scope:

Scope

Method A simulates conditions which contribute to breakdown of polyurethane foam, resulting in loss of load bearing properties and loss of thickness. A test specimen is measured for thickness under a specified load, mounted on the fixture shown in the illustration and subjected to dynamic fatigue by compression and directional deformation. This is accomplished by rolling the specimen diagonally under constant load for a specified number of cycles. Specimen thickness under a constant load is obtained after a one hour recovery period following dynamic fatigue to determine loss in foam thickness and load bearing characteristics. Method B simulates heel action on the carpet which could be a contributor to the breakdown of brittle fibers in the carpet underlayment. The test specimen is examined for fiber separation, breakdown and destruction after dynamic flexing.