Berkshire's Cleanroom Wiper Test Methods

Berkshire tests properties which contamination control professionals identify as most critical. These test methods are vital to Berkshire 's product development and quality assurance. All test methods are based on IEST (Institute of Environmental Sciences and Technology - www.IEST.org) IEST-RP-CC004.3: Evaluating Wiping Materials Used In Cleanrooms and Other Controlled Environments.

	The following are brief descriptions of Berkshire 's Wiper Tests:

Cleanliness Fibers: A wiper is washed in water using a biaxial shaker for five minutes. The fibers released into the water are filtered onto a membrane and counted microscopically. The results are expressed as fibers ≥ 100µm per square centimeter of wiper. (IEST-RP.CC004.3, Section 6.2.2.2) Particle Generation - Biaxial Shake Test: A wiper is "washed" in water using a biaxial shaker for five minutes. The particles released into the water are counted by a liquid-borne particle counter. By dividing the total number of particles released by the area of the wiper, the results are expressed as particles ≥ 0.5µm per square centimeter of wiper. (IEST-RP.CC004.3, Section 6.1.3) Airborne Particles – Helmke Drum Test: Under controlled conditions, 10 wipers are tumbled in a rotating drum to release particles from the wiper fabric. Released particles are counted by an airborne particle counter and results are expressed as the number of particles per square meter of wiper per cubic foot of air sampled. (IEST-RP-CC00 3.3 Section B2.5) Sorbency Sorbency : A sample piece of material is saturated with as much fluid as it can hold. After one minute, the material is weighed, and results are expressed in millileters of fluid per square meter. (IEST-RP.CC004.3, Section 8.1 - modified) Efficiency: This calculation indicates how well a material absorbs, relative to others. Results, expressed in milliters of liquid per gram of material, assist in comparing one raw material with another. (IEST-RP. CC004.3. Section 8.1 - modified) Rate: This test is a measurement of the time it takes a wiper to absorb half the total liquid it can hold. Results are expressed in seconds. (IEST-RP. CC004.3. Section 8.1 - modified) Purity Non-Volatile: Berkshire generates non-volatile data using both deionized water and 2-Propanol. Results are expressed in grams of extractables per square meter which is a useful guide to relative purity of wipers. ( IEST-RP.CC004.3, Section 7.1.2) Metallic Ions : Ions are extracted in deionized water and quantitatively analyzed by Ion Chromatography . Results are stated in parts per million (ppm). .(IEST-RP.CC004.3, Section 7.2.2.)