| Types | Product Protection | Minimum Inflow Velocity (FPM) | Are volatile toxic chemicals, gases or radionuclides allowed |
| Class 1 | no | 75 | no |
| Class 2 | A1 | yes | 75 | no |
| A2 | yes | 100 | no, unless canopy is connected to HVAC system |
| B1 | yes | 100 | yes, limited |
| B2 | yes | 100 | yes |
| Class 3 | yes | 100 | yes |
Biosafety cabinet class 1
A Class 1 biological safety cabinet is a fume hood that protects the environment and personnel. In summary, it protects only personnel and the laboratory environment, not the products inside.
Class I BSCs have openable window frames and generate inward airflow to prevent aerosols generated inside the BSC from drifting into the laboratory. The exhaust air then passes through a HEPA and carbon filter before being vented.
It is suitable for circulation protection of air in low to medium-risk experiments. It is not recommended for use in laboratories with high demands on the operating environment, such as aseptic laboratories. This is because of its weak biological protection.
Class 1 BSC can only provide air filtration and microbiological protection, not advanced features such as airflow and negative pressure control. Class 1 biosafety cabinets do not have negative pressure control, so there is no guarantee that the air inside the lab will not contaminate the outside. For high-risk experiments or the use of highly pathogenic microorganisms, it is recommended to use a higher-level biosafety cabinet to provide a higher level of biological protection and environmental control.
Biosafety cabinet class 2
BSC class 2 is a higher-level biosafety cabinet for clinical, microbiological research and other laboratory environments to provide better biological protection and environmental control. Biosafety cabinet Class 2 has airflow control and negative pressure control. It provides two airflow streams to form a barrier between the BSC and the laboratory. The first airflow flows from the laboratory into the front grille of the BSC, ensuring personnel protection. The second airflow protects samples in the BSC from contamination by cleaning aerosols inside the cabinet. Depending on the amount of circulating air and how the exhaust system is connected, it is classified as A1, A2, B1, B2 and C1.
The BSC Class 2 also removes microorganisms and particles from the air using a high-efficiency filter, thus ensuring clean air in the laboratory.
BSC Class 2 is usually used for higher-risk biological experiments, such as infectious virus/cell culture, genetic engineering, and drug discovery and development.
The airflow of Class I and Class II BSCs can be easily disturbed. Therefore, they should be placed away from doors or areas with airflow variations.
Class II A1 BSC
Class II A1 and A2 BSCs are typically used for class 1-3 biological protection. The A1 BSC has a minimum inflow velocity of 75 lfpm (0.38 m/s) and a low filtration efficiency, making it unsuitable for use with highly infectious or hazardous materials. A1 has a relatively low protection capability and is unsuitable for chemical use.
Class II A2 BSC
The A2 has a wider range of applications than the A1 and is one of the most commonly used BSC types today.
The main difference between the A2 and B2 BSC types is the airflow pattern and exhaust type in the other.
The A2 BSC typically exhausts HEPA-filtered air back into the lab and can be canopy-connected to the lab's exhaust system to handle odorous chemicals. With the canopy attached, the A2 biosafety cabinet can handle small quantities of chemicals and control safe concentrations of chemicals. It is specified to have an air inflow rate of at least 100 lfpm (0.51 m/s) to circulate air quickly. Part of the inflow air is exhausted, while the other part is recirculated inside the cabinet.
Class II B1 BSC
Class II B1 has an air inflow velocity of at least 100 lfpm (0.51 m/s) and must be connected to the laboratory exhaust system.
Class II B1 has a large working area and good filtration, suitable for medium-risk biological laboratory protection.
It works on the biological protection and safety control principle using airflow and negative pressure controlled together. The BSC Class II B1 has a two-layer filter that filters limited amounts of radionuclides and volatile chemicals. However, this new design of the B1 biosafety cabinet also poses significant safety risks to the operator.
Firstly, when working with highly infectious or hazardous chemicals, the user needs to work behind the fume separator. When the laboratory's air pressure changes, the smoke diverter's invisible line moves towards or away from the user.
To use the B1 properly and safely, operators must be trained to work with hazardous chemicals behind moving invisible lines.
Class II B2 BSC
The B2 biosafety cabinet has a minimum air inflow velocity of 100 lfpm (0.51 m/s). Compared to the B1, it has a higher level of protection. It is suitable for filtering trace amounts of radionuclides and limited amounts of volatile chemicals, ensuring clean air in the laboratory. However, it is more expensive, more costly to maintain, and takes longer to warm up and exhaust.
Class II C1 BSC
Class C BSCs are the newest addition to the Class II BSC segment.C1 cabinets are unique in that they can operate as an A cabinet in recirculation mode or as a B cabinet when connected to a remote exhaust.
Innovations in directional airflow make Model C biosafety cabinets safer than Model A and Model B BSCs while maintaining lower energy costs.
The C1 class cabinet does not require a dedicated exhaust system or dedicated blowers, making it easier and more cost-effective to exhaust the cabinet.
The C1 class biosafety cabinet clearly defines areas where users can work safely compared to B1. It requires that all biologically contaminated ducts and static pressure chambers are negatively pressurized or surrounded by negatively pressurized ducts and static pressure chambers with direct exhaust. Cabinet type C1 provides additional protection by maintaining containment of biological and chemical hazards during building exhaust failures.
Biosafety cabinet class 3
Class 3 BSCs are fully sealed gas-tight cabinets that provide the highest protection for people, the environment and samples. Class 3 BSCs are the only biosafety cabinets suitable for use with Biosafety Class 4 materials. The sealed construction with rubber gloves for handling in the cabinet enables laboratory work to be carried out without contact with hazardous materials.
How to choose a biosafety cabinet
A biosafety cabinet is costly, so you should be careful before buying one. Apart from the machine's price, its size, efficiency, and testing standards are all important factors you should consider before making a purchase.
Laboratory level
One of the most important factors in selecting a biological safety cabinet is the appropriate type according to the laboratory level and the experiment's risk. Regardless of the considerations, a biological safety cabinet is essentially a piece of safety equipment that protects the laboratory operator and environment. Any additional features and considerations should be based on the type of laboratory.
Price and Size
Before purchasing any equipment, price is an important factor that influences the purchase scope. Of course, the product has to be considered for the operational cost in addition to the purchase price. It is necessary to know when and what the free warranty of the biosafety cabinet is before purchasing. Of course, the size of the machine is especially important for laboratories with little usable space. You need to set aside enough area for the benchtop biosafety cabinet.
Functions
Some of the features advertised by the vendors need to be added or upgraded for a fee, which you need to check with the vendor before purchasing. You can also ask the vendor for customized services, such as faster airflow or more powerful work capabilities. You can also remove unused features to minimize waste.
Energy Efficiency
Energy-efficient design, improved filtration efficiency and low flow modes reduce energy consumption. In addition to being more environmentally friendly, this saves on operating costs and extends the machine's life.
Testing Standards
Internationally recognized reliable testing standards include NSF/ANSI 49 (usa), EN 12469 and GB 19489-2003 (CHN), which affect filtration efficiency, airflow rate, noise and other requirements. So before choosing, you need to check the purchase of the machine belongs to the implementation of testing standards.
Ergonomics
A good touch control panel, an easy-to-clean workspace and low noise levels will all contribute to your comfort during use. Consider the machine's ergonomics after considering the cost, after sales, and testing standards.
What is the structure of the biosafety cabinet
A biosafety cabinet typically consists of the following main components:
Work Area: This is the area where the operator performs the tasks inside the cabinet. It is usually made of stainless steel and is designed to be easy to clean and decontaminate. The work area may have a built-in sink, electrical outlets, and other necessary equipment.
Front Opening: The front of the biosafety cabinet has a transparent window or sash that allows the operator to view and access the work area. The sash can be raised or lowered to control airflow and provide protection.
HEPA Filters: Biosafety cabinets are equipped with High-Efficiency Particulate Air (HEPA) filters. These filters remove airborne particles, including microorganisms, to maintain a clean and sterile work environment. There are typically multiple filters in the cabinet, including pre-filters and main HEPA filters.
Airflow System: Biosafety cabinets have a specialized airflow system that creates a controlled environment. The air is drawn into the cabinet through the front opening, passes through the filters, and then is either recirculated back into the cabinet or exhausted outside, depending on the type of cabinet.
Exhaust System: Some biosafety cabinets have an exhaust system that removes air from the cabinet and expels it outside the building. This helps to prevent the release of potentially hazardous substances into the laboratory or surrounding environment.
Control Panel: The control panel is located on the front or side of the biosafety cabinet. It allows the operator to control various functions, such as airflow velocity, lighting, and alarms.
Overall, the structure of a biosafety cabinet is designed to provide a contained and controlled environment for working with hazardous materials, ensuring operator safety and preventing contamination of the laboratory and personnel.
What are the steps to using biosafety cabinet
Wear protective equipment: Wear personal protective equipment (PPE), including, but not limited to, safety glasses, masks, and lab coats, before using the biological safety cabinet.
Clear Balanced Scorecard: If equipment is turned off before use, turn it on at least 5 minutes before work begins. Disinfect and wipe down work areas, window frames, and observation windows with 70% ethanol or other disinfectant. It is up to you whether or not you need UV radiation after wiping.
Preparation for use: Before starting work, you need to arrange the materials, make sure the grids are not blocked and place aerosol-generating instruments as far back as possible in the biosafety cabinet.
During the experiment: if the lower rated biosafety cabinet is in operation, try to move as slowly as possible to prevent destabilizing the airflow. Do not use open flames unless necessary; if you must use an open flame, use a Bunsen burner that can ignite on demand.
You can use an internal vacuum system or a stand-alone pumping unit to pump and collect biofluid waste.
At the end of the experiment: First, seal all biohazard bags and then clean and sanitize the balanced scorecard. Once cleanup is complete, the blower will continue to run for at least another 5 minutes before shutting down.
Biosafety cabinet vs fume hood
Chemical fume hoods and biosafety cabinets are both special types of laboratory equipment. Although biosafety cabinets and fume hoods look similar, their functions, operations, and significant differences exist. The differences between the two are described next.
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