1. Air velocity measurement in HEPA filters fixed in the area, if HEPA provides desired CFM as per design specification (heat load calculation) then we calculate ACPH of particular area (as per ISO 14644-1).
2. After achieving desired velocity , the next test is leak test study or PAO/DOP test (as per ISO 14644-1), if leakages found beyond acceptance limit then filter is changed and PAO test repeated.
3.To confirm the laminarity smoke test was done, smoke is generated by smoke/aerosol generator (as per ISO 14644-1). Now a days titanium tetrachloride is not recommended for smoke test by regulatory agencies. So, glycerin-water or dry ice use for this test or many new methodology under development.
3.If all above mentioned test are pass then we kept the area under observation consecutively 3 days for temperature (NMT 25 deg C) , relative humidity (NMT 60% RH) and differential pressure.
As we know differential pressure are maintained to differentiate within grade (05-10 Pa) or grade to grade area (at least 15 Pa) as per USFDA or EU guidelines. Simultaneously area cleaning also performed with approves validated disinfectant, specially grade A and grade B area clean with sterile disinfectant.
Proper cleaning procedure with frequency of cleaning should to be established. Some time fogging with disinfectant solution helpful to reduce microbial contamination in the area.
As we know all the above mention equipment maintained grade A conditions. So, non viable particle count limit as per guidelines is 1m3 (1000 L), normally Particle counter available in facilities is 100 LPM, it means it will take 10 min each sample. At least three or multiple sample from different location in equipment if preferable sampling numbers can be calculated by tacking reference from ISO 14644-1. Same sampling volume is also preferable for Grade B area also.
For lower grades like grade C and Grade D 2 liter should sample volume and sample time should to be not less than 1 minute. Limits of At rest and In Operation conditions are well described in WHO guideline 961 annex 6 and EU GMP guidelines.
In viable study settle plates are distributed for average 4 hr., active air sampling done from different area as per location plan and swab is taken from working surfaces.
Method of this study should well defined in Qualification Protocol and SOP must be effective before execution. Training of personnel is also strongly recommended. All microbiological study will performed under observation and guidance of approved microbiologist.
Alert and action limits are well defined in WHO guideline 961 annex 6 and EU GMP guidelines. All the media plates are collected and incubated in typically temperature in the 22.5±2.5 deg C and 32.5±2.5 deg C range have been used with an incubation time of 72 and 48 hours, respectively.
In my above article I shared different level of qualification activity involved in Area Qualification of clean rooms of during Performance qualification.
Dear Palash
it is so many thanks for your article as it have a good summerization for the concept. Also i need to ask you in class- D have i need to perform PQ at rest and at operation (both), also after finishing qualification activity shall i perform both of them in the routine environmental monitoring.
also if you wish dear how can i design the action and alert limits?