How to determine the sampling point of the dust particle counter?

In order to meet GMP specifications, clean rooms used for pharmaceutical manufacturing need to meet the corresponding grade requirements. Therefore, these aseptic production environments require strict monitoring to ensure the control of the production process. A dust particle monitoring system is generally installed in the environment that requires key monitoring, which includes: control interface, control equipment, particle counter, gas pipe, vacuum system and software.

Each key area is equipped with a continuous measurement of laser dust particle counter, each area is continuously monitored and sampled through the workstation computer command, the monitored data is transmitted to the workstation computer, the computer receives these data can display and issue a report to the operator. The selection of the location and quantity of online dynamic monitoring of dust particles should be based on risk assessment studies, and it is required to cover all key areas.

The determination of the sampling point by the laser dust particle counter refers to the following six principles:

1, ISO14644-1 specification: for unidirectional flow clean room, sampling port should be in the direction of air flow; For non-unidirectional flow clean rooms, the sampling port should face up, and the sampling speed at the sampling port should be as close as possible to the indoor air flow speed.

2, GMP principle: sampling head should be installed close to the working height and product area;

3, the sampling position will not affect the normal operation of production equipment, and will not affect the normal operation of personnel in the production process, to avoid affecting the logistics channel;

4. The sampling position will not cause large counting errors due to particles or drops generated by the product itself, resulting in measurement data exceeding the limit value, and will not cause damage to the particle sensor;

5, the sampling location should be above the level of the key point, and the distance from the key point should not exceed 30cm. If the special location has the splash or overflow of the drug solution, resulting in the measurement data under the simulated production condition exceeding the standard of the class area, the vertical distance limit can be appropriately relaxed, but it should not exceed 50cm;

6, should try to avoid the sampling position is placed above the container, so as not to cause insufficient air above the container and produce turbulence.

After all candidate sites were determined, under the conditions of simulated production environment, the laser dust particle counter with sampling flow rate of 100L per minute was used to sample each candidate site in each key area for 10 minutes, and the dust particle sampling data of all sites were recorded.

The sampling results of several candidate points in the same area were compared and analyzed, and the high-risk monitoring point was found out, so that the point was determined as the suitable installation location of the sampling head of the dust particle monitoring point.