Compression Modulus (Support Factor)

Hi Ioway,

There are a few other terms that are also used as well including SAC factor, comfort factor, hardness ratio, and modulus (see here) just to confuse things even more (although you rarely see SAC factor or hardness ratio used)

I differentiate “support” into two different types that I call primary support and secondary support depending on whether you are talking about upper layers or deeper layers. You may have read this already but there is more about primary or “deep” support and secondary or “surface” support and their relationship to firmness and pressure relief and the “roles” of different layers in a mattress in post #2 here and in post #4 here that may be helpful in clarifying the differences between firmness and “support” and “pressure relief” and “feel”.

HR polyfoam by definition has a density of 2.5 lb/ft3 or higher, a compression modulus of 2.4 or higher, and resiliency of 60% (measured by ball rebound) so it can approach the specs of Talalay and some of the newer higher density/high performance polyfoams (that range from about 2.5 lbs to 5 lb density) can be manufactured to approximate the specs of latex as well.

Phoenix