Procedure for measuring wind speed and volume and calculating ventilation frequency in clean rooms of pharmaceutical plants

Purpose

To establish standard operating procedures for Wind speed, Air volume measurement and Ventilation frequency calculation in clean rooms of pharmaceutical plants.

Scope

Applicable to wind speed, Air volume measurement and ventilation frequency calculation in clean rooms.

Responsibility

Equipment and Power Department is responsible for implementation.

Content

1. In various tests on clean rooms, air volume and wind speed tests must be carried out first, and the various effects of air purification and conditioning systems must be obtained under the designed air volume and wind speed conditions.

2. Before Air volume testing, it is necessary to first check whether the fan is operating normally, whether the components in the system are installed correctly, whether there are any obstacles (such as whether the filter is blocked or blocked), all valves should be fixed in a certain open position, and the size of the measured air outlet and air duct must be actually measured.

3. For unidirectional flow (laminar flow) clean rooms, the air supply volume is determined by multiplying the average wind speed of the section and the cross-sectional area. The measurement section of the vertical unidirectional flow (laminar flow) clean room is a horizontal section 0.8m from the ground; the horizontal unidirectional flow (laminar flow) clean room is a vertical section 0.5m from the air supply surface. The distance between measuring points on the cross section should not be greater than 2m, and the number of measuring points should be no less than 5, evenly arranged, and the detection instrument can be a hot ball anemometer.

4. For turbulent clean rooms, the air outlet method or the air duct method is used to determine the air supply volume.

5. For the air outlet where the filter is installed, an auxiliary air duct can be selected according to the air outlet form, that is, a straight pipe section with the same cross-section as the air outlet and a length equal to 2 times the side length of the air outlet can be made of hard plate. Connected to the outside of the filter air outlet, on the outlet plane of the auxiliary air duct, the measuring points are evenly arranged with a minimum of no less than 5 measuring points, and the wind speed at each point is measured with a hot ball anemometer. The air volume is determined by multiplying the average wind speed of the wind section by the net cross-sectional area of the air outlet.

Air volume at air outlet (m3/h) = average wind speed (m/s) x ventilation area of air outlet (m2) x 3600

6. For rectangular air ducts, the measuring section is divided into several equal small sections. Each section should be as close to a square as possible, and the side length should preferably not be greater than 200mm. The measuring point is set at the center of the small section, but the number of measuring points on the entire section should not be less than 3. For circular air ducts, the measuring section and the number of measuring points should be divided according to the equal area ring method. A hole is made on the outer wall of the air duct to insert the hot-bulb anemometer rod or pitot tube. When using the pitot tube, first measure the dynamic pressure, and then determine the air volume by the following formula.

7. Calculation of ventilation times：

The calculation of ventilation times is to divide the total air supply per hour by the spatial volume of the room. The calculation formula is: