Norme EN 13053
Ventilation of air treatment boxes. Filters installed in the air treatment boxes.
The first filtering step must be placed on the air intake side, as close as possible to the outside air intake opening, in order to preserve the highest cleanliness of the air treatment elements . The use of additional pre-filters G1 to G4 is authorized. The second filtering step is installed on the side of the outlet, at the beginning of the air supply duct, to keep it clean.
If only one filtering stage is used for the supply system, a filter of class F7 or higher must be installed.
If two stages of filtration are used, the air supply fan should be placed between the first and second stages of filtration. In order to prevent the development of microbes in second or higher stage air filters, the relative humidity of the filter area should be limited to 90%; Always avoid temperatures below the dew point temperature. Air filters should not be installed immediately after the dehumidification cooling coils or after the humidifiers (except steam humidifiers).
When using bag filters, the filtering area must be at least 10 m² x 1 m² of equipment cross section. The joints used must be of a closed cell type, they must not absorb moisture and must not form nutritious substrates for microorganisms. Permanent fixing must be ensured for the caulking (for example, operation on the dirty air side). The filter sections from an interior height of 1.6 m must have an inspection window (with an interior diameter of 150 mm minimum) and interior lighting.
In fan selection, in order to establish the filter pressure loss value when designing the air flow rate, this must be equal to the average between the initial and final losses of the clean filters and the dust-filled filters, respectively.
The pressure loss of a filter section filled with solid particles must not exceed the values in Table 9. Lower pressure drops can also be specified, if necessary.
Filters installed in air handling boxes used for human occupation must be tested and classified according to the provisions of Standard EN 779.
Final pressure drop for filters
Final pressure drop
G1 – G4
M5 – F7
F8 – F9
The following information must be clearly visible (on a label) in the filter section: filter class, type of filter medium, final pressure drop. When changing filters, the user is responsible for checking and updating this information.