Top 10 Benefits Of Memory Foam Mattress Toppers

What is IFD or Initial Force Deflection?

April 13, 2009
In the Bedroom

IFD or Initial Force Deflection is one of many factors to take into consideration while shopping for a new mattress, in particular one that is constructed using either polyurethane or memory foam. Just looking at these two different types of foams, they all pretty much look the same, but are available in countless IFD variations. If you were to take a more scientific approach and measure these frequently used foam mattress paddings, you will see that there are some real major differences in foam. These measurable differences give you away to compare what is called IFD or Initial Force Deflection, just one of several important comparison factors to consider when you buy your next new mattress that contains foam. This precise measurement will assure you that you are getting what you paid for and just as important that you are comparing apples to apples.

Why is Initial Force Deflection or IFD important?
This firmness measurement often directly relates to the feel you will experience on your new mattress, sofa, or chair etc. and gives the shopper a way to distinguish a measurable dissimilarity between two pieces of foam.

So what is Initial Force Deflection or IFD?
The straightforward answer is that it is the measurement of a firmness taken on a piece of foam. The foam is usually a polyurethane foam or memory foam.

How is the Initial Force Deflection Measurement (IFD) taken?
Using a round disc measuring fifty square inches or eight inches in diameter, the disc is placed upon a measured block of foam usually four inches in thickness. The disc is then forced down into the foam block until the foam has been compacted down to Seventy five percent of its original thickness. The sample block of foam having an original thickness of 4 inches will now only measure 3 inches.  A measurement is then taken in pounds of force that is required to squash the piece of foam down to the standardized twenty five percent.

Is IFD and ILD the same thing?
Yes, they are in essence the same thing. ILD Initial Load Deflection was the original name and later was changed to the acronym IFD that is commonly used today and stands for Initial Force Deflection. The IFD or ILD ratings for flexible foams range from a super soft 10 to a semi-rigid 80.

Is Density and IFD the same thing?
No, Density is the measurement of weight taken on a 1 cubic foot piece of foam but is commonly confused with IFD.

Where can I learn more about IFD or Initial Force Deflection?
Contact STLBeds for more information.

Coming soon other measurable ways to compare mattresses!