over a chamber and creating a specified constant air-pressure differential. The rate of flow of air required to maintain this pressure differential is the air-flow value.
Air-flow value is the volume of air per second at standard temperature and atmospheric pressure required to maintain a contstant pressure differential of 125 Pa across a flexible foam specimen approximately 2" by 2" by 1".
Photo taken of competitor's foam at 200x.
Note erratic cellular structure and membranes closing cells.
Tests were conducted with a competing foam. We were unable to have any readable air flow throughout the foam. In fact, this foam has a pneumatic feel.
This has many disadvantages. First, this means many of the cells are closed, whereby a window or thin membrane of material is still in place slowing air-flow through the foam. This is one way to create slow recovery foam. Occluded air-flow causes the cells to recover more slowly by disallowing air to easily return to the cell or re-inflate. Foams that have many closed cells will soften over time as these cells pop or break open. This will also speed recovery as air is able to quickly enter the foam.
Photo taken of Bergad viscoelastic standard peach 5lb foam at 200x.
Note uniform cellular structure, large open cells and thick supporting struts.
Foam strength and lengevity comes from strong thick struts. Struts are the supports of the cell. By opening the cell competely, any material that would be in the window of the cell is now in the supporting strut.
Foams that have a completely open structure will not soften over time as the cells are already "popped" or open. Thicker struts also add to the longevity of the foam since there is more material supporting the cells.
Most foams manufactured by Bergad Specialty Foams and Composites have an air-flow of at least 0.50 air-flow some as high as 3.0.