To All Valid
Can you tell us more about Air Flow Parallelism Test
Regards
A.Aziz
Al Pharao Air Data
To All Valid
Can you tell us more about Air Flow Parallelism Test
Regards
A.Aziz
Al Pharao Air Data
This problem may either be resolved by now, or else accepted “as is”.
Some points to consider:
So cascade would look like this:
ACHlab > ACHgowning > ACHhallway
NOTE: Incoming = Exhaust - Leaks;
if using Incoming > Exhaust & Leaks, then the room would continue to build up pressure to intolerable and dangerous levels; this is what one commentor meant when he stated “the system will balance itself”.
Cleanroom pressures are actually measured by taking incosideration with adjescent room pressures.
If you look the EU guidance:
Pressure differential between rooms of different classes should be 10–15 Pa, and 12.5 Pa between a classified and nonclassified room.
The most widely accepted pressure differential for achieving containment between two adjacent zones is 15 Pa, but pressure differentials of between 5 Pa and 20 Pa may be acceptable. Where the design pressure differential is too low and tolerances are at opposite extremities, a flow reversal can take place. For example, where a control tolerance of ± 3 Pa is specifi ed, the implications of the upper and lower tolerances on containment
should be evaluated.
The pressure differential between adjacent rooms could be considered a critical parameter, depending on the outcome of risk analysis. The limits for the pressure differential between adjacent areas should be such that there is no risk of overlap, e.g. 5 Pa to 15 Pa in one room and 15 Pa to 30 Pa in an adjacent room, resulting in no pressure cascade, if the fi rst room is at the maximum tolerance and the second room is at the minimum tolerance.
[quote=DURGA PRASAD]Cleanroom pressures are actually measured by taking incosideration with adjescent room pressures.
If you look the EU guidance:
Pressure differential between rooms of different classes should be 10–15 Pa, and 12.5 Pa between a classified and nonclassified room.[/quote]
Mr. Shahnawaz,
Thanks for sharing & I do agree that the system should not be maintained at Lower & upper cascade range of pressure in adjescent rooms.
In addition to this few facts:
Opinions…
Happy Reading !
[quote=vijaypedineni]Mr. Shanwaz,
I have a doubt reg. differential pressures,
Pl correct my statement, clean room differential pressures should be individual and should be compared with atmospheric pressure and not with the adjacent lower class. [/quote]
Dear Mr Vijay,
No, differentail pressure should be consider with adjacent area and also consider the pressure cascading from process core (clean area) to transition zone, then to Ancillary area and in the end outdoor environment.
I hope it will be cleared your query and doubts.
Regards,
Dr. Shahnawaz Sajid