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Choosing the blower

When choosing the blower we have to make sure that it is able to transport the required quantity of air through the filter pad and the HEPA filter. We know the dimension of the HEPA filter and the required air speed in the working area (0,5 m/s) so we then can calculate the airflow per hour.

width of the HEPA filter:
0,305 m

height of the HEPA filter:
0,61 m

required air speed:
0,5 m/s


airflow = width * height * air speed =
= 0,305 m * 0,61 m * 0,5 m/s =
= 0,093025 m?/s


When we multiply this result by 3600 seconds (60 * 60) we get the airflow in m?/h.

airflow = 0,093025 m?/s * 3600 = 334,89 m?/h


On many English websites you?ll find the airflow in Cubic Foot per Minute (CFM) and not in cubic meters per hour (m?/h). One ft (foot) is 0.3048 m so one cubic foot is 0,0283 m? (0,3048 m * 0,3048 m * 0,3048 m).

1 m?/h = 0,5886 CFM

1 CFM = 1,6990 m?/h


In the next step we have to read from the diagram below how much pressure is necessary to transport 334,89 m?/h air through the HEPA Filter. An airflow of 334,89 m?/h is about 60% of the nominal airflow so the required pressure is 150 Pa.

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