There is a question about particulate matter in grade A . why is the count of particles in “at rest” is same as “in operation” in grade A ??
I’m not sure, exactly. If anybody knows, please fill us in. In my education, I was taught that Grade A does not typically have people present in the area (the greatest source of particles), and so particles shouldn’t change much between “at rest” and “in operation”. Grade A areas are now (current GMP) expected to be in isolators, or RABs.
Overall, I’m not sure.
From Wikipedia regarding clean room classifications:
Hey I found another reference. That WHO (world health organization) expects Grade A to have zero 5 micron particles. But statistically (and due to sensitivity of instruments/calibration and testing methods, etc.) zero is impractical - and so they have established 20 as a limit for Grade A in operation. Since you cannot get fewer than 0, I assume we have just hit the limits of detection/sensitivity based on current science. (Similar to a limits of detection, LOD, or a limit of quantification, LOQ, in the labs). I don’t know much more about the calculations or statistics, but that wasmy quick and dirty research. Anybody else know anything about this?
tnx for reply…But there is areas that have grade A and in these areas the equipment are in operation and personal work. so we have still a Question mark for this question ? particulate matter count in the mood of “At rest” and “in operation” are the Same…
(corrected post) So you asked why Grade A in use and at rest have the same particle requirements. My last reply should have answered that question, because at rest the requirement is 20 particles for 5 micron, which would be 0 particles for 5 micron, but that is not possible with the current measuring devices and measuring practices. So 20 particles/m^3 is kind of a “floor” ISO/EU has set (because they cannot get 0 at rest). If at rest is 0 (20 with noise in the measuring) then in use is also 0 (20 with noise in the measuring) so they just set it at the same level.
I guess in summary, though, the “why” might not make a difference. I don’t think there is any level of risk assessment, or discussion, or defense to set different limits for in operation. I don’t think you can really challenge the universally acceptable and documented limits for each Grade. There isn’t any wiggle room here, unfortunately.
Thanks for you kind attention to my question.
as you know in new version of 14644 (2015) there is no more defines particles for 5 microns. and now we have 3520 particles for both …so your supposition about this cant be wrong. however thanks for you reply.
Your question is " why is the count of particles in “at rest” is same as “in operation” in grade A ??
My views are as under.
The condion “at rest” to demonstrate with proof that the equipment (LAF OR ISOLATOR) is designed, fabricated,commisioned, operating and performing well to Maintain class 100 clean environment with in the defined area.
Since the most critical activities and operation, which have impact on product safety, purity,efficay of the product, it is expected that these activities and operations are executed with least or preferably no risk. Maintaining and sustaining the class 100 “at rest” scenario while executing the activities and operations is enevitable. The expectation is that the class 100 clean room behaviour and work practiced ought to be designed and implemented in a manner that does not compromise the "at rest status"
That’s why manual interuptions are often matter of serious concern in aseptic processing operations executed under class 100.
Hope this helps u understand why is the count of particles in “at rest” is same as “in operation” in grade A ??
The operation of machine is not expected to disturb the scenario at rest if the LAF ( HORIZONTAL FLOW OR VERTICAL FLOW) delivers air with adequate CFM, VELOCITY and AIR FLOW PATTERN accross the work area.