We are using following formulae for calculating No. of sampling location in designated room;
NL = √A
Where NL is the minimum number of sampling locations and
A is the area of clean room in m2
If area of room is 50m2 (10 x 5), so number of sample will be 7.07 ≈ 7 Nos.
With unidirectional vertical air flow.
How we will select the exact location in room, is there any guidelines available for describing location allocation or rational.
Hello Kashifa,
You are measuring this area and performing a settle plate test as per that calculation. In this method a prescribed media is made in required number of petri dishes and exposed for 3-4 hours and allow the viable particles(Bacteria/Moulds) to settle down and you incubate to a suitable time and then evaluate microbial or Mould (Fungal) colonies as Colony Forming Units (CFU’s).
Another way of finding the viable cells is to have a air sampler and evaluate the air sampled (As per pharmacopoial limit 75 or 750 litets /hr–Iam not sure of this limit–you need to check it once), incubate the sample petridish and find the CFU’s.
The non -viable particles can be evaluated by a instrument which measures the particle counts in Clean rooms from sizes 0.1, 02, 0.3,0.5,1.0, etc…in microns. This is called the Particulate Sampler and most popular instrument for this is METONE.
Companies do buy this instrument or at times contractors will perform and give you the readings after they perform this test.
This can be performed as a frequency of every 6months or 12 months once in an year as an annual validation programe.
We are using following formulae for calculating No. of sampling location in designated room;
NL = √A
Where NL is the minimum number of sampling locations and
A is the area of clean room in m2
If area of room is 50m2 (10 x 5), so number of sample will be 7.07 ≈ 7 Nos.
With unidirectional vertical air flow.
How we will select the exact location in room, is there any guidelines available for describing location allocation or rational.
Please reply to clarify the understanding.
Kashifa Khanum[/quote]
Dear Kashifa,
For calculation of location number for nonviable & viable - formula is correct. But I would suggest you to select 8 location for (~7.07).
Selection of location could be done according worst case location e.g. near door , near riser, man/material movement. These are main criteria for selection of location.
If you select the settle plate method you have to validated the height also. At what height this petri dishes to be placed. For this SS stands to be used.
For locations the worst locations should be decided internally based on the HVAC validation.
the no locations can be claculated converting the room area to square meters then the root of area and please round off the location .exact location shall be identifed as the worst case where the chance of contamination is more and this selection of the location shall be justified.guideline doesnot say abot the location its upto the user to demonstrate.this is applicable for both non viable and bioload
regards.benny thomas
now a days companies are ussing continous monitering systems under LAF operation during aspetic preparation.
i have used metone and merck sampling tool for viable air monitering at 1000liters / 7 and 10 minutes respectively