Class 1 Biological Safety Cabinets – The Class 1 biological safety cabinet provides personnel and environment protection for the safe handling when working with chemicals and powders. The air enters the cabinet via the front aperture passing through a built-in exhaust fan, HEPA and/or Carbon filter, thus providing operator and environmental protection. The air then exits the cabinet at the rear of the work surface. The escape of any airborne particulates generated within the cabinet are therefore controlled by means of the inward airflow through the front aperture and by filtration/absorption of the exhausted air. Unlike fume hoods, the HEPA filter in the cabinet protects the environment by filtering the air before it is exhausted. A Class 1 Safety Cabinet is not appropriate for handling research materials that are vulnerable to airborne contamination, since the inward flow of unfiltered air from the laboratory can carry microbial contaminants into the cabinet. In these circumstances a Biological Safety Cabinet Class II is more applicable.

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What is the difference between Class 1 and Class 2 biological safety cabinet?

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. The main differences are their minimum inflow velocities and exhaust systems.

What is a Class I biosafety cabinet?

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.

1. In pharmacy settings, these hoods are referred to as chemo hoods.
2. Class II BSCs are designed with an open front with inward airflow (personnel protection), downward HEPA-filtered laminar airflow (product protection) and HEPA-filtered exhaust air (environmental protection).
3. These cabinets are further differentiated by types based on construction, airflow and how they interface with exhaust systems — A1, A2, B1, B2 and C1.

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 the 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.

What is the difference between a biological safety classes I II and III cabinet and a fume hood?

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 a Class 2 microbiological safety cabinet?

Frequently Asked Questions – – Handling of low to moderate risk biological agents -Applicable for handling pathogens under Risk Groups 1,2, and 3 Class II Biosafety Cabinets are open-fronted which protect the laboratory workers and the environment from harmful biological agents.

1. Class II BSCs also prevent biological materials (i.e cell cultures, microbiological stocks) inside it from being contaminated.
2. Yes, Class II BSC is the most common type used for handling blood, serum, and urine samples.
3. The Class II BSC provides a sterile environment for the samples and reduces the risk of cross-contamination while protecting the operators from the biohazards.

Gaseous decontamination is required when: – the biological safety cabinet needs to have its filter replaced. – the biosafety cabinet is relocated to another area or facility – the BSC will undergo certification. The decontamination provides more protection for the engineer who will be certifying the cabinet.

– there are cases of major spills Esco recommends the use of 70% Isopropyl alcohol as a cleaning agent for all biosafety cabinets. Cleaning agents with bleach or are chlorine-based must be avoided as it may cause rusting or staining. No. Open flame should not be used in a BSC. The heat from the flame disrupts the airflow containment and can be dangerous when volatile or flammable substances are also used.

Microburners, microincenerators, or electric furnaces are available as alternatives. When deemed absolutely necessary, the bunsen burner can only be used with its flame at its lowest level. Type A biological safety cabinet has a ductless design. It has a plug-and-play feature which means that once the unit is delivered and installed, it can be immediately used.

1. Type B biosafety cabinet requires a ducting system.
2. The laboratory must have a sufficient space and height clearance since this type of BSC needs an installation and exhaust blower.
3. Some microbiological processes require small amounts of chemicals.
4. This type of handling is allowed as biological safety cabinets may be upgraded to have a thimble ducting or carbon filter to accommodate small volumes of chemicals.

However, a high concentration of corrosive acids is not allowed as it may damage the ULPA filters and cause corrosion. Esco Class II Biosafety Cabinets have audio and visual alarms for: – unsafe sash height – airflow failure Yes. For additional convenience, Class II BSCs can be customized to have a microscope pouch.

What is a Class 3 biosafety cabinet used for?

Article – 12/14/2020 John Peters The Class III biological safety cabinet was designed for work with biosafety level 4 (BSL-4) microbiological agents, and provides maximum protection to the environment and the worker. It is a gas-tight enclosure with a non-opening, completely sealed, viewing window.

• Access to the interior of the cabinet is through a double-door pass-through “interchange” box (such as an autoclave) that can be decontaminated between uses and/or a dunk tank that is accessible through the cabinet floor into the floor of a Class I or Class II cabinet.
• Reversing that process allows for safe removal of materials from the Class III biosafety cabinet.

Both supply and exhaust air are HEPA filtered. Exhaust air must pass through two HEPA filters, or a HEPA filter and an air incinerator, before discharge to the outdoors. Air flow is maintained by a dedicated independent exhaust system exterior to the cabinet, which keeps the cabinet and all associated ducting under negative pressure (usually about 0.5 inches of water pressure).

• Long, heavy-duty rubber gloves are attached in a gas-tight manner to ports in the cabinet and should permit replacement without compromising containment.
• Although these gloves restrict movement for the manipulation of the materials isolated inside the cabinet, they prevent the user’s direct contact with the hazardous materials.

The trade-off is clearly on the side of maximizing personal safety. Depending on the design of the cabinet, the supply HEPA filter provides particulate-free, somewhat turbulent, air flow within the work environment. To minimize interior turbulence, however, the inflow air should be ducted to a distribution manifold located on the rear wall just above the work surface.

The distribution manifold also provides the means to house an anti-static bar, bathing plastic materials with both positive and negative ions. Several Class III cabinets can be joined together in a “line” to provide a larger work area. Such cabinet lines are custom-built; the equipment installed within the cabinet line (e.g., refrigerators, small elevators, shelves to hold small animal cage racks, microscopes, centrifuges, incubators, etc.) is generally custom-built as well.

Furthermore, Class III cabinets are usually only installed in maximum containment laboratories that have controlled access and require special ventilation or other support systems (such as steam for autoclaves). The reader should consult more definitive literature on these systems.

What is the difference between Class 2 A2 and B2?

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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.

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.
2. A2 type is 30% efflux, 70% internal circulation; B2 type is 100% efflux, 0 internal circulation.2.
3. 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.

1. Designed for the possible generation of infectious aerosols and splashes.
2. Biological safety cabinets are widely used in medical and health care, disease prevention and control, food hygiene, biopharmaceuticals, environmental monitoring, and various biological laboratories.
3. 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 are the 3 biological safety cabinets?

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 a Class 2 Type A2 biosafety cabinet?

class-ii-type-a2-biosafety-cabinet-how-it-works-article 12/4/2020 Seth De Penning A Class II, Type A2 Biosafety Cabinet is given its Class and Type based on performance criteria developed by performance standard NSF/ANSI 49. A Class II, Type A2 Biosafety Cabinet (BSC) provides personnel, product, and environmental protection through filtered air, laminar or unidirectional air, and a motor blower.

1. Room air is drawn in through the front grill of the cabinet.
2. The air is pulled under the work surface and through a back wall plenum through a motor blower.
3. This contaminated air is then pushed into the central plenum, where a small portion (30%) of air is exhausted out of the top of the cabinet through a HEPA filter.

The remaining air (70%) is re-circulated back into the work zone through a HEPA filter in a laminar (unidirectional) pattern. The air then splits on the work surface, pulled through the back wall grill, around the edges of the work surface, and back through the front airflow grill, where it is pulled under the work surface to start the air recirculation process. Personnel protection is created by an air barrier at a minimum of 100 FPM (0.51 m/s) at the front of the cabinet, where laboratory and work surface air are pulled into the front air grill. Product protection is created through laminar airflow over the work surface.

1. The unidirectional pattern minimizes cross-contamination.
2. Environmental protection is created by filtering the exhaust airflow through a HEPA filter.
3. A Class II, Type A2 BSC used for work with minute quantities of non-flammable or explosive volatile toxic chemicals and tracer amounts of radionuclides required as an adjunct to microbiological studies must be exhausted through properly functioning exhaust canopies.

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. Class II Type A2 Biosafety Cabinets The NU-581 LabGard® is specialized for work with cytotoxic powders by integrating a third tier of HEPA filtration under the work surface and using the most sophisticated airflow monitoring and user interface.

Class II Type A2 Biosafety Cabinets The console style NU-640 biological safety cabinet features the tall work access opening needed to work with large cages but in a low-profile configuration designed to fit in vivariums with low ceiling heights. What you should know about the physics governing biosafety cabinet functions, construction, specifications, and practical implications of these properties.

Understand how a Class II, Type B2 Biosafety Cabinet operations. Cookies help us improve your website experience. By using our website, you agree to our use of cookies. : class-ii-type-a2-biosafety-cabinet-how-it-works-article

What is Class II B2 biosafety cabinet?

How a Class II, Type B2 Biosafety Cabinet Works 2/22/2021 Seth De Penning Class II Type B2 biosafety cabinet, the inflow into the front access opening provides personnel protection, the filtered and laminar downflow in the work zone provides product protection, and the filtered exhaust provides environmental protection, just like they do in any Class II biosafety cabinet.

However, the Type B2 cabinet cannot function autonomously, It must be matched with an external exhaust blower that has enough power to not only pull the inflow into the front of the cabinet but also continue to pull the exhaust air through and out of the cabinet and inside the ductwork towards itself.

The internal motor’s only contribution is to draw new air in from the room through an opening at the top of the cabinet and propel it past the supply HEPA filter towards the work zone to provide downflow. Suppose the external exhaust blower stops working and no longer creates enough “pull” to keep air flowing toward the work zone.

• In that case, it is critical that the internal blower no longer force air down into that work zone where it can ultimately flow out towards the user and carry hazardous particles with it.
• Under normal operation, the air that the internal blower pushes down into the work zone merges with the air that is sucked into the front access opening.

Together, both are pulled out of the cabinet entirely by the external exhaust blower. No air is ever rerouted back to the work zone downflow.

What is Class 2 type B2 biosafety cabinets?

Labculture® Class II Type B2 (Total Exhaust) Biosafety Cabinets LB2-_B_-E Esco Labculture® Class II Type B2 biosafety cabinets (LB2) are NSF-49 certified and are designed to provide operator, product, and environmental protection in experiments where recirculation of filtered air is prohibited, most likely due to the presence of chemical fumes emitted during the process.

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Labculture® Class II Type B2 (Total Exhaust) Biosafety Cabinets

What does a Level 2 biosafety cabinet protect?

Class 3 – Class 3 biosafety cabinets provide the highest level of protection possible. They protect people, the environment, and work samples, and they can be used with extremely infectious biological agents. Class 3 BSCs are fully-sealed, airtight cabinets that put a comprehensive physical barrier between workers and the substances they’re handling.

Biosafety Level 1: Level 1 microbes aren’t known to cause disease in healthy adults and pose a minimal risk for both workers and the environment. No special containment equipment is required for level 1 projects, and the work can be conducted at a standard lab bench, Biosafety Level 2: Level 2 microbes are moderately pathogenic and can cause disease. Labs working with level 2 materials have self-closing doors and require workers to wear protective equipment. Biosafety Level 3: Level 3 microbes can be transmitted through the air and inhaled. They can cause serious and sometimes life-threatening diseases. Labs working on level 3 projects have self-closing and self-locking doors. Exhaust is never recirculated, but instead replaced by fresh outside air. These labs require workers to wear protective equipment, and they may require respirators as well. Biosafety Level 4: Level 4 microbes are highly contagious and extremely life-threatening. In many cases there aren’t treatments available for those who become infected. Level 4 projects require maximum containment and protection at all times. Workers must change clothes upon entering the lab, and they must shower and decontaminate all materials before leaving the protected area.

Is a biological safety cabinet the same as a biosafety cabinet?

From Wikipedia, the free encyclopedia

A biosafety cabinet ( BSC )—also called a biological safety cabinet or microbiological safety cabinet —is an enclosed, ventilated laboratory workspace for safely working with materials contaminated with (or potentially contaminated with) pathogens requiring a defined biosafety level,

Can you use a BSC as a fume hood?

Are Ductless Fume Hoods the Same as Biosafety Cabinets? – BSCs may be referred to as ductless fume hoods. However, fume hoods are meant specifically to protect against chemicals and vapors from entering into the lab environment. Ductless fume hoods are not officially BSCs, but they can offer protection from particulates when fitted with HEPA/ULPA filters.

What is the difference between laminar flow hood and biological safety cabinet?

A Laminar Flow Hood (LFH), is not a biological safety cabinet. These devices do not provide any protection to the worker. They are designed to provide a sterile environment to protect the product. Air potentially contaminated with infectious agents may be blown towards the worker.

What is the difference between Class 1 and Class 2 hoods?

So to break it down as simple as possible – go with a Type 1 Hood for cooking equipment that can lead to grease and grease by-products, and go with a Type 2 Hood for other kitchen appliances and equipment that require removal of heat and moisture.

What is the difference between biosafety cabinet Class 2?

Class II A2 (Recirculating) – Class II biosafety cabinets take that level of protection up a notch, and in some cases, the design can become quite complex. In the simplest terms, this class of cabinet offers the same as Class I, but in addition to protecting the user from hazards, it also protects the sample in the cabinet from the surrounding environment.

In a similar design to Class I, there is still an inward airflow through the open front sash. A HEPA filter still cleans the exhausted air, but a key difference is that an additional HEPA filter filters 70% of the air and directs it vertically down onto the work surface in a Laminar Flow. This laminar flow clean air stream ensures the sample being worked on maintains its sterility and prevents cross-contamination.

There are minimum average airflow velocity requirements (depending on the type) and a range of exhaust arrangements that can recirculate clean air within the exhaust and the working chamber. This class of cabinet in A2 format are a primary focus of TION, as these are by far the most popular specifications in the industry.

Class II B2 (Ducted) A Class II B2 Biosafety cabinet works exactly the same as a Class II A1 cabinet, with one difference. Instead of recirculating the air in the chamber, 100% of the contained air is exhausted to the atmosphere through a HEPA filter. To maintain a vertical stream of laminar flow clean air onto the workbench, an auxiliary fan is installed in the cabinet that draws air through a HEPA filter and onto the work surface.

This air is then extracted through the exhaust HEPA and to the atmosphere.

What is the difference between Type A and Type B biosafety cabinet?

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

Type A Cabinets The two major differences between Type A1 and Type A2 cabinets:

1. 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.
2. 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

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:

1. A user must work behind the smoke split when handling hazardous chemicals and therefore must be trained to work very conscientiously.
2. The smoke split is an invisible line that can only be identified by using smoke or another visual aid.
3. 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 most common biosafety cabinet?

Sensors, Sash, and Controls –

• These parts can wear out over time
• They may require gaseous decontamination depending on where the part is located and whether it could have come in contact with contaminated air

Gaseous decontamination is required before the replacement of HEPA filters, repair of blower motors, or disposal of a BSC. There are multiple methods: Vaporous hydrogen peroxide (VHP) is the preferred method:

• Shorter decontamination time
• Generally an overnight process
• Lower chemical safety risk than formaldehyde gas
• The cabinet is sealed during decontamination, but the lab is generally inaccessible for 8 hours
• Generally costs around $500

Formaldehyde Gas:

• Longer decontamination time (generally 24 hours)
• Higher chemical safety risk due
• Gas must be scrubbed after decontamination
• Cabinet sealed but the lab is inaccessible during decontamination
• Generally costs around $500

The use of UV light sterilization has been a traditional staple of sterile tissue culture work in BSCs. However, current guidance does not recommend relying on UV sterilization to ensure disinfection as multiple studies found that labs were not properly maintaining their UV lights and there are no established standards for testing UV lights.

• UV lights are not tested during annual certification.
• MIT Biosafety does not recommend the use of UV lights.
• For more information, please see the topics below.
• UV Lights are only effective for surface decontamination of areas exposed to the UV light.
• Areas in the shadows of equipment or beneath paper/plastic will not be decontaminated.

UV bulbs have a limited shelf life before they lose effectiveness:

• Average 6-8 month shelf life
• Light will shine blue even after expired
• Only 85% efficiency after 6000 hours of use

Particles can build up on the surface of the bulb:

• Reduces efficiency
• Requires weekly surface decontamination

There are no NSF/ANSI standards for testing and they are not tested during annual certification of the BSC. UV lights are no longer recommended by:

• American Biological Safety Association (ABSA International, 2000)
• National Sanitation Foundation (NSF International 2004)
• Centers for Disease Control and Prevention (CDC, 2009)

1. Research showed labs were not replacing and maintaining bulbs regularly which generated a false sense of security regarding sterility.
2. Newer cabinets are not constructed with UV lights and UV lights must be added as a custom feature (required additional cost).
3. UV light use can lead to exposure and harm upon skin or eye contact.
4. Guidance for Labs Who Choose to Use UV Lights

• Always use chemical disinfectant before and after BSC use; UV sterilization cannot be used as the primary method of disinfection
• Do not use UV lights while research is being performed in the cabinet; newer cabinets have interlocks that prevent the UV light from activating when the sash is open, but older cabinets may not have this safety feature
• Minimize equipment stored in the BSC to prevent unnecessary exposure; UV light will degrade plastic over time (such as pipettes, waste containers, and vacuum line tubing)
• Use appropriate exposure time:
  • Most agents are inactivated after 10-15 minutes
  • Maximum sterilization time should be limited to 30 minutes – after 30 minutes there is no additional benefit
  • Turn UV light off after sterilization time to conserve bulb life and energy (sustainability)

For additional information, please refer to the following articles:

• American Biological Safety Association (2000). Position Paper on the Use of Ultraviolet Lights in Biological Safety Cabinets
• Burgerner, J. (2006). Position Paper on the Use of Ultraviolet Lights in Biosafety Cabinets. Applied Biosafety 11 (4): 228–230
• Meechan P, Wilson C (2006). Use of Ultraviolet Lights in Biological Safety Cabinets: A Contrarian View. Applied Biosafety 11 (4): 222–227
• Centers for Disease Control and Prevention; The National Institutes of Health. Biosafety in microbiological and biomedical laboratories.5th ed. Washington, DC.2009
• NSF International (NSF); American National Standards Institute (ANSI). NSF/ANSI Standard 49-2007. Class II (laminar flow) biosafety cabinetry. Ann Arbor (MI); 2004

• Spills on the Cabinet Work Surface
• Keep cabinet running to contain aerosols and follow the normal biological spill cleanup protocol:

• Keep cabinet running
• Assess situation and ensure you are wearing appropriate PPE
• Gather your biological spill kit and appropriate disinfectant
• Cover spill with paper towels
• Saturate paper towels with disinfectant
• Allow 10 minute contact time
• Pick up paper towels and debris with tongs and dispose as biowaste or biosharps (for any broken glass)
• Surface disinfect to remove any residual contamination and wait 5-10 minutes or until air dry
• Rinse with 70% ethanol or sterile water to remove residual disinfectant (this is required if you use 10% bleach)
• Dispose of all paper towels as biowaste, remove gloves, and wash hands

1. Large Spills into Catch Basin

• Keep cabinet running
• Assess situation and ensure you are wearing appropriate PPE
• Gather your biological spill kit and appropriate disinfectant
• Ensure drain valve is closed
• Pour disinfectant onto surface and through grills
• Allow at least 10 minute contact time
• Use paper towels to soak up residual disinfectant from work surface
• Pick up paper towels and debris with tongs and dispose as biowaste or biosharps (for any broken glass)
• Connect flexible tubing to drain valve
• Drain basin into disinfectant filled container
• Lift work surface
• Decontaminate catch basin (see maintenance section above for details) with appropriate disinfectant and wait 5-10 minutes
• Rinse with 70% ethanol or sterile water to remove residual disinfectant (this is required if you use 10% bleach)
• Dispose of all paper towels as biowaste, remove gloves, and wash hands

Researchers should receive training prior to working in a BSC. Often labs will have a more experienced researcher provide training to a new lab member. Biosafety can provide Biosafety Cabinet Training (EHS00257C) if requested, This training is recommended even for experienced users starting at MIT, but is not currently required unless researchers will work in BL2+ containment labs.

• Contact for additional guidance and consultation if you plan to relocate a BSC or purchase a new one.
• Other Ventilation Equipment

There are a variety of different styles of ventilation equipment used under different conditions. Some provide containment, others do not. The nature of your material and whether the material needs to be handled in a sterile environment will determine what type of ventilation you need.

Even different styles of BSCs can vary in function and protection provided. Chemical Fume Hoods are used to protect personnel from toxic chemical fumes. Hazardous chemicals are handled inside the fume hood chamber. Single pass air draws toxic fumes through building exhaust fans and leaves an air stack at top of the building.

Fume hoods can be either constant flow (less energy efficient) or variable flow (more energy efficient as air flow is adjusted depending on whether the hood is in use). Key Features:

• Lacks internal blower motor so is completely reliant on building exhaust fan to provide airflow
• For use with toxic chemicals
• Provides personnel protection only
• No supply HEPA filters so workspace is a non-sterile environment (no product protection)
• No exhaust HEPA filters (so no environmental protection from biological agents; chemical concentration reduced to acceptable levels through dilution with environmental air)

1. Clean Bench/Laminar Flow Hood

Clean bench or laminar flow hoods are for use with nonhazardous sterile work (such as PCR or media preparation). They should not be used with hazardous materials (including biological material, hazardous chemicals, or radionuclides). Key Features:

• For use with nonhazardous sterile work (such as PCR or media preparation)
• Supply HEPA filter provides product protection
• No exhaust HEPA filter (so no personnel or environmental protection)

Some laminar flow hoods can be easily mistaken for a biosafety cabinet at a glance. If the instrument blows air into your face, it is not a biosafety cabinet and provides no containment.

• Animal Transfer/Cage Changing Station

Animal transfer or cage changing stations are generally used to reduce allergens when working with animals. They must not be used with animals containing hazardous material including biological material, hazardous chemicals, or radionuclides. Key Features:

• Supply HEPA filters provide some product protection
• Exhaust HEPA filter provides some room protection
• Does not provide full personnel or environment protection since the sash is open

This is the original style of biosafety cabinet. Key Features:

• Only provides personnel and environmental protection
• No supply HEPA filter (no product protection); not a sterile chamber
• Largely replaced by Class II biosafety cabinets
• Only used in specialized circumstances where product protection is not needed

This is an older style of biosafety cabinet. Key Features:

• Similar to Class II Type A2 except that the plenum is under positive pressure due to the motor placement
• Does provide personnel, product, and environmental protection
• Requires plenum seal to be leak tested during annual recertification
• Increased safety risk since a plenum seal leak could lead to non-HEPA filtered and contaminated air escaping into the lab
• Largely replaced by Class II Type A2 cabinets

This BSC is used for biological work with higher concentrations of hazardous chemicals. Key Features:

• “Partial Exhaust” cabinet in that work done in front part of chamber is recirculated and work done in rear of chamber is completely exhausted
• Hazardous chemical work done in rear of chamber for complete exhaust
• Blower motor interlocked with building exhaust fan
  • If building exhaust fails, blower motor turns off to avoid pressurization
  • Protects operator from exposure to hazardous biological and chemical material
• Airflow patterns are complicated and this BSC requires special installation and recertification
• 3 rd HEPA filters can require more expensive maintenance
• More energy efficient than a Class II Type B2 BSC, but more energy intensive than a Class II Type A2 with a canopy connection
• Only required for specialized situations where higher concentrations of volatile toxic chemicals must be used with biological material under sterile conditions
• Contact your biosafety officer for a risk assessment before purchasing a Class II Type B1 BSC

The BSCs are used for biological work involving higher concentrations of hazardous chemicals. Key Features:

• Similar to a chemical fume hood with HEPA filters
• “Total Exhaust” cabinet since no air is recirculated (single-pass air)
• Blower motor interlocked with building exhaust fan
  • If building exhaust fails, blower motor turns off to avoid pressurization
  • Protects operator from exposure to hazardous biological and chemical material
• Single pass air is very energy inefficient
• Airflow patterns are complicated and this BSC requires special installation and recertification
• Only required for specialized situations where higher concentrations of volatile toxic chemicals must be used with biological material under sterile conditions
• Contact your biosafety officer for a risk assessment before purchasing a Class II Type B2 BSC

These are a new style of cabinet that can function either as a Class II Type A2 cabinet or a Class II Type B cabinet. Currently only one vendor manufacturers this cabinet. Please visit the for more details. Key Features:

• Allows flexibility since the connection type can be modified to meet changing research needs
• More energy efficient than Class II Type B cabinets
• Has improved safety features for handling hazardous chemicals

Modes of Operation:

• Operate non-ducted for only biological material
• Can be canopy connected for work with biological material and small amounts of chemicals (requires MIT Facilities work to convert into or out of this mode)
• Can be hard ducted for work with biological material and higher concentrations of chemicals (requires MIT Facilities work to convert into or out of this mode)

These BSCs have a gas-tight containment chamber with gas-tight sealed sash. Key Features:

• User has no direct contact with the samples
• Samples enter chamber through a bypass chamber
• User interacts with samples through thick gloves built into the chamber
• Differs from a chemical glove box used to handle chemicals under inert gas conditions in that Class III BSC’s are under negative pressure (air would flow into the chamber from the room upon a leak) whereas chemical glove boxes are generally under positive pressure (gas would flow out of the chamber into the room upon a leak)

• U.S. Department of Health and Human Services; U.S. Public Health Services; Centers for Disease Control and Prevention; U.S. National Institutes of Health (2009). Biosafety in Microbiological and Biomedical Laboratories, 5th edition, 2009, pp.290-325.
• ABSA Principles & Practices of Biosafety, Containment Equipment module, 2014, Paul Meechan, Hallie Hoskins; ABSA International
• Eagleson Institute, Safety Cabinet Technology, Introduction to Biological Safety Cabinets module, 2016, Dave Stuart

A biosafety cabinet (BSC) is a primary containment device used with biological material. While handling biological agents, it is the biological equivalent of using hazardous chemicals inside a fume hood. Like a chemical fume hood, a biosafety cabinet protects the user from hazardous material using directional air flow.

2. How Biosafety Cabinets Work

The Class II Type A2 biosafety cabinet is the most common cabinet on campus. It uses a curtain of air and HEPA filters to provide both containment and a sterile environment. Biosafety cabinets can be used with any biological agent including bacteria, viruses, viral vectors, fungi, parasites, human/animal tissue and cell lines, and prions. They should not be used with:

• Large amounts of volatile or toxic chemicals
• Concentrated flammable chemicals
• Volatile radionuclides
• Open flames (for more information see the Policies section below)

A biosafety cabinet provides three layers of protection:

1. Personnel — Air curtain and HEPA filters protect users from biohazardous aerosols generated inside the chamber
2. Sample Protection — Recirculating and unidirectional HEPA filtered air protect samples from contamination from unsterile lab air
3. Lab/Environmental protection — HEPA filtered exhaust from top of cabinet protects the lab environment from contamination by biohazardous aerosols generated inside the chamber

HEPA filter (High-Efficiency Particulate Air or High-Efficiency Particulate Arresting filters) are fibrous filters that remove particles from air passing through them. HEPA filters consist of a metal or wood frame holding a long, folded strip of cellulose or borosilicate fiber.

• Fibrous material is used to separate biological material from air passing through the filter
• Particles are “trapped” by the fibers and removed from the air as it flows through the filter
• Multiple, folded sheets of fibrous material drastically increase the surface area of the filter
• Increased surface area drastically increases the efficiency of filtration

HEPA filters remove biological aerosols through several mechanisms:

• Fast-moving particles are filtered through direct impact with fibers
• Large particles are removed by straining effect when particles become trapped between two fibers
• Smaller particles are removed by interception
• Very small particles move by Brownian motion and are removed by diffusion when they come in contact with fibers
• Negatively charged particles (such as some viral particles) are removed by electrostatic attraction to the slightly positive charge of the fibers

1. Nonsterile room air is drawn into the front of the cabinet and mixes with contaminated air from the chamber
2. Contaminated air:
   • pushed below the work surface
   • then drawn up through the plenum
   • then pushed through the HEPA filters by the cabinet blower motor
3. Around 30% of the air passes through the exhaust HEPA filter at the top of the cabinet and recirculates into the room or is removed by the canopy exhaust
4. Around 70% of the air passes through the supply HEPA filter, enters the cabinet from above, and flows back down on work surfaces under unidirectional flow

There are three different connection types for biosafety cabinets (BSC):

1. Non-ducted or recirculating biosafety cabinets (also called unducted or free standing)
2. Canopy/thimble connected biosafety cabinets
3. Hard ducted/direct ducted biosafety cabinets (no longer NSF compliant)

• Class II Type A2 cabinets are designed to function independently from the building or room exhaust (non-ducted BSC)
• Biological material passes through the exhaust HEPA filter of the cabinet and is removed
• Exhaust air can safely recirculate back into lab if handling biological material at BL1 or BL2 containment
• Volatile or toxic chemicals and volatile radionucleotides require a canopy connected cabinet
• Most work at BL2+ containment requires a canopy connected cabinet as an extra precaution; for some BL2+ research, the PI can request an exemption from the CAB/ESCRO which will be reviewed on a case-by-case basis

• Canopy/Thimble Connected BSCs
• Class II Type A2 cabinets can be connected to the building exhaust through the addition of a canopy or thimble connection:

• This leaves a small air gap between the exhaust of the cabinet and the connection to the building exhaust which avoids the airflow reversal problems of hard ducted cabinets describe below
• A canopy can be used with minute amounts of volatile or toxic chemicals or volatile radionuclides
• The HEPA filters will not remove chemicals but these particles will be exhausted through the building exhaust
• If building exhaust fails, the canopy will allow the exhaust to flow back into the room rather than pressurizing and blowing non-HEPA filtered air back into the operators’ face
• NSF standard 49 also calls for the addition of a canopy airflow alarm which warns operators that building exhaust is no longer sufficient to remove the exhaust air from the canopy (see below)

NSF standard 49 requires that canopy connected Class II Type A2 biosafety cabinets have an airflow alarm. Airflow alarms monitor the airflow passing through the canopy and measures whether it is sufficient to capture the exhaust air exiting the cabinet:

• When airflow is disrupted (typically because an exhaust fan has failed or lost capacity), the alarm will alert the operator they have lost containment of exhaust and the cabinet is now recirculating back into the lab
• This does not pose a safety risk for experiments only handling biological agents since the exhaust air has already passed through the HEPA filters
• For experiments using minute amounts of volatile toxic chemicals or volatile radionuclides, this could cause an exposure risk depending on the nature and concentration of the material

Alarms can be integrated into the cabinet or installed as a separate piece of hardware.

How many levels of biosafety cabinet are there?

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.

1. There are many ways to combine equipment, practices, and laboratory design features to achieve appropriate biosafety and biocontainment.
2. These are determined through biological risk assessments specifically conducted for each experimental protocol.
3. 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 the difference between a B1 and B2 biosafety cabinet?

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.

• Eep 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

Type A Cabinets The two major differences between Type A1 and Type A2 cabinets:

1. 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.
2. 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

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:

1. A user must work behind the smoke split when handling hazardous chemicals and therefore must be trained to work very conscientiously.
2. The smoke split is an invisible line that can only be identified by using smoke or another visual aid.
3. 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 the classes of biosafety cabinets?

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 biosafety cabinet Class 2?

Class II A2 (Recirculating) – Class II biosafety cabinets take that level of protection up a notch, and in some cases, the design can become quite complex. In the simplest terms, this class of cabinet offers the same as Class I, but in addition to protecting the user from hazards, it also protects the sample in the cabinet from the surrounding environment.

In a similar design to Class I, there is still an inward airflow through the open front sash. A HEPA filter still cleans the exhausted air, but a key difference is that an additional HEPA filter filters 70% of the air and directs it vertically down onto the work surface in a Laminar Flow. This laminar flow clean air stream ensures the sample being worked on maintains its sterility and prevents cross-contamination.

There are minimum average airflow velocity requirements (depending on the type) and a range of exhaust arrangements that can recirculate clean air within the exhaust and the working chamber. This class of cabinet in A2 format are a primary focus of TION, as these are by far the most popular specifications in the industry.

Class II B2 (Ducted) A Class II B2 Biosafety cabinet works exactly the same as a Class II A1 cabinet, with one difference. Instead of recirculating the air in the chamber, 100% of the contained air is exhausted to the atmosphere through a HEPA filter. To maintain a vertical stream of laminar flow clean air onto the workbench, an auxiliary fan is installed in the cabinet that draws air through a HEPA filter and onto the work surface.

This air is then extracted through the exhaust HEPA and to the atmosphere.

What does a Level 2 biosafety cabinet protect?

Class 3 – Class 3 biosafety cabinets provide the highest level of protection possible. They protect people, the environment, and work samples, and they can be used with extremely infectious biological agents. Class 3 BSCs are fully-sealed, airtight cabinets that put a comprehensive physical barrier between workers and the substances they’re handling.

Biosafety Level 1: Level 1 microbes aren’t known to cause disease in healthy adults and pose a minimal risk for both workers and the environment. No special containment equipment is required for level 1 projects, and the work can be conducted at a standard lab bench, Biosafety Level 2: Level 2 microbes are moderately pathogenic and can cause disease. Labs working with level 2 materials have self-closing doors and require workers to wear protective equipment. Biosafety Level 3: Level 3 microbes can be transmitted through the air and inhaled. They can cause serious and sometimes life-threatening diseases. Labs working on level 3 projects have self-closing and self-locking doors. Exhaust is never recirculated, but instead replaced by fresh outside air. These labs require workers to wear protective equipment, and they may require respirators as well. Biosafety Level 4: Level 4 microbes are highly contagious and extremely life-threatening. In many cases there aren’t treatments available for those who become infected. Level 4 projects require maximum containment and protection at all times. Workers must change clothes upon entering the lab, and they must shower and decontaminate all materials before leaving the protected area.

Jack Gloop