FPF Background

Flexible Polyurethane Foam Slide Presentation


Slide 14 of 31

Surface Firmness

Measured at 25% IFD IFD, or Indentation Force Deflection, is a measurement of foam surface firmness. It is the force, measured in the pounds of pressure, required to compress a foam sample 25% of its height using a 50 square inch indentor plate. On a four inch thick sample, the reading would be taken at a 1" compression.