Cleanroom Question

[Milas]

Hi

We are manufacturing some products in a class 8 cleanroom and regularly find contamination. The contamination, based on texture, looks like human hair and in some cases look like fibres that has come from the clothing which the operators are wearing. We have raised this issue many a time with our colleagues in Quality who continually monitor and assess the cleanrooms and claim there are no issues. Question is, should such contamination be detected during routine checks and assessments i.e. flow and pressure tests ?

Thanks

 

[Jen Kirley]

Hello Milas,

Pardon me, it is late in the day: flow and pressure tests are designed to check what, besides flow and pressure? Seriously, particle size is a different type of check isn't it?

My understanding is that ISO 8 cleanrooms, also known as Class 100,000 cleanrooms, can be modular or soft-walled and have a maximum particle count of 100,000 particles (≥0.5 um) per cubic foot of interior air. They are required to have HEPA filtration coverage over 4-5% of the area and provide a minimum of 20 air exchanges per hour with air flow rates of 4-8 CFM per square foot.

What are your clean room controls?

 

[ChrisM]

Cleanroom air quality monitoring with the "usual" type of machine won't find large, settled contaminants such as human hairs. What controls on clothing etc are in place? I hope that you have a gowning area where cleanroom clothing including hair coverings etc must be donned before entering the clean room itself. Do you have a procedure that checks for settles contaminants such as debris from the building structure, human hairs, remnants of clothing etc?

 

[AgnieszkaSz]

Air cleanliness in cleanroom is just a part of the system targeting product cleanliness and safety. It detects airborne particles, nothing else. If hair and fibres are found, I would advise tightening gowning rules - coveralls, dedicated shoes, head caps - and checking whether the gowning rules are observed. Our operators are not allowed to wear jeans because cotton sheds fibers even when it is covered by coveralls. Bare legs are not acceptable, either, they shed enormous quantities of hair.

 

[John Predmore]

Hairs and other heavy fibers might not show up on filter tests and particle counters. You should have tacky mats at the entrance to your cleanroom which will trap loose hair/fibers sliding around on the floor from air currents, as well as fibers on the bottom of shoes. You can differentiate human hair from other fibers under a microscope. Instead of throwing mats away, maybe you can identify fibers (pull the big ones off with tweezers) and a Pareto chart will tell you the greatest source of contamination. Wrap a loop of clear shipping tape around your hand and pat work surfaces on your work stations for a spot-check sampling of contamination, close to where you manufacture product. As I recall, over 70% of clean room contamination comes from human sources.

 

[ChrisM]

^
I suspect that a vast majority of cleanroom contamination will indeed be human skin, since we are shedding and renewing our skin constantly, hence the need for hair nets, covered legs and arms etc (but not full face coverings and not gloves on hands in the lower levels of clean rooms)

 

[Milas]

Thank you for you feedback

We do have cleanroom controls in that, operators have a separate area for gowning prior to entering the cleanroom. However, we do not have a procedure which checks for settled contaminants nor, do our operators wear full cleanroom gowns, they wear hair nets and 3/4 lengths overalls

 

[optomist1]

Hairs and other heavy fibers might not show up on filter tests and particle counters. You should have tacky mats at the entrance to your cleanroom which will trap loose hair/fibers sliding around on the floor from air currents, as well as fibers on the bottom of shoes. You can differentiate human hair from other fibers under a microscope. Instead of throwing mats away, maybe you can identify fibers (pull the big ones off with tweezers) and a Pareto chart will tell you the greatest source of contamination. Wrap a loop of clear shipping tape around your hand and pat work surfaces on your work stations for a spot-check sampling of contamination, close to where you manufacture product. As I recall, over 70% of clean room contamination comes from human sources.

Yep, great post, as I recall my first post graduation position...."shave the mustache, and a list of approved/prohibited clothing etc., this was for all clean room levels 100K to 100, a good procedure indeed...

Hope this helps

Optomist1

 

[indubioush]

What is your protocol for clean room cleaning (vacuuming, disinfecting surfaces, etc.)? Also, do you have sticky mats at the entrances?

 

[optomist1]

Hi indubiosh, off to a meeting but will provide info later today, still pretty fresh in my mind though...Cheers Optomist 1