Experimental operation of medical mask bacterial filtration efficiency tester

The medical mask bacterial filtration efficiency tester adopts a dual gas path simultaneous comparison sampling method to improve the accuracy of sampling. It is used to test the bacterial filtration efficiency of disposable medical masks, medical surgical masks, civilian masks, and other daily protective masks and melt-blown cloth for mask production. It is suitable for metrology and calibration departments, scientific research institutes, mask manufacturers, and other related departments to test the performance of mask bacterial filtration efficiency.

Shanghai Qianshi Precision Electromechanical Technology Co., Ltd. was established in 2012. It focuses on the research and development, design, and production of textile testing instruments, and provides textile testing instruments and services for academic research units and testing institutions. Shanghai Qianshi is currently one of the most competitive R&D textile testing instrument manufacturers in China. The R&D team is composed of a group of experienced engineers. We are committed to serving customers wholeheartedly and striving to promote technological innovation in textile testing instruments.

Applicable standards:

Appendix B Bacterial Filtration Efficiency (BFE) Test Method B.1.1.1 in YY0469-2011 Technical Requirements for Medical-Surgical Masks

ASTMF2100, ASTMF2101, European EN14683

Experimental operation:

1.Preparation of bacterial suspension:

Take the 3rd generation 24h fresh broth culture of Staphylococcus aureus and dilute it with 1.5% phosphate buffer containing peptone to prepare a bacterial suspension with a concentration of 5.0×105cfu/mL.

2. Sample pretreatment:

Before testing, place the mask sample in an environment with a temperature of (21±5)°C and a relative humidity of (85±5)% for at least 4h. Take three samples from the same batch from each company.

3. Bacterial filtration efficiency test:

① According to the medical surgical mask standard YY0469-2011, the two sampling ports of the Henderson pipeline of the BFE system detector are connected to the Anderson six-stage sampler respectively.

② The 90mm diameter sampling plate is loaded into the Anderson six-stage sampler. The gas flow rate of the sampler is controlled at 28.3L/min, the peristaltic pump flow rate is 0.180mL/min, the liquid supply time is set to 1min, the sampling time is set to 2min, and the system cleaning time is set to 1min. A positive quality control is tested before the test.

③ After the sample test is completed, the positive quality control is tested again. Then collect the air sample in the aerosol chamber for 2 minutes as a negative quality control. During this process, the bacterial suspension cannot be delivered to the sprayer.

④ Place the agar plate upside down in a (37±2)°C incubator for (48±2)h. Then count the colony units (positive holes) formed by the bacterial particle aerosol and convert them into the possible number of impact particles using the positive hole conversion table.

The formula for calculating bacterial filtration efficiency is BFE=(C-T)/C×100% (where C: average value of positive quality control; T: sum of sample counts). "Technical Requirements for Medical Surgical Masks" (YY 0469-2011) stipulates that the bacterial filtration efficiency should be greater than 95%.

2024-11-25 11:24