Biosafety Cabinets – Biosafety cabinets (BSCs) are one type of biocontainment equipment used in biological laboratories to provide personnel, environmental, and product protection. Most BSCs (e.g., Class II and Class III) use high efficiency particulate air (HEPA) filters in both the exhaust and supply system to prevent exposure to biohazards.
There are several designs of biosafety cabinets which provide different levels of protection to the worker and to the research material. There are three classes of biosafety cabinets designated in the United States: Class I, Class II, and Class III. Class I biosafety cabinets are infrequently used and provide personnel and environmental protection but no product protection.
Class II and Class III cabinets provide personnel, environmental, and product protection. Class II biosafety cabinets are widely used in biological research laboratories and are differentiated into types such as A1, A2, B1, or B2.The classification for the majority of biosafety cabinets used in the United States is Class II Type A2.
- The naming system given here is the one used in the United States and in CDC/NIH guidance Biosafety in Microbiological and Biomedical Laboratories Appendix A,
- Other naming conventions have been used in the past or in other countries.
- Laminar flow hoods (e.g., “clean benches”) are not biosafety cabinets.
Laminar flow hoods provide a clean or sterile area to protect the work product, but discharge air towards the worker. In work with infectious agents, toxins, or cultures, use of laminar flow hoods may expose the worker to the biological material. Likewise, chemical fume hoods cannot be used in place of biosafety cabinets,
Contents
- 1 What are the different types of biosafety cabinets?
- 2 What is the difference between A1 and A2 BSC?
- 3 How many classes are there in biological safety cabinet?
- 4 What is Class 2 BSC used for?
- 5 What is a Class 1 BSC?
- 6 What is the most commonly used type of biological safety cabinet in clinical works?
- 7 What is the difference between biosafety cabinet 1 and 2?
What are the different types of biological cabinets?
Biosafety cabinets are divided into three classes: I, II and III. Class I provides protection for the user and surrounding environment, but no protection for the sample being manipulated. Class II provides protection for the user, environment and sample, and is divided into four types: A1, A2, B1 and B2.
What are the different types of biosafety cabinets?
Classes of biological safety cabinets – Biological safety cabinets (BSCs) are used to protect personnel, products and the environment from exposure to biohazards and cross contamination during routine procedures. When choosing a biological safety cabinet for your work space, EH&S can help you select the class of cabinet that will provide the best protection.
Class I BSCs are suitable for work involving low to moderate-risk agents. Since incoming air is not filtered, Class I BSCs should not be used with research materials (e.g., cell lines) that must be handled under sterile conditions. Class I cabinets are used to enclose equipment (e.g., centrifuges, harvesting equipment or small fermenters) or procedures with potential to generate aerosols (e.g., cage dumping, tissue homogenization or culture aeration). Because outgoing air is filtered, research personnel are protected while using a Class I BSC. Class II BSCs provide a partial barrier for the safe manipulation of low, moderate and high-risk microorganisms. Class II cabinets, which are the most frequently used in research and clinical laboratories, are divided into four types (Types A1, A2, B1 and B2). The Class III BSC is a totally enclosed, gas-tight ventilated cabinet, and provides the highest level of personnel, environmental and product protection. Operations within a Class III BSC are conducted through attached rubber gloves.
What are the different types of biological safety?
Biosafety levels (BSL) are used to identify the protective measures needed in a laboratory setting to protect workers, the environment, and the public. The levels are defined in Biosafety in Biomedical Laboratories (the BMBL), Biosafety level designations in the BMBL outline specific practices and safety and facility requirements.
- There are many ways to combine equipment, practices, and laboratory design features to achieve appropriate biosafety and biocontainment.
- These are determined through biological risk assessments specifically conducted for each experimental protocol.
- Risk assessments are conducted by evaluating the way in which the infectious agents or toxin is transmitted and its ability to cause disease, the activities performed in the laboratory, the safety equipment and design elements present in the laboratory, the availability of preventive medical countermeasures or treatment, and the health and training of the laboratory worker.
For example, some procedures with an infectious agent or toxin may be conducted under BSL-2 conditions, but other procedures with the same infectious agent or toxin that increase the risk to the worker or environment, such as the creation of airborne droplets or sprays, or large scale production, may require that the work be conducted under BSL-3 conditions.
At any given biosafety level, there will be strict requirements for laboratory design, personal protective equipment, and biosafety equipment to be used. Standard Microbiological Practices are required at all biosafety levels and are good practice for experiments below the BSL-1 threshold. Activities and projects conducted in biological laboratories are categorized by biosafety level.
The four biosafety levels are BSL-1, BSL-2, BSL-3, and BSL-4, with BSL-4 being the highest (maximum) level of containment. There are additional specific rules and designations for animal research (ABSL), agricultural research (BSL-Ag), and other types of research.
What is a Class 2 safety cabinet?
The Class 2 Biological Safety Cabinet utilises a specially ventilated enclosure, developed for sterile material handling and sensitive processes where biological samples are applied requiring a safe work zone, providing protection for the user, sample and surrounding environment.
What is the difference between A1 and A2 BSC?
A Note on BSC Safety All Class II Biological Safety Cabinets provide the same level of protection against hazardous aerosols and particulates. The following analysis examines how the different Types of Class II BSCs protect users from nuisance odors and vapors, hazardous vapors and hazardous radionuclides.
Keep in mind, the safest BSC in the world cannot offer protection if used in an unsafe manner. Safety Gap Analysis If chemical safety is not a concern for your microbiological processes, then a recirculating Class II, Type A2 Biosafety Cabinet is perfectly suitable; however, if chemical safety is a concern, then you should use a vented Class II BSC.
The Class II, Type C1 Biosafety Cabinet offers the greatest combination of safety and flexibility, and is therefore the “no-brainer” choice in most circumstances. Know your needs
| Chemical Safety Features | Type A2 | Type B1 | Type B2 | Type C1 |
| Single Pass Airflow | x | ✔ | ✔ | ✔ |
| Intuitive use of work space | ✔ | x | ✔ | ✔ |
| Easy installation and building demands | ✔ | ✔ | x | ✔ |
| Confident chemical safety | x | x | ✔ | ✔ |
| Active Protection | x | x | x | ✔ |
Type A Cabinets The two major differences between Type A1 and Type A2 cabinets:
- Inflow velocity: Type A1 BSCs are required to have a minimum of 75 lfpm (0.38 m/s) inflow, while Type A2 BSCs must have a minimum 100 lfpm (0.51 m/s) inflow.
- Canopy (or Thimble) installation : Canopies can be used on A2 BSCs to control odors as well as safe concentrations of chemicals; however, a canopy can be used on an A1 only to control nuisance odors.
Type A2 Chemical Safety
| Type A cabinet with room exhaust | Type A cabinet with canopy/thimble connection |
| Since Type A cabinets have a shared plenum (meaning all of the air moved by the cabinet is allowed to mix before being redistributed through the cabinet), chemically contaminated air will be returned over the work zone. | Class II A1 & A2 BSCs have the same cross section and can both be outfitted with a canopy (or thimble) in order to remove the exhaust from these cabinets much like a fume hood would. |
The shared plenum acts as a “mixing bowl” for the BSC’s air prior to being resupplied over the work surface or exhausted from the cabinet, and HEPA filters do not trap chemical vapors; therefore, the column of air supplied over the work zone should be considered chemically contaminated. From the view of an operator, this means that the entire work surface of a Type A BSC is susceptible to chemical contamination if vapors are being emitted in the cabinet’s work zone. Again, the blue shading indicates the area of the work zone where air can recirculate. Whereas Type A Biosafety Cabinets always pass HEPA filtered air recycled from the cabinet’s interior over the work surface, Type B2 Cabinets always pass only HEPA filtered room air over the work surface. Type B2 BSCs incorporate a single pass airflow system throughout the cabinet.
No air is recycled. Also known as Total Exhaust BSCs, the sole purpose of the Type B2 is to handle situations where biological and chemical hazards are used together. Handling Hazardous Chemicals & their Vapors If you follow the arrows in the cross sectional diagram for the B2, you can see that all of the air that is brought into the cabinet finds its way through the exhaust HEPA filter.
This allows work with chemical hazards to be performed inside this BSC design without risk to the operator or the samples. None of the air is resupplied back over the work zone. The red shading indicates the area of the cabinet that is safe to work with chemicals. Type B1 Cabinets A less commonly seen type of Class II BSC is the B1 Type. This type of cabinet brings some interesting solutions to BSC design problems, but in doing so, brings about its own safety concerns. The B1 cabinet functions by directing various columns of air to different channels, thereby increasing chemical safety in specific parts of the cabinet’s work zone. Understanding the B1’s upside
- The B1 uses far less exhaust air than a B2, more similar to an A2 with a canopy.
- The B1’s single pass airflow in the back provides superior chemical safety over an A2 with a canopy.
The B1 quite literally splits the work zone’s column of supply air from the face of the cabinet to the back. Air behind this split (commonly referred to as the “smoke split”) is pulled into the direct exhaust of the B1 cabinet by the roof-mounted exhaust blower.
- The B1 uses far less exhaust air than a B2, more similar to an A2 with a canopy.
- The B1’s single pass airflow in the back provides superior chemical safety over an A2 with a canopy.
Where the B1 falls short While it certainly is a valiant attempt to merge the efficiency of Type A’s with the chemical safety of Type B BSCs, the B1’s design creates its own host of issues. Unfortunately, these shortcomings result in serious safety concerns:
- A user must work behind the smoke split when handling hazardous chemicals and therefore must be trained to work very conscientiously.
- The smoke split is an invisible line that can only be identified by using smoke or another visual aid.
- The invisible line of the smoke split will move toward or away from the user any time air pressure in the room or workspace changes and as the BSC’s filters load.
In order to use a B1 properly and safely, the operator must be trained to handle hazardous chemicals behind an invisible line that shifts and moves. The red zone in this image indicates where hazardous chemicals can be used safely, and the blue zone shows where in the work area the air will be recirculated. Type C1 Cabinets The most recent addition to the world of Class II biosafety cabinets is the Type C. This cabinet directly addresses the gaps in safety that exist in Type A and Type B BSCs. The Type C is flexible enough to take on the jobs of both Type A and Type B cabinets.
- Innovations in directional airflow have allowed the Type C to be safer than Type A and Type B BSCs, while maintaining low energy costs.
- Active Protection Protocol In Type B cabinets, the CDC writes, “Should the building exhaust system fail, the cabinet will be pressurized, resulting in a flow of air from the work area back into the laboratory.” Type C cabinets maintain negative pressure in the event of an exhaust failure for up to five minutes (programmable), preventing the flow of air into the laboratory,
Chemical Zone
- Safer than Type A: The Type C is also safer than a Type A2 cabinet because all of the air that passes through the chemical zone is expelled from the cabinet in a single pass.
- Safer than Type B: Working with chemicals in the Type C is safer and more intuitive than in Type B1 BSCs because of its chemical zone, a clearly defined area for chemical handling. Air in this heavily perforated area of the work surface is exhausted in a single pass. Furthermore, safety is also improved because the size and shape of the chemical zone does not change while in use as it can within a Type B1 cabinet. The Type C is also safer than the Type B2 due to its programmable Active Protection Protocol.
*republished with permission from Labconco Corporation For more information on Labconco or other brands of biosafety cabinets, contact our Technical Services Manager, Rand Weyler – http://web.newenglandlab.com/contact-our-technical-services-manager, Topics: biosafety cabinets
What is the difference between A2 and B2 BSC?
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Home Posts Blog How to choose the right one from A2 & B2 Type Class II Biological Safety Cabinet
The difference between A2 and B2 of the Class 2 biological safety cabinets is that the exhaust airflow of the A2 type safety cabinet is discharged back to the room after high-efficiency filtration, and the exhaust airflow of the B2 type safety cabinet is discharged outdoors after high-efficiency filtration.1.
- Since the two types of Class 2 biological safety cabinets are filtered and then exhausted, in terms of biological safety, there is not much difference between the two types of safety cabinets.
- A2 type is 30% efflux, 70% internal circulation; B2 type is 100% efflux, 0 internal circulation.2.
- If your experimental object may escape radioactive gas, toxic and irritating gas, please choose B2 type safety cabinet, otherwise you can choose A2 type safety cabinet.
Biological safety cabinets are used to protect the operator, the laboratory environment and experimental materials from exposure to the above-mentioned operations when operating infectious experimental materials such as primary cultures, bacterial strains, and diagnostic specimens.
Designed for the possible generation of infectious aerosols and splashes. Biological safety cabinets are widely used in medical and health care, disease prevention and control, food hygiene, biopharmaceuticals, environmental monitoring, and various biological laboratories. They are an important basis for ensuring biological safety and environmental safety.3.
If you choose a B2 type safety cabinet, please ensure that the laboratory has enough ventilation, otherwise it will cause the safety cabinet to inhale the wind speed too low, cause an alarm and seriously reduce its biological safety.4. If the selected B2 biological safety cabinet is used in midsummer or severe winter, due to its large air exchange rate, a large amount of outdoor air will flow into the room, which may cause the laboratory environment to be too hot or cold.
What is biological safety level 3 examples?
BSL-3 – Again building upon the two prior biosafety levels, a BSL-3 laboratory typically includes work on microbes that are either indigenous or exotic, and can cause serious or potentially lethal disease through inhalation. Examples of microbes worked with in a BSL-3 includes; yellow fever, West Nile virus, and the bacteria that causes tuberculosis.
Standard personal protective equipment must be worn, and respirators might be required Solid-front wraparound gowns, scrub suits or coveralls are often required All work with microbes must be performed within an appropriate BSC Access hands-free sink and eyewash are available near the exit Sustained directional airflow to draw air into the laboratory from clean areas towards potentially contaminated areas (Exhaust air cannot be re-circulated) A self closing set of locking doors with access away from general building corridors
Access to a BSL-3 laboratory is restricted and controlled at all times. List of Biological Safety Level III agents.
How many classes are there in biological safety cabinet?
Biosafety Cabinets – Biosafety cabinets (BSCs) are one type of biocontainment equipment used in biological laboratories to provide personnel, environmental, and product protection. Most BSCs (e.g., Class II and Class III) use high efficiency particulate air (HEPA) filters in both the exhaust and supply system to prevent exposure to biohazards.
- There are several designs of biosafety cabinets which provide different levels of protection to the worker and to the research material.
- There are three classes of biosafety cabinets designated in the United States: Class I, Class II, and Class III.
- Class I biosafety cabinets are infrequently used and provide personnel and environmental protection but no product protection.
Class II and Class III cabinets provide personnel, environmental, and product protection. Class II biosafety cabinets are widely used in biological research laboratories and are differentiated into types such as A1, A2, B1, or B2.The classification for the majority of biosafety cabinets used in the United States is Class II Type A2.
- The naming system given here is the one used in the United States and in CDC/NIH guidance Biosafety in Microbiological and Biomedical Laboratories Appendix A,
- Other naming conventions have been used in the past or in other countries.
- Laminar flow hoods (e.g., “clean benches”) are not biosafety cabinets.
Laminar flow hoods provide a clean or sterile area to protect the work product, but discharge air towards the worker. In work with infectious agents, toxins, or cultures, use of laminar flow hoods may expose the worker to the biological material. Likewise, chemical fume hoods cannot be used in place of biosafety cabinets,
What is the difference between Class 2 and Class 3 BSC?
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What is the difference between biosafety cabinet 1 and 2?Biosafety Cabinet History – The development of BSCs was a lengthy process, as the 1991 Clinical Microbiology Reviews paper, Biological Safety Cabinetry makes clear.1 The first report of an infection that was the result of exposure to materials in a lab came in 1893. The first survey of a laboratory-acquired disease, typhoid fever, primarily the result of pipette use, began in 1915. By the middle of the 1900s, the link between laboratory practices and potential contamination and infection was more fully understood. A 1950 survey reported at the annual meeting of the American Public Health Association noted that 5,000 laboratories recorded 1,342 instances of laboratory-acquired infections. Thirty-nine deaths resulted. Of the 1,342 infections, only 467 had previously been made public. This pattern of infection continued in the following decades, as reported by the Centers for Disease Control and Prevention (CDC) and the National Animal Disease Center.
An enclosed cabinet was first mentioned in the scientific literature in 1943. By the early 1950s, the U.S. Army Biological Laboratories at Fort Detrick, Maryland developed and implemented sophisticated containment cabinet technology.2 The use of containment cabinets began to spread, continuing to the present.
Is there an acceptable degree of exposure in a particular instance? Does a standard exist by which the effectiveness of BSCs from different manufactures can be measured? For those reasons and others, NSF International, a standards development organization, created standard NSF/ANSI 49 that classifies BSCs into classes and types based upon the performance and protection each must meet.
To understand BSCs in light of a lab’s safety requirements, an extended look at BSCs is necessary. A cabinet that can be recirculated back into the laboratory or be exhausted through a facility’s HVAC system. It uses negative pressure from an interior blower motor or the external exhaust system, creating an air barrier at the front of the cabinet at a minimum speed of 75 linear feet per minute with the air then circulating through the cabinet.
They protect personnel and the lab environment but not the work product in the cabinet. A cabinet with a partially open front for worker access. Class II is similar to Class I in that it uses negative pressure to keep air from moving through a supply opening and the access panel. The primary difference between Class I and Class II cabinets is that a Class II cabinet creates an air barrier at the front of the cabinet by creating a vacuum using an airfoil that directs air under the work surface instead of over the work area.
There are four subtypes of Class II cabinets. Air is drawn through the cabinet’s front opening at a minimum speed of either 75 linear feet per minute or 100 linear feet per minute, depending on the subtype. Some portion or all of the air is either reintroduced into the cabinet’s work area through a supply HEPA filter or discharged back into the laboratory or building’s exhaust system through an exhaust HEPA filter. An enclosed cabinet that protects personnel and the environment. Typically designed for biosafety level 4 pathogens. Users place their hands into mounted gloves that pass through a non-open window and manipulate all work in that fashion. Blowers create a negative pressure of at least 0.5 inches of water gauge.
Materials pass into the workspace through a dunk tank on the floor of the cabinet or through a double-door pass-through box that can be decontaminated between uses. The cabinets are designed for high-risk biological substances. The Class II BSC has the broadest use and is the most commonly found in labs. Kruse, RH, et. al.; “Biological safety cabinetry”; Clinical Microbiology Reviews; April 1991; pp.207-241 Barbeito, Manuel S. and Kruse, Richard H.; “A History of the American Biological Safety Association Part I: The First 10 Biological Safety Conferences 1955-1965”; American Biological Safety Association; https://www.absa.org/abohist1.html “Biosafety in Microbiological and Biomedical Laboratories”; Centers for Disease Control; December 2009; https://www.cdc.gov/biosafety/publications/bmbl5/index.htm Class I Containment Ventilated Enclosures The NU-813 Class I Containment Ventilated Enclosure (CVE)’s versatile design can be configured to compound non-sterile drugs in pharmacies or to provide personnel protection in microbiology labs. Class II Type A2 Biosafety Cabinets The NU-543 is configurable for a broad range of applications and geographies with a choice of NSF listed access openings, an optional smooth interior, EN 12469 listed configurations, and a global supply chain.
Minimize workplace injuries working in the comfort of a LabGard Biosafety Cabinet. : biosafety-cabinet-classes-article What is the difference between Class 1 and Class 2 safety?SafetyGearOnline.com is proud to offer top quality safety gear for working professionals. We understand that different jobs and industries have different standards when it comes to safety apparel. That’s why we offer a full spectrum of safety vests certified by the American National Standards Institute (ANSI). An ANSI safety vest can have one of three classifications: Class 1, Class 2 and Class 3. Each of the ANSI safety ratings are designed to help workers choose a proper vest for the job based on their working environment. Learn more about the ANSI safety vest classes below. Class 1 ANSI Safety Vest Class one vests are for workers whose job puts them at the lowest risk level. These would be jobs in areas where traffic is traveling at or below 25 mph, and work is taking place at a safe distance from a roadway. An example of this type of work would be sidewalk repair in a small residential neighborhood. According to the ANSI in order for a vest to qualify as a Class 1 safety vest it must be one of the safety vest colors, either a safety yellow or safety orange, and have a minimum of 155 square inches of reflective tape.
These vests are larger than their class 1 counterparts because they require more high visibility and reflective areas to be present. A Class 2 vest must have at least 775 inches of safety yellow or safety orange back ground material and 201 square inches of reflective striping. These ANSI safety vests are commonly worn by survey crews, airport baggage handlers, and school crossing guards. Class 3 ANSI Safety Vest Class 3 jackets and vests are reserved for people working in the most dangerous environments where visibility is the highest priority. This includes roadways where traffic is traveling in excess of 50mph, but it can also apply to emergency personnel or tow truck operators working in blizzard or hurricane conditions where visibility is at a minimum. ANSI Class 3 safety vests are the largest of the ANSI vests because they require the most background fabric and reflective striping. Because a class 3 vest requires a whopping 1,240 inches of safety yellow or safety orange background and 310 square inches of reflective striping, it often resembles a short sleeve t-shirt more than a traditional vest. What is Class 2 BSC used for?Class II biological safety cabinets are primary engineering controls typically used for microbiological studies, cell culture, pharmaceutical procedures and toxicology. BSC classifications and standards for the United States are set by NSF International (formerly the National Sanitation Foundation). What is a Class 1 BSC?Class II – A Class II cabinet is defined as a ventilated cabinet for personnel, product and environmental protection, often used for microbiological work or sterile pharmacy compounding. In some labs, these containment hoods are referred to as cell culture or tissue culture hoods.
All Class II BSCs require all biologically contaminated ducts and plenums to be under negative pressure or surrounded by negative pressure ducts and plenums. This provides a fail-to-safe feature that protects the user even in the event of a plenum failure. Type B2 cabinets take this a step further, requiring all biologically contaminated ducts and plenums to be under negative pressure or surrounded by directly exhausted negative pressure ducts and plenums. Type C1 cabinets provide even more protection by maintaining containment from biological and chemical hazards during building exhaust failures. Like Class I cabinets, Class II cabinets are safe for work using agents classified as BSL 1, 2, 3 or 4, in conjunction with other protective measures required for these biosafety levels. What is Class II Type A B3 BSC?Thermo Scientific Forma II Type A/B3 1184 & 1186 Safety Cabinets | GMI – Trusted Laboratory Solutions Ultra clean laminar airflow and total exhaust Available in 4-ft. and 6-ft. models Designed for work with agents on biosafety levels 1, 2, or 3 Easy and safe operation Convenient modular control center The Thermo Scientific Forma® Class II Type A/B3 Biological Safety Cabinets maintain ultra clean laminar airflow and total exhaust of the entire work area. Offering maximum personnel, product, and environment protection, the cabinets are ideal for work that generates non-explosive chemical vapors and gases. The units are available in the 4-ft. Model 1184 and 6-ft. Model 1186. As Type A/B3 biosafety cabinets, the Thermo Forma® 1184 and 1186 may be used for work with agents assigned to biosafety levels 1, 2, or 3 treated with volatile, toxic chemicals and radionuclides are required as an adjunct to microbiological studies. The Forma® 1184 and 1186 biological safety cabinets are designed for safe and easy operation. All positive pressure plenums are bounded by negative pressure interface with the cabinet shell. The convenient modular control center also provides all-out control and command along with easy maintenance. GMI was a very professional business to work with. Shipping was quick and easy. Technical Support was quick to respond. I would highly recommend GMI for all your laboratory equipment needs. Top notch customer service and vast selection of inventory. Highly recommend. Great costumer service, over delivered and got everything I needed ahead of time. Very professional transaction. Would definitely buy from GMI again. GMI were very easy and nice to work with, they quickly got in touch with me regarding a specific piece of equipment and were able to secure several options for me to choose from, letting me get to my experiments with minimal turnaround time. As a small business owner that depends on specific laboratory equipment to operate, GMI delivered on every front. We bought a Leitz 1512 microtome for our lab from this company and the product is great. Costumer service is fantastic. We are happy with our purchase and highly recommend GMI to everybody. A+ supplier. Very helpful and materials received new and ready for use right out of the box. Great experience purchasing equipment from GMI in the past and will certainly be going with them for potential future purchases! Quick responses, understood my needs and great prices! I have bought several pieces of equipment from GMI. In each case, my experience was fantastic.
I would recommend them to anyone who needs to use their services. : Thermo Scientific Forma II Type A/B3 1184 & 1186 Safety Cabinets | GMI – Trusted Laboratory Solutions What is the most commonly used type of biological safety cabinet in clinical works?The Class II Type A2 biological safety cabinet is the most common Class II cabinet. What is the difference between biosafety cabinet 1 and 2?Biosafety Cabinet History – The development of BSCs was a lengthy process, as the 1991 Clinical Microbiology Reviews paper, Biological Safety Cabinetry makes clear.1 The first report of an infection that was the result of exposure to materials in a lab came in 1893.
Thirty-nine deaths resulted. Of the 1,342 infections, only 467 had previously been made public. This pattern of infection continued in the following decades, as reported by the Centers for Disease Control and Prevention (CDC) and the National Animal Disease Center. Such reports may not have addressed the full scope of harm. Focusing only on human infection may overlook the adverse effects of poor contamination control on the work product of the labs involved. The forerunner of the biosafety cabinet appeared in 1909 when a company offered a ventilated hood to prevent infection with tuberculosis when preparing tuberculin. An enclosed cabinet was first mentioned in the scientific literature in 1943. By the early 1950s, the U.S. Army Biological Laboratories at Fort Detrick, Maryland developed and implemented sophisticated containment cabinet technology.2 The use of containment cabinets began to spread, continuing to the present.
Is there an acceptable degree of exposure in a particular instance? Does a standard exist by which the effectiveness of BSCs from different manufactures can be measured? For those reasons and others, NSF International, a standards development organization, created standard NSF/ANSI 49 that classifies BSCs into classes and types based upon the performance and protection each must meet.
To understand BSCs in light of a lab’s safety requirements, an extended look at BSCs is necessary. A cabinet that can be recirculated back into the laboratory or be exhausted through a facility’s HVAC system. It uses negative pressure from an interior blower motor or the external exhaust system, creating an air barrier at the front of the cabinet at a minimum speed of 75 linear feet per minute with the air then circulating through the cabinet.
They protect personnel and the lab environment but not the work product in the cabinet. A cabinet with a partially open front for worker access. Class II is similar to Class I in that it uses negative pressure to keep air from moving through a supply opening and the access panel. The primary difference between Class I and Class II cabinets is that a Class II cabinet creates an air barrier at the front of the cabinet by creating a vacuum using an airfoil that directs air under the work surface instead of over the work area.
There are four subtypes of Class II cabinets. Air is drawn through the cabinet’s front opening at a minimum speed of either 75 linear feet per minute or 100 linear feet per minute, depending on the subtype. Some portion or all of the air is either reintroduced into the cabinet’s work area through a supply HEPA filter or discharged back into the laboratory or building’s exhaust system through an exhaust HEPA filter. An enclosed cabinet that protects personnel and the environment. Typically designed for biosafety level 4 pathogens. Users place their hands into mounted gloves that pass through a non-open window and manipulate all work in that fashion. Blowers create a negative pressure of at least 0.5 inches of water gauge. Air enters the cabinet through a HEPA filter. Exhaust air passes through two separate HEPA filters, or a HEPA filter and an air incinerator, and finally through ducting to discharge into an exhaust system separate from the general laboratory exhaust system. Class III BSCs typically do not offer laminar airflow within the internal work area. Materials pass into the workspace through a dunk tank on the floor of the cabinet or through a double-door pass-through box that can be decontaminated between uses. The cabinets are designed for high-risk biological substances. The Class II BSC has the broadest use and is the most commonly found in labs. Kruse, RH, et. al.; “Biological safety cabinetry”; Clinical Microbiology Reviews; April 1991; pp.207-241 Barbeito, Manuel S. and Kruse, Richard H.; “A History of the American Biological Safety Association Part I: The First 10 Biological Safety Conferences 1955-1965”; American Biological Safety Association; https://www.absa.org/abohist1.html “Biosafety in Microbiological and Biomedical Laboratories”; Centers for Disease Control; December 2009; https://www.cdc.gov/biosafety/publications/bmbl5/index.htm Class I Containment Ventilated Enclosures The NU-813 Class I Containment Ventilated Enclosure (CVE)’s versatile design can be configured to compound non-sterile drugs in pharmacies or to provide personnel protection in microbiology labs. Class II Type A2 Biosafety Cabinets The NU-543 is configurable for a broad range of applications and geographies with a choice of NSF listed access openings, an optional smooth interior, EN 12469 listed configurations, and a global supply chain.
Minimize workplace injuries working in the comfort of a LabGard Biosafety Cabinet. : biosafety-cabinet-classes-article What is the difference between biosafety cabinets?Biosafety Cabinets vs. Fume Hoods – Both chemical fume hoods and biosafety cabinets are specialized types of laboratory equipment. While chemical fume hoods and biosafety cabinets look similar and both protect laboratory workers from laboratory hazards – their purpose, function, and operation differ significantly.
A chemical fume hood protects the user while a biosafety cabinet protects the user, the environment, and the material. Biosafety cabinets have high-efficiency particulate air (HEPA) filters while chemical fume hoods do not. The HEPA filter in the exhaust system of a biosafety cabinet will effectively trap all known infectious agents and ensure that only microbe-free exhaust air is discharged from the cabinet (i.e., 99.97% of particles 0.3 µm in diameter and 99.99% of particles of greater or smaller size).
The chart below characterizes the differences between a chemical fume hood and a biosafety cabinet. What is the primary difference between the Class II type A1 A2 and B1 B2 cabinets?NSF defines four types of Class II cabinets (A1, A2, B1 and B2) that are distinguished by differences in airflow patterns and velocities, HEPA air filter positions, ventilation rates and exhaust methods.  
By Jack Gloop |