Discussion on performance confirmation test and acceptance standard of negative pressure weighing cover under new GMP

1 Background: with the development of the new GMP and the continuous improvement of regulatory requirements, the negative pressure weighing cover, as a weighing protection device, has been widely used in the sampling room and workshop weighing and batching room of pharmaceutical enterprises In the process of weighing in the negative pressure weighing cover, the product is often exposed, so it naturally belongs to the direct impact system which directly affects the product quality According to the principle of risk control, it must be verified and its performance confirmed Next, we discuss some concerns about the performance confirmation of negative pressure weighing cover 2 Test content: the test of the negative pressure weighing cover should generally focus on the field leakage detection, air flow pattern, wind speed and uniformity, exhaust air volume ratio, illumination, temperature, noise, cleanliness and other parameters 2.1 leakage detection if leakage detection is not carried out after installation, the installation effect and whether damage is caused during transportation cannot be guaranteed Therefore, after installation, leakage detection will be carried out on site Calibrated photometer and aerosol generator are used in the test, and the aerosol generator with cold smoke is usually used for symmetrical measuring hood When the aerosol concentration generated in the upstream is stable between 20-30ug / L, record the concentration on the record, and then start scanning the downstream of the filter The scanning speed should be 3-5cm / s, 2-4cm away from the filter surface The scanning route should cover all filter surfaces and frame areas to ensure that each area is scanned Judgment standard: no leakage rate more than 0.01% is detected downstream 2.2 Air flow pattern during air flow pattern test, the product exposed position, operator position and air flow direction from clean to dirty shall be considered comprehensively Ensure that the product is in contact with the uncontaminated "clean air of * * hand", and ensure that there is no air vortex, backflow or diffusion to the breathing area of the operator to cause injury to the operator The special water mist generator for air flow pattern test is used in the test, and the air flow pattern is recorded with camera equipment Judgment standard: the air flow is unidirectional and there is no eddy current, backflow or diffusion 2.3 The protection function of the wind speed and evenness negative pressure weighing cover is formed by the good air flow with a certain wind speed Only the uniform air supply and return can form a good air flow, and only a certain wind speed can achieve the effect of controlling dust diffusion A use a calibrated anemometer to measure the air supply at 5-15cm below the air outlet surface, and take points for test at each current sharing membrane panel Take 5 points for each membrane surface, and calculate the average value and air volume Judgment standard: the air supply speed is 0.36-0.54m/s, and the average speed of each membrane surface is also within 10% of the total average speed error In addition, no point deviated from 12% of the mean value of the membrane surface B return air use a calibrated anemometer to measure the return air speed at a distance of 3-5cm from the return style grid Take 5 points for each return air grille and calculate the average value Judgment standard: the average speed of each part is within the error range of 10% of the total average value, and none of the data is more than 12% of the average value of the grid wind speed 2.4 the reason why the negative pressure is formed by the negative pressure weighing cover is that the air volume on the supply side is less than the return air volume on the return side due to the air volume discharged from the top of the cover, so that the equipment must draw some air from the operating room to make up the difference between the two and form the negative pressure area The proportion control of exhaust air volume directly determines the effect of negative pressure protection Use the air volume hood to measure the exhaust air volume, record the data, and then calculate the ratio between the two according to the air volume obtained from the wind speed and uniformity test Judgment standard: the exhaust air volume shall be between 5% and 15% of the total air volume 20170223102137_-1 2.5, the temperature is due to the heat generated during the operation of the fan in the weighing hood If there is no cooling measures, long-term operation will cause the indoor temperature to rise to an inappropriate value Generally, the cooling coil can be used to cool down the weighing hood that needs to run for a long time For the weighing hood that doesn't run for a long time, the method of specifying * using continuously for a long time can be used to ensure that the temperature doesn't exceed the standard It can also be solved by cooling the room alone There should be exhaust air, and the weighing cover is an open device If there is a temperature rise, it will affect the whole temperature rise of the operating room in which it is located According to the area distribution, the sampling points shall be no less than 0.5m away from the wall, 5 points shall be evenly distributed (at least one point inside the weighing cover shall be ensured), and the height of the working face shall be measured Use a calibrated thermometer to record the indoor temperature and calculate the average value before opening the weighing cover Then turn on the equipment for operation, measure the indoor temperature again before the end of the work, i.e * long running time, and calculate the average value Judgment standard: the operation of the negative pressure weighing cover will not cause the indoor temperature to rise by more than 2 ℃ 2.6 noise / illuminance: because there are operators in the operation room, a certain level of noise and illuminance is conducive to the comfort of the staff, so as to reduce the probability of error From the EHS point of view, noise is also an indicator that should be controlled Judgment standard: noise: 75db or negotiated by both parties; illumination: 500lx or negotiated by both parties 2.7 The cleanliness negative pressure weighing cover is similar to A-level air supply in GMP C + A to some extent, and its cleanliness must reach A-level requirements in static state During the measurement, the required sampling points are calculated according to the area of the air outlet surface Evenly arrange sampling points at 0.8m above the ground for testing Judgment standard: meet class a static requirements 3 Precautions and suggestions: in addition to the above performance, microbiological control is also very important However, because microbiological control is more dependent on the overall software and hardware management level of enterprise air conditioning and clean room, rather than just on the negative pressure weighing cover itself, this item is usually carried out when the performance of air conditioning and clean room is confirmed, not here.