Description
The international standard GOST R ISO 14644-1-2002 defines the concept of clean room as follows:
cleanroom: The room in which the concentration of airborne particles is controlled, constructed and used to minimize the entry, separation and retention of particles inside the room, and allowing other parameters, such as temperature, to be monitored as necessary. humidity and pressure.
Clean rooms are necessary for the production of products in such sectors as health care, aerospace, microelectronic, food and pharmaceutical industry, the production of medical products, dietary supplements, veterinary drugs.
Depending on the purpose and processes that take place inside a clean room or clean zone, the requirements for cleanliness class may vary.
Cleanroom Classes
The purity of the room for particles suspended in air is designated by the classification number N. The maximum permissible concentration of particles Cn, particles / m3, with dimensions equal or larger than a given size D, for a given purity class is determined by the formula:
ISO classification number
where - N is the ISO classification number, which must not exceed the value 9. Intermediate numbers of the ISO classification can be determined with the smallest admissible increment equal to 0.1;
0.1 is a constant, micron;
D is the specified particle size, microns.
Cn (particle concentration) is rounded to the nearest whole number, using no more than three significant digits.
Table 1 shows the limiting values of particle concentrations for ISO classes 1–9 for certain particle sizes.
Table 1. Classes of purity by airborne particles for clean rooms and clean areas
ISO class (classification number) Maximum permissible concentrations of particles, particles / m3, with dimensions equal to or greater than the following values, microns
0.1 0.2 0.3 0.5 1.0 5.0
Class 1 ISO 10 2 - - - -
Class 2 ISO 100 24 10 4 - -
Class 3 ISO 1000 237 102 35 8 -
Class 4 ISO 10000 2370 1020 352 83 -
Class 5 ISO 100000 23700 10200 3520 832 29
Class 6 ISO 1000000 237000 102000 35200 8320 293
ISO Class 7 - - - 352000 83200 2930
ISO Class 8 - - - 3520000 832000 29300
Class 9 ISO - - - 35200000 8320000 293000
Measurement class clean room
Determination of compliance of a clean room with a certain cleanliness class is carried out according to the methods given in GOST R ISO 14644-3-2007 "Clean rooms and associated controlled environments. Part 3. Test methods".
The parameters of the tests are agreed between the customer and the testing laboratory, depending on the type and purpose of the cleanroom. Thus, in clean rooms in pharmaceutical production, measurements are taken in channels> 0.5 and> 5.0 μm to determine compliance with the requirements of the “Rules of production and quality control of medicines” (GMP).
Clean rooms of medical institutions in accordance with GOST R 52539-2006 are classified and tested for particles> 0.5 microns.
For the microelectronic industry, it is customary to control particles with sizes larger than 0.1 microns.
Depending on the requirements of specific technological processes, other particle sizes may be selected.
Classification, primary and periodic certification of cleanrooms by cleanliness classes
Clean rooms should be classified in accordance with GOST ISO 14644-1-2002 "Clean rooms and associated controlled environments. Part 1. Classification of air cleanliness". During the initial and periodic certification of clean rooms according to the cleanliness classes, the compliance of the concentration of aerosol particles with given sizes and cleanliness class to the established requirements is checked.
Purity Class Measurement Protocols
The test report on clean rooms according to cleanliness classes contains data on the average and maximum concentration of particles, the resulting classification number and conclusions on the compliance of the cleanliness class of the room with the specified requirements.
