From: Pat M.
To: Chris H.
Subject: ESD shoe covers
Q: Hello, Chris. I’m an electrostatics engineer. I’d like to find the standards that are used to control clean room contamination. Can I obtain these standards and if so, which ones are pertinent to ESD products such as shoe covers?
- What is P010 and IES-RP-CC-003.2 and what are its limits?
- What are clean room limits for various clean rooms: for example 100,000 and 10,000 clean rooms?
- Do you know anything about an ISO Class 8 clean room and its qualifications?
Thanks in advance for your time. If you can find these answers, great; otherwise, you may be able to steer me in the right direction.
A: Pat, You ask some good yet open ended questions. The IEST specification you referenced is a standard for testing clean-room materials (gloves, wipes, cots, etc). The new version is 3.3 which I have attached for your reference. I also have included a clean-room consumable guide we have published. It does speak to the different environment classifications and appropriate materials for each.
A class 10,000 environment means: there are less that 10,000 particles per square foot of size .5 micron or larger. For a class 100,000, there are less than 1,000,000 particles per cubic foot of size .5 micron and larger. These really refer to air quality (which is achieved by mass filtration) and not materials. However, different materials have different out gassing or shedding (of particles) characteristics, so they can be selected based on their cleanliness. For a class 100,000 or class 10,000 clean-room the standards are pretty minimal and a standard polypropylene shoe cover is acceptable. It is when you get to class 1,000 or 100 or 10 that it gets much more specific in acceptability.