A, biological safety cabinet in the installation of handling process, it is forbidden to place its fallen and remove, should be disassembled packing at the scene of the move to install.
Second, biological safety cabinet installation location should avoid when designing unspecified people frequently, and should avoid the interference of airflow on operating room air curtain.
Three, the back of the installation of bio-safety cabinets, lateral distance from the wall should be kept between 80 ~ 300 mm. For the safety of the bottom and the bottom is clingy ground ark, all along the juggle seam should be sealed.
Four, biological safety cabinet exhaust pipe connection, must be determined to replace exhaust filter is convenient.
(1) class I biological safety cabinet
To protect workers and the environment and don't protect the samples. Principle and experimental cleanroom airflow fume hood, differed from the vent installed with HEPA filters. All types of biological safety cabinet use HEPA filters in outlet and inlet. Class I biological safety cabinet, no fan, rely on outside through duct fan drive in the air, unable to test products or provide protection has now use fewer, as shown in figure 5-3.
(2) grade Ⅱ biological safety cabinet
Ⅱ level of biological safety cabinet is the most widely used type ark. Level and grade I biological safety cabinet, Ⅱ biological safety cabinets have airflow into the front window openings, referred to as "into the air," when used to prevent the microbial action might generate aerosols once upon a time window to escape. And grade I biological safety cabinet, unfiltered air intake flow was captured by the intake grille before arrived in the working area, so the experiment was not influenced by outside air pollution. Ⅱ level a biological safety cabinet is unique in the vertical laminar air flow with HEPA filter from the safety cabinet top, referred to as "sinking airflow. Sinking airflow blows over safety cabinet work area constantly, in order to protect the ark of the experiment has not been outside dust or bacteria pollution, as shown in figure 5-4.
Level according to the the NSF49, Ⅱ biological clean room safety cabinet according to the population flow speed, exhaust mode and cyclic mode can be divided into four levels: Al, A2 type (B3), B1 and B2. All grade Ⅱ biological safety cabinet can provide protection for workers, the environment and product.
A1 type safety cabinet front window air velocity or measurement of the minimum average value should be at least 0.38 m/s. 70% gas through a HEPA filter recirculation to workspace, 30% of the gas filter out through the vent port.
A2 type safety cabinet front window should be at least as air velocity or measurement of the minimum average o. 5 m/s. 70% gas through a HEPA filter recirculation to workspace, 30% of the gas filter out through the vent port. A2 type safety cabinet pollution area design is surrounded by negative pressure, prevents the substances contained in the leak.
Ⅱ grade B biological safety cabinet are connected to the exhaust system safety cabinet. Fan safety cabinet exhaust pipe connections of emergency power supply, the purpose of this power can still maintain safe cabinet under negative pressure, so as to avoid dangerous gas leakage to the laboratory. The front window air velocity or measurement of the minimum average should be at least 0.5 m/s (FPM). Bl type HEPA filters to exclude 70% gas through vent, 30% of the gas by gas supply HEPA filters to cycle to work. B2 type was 100% the platoon type safety cabinet, internal circulation flow, can provide the safety of the biological and chemical control at the same time.
Ⅱ levels of biological safety cabinets for various types of cabinet put oneself in another's performance comparison are shown in table 5-3.
(3) the level Ⅲ biological safety cabinet
Ⅲ level was a category four biological safety cabinet is designed experimental sterile clean room biosafety level, is currently the world's top security protection grade safety cabinet. Cabinet put oneself in another's position completely airtight, 100% of the total discharge type, all gas does not participate in circulation, the staff by connecting the cabinet put oneself in another's position of gloves, commonly known as the glove box (golve box), the experiment through a two-door pass box in and out of safety cabinet to ensure that is not contaminated, suitable for high wind face of biological test, as shown in figure 5-5.
Under the condition of allow circulation chemical gas operation, can use an external drain cover (exhaust clooar) type A2 level Ⅱ biological safety cabinet (FIG. 5-6). Discharge pipe of the cover is different from general hard tube is inhaled air inlet hole; Drain cover and outside pipe connection, and then received a discharge of fan. Discharge pipe into the hole on the cover for biological safety cabinet type A2 Ⅱ level through the air at the intake airflow and sinking of built-in fan keep balance is very important. If you use the seal external duct, the air flow will be more likely lead to safety cabinet; the protection of the effect of product And discharge pipe into the hole on the cover they can absorb from the indoor air, and will not affect the safety of contained in the air balance. This condition is applicable only to trace toxic chemicals. If it does not allow circulation chemical gas equipment must be used hard tube type B2 level Ⅱ biological safety cabinet. Because of B type safety cabinet is not independent balance system, it can only produce sinking airflow, the built-in fan safety cabinet relying on outside fan manufacture into the air. This type of safety cabinet during installation and maintenance is relatively complex, because outside must maintain a balance with a built-in fan fan, otherwise will lead to the safety of the operator or product performance failure.
(4) cytotoxic safety cabinet
If sterile clean room in biological experiment involving cytotoxic drugs, such as some chemotherapy drugs, these cytotoxic drugs with high toxicity; And microbial products, they can not be formalin or hydrogen peroxide, cytotoxic safety cabinet is specially high toxicity of cytotoxic drugs test and production design, one of the main characteristic is can replace the HEPA filters when fan operation, so that we can keep the negative pressure, to ensure the safety of maintenance personnel.
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