Integrity test and analysis of filter of biological safety cabinet

Test and analysis of filter integrity of biosafety cabinet the integrity of the filter is an important performance of the biosafety cabinet for safe use, and it is also a frequently encountered problem in the process of highly concerned and tested by the operating users Through the test, analysis and evaluation of the filter integrity of the biosafety cabinet, it can provide for the research of the biosafety cabinet detection / calibration method and the development of the performance evaluation method of the biosafety cabinet, so as to ensure the safety and reliability of the biosafety cabinet in use [Key words] biosafety cabinet; filtration; test analysis; aerosol; biohazardous particle [CLN] th789; tb9 [document code] B [article number] 1674-1633 (2010) 05-0054-03 Background: the national medium and long term plan for science and technology development (2006-2020) and the 11th Five Year Plan for science and technology development of the General Administration of quality supervision, inspection and Quarantine (AQSIQ) have clearly listed biosafety assurance in the field of the plan and its priority theme Therefore, the General Administration of quality inspection and Quarantine of the people's Republic of China has issued the scientific and technological plan project (Project No.: 2008qk285) of the research on the detection / calibration methods of biosafety cabinets to our institute; meanwhile, the quality and Technical Supervision Bureau of Guangdong Province has also issued the plan project (Project No.: [2008] 354-26) of the development of the local standards of the performance evaluation methods of biosafety cabinets to our institute It is mainly to establish the detection items and technical requirements of the biosafety cabinet, select the appropriate accuracy and accuracy, traceable detection standard device, and develop the standard method of performance evaluation of the biosafety cabinet Terminology analysis: biological safety cabinets (BSCs) are air purification safety devices to prevent harmful or unknown biological aerosols from escaping in the process of experimental operation Evaluation: the application of this method will make the detection methods and technical indicators of the biosafety cabinet standardized and unified, ensure the safety and effectiveness of the use of the biosafety cabinet, and at the same time, protect the safety of the environment It has a good application prospect and will produce great social benefits The air particle filter of biosafety cabinet, referred to as HEPA, is a dry filter with extended / wrinkled media filter membrane Its main purpose is to filter the dust and other particles in the air flowing into the working area of the safety cabinet, so as to ensure that the air in the safety cabinet reaches a certain degree of cleanliness; and to filter out the aerosol and other dangerous particles generated by the samples during the test operation, so as to protect the samples, avoid cross contamination between samples and prevent the biological dangerous particles from damaging the test operators [1] At the same time, it can avoid the aerosol and other dangerous particles directly discharged into the environment, so as to protect the environment The filter membrane of the biosafety cabinet filter is a kind of disposable filter facility, which needs to be tested regularly If there is leakage, it must be replaced Otherwise, it will cause biological hazard Therefore, the effectiveness and integrity of biosafety cabinet filtration is an important performance index to measure the biosafety cabinet In order to complete the science and technology plan project of research on detection / calibration methods of biosafety cabinets approved by the General Administration of quality inspection and Quarantine of the people's Republic of China, as well as the task of establishing local standards of performance evaluation methods of biosafety cabinets by Guangdong Provincial Bureau of quality and technology supervision, and to obtain more test data Three different media (1.5% Ki, 0.9% NaCl, 10% C6H12O · 6H2O) were used for aerosol generation Through the use of aerosols produced by these three different media materials, the integrity of the biosafety cabinet filtration is tested in practice, and the analysis is based on the test data, so as to provide a reliable data basis for the safe use of the biosafety cabinet 1 Test instruments and methods 1.1 test instruments ⑴ aerosol generator is used to produce multi dispersed and high concentration aerosol, which can be produced by different materials (such as PSL, DOP, silicone oil, salt, sugar, etc.); the diameter of aerosol particles is between 0.01-2 μ M (2) sensor type of aerosol photometer: 90 ° light scattering instrument, 670 μ m laser tube; aerosol concentration measurement range: 0.001 ~ 20mg / m3; zero point stability: 24h ± 0.001 mg / m3 1.2 test method: turn on the fan and lamp of the biosafety cabinet, and remove the diffusion device and protective cover of the filter Place and turn on the aerosol generator, and guide the aerosol into the safety cabinet according to the aerosol introduction position set by the manufacturer, so that the aerosol is generated and evenly distributed in the upstream air flow of the filter If the manufacturer does not set the aerosol introduction position, the aerosol shall be introduced in such a way that it is fully mixed in the airflow of the safety cabinet [2] Open the aerosol photometer and sample the upstream gas stream containing aerosol in the filter The aerosol concentration shall not be less than 10mg / m3 Place the aerosol photometer detection port on the tested surface not more than 25 mm away from the test surface, and move it at a scanning rate of less than 50 mm / s, so that the probe scans the whole downstream airflow side of the filter and the edge of each combined filter, and the scanning route should overlap slightly Carefully test around the entire filter periphery, along the joint of the combined filter and the frame, and around the seal between the filter and the device [3] For the safety cabinet with exhaust pipe, the scanning detection of exhaust filter cannot be carried out The detection of aerosol concentration in the gas flow downstream of the filter is to drill a hole with a diameter of about 10 mm on the pipe of the gas flow downstream, and insert the detection port with a hard tube photometer into the hole for detection [4] 2 The test results were commissioned by an occupational disease prevention and control hospital in our city to test the integrity of the filtration of 12 biosafety cabinets in use in the hospital (including 4 of class II and 8 of class III) At present, the integrity test of biosafety cabinet filtration is mainly based on yy0569-2005 "biosafety cabinet" pharmaceutical industry standard, combined with European Union's en12469:2000 "biotechnology performance criteria for microbiological safety cabinets" and other technical requirements [5,6] The integrity of the filtration of these 12 biosafety cabinets was tested with aerosols produced by three different media materials The results are shown in Table 1.