Biosafety Laboratory Special: Innovation and Practice of Tuyere Exhaust High Efficiency Filtration Device
Biosafety Laboratory Special: Innovation and Practice of Tuyere Exhaust High Efficiency Filtration Device
Background
At present, all kinds of infectious diseases (Infectious Diseases) faced by human beings are caused by various pathogens, which can spread between human and human, animal and animal or human and animal. Looking at the history of human development, all major infectious disease pandemics have brought irreparable serious losses to the human society at that time. On March 4, 1918, influenza occurred in a military camp in Kansas, USA, followed by influenza in China, Spain, and the United Kingdom on all continents except Australia. The only symptoms at the time were headaches, high fever, muscle aches and loss of appetite. But in the autumn of 1918, a large number of outbreaks in the world, to the spring of 1920, causing about 1 billion people infected in the world, about 50 million to 0.1 billion people died. Because of this pandemic flu, all countries involved in the war did not have extra troops to fight. In the shadow of death, the First World War ended hastily. The number of people who died of infectious diseases was much higher than that of the war. As far as the general situation of airborne diseases is concerned, indoor airflow organization and the isolation and treatment of indoor polluted air are important measures to prevent the infection of pathogenic microorganisms between indoor personnel and to the outdoor environment.
Article 5.3.2 of "Technical Code for Building Biosafety Laboratory" GB 50346-2011 states with mandatory provisionsThe exhaust air of the three and four biosafety laboratory protection areas must be filtered by high-efficiency filters and discharged.". High efficiency air filter, referred to as high efficiency or HEPA filter, is the main means of air pollution prevention in biosafety laboratories. At present, the filtration efficiency of HEPA filter can not reach 100, so there is still the risk of leakage diffusion and surface pollution diffusion. Pathogenic microorganisms trapped on HEPA filter have the possibility of survival and proliferation, which may lead to the spread of pathogenic microorganisms under certain conditions.
HEPA Filter
1. Accidental damage during installation or damage under the long-term action of disinfectants, power exhaust, etc;
2. Leakage of the border due to uneven squeezing of the filter border.
In view of the risk of leakage of HEPA filters and the survival and proliferation of surface pathogenic microorganisms, the WHO Laboratory Biosafety Manual (3rd Edition) requires that all HEPA filters in high-level biosafety laboratories must be installed in a manner that allows for gas disinfection and testing. The General Requirements for Laboratory Biosafety GB 19489-2008 also stipulates that high-level biosafety laboratories should be able to sterilize and check the exhaust HEPA filter in situ. Exhaust high-efficiency filters with in-situ disinfection, sterilization and leak detection functions are generally dedicated biosafety exhaust high-efficiency filtration devices (hereinafter referred to as exhaust high-efficiency).
exhaust
High-efficiency exhaust vents are mainly used for biological pollution control in biological safety laboratories, infectious disease hospitals, and negative pressure isolation wards.
In terms of use characteristics, the exhaust high-efficiency filtration device used in high-level biosafety laboratories is dividedtuyere type(installed on the laboratory enclosure) andpipe type(also called unit type, installed outside the laboratory protection area and connected to the laboratory through a closed exhaust pipe).
tuyere type exhaust air efficient filtering device
air outlet type high-efficiency exhaust filter device is installed in the laboratory and can be directly operated in the laboratory. HEPA filter is arranged at the air inlet end of the exhaust box, and biological closed valve is arranged at the air outlet end of the box item or side.
Pipeline exhaust high efficiency filtering device
pipeline exhaust high efficiency filtration device is known as BIBO(Bag in and bag out). BIBO high efficiency unit consists of aerosol generation section, mixing section, upstream aerosol sampling section, HEPA compression section, scanning detection section and other parts.
Outlet type exhaust efficient structure characteristics
tuyere type exhaust high efficiency filter device is mainly installed on the laboratory enclosure structure, and can generally carry out in-situ disinfection and leak detection. It is usually equipped with downstream sampling port, driving mechanism, disinfection port, exhaust high efficiency filter, filter resistance monitor, etc. The efficiency of the matching high-efficiency filter reaches H14. The box body is made of stainless steel plate SUS304, and the surface is brushed, beautiful and corrosion-resistant.
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filtration efficiency:>99.97 @ 0.3um
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filter leak detection method: indoor automatic scanning leak detection
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disinfection method: can realize in-situ gas disinfection inside the filter and box, and can verify the disinfection effect.
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box pressure: 2500Pa
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Corrosion resistance: The box body and scanning leak detection sampling device are made of 304 stainless steel.
Tuyere type exhaust efficient filter device how to leak detection?
Generally performs in-situ leak detection on the tuyere-type exhaust high-efficiency filtering device. A scanning leak detection sampling device is installed on the air outlet side of the filter. The "line scanning method" is adopted. The line scanning sampling probe is connected to the scanning driving mechanism in the centralized interface box through a mechanical transmission mechanism, and the particle counting device is connected to the scanning leak detection sampling port in the centralized interface box through a sampling pipe, and then physical aerosol is generated at the upstream of the filter, after the aerosol concentration meets the standard requirements and is stable, the filter is scanned and leak detected by using the scanning and leak detection control device control line scanning sampling probe.
Tuyere exhaust efficient how to disinfect?
In-situ disinfection of tuyere filters is carried out synchronously with the overall disinfection of laboratory gases. General disinfection process: close the biological sealing valve of the air outlet, connect the disinfection pipeline of the gas circulation disinfection device to the gas disinfection interface, place the biological indicator in the disinfection verification port, open the closed isolation valve between the gas disinfection interface and the disinfection verification port, and open the gas circulation disinfection device; after the personnel leave, release the gas disinfectant meeting the disinfection requirements in the laboratory through remote control or remote operation mode, such as formaldehyde, gaseous chlorine dioxide, vaporized hydrogen peroxide (VHP), etc. The circulating fan of the gas circulation disinfection device makes the gas disinfectant continuously penetrate the HEPA filter to disinfect the filter thoroughly; after the exposure time of the gas disinfectant in the room meets the disinfection requirements, close the gas disinfectant generator, open the biological closed valve of the air outlet of the air outlet device, start the laboratory ventilation and air conditioning system, and discharge the gas disinfectant that meets the environmental protection requirements; after the concentration of the gas disinfectant in the room drops to a safe level, personnel enters the laboratory, close the gas circulation disinfection device, close the airtight isolation valve of the gas disinfection interface and the disinfection verification port, take out the biological indicator and culture it to judge whether the disinfection effect meets the requirements. General biological indicator selection of Bacillus subtilis bacillus tablets.
References:
JG/T 497-2016 Exhaust Air Efficient Filtering Device
GB 50346-2011 Technical Code for Biosafety Laboratory Building
