Terminology Glossary

Air Flow - Amount of air expressed in cubic feet per minute, that can be drawn through a 2" x 2" x 1" FPF sample at .5-inch water pressure differential.

ASTM - American Society for Testing and Materials. An organization devoted to the establishment of standard methods and procedures for testing materials.

Auxiliary Blowing Agent (ABA) - An additive used in the production of FPF which supplements the primary blowing agent (water) and can be used to make FPF softer or lighter. Compounds used to produce gases to expand, or blow, FPF during production. Auxiliary blowing agents are low temperature boiling solvents, such as super-critical liquid carbon dioxide (recovered from the atmosphere), acetone, and isopenthane. Chlorofluorocarbons and methylene chloride are not used in the US in the manufacture of FPF.

Ball Rebound - A test procedure (ASTM D3574) used to measure the surface resilience of FPF. The test involves dropping a standard steel ball on known mass from a predetermined height onto a FPF sample and measuring the percent of rebound.

Board Foot - A unit of FPF measurement equal to a square foot of material one inch in thickness.

Bottom Out - Lack of support under full weight load.

Bun - A segment of FPF cut off from continuously produced slabstock type of FPF.

California Technical Bulletin 117 FPF - FPF that will meet the component combustibility requirements of this standard.

Compression Set - A permanent loss of initial height of an FPF sample after compression due to a bending or a collapse of the cell framework within the FPF sample. It is most commonly expressed as a percent of original height.

Convoluted - An FPF product resulting from a fabrication process involving the use of special cutting equipment to produce an FPF sheet with peaks and valleys.

Crushing - A conditioning process using a mechanical or vacuum-assisted procedure to open the closed cells of a high resilience slabstock or molded FPF.

Density - A measurement of the mass per unit volume. It is measured and expressed in pounds per cubic foot (pcf) or kilograms per cubic meter.

Durability - How well an FPF retains its comfort, support and shape with use.

Dynamic Fatigue - A durability test performed in the laboratory using roller-shear or pounding type mechanisms.

Flex Fatigue - The loss of FPF firmness after flexing the FPF a predetermined number of cycles.

FPF - The new acronym used to describe flexible polyurethane foam.

Hand - The feel of the FPF as the hand is rubbed lightly over the surface. In home furnishings, FPF with a good hand has a springy, velvet feel.

High Resilience (HR) FPF - High Resilience FPF have a high support factor and greater surface resilience hat conventional FPFs and are defined in ASTM D3770. High resilience FPF has a less uniform (more random) cell structure, different from conventional products. The different cell structure helps add support, comfort, and resilience or bounce.

Hysteresis - The ability of FPF to maintain original characteristics after flexing. Lower hysteresis values, or less IFD loss are desirable. Indentation Force Deflection (IFD) - IFD is generally measured as the force (in pounds) required to compress a 50-square-inch circular indentor foot into a four inch thick sample, typically 15 inches square or larger, to a stated percentage of the sample's initial height. Common IFD values are generated at 25 and 65 percent of initial height. Note: Previously called "ILD (Indentation Load Deflection)."

Preflex - The practice of compressing an FPF sample up to six times to a predetermined thickness before determining IFD.

Resilience - An indicator of the surface elasticity or "springiness" of FPF. It is measured by dropping a standard steel ball onto the FPF cushion from a given height and measuring what percentage the ball rebounds.

Static Fatigue - The loss in load-bearing properties of an FPF sample after being under constant compression.

Support Factor (see Compression Modulus) - Support Factor is a ratio os 65% IFD.25% IFD. When the support factor is known, it can be used in conjunction with a known 25% IFD value to determine the 65% IFD value. Seating FPFs with low support factors are more likely to bottom out.

Surface Firmness - The number of pounds of force necessary to indent an FPF sample by 25% of its original height.

TDI An abbreviation for toluene diioscyanate.

Tear Strength A measure of the force required to continue a tear in a foam after a split or break has been started and expressed in pounds per inch (lbs/in.). This property is important in determining suitability of foam in applications where the material is sewed, stapled, or otherwise anchored to a solid substrate. Also important in demoldability. (ASTM D3574).

Tensile Strength The pounds per square inch of force required to stretch a material to the breaking point. (Reference ASTM D3574).

Urethane Actually a misnomer as applied to polyurethane foam. A colorless, crystalline substance used primarily in medicines, pesticides, and fungicides. Urethane is not used in the production of urethane polymers or foams. The urethanes of the plastics industry are so named because the repeating units of their structures resemble the chemical urethane.

Windows The thin membranes formed between cell struts.Windows may be present (a closed-cell foam) or absent (an open-cell foam) depending on the particular foam chemistry used.