The Industry Panel No Dwell IFD Test added to ASTM D3574-25

This test method proposed by the Molded Foam Industry Panel has been added to the 2025 updated version of ASTM D3574, Standard Test Methods for Flexible Cellular Materials—Slab, Bonded, and Molded Urethane Foams. The advantage of this test method versus the traditional IFD test is that it yields multiple outputs in a single test instead of a singular force value after a 60 second hold and it reduces test time by 50%. The output from the No Dwell IFD test is a full compression that yields multiple values including the force value or stiffness at any compression point along the full curve and hysteresis loss. Removing the 60 second dwell from the IFD test also provides a true output of the foams stiffness which is neutralized by the dwell at each compression point. Because of this relaxation time, two foams of different hysteresis and stiffness levels can yield the same IFD value. This improved test method gives the seat or foam engineer more test outputs and detailed information about a seat foam.