In Federal Standard No. 209E (last revised Sept.11,1992) the United States Government provides requirements for three classes of air cleanliness. Classifications are based on particle counts taken at a location within the clean bench which will yield a particle count of air as it approaches the work location. It is important to note that government classifications reflect performance when the bench is "at rest," or free of materials or work activity within the hood.
Air Cleanliness Classes, Federal Standard No. 209E | |
---|---|
Class 100 | Particle count not to exceed a total of 100 particles per cubic foot of a size 0.5 micron and larger. |
Class 10,000 | Particle count not to exceed a total of 10,000 particles per cubic foot of a size 0.5 micron and larger, or 65 particles per cubic foot of a size 5.0 micron and larger. |
Class 100,000 | Particle count not to exceed a total of 100,000 particles per cubic foot of a size 0.5 micron and larger, or 700 particles per cubic foot of a size 5.0 micron and larger. |
In tests conducted by The Baker Company, the Baker EdgeGARD® clean bench, with patented high velocity return air slots, has been proven to reduce backwash. Tests were conducted under conditions at and beyond minimum standards established in Federal Standard No. 209E.
Baker EdgeGARD® Clean Bench | With High Velocity Return Air Slots Covered To Simulate Conventional Clean Bench | With High Velocity Air Slots Uncovered To Deliver Maximum Protection |
---|---|---|
Operating, Empty (Federal Minimum Standard) | Particle count within Class 100 limits | Particle count within Class 100 limits |
Operating, With Common Equipment In Hood (Baker Standard) | Particle count exceeds limits of Class 100 and Class 10,000 air quality performance | Particle count within Class 100 limits due to performance of high velocity return air slots |
Operating, Work Being Performed In Work Area (Baker Standard) | Particle count exceeds limits of Class 100 air quality performance | Particle count within Class 100 limits due to performance of high velocity return air slots |