Frazier Air Permeability - Universal Specimen Holder - FAP-USH - Family of Specimen Holders 

The Universal Specimen Holder is an add-on accessory for the Frazier Differential Pressure Air Permeability Instrument that is used to increase the instrument’s versatility in checking the permeability of depth type materials.

The Frazier Differential Pressure Permeability Instrument was originally developed by the U.S. Department of Commerce (National Bureau of Standards - NBS) to measure the air flow (permeability) through thin flat media such as cloth, non-wovens, and other textile like materials that were no more than ½ inch thick. With the advent of non-wovens and multiple layers it was discovered by our customers that the Frazier Instrument gave very good readings of permeability with these materials that could be depended upon to be very repeatable.

Later research has shown that the instrument can also be reliably used to test the relative permeability of in depth media such as open cell foam, fiber glass, loose material and other materials that were not flat or confined between other materials. This is accomplished through the use of a special adaptor designed to confine the materials and direct all of the air flow vertically through the test material.

The issue with the instrument’s standard clamp is that the thicker the materials, when compressed around the edges cause distortion across the face of the sample and can cause a change in its perceived permeability. The universal adaptor eliminates this effect. It is used by taking a core type sample of the high loft materials and inserting it into the sample holder. It can also be used to check the relative permeability of lose fill types of material if it is checked under a uniform compression.

This test can be accomplished by a jig such as our Universal Sample/Specimen Holder (USH) that is available from the Frazier Company as an add-on accessory to our Differential Pressure Air Permeability Instrument.

The USH is now the standard method for testing deep samples on the Frazier Air Permeability Tester.


The Universal Specimen Holder is offered in various models depending upon needs of user.



FAP-USH-1 - The 1" Deep Universal Specimen Holder is a unit that easily adds on to the Frazier Air Permeability Tester to test samples up to 1 inch (25 mm) in thickness. Samples can be quickly loaded and unloaded easily into unit. This holder will accept different shape samples with a parallel top and bottom up to 1" thick. Custom inserts that are the same thickness and shape as the specimen to be tested are used to hold the sample in position and seal tightly on the sample to eliminate edge leakage while avoiding compression of sample. Samples must fit into a 4" dia circle. The standard minimum sample size is 1.128" dia (1 sq in). Smaller custom sample sizes down to about 0.75" dia are available.

FAP-USH-1 details



FAP-USH-6 - The 6" Deep Universal Specimen Holder is a unit that easily adds on to the Frazier Air Permeability Tester to test samples up to 6 inches (152 mm) in thickness.  These samples can be solid materials or loose fiberous materials. Multiple Holders (FAP-USH-6-Holder) can be purchased so that samples can be preloaded to save testing cycle time. Sample size is limited to 3.5" dia by 6" thick.

FAP-USH-6 details



FAP-USH-6-c (not shown - call for details) is a canister based unit for finer materials.  This unit uses the standard FAP-USH-6-Base with a "canister type" FAP-USH-6-c-Holder and "canister type" FAP-USH-6-c-Sleeve.  Reusable canisters of different sizes can be used.   Canisters keep finer particles contained while loading and unloading the unit. This also allows for loading and unloading of samples into canisters while other canisters are in the unit being tested.


FAP-USH - Price Quote

Guide for use of the FAP-USH

Universal Specimen Cutter for cutting 3.5" dia samples up to 6" thick for use in the Universal Specimen Holder.