Norms - Air Treatment
Air Treatment in Health Institution
In the hospital field, the fight against borne diseases is a leading struggle for all health actors around the world. ATA has made of it a priority for over the last 25 years to become one of the main actors in this market and be recognized today as one of the leading expert in terms of air treatment in risks areas.
To obtain an appropriate air quality it is important to take into account of the particular features of risk area as well as the objectives to obtain in terms of clean room and bacteriological standards.
The performance of any air treatment system depends on the following parameters which must be carefully defined:
- Air distribution technique
- Filtration efficiency
- Supply air flow (rate at wich the air is mixed)
- Fresh air flow (air renewal rate)
- Intake air flow (air recycling rate)
- Noise level control to provide user's comfort
Despite various individual approaches to the choice of air handling units, everyone agrees that only high-performance hygienic equipment will guarantee effective eradication of living micro-organisms (bacteria, viruses, mold, yeast ...) which use inert air particles to move. The peculiarities of design, manufacturing, operation and maintenance of air treatment systems in operating theatres, are governed directly by health safety requirements (NF S 90-351 Standard for France and European Standards 14644). These systems are used in: operating theatres, post-treatment, intensive care units, resuscitation, critical care, pharmacy, sterilisation wards, and laboratories.
Clean room and clean area classification
For french installations, risk analysis is carried out by CLIN (Committee in Charge of Hospital-Borne Diseases Prevention) in order to specify the clean room classification. The decontamination kinetics and the bacteriological standards are defined and specified by NF S 90-351 and EN14644 standards.
Clean room classes which are specified by NF EN ISO 14644-1 standard are given below.
| ISO Classification N° | Maximum concentration of particles allowed (particles/m3) of sizes equivalent or higher than those shown below | |||||
| 0,1 micron/m3 | 0,2 micron/m3 | 0,3 micron/m3 | 0,5 micron/m3 | 1 micron/m3 | 5 micron/m3 | |
| ISO 1 | 10 | 2 | ||||
| ISO 2 | 100 | 24 | 10 | 4 | ||
| ISO 3 | 1.000 | 237 | 10 | 35 | 8 | |
| ISO 4 | 10.000 | 2.370 | 1.020 | 352 | 83 | |
| ISO 5 | 100.000 | 23.700 | 10.200 | 3.520 | 832 | 29 |
| ISO 6 | 1.000.000 | 237.000 | 102.000 | 35.200 | 8.320 | 293 |
| ISO 7 | 352.000 | 83.200 | 2.930 | |||
| ISO 8 | 3.520.000 | 832.000 | 29.300 | |||
| ISO 9 | 35.200.000 | 8.320.000 | 293.000 | |||
Decontamination kinetics class
Particles decontamination kinetics at a level of 0,5 micron/m3 is set by the time necessary to reach a 90% decontamination rate from the initial pollution peak level. The class is defined by maximum time level needed for decontamination.
| Particles decontamination kinetics standard at 0,5micron/m3 | Necessary time to reach 90% decontamination rate (min) |
| CP > 40 | >40 |
| CP 40 | < or equal to 40 |
| CP 20 | < or equal to 20 |
| CP 10 | < or equal to10 |
| CP 5 | < or equal to 5 |
Bacteriological class
Three bacteriological classes are distinguished.
| Bacteriological standard |
Maximum concentration of number of viable particles per cubic meter of air (ufc/m3) |
| B 100 | 100 |
| B 10 | 10 |
| B 5 | 5 |
| B 1 | < or equal to 1 |