Biological Safety Cabinet Purchasing Guide

March 13, 2022 | Buyers' Guide

Frequent exposure to various biohazards during laboratory operations can lead to potentially harmful and even deadly outcomes when left uncontrolled. Which is why acquiring a Biological Safety Cabinet for your facility is so necessary. By purchasing a BSC, you help protect your personnel and the lab environment from accidental contamination caused by viruses, bacteria, toxic chemicals, bodily fluids, and other materials.

To ensure that your laboratory functions at the highest level of safety, you should purchase a Biological Safety Cabinet that not only fits well into your lab space, but also houses the correct BSC class and functionalities appropriate for your lab application. However, choosing a good BSC unit amongst all the available manufacturers that also comes at a reasonable price is easier said than done.

To save you some time on comprehensive equipment comparisons and research, Laboratory App has prepared a complete and detailed guide to walk you through all the important factors to consider. Learn how to assess your laboratory's biological safety level and area compatibility, distinguish between BSC classes, and pick out customizable features. Plus, get additional tips on buying a biological safety cabinet that's friendly on the pocket and learn about the various warranties and services that you should expect from your potential equipment provider.

Assessing Your Laboratory's Application Demands

The first thing to consider when selecting a BSC unit is to determine which cabinet classification and type can best meet your needs while providing maximum protection throughout your application procedures. There are three main biological safety cabinets classifications: Class I, Class II, and Class III. Each class provides protection through the use of high efficiency particulate air (HEPA) filters that are combined with different cabinet configurations per class.

To identify which classification would suit your facility, you have to select the class in accordance to your application’s biosafety level, the type of protection you need, and whether you need protection from radionuclides and volatile toxic chemicals. 

Here’s a breakdown of guide questions to help assess your application demands so you can properly identify which BSC class is suitable for your lab:

1. What is your laboratory’s biological safety level:

Get in touch with either a Certified Biosafety Professional (CBSP) or an Industrial Hygienist and have them perform a proper risk assessment of your laboratory and the materials you are using. Knowing your lab’s biological safety level will help you identify the appropriate biosafety cabinet class that will provide you the specific protection you need for your research applications.

There are four established levels of biological safety, each ranked according to the agents or organism being used. The first biological safety level refers to the work involving materials that are non-pathogenic agents. Biosafety level one has the lowest level of risk since it poses no threat of infection to staff. Because of the minimal potential threat, standard microbiology practices are more than enough to keep laboratory workers safe. The second biosafety level applies to research involving pathogenic or infectious organisms, agents associated with human diseases like influenza or HIV. Biosafety level 3 facilities are often characterized by procedures that deal with agents that can cause potentially lethal diseases like tuberculosis, yellow fever, West Nile virus, and St. Louis encephalitis. Work in BSL 3 facilities adhere to stringent safety measures and the environment is very carefully controlled. Still, all of these three levels pose little to moderate risk agents and can be performed with either class 1 or 2 BSCs. The fourth biosafety level however, is a different story. BSL 4 agents pose the highest individual and community threat because of their potential to cause serious or lethal diseases with no therapeutic and preventive intervention available. Applications with this degree of risk are best performed within a Class III BSC.

2. What do you need to protect?

Once you have assessed your workspace biosafety level, the next step is to identify the biosafety cabinet class that can provide you with the protection you need.

Class I BSC’s were mainly designed for personnel and environment protection. Personnel protection is achieved through constant air movement directed into the cabinet and away from the user. Before the air is exhausted it passess through a filter which prevents the release of harmful fumes into the surrounding environment. While class one biosafety cabinets are suitable for facilities that work with low to moderate risk agents needing containment, bear in mind that this BSC class does not protect products from contamination. 

If product safety is also a priority for your research work, consider getting biosafety cabinets that are of the class II variation or higher. Class II biosafety cabinets are the most commonly used types and offer protection of personnel, the material, and the environment through its built-in HEPA filtration feature. This class is further subdivided into 4 types namely, Type A1, Type A2, Type B1, and Type B2. While all of these types cover the same area of protection, they differ in terms of design, performance, and installation. Each Class II subtype provides different degrees of air recirculation and exhaust airflow, which will be explained later on in this guide.

Class III cabinets, which are also known as glove boxes or barrier isolators provide maximum protection for the environment and its users. They are designed to handle highly infectious microbiological agents, unknown agents, and other hazardous applications. BSCs of this class are gas tight and only provide access to the workzone through an isolation are. Personnel access the workzone and maneuver around the agents using heavy duty rubber gloves. Before the air is completely discharged into the outdoor environment, the exhausted HEPA filtered air must go through either two additional HEPA filters or another HEPA filter and air incinerator.

3. Do you need special protection from toxic fumes and gases?

Applications like cell culture experimentation, toxicology, or drug preparation involves handling products that emit toxic fumes or gases that can prove harmful to personnel. To minimize such risks, we recommend the use of either Class II or Class III biosafety cabinets. 

As previously mentioned, Class II BSCs have four subtypes (A1, A2, B1, B2) that differ according to the ratio of recirculated air vs outwardly exhausted air. Both Class II A1 and Class II A2 biosafety cabinets recirculate 70% of the air inside the cabinet and exhaust 30% back into the lab. However, A1 BSCs provide lower air velocity than their A2 counterparts. 

Class II A1 biosafety cabinets are best used for applications that require sterile conditions but do not involve the use of volatile or toxic chemicals. Class II A2 biosafety cabinets have the same limitations. However, once connected to your building’s exhaust systems via a thimble duct or canopy, Class II A2 BSCs become safe enough to use with minute quantities of dangerous chemicals and radionuclides.

Class II Type B cabinets, on the other hand, must be connected to a dedicated exhaust system to safely expel the air to an external environment. Both Class II B1 and Class II B2 cabinets have the same minimum intake air velocity of 100 fpm/min and use single pass airflow to direct the chemical vapors. However, Class II B1 cabinets recirculate approximately 40% of the air within the cabinet as downflow while the remaining 60% is exhausted. On the other hand, Class II B2 cabinets do not recirculate any air within the cabinet and exhausts 100% of it outside the system.  

Like Class II A2 BSCs, Class II B1 cabinets are only suitable for applications involving minute quantities of dangerous chemicals. Because the fumes are exhausted at the back of the cabinet, the CDC advises researchers to do their work directly within the exhausted portion of the cabinet. Class II B2Biosafety cabinets, which are also called total exhaust cabinets, are best used in toxicology practices and similar applications.

Design and Construction Considerations

A. Choosing the proper size for your laboratory

Once you have decided on your BSC class, the next thing to consider is to select a proper size for your cabinet that will fit and serve you best in your workplace. BSCs can come in either sizes of 4ft. or 6ft. Examine your maximum space allotment so that you wont end up with a cabinet that is too big for your lab or too small that you can’t work.

B. Customization: UV Light, Stand, Outlets, Service Ports for gas or vacuum


A common accessory in many BSCs is Ultraviolet (UV) light. While it is not necessary for most applications to have on installed in your unit, there are biosafety cabinets that come with pre-installed UV light. Alternatively, you can have one installed later on, Just make sure that it does not disrupt the cabinet’s airflow and containment performance.

Because of its biocidal qualities, UV light is often used as an extra layer of protection against exposure to infectious agents and keep experimental materials free from contaminants. For procedures involving PCR. cell cultures, or other genetic materials, the use of UVc comes recommended because of its efficiency in breaking chemical bonds and denaturing DNA & RNA. Take note however, UV lamps should not be used to substitute chemical disinfection. Chemical disinfection should always be performed, whether or not you are using a UV lamp.


BSC stands help ease discomfort caused by working long hours at your station. Installing a stand for your biosafety cabinet provides personnel with the ability to sit and stand at a variety of heights according to their personal preferences.

There are a range of options available including fixed-sitting or fixed-standing height stands, manual adjustable stands, electric adjustable stands, hydraulic stands, and rolling castor stands. Note that some models can weigh up to 900 pounds, so it is important to attach the cabinet to the manufacturer’s recommended base stand to properly support the unit’s weight. Also, take note of the specified maximum height requirements that your stand of choice requires to prevent overturning of the BSC.


Some manufacturers provide you with the option to install electrical sockets within your BSC for you. This serves as a convenient power source for the electrical equipment you need to use within your cabinet. If you prefer to have one installed, it is important to consider the outlet standards for voltages, frequencies and plug configurations. Usually the outlets in the work area are limited to the rating of its amperage because of the amperage requirements of the BSC's lighting, motor, and other electrical components. There are specialized outlets like Ground Fault Circuit Interrupters that should be installed and tested by the manufacturer. With some cabinets, you can also mount the outlet either on the sides, back, or ceilings of the cabinets.

Installing a voltage regulator may be required to reduce the potential of variations in airflows since variations in line voltage from the laboratory wall outlet may affect the cabinet airflows.


Another option you can add to your BSC is a service port plumed into your cabinet that will provide you a convenient source for gases, vacuum lines, or air. Some models have the option to have these ports easily installed after purchase, however it is easier and less expensive to install the required number of valves when you place your order. Note that even though many users connect natural gas to a service valve in the cabinet, this practice should be avoided if possible because open flames may disrupt the airflow and a possible buildup of flammable gas might occur while the air recirculates in Class II BSCs.

C. Does your lab meet the requirements for installing BSCs?

Now that you know which BSC fits your application demands, you may already have an idea what cabinet to purchase and what additional accessories you may opt to install. But you also have to make sure that the equipment you purchase will fit your facility perfectly and will operate without any airflow disruptions. So, before making any purchasing decision, examine your proposed installation site to see if it will meet the requirements of proper cabinet operation.


Ideally, a BSC should be located with a minimum clearance height of at least 6 inches above the cabinets and at its sides. This ensures that the air re-circulated to the laboratory is not disrupted and allows the staff to easily access maintenance.

On the other hand, BSCs that are not connected to an exhaust system should have a clearance area of at least 12 inches from the face filter and any overhead obstructions. It should also have at least 12 inches (300 mm) of clearance when calculating cabinet inflow velocity with the use of a thermal anemometer exhaust velocity measurement.

Proper clearance must be carefully taken into consideration to ensure maximum effectiveness of the BSC you are purchasing.


As for the location requirements, it is important to install the BSC in a location away from doors, fans, ventilation registers, fume hood, high traffic patterns, and any device that could disrupt its airflow patterns. Windows within the room must be closed. So before making a purchase, be sure to plan ahead and set aside a location where your cabinet will be free from high traffic patterns to prevent any disruption with the airflow system.


If the cabinet needs to be connected to an external mechanical exhaust system, first evaluate the location to ensure that it is compatible exhaust outlet of the cabinet. Then check the area directly above the cabinet’s exhaust outlet. It should be clear of structural elements, water, utility lines, or other fixed obstructions. The passage of a 10-inch or 12-inch diameter duct should be allowed for enough clearance. Avoid locations that need an elbow directly on top of the cabinet’s exhaust connection or excessive number of elbows to clear other items.

When you are operating in a Biosafety level 3 and 4 area that involves dealing with potentially contaminated agents, it is important to ensure that the exhausted air is being directed outside the building. If the building exhaust system is used to bend a ducted BSC, the system should have sufficient capacity to maintain the exhaust flow if changes in the static pressure within the system occur.


When it comes to the required service line for the BSC, it should meet the local building codes and be equipped with an easily accessible external shut-off valve for Biosafety cabinets that have propane or natural gas provided inside.

Utility lines within the Biosafety cabinets should be planned thoroughly, All electrical outlets inside the cabinet must be protected by ground fault circuit interrupters. When you need to use compressed air within a Biosafety cabinet, extra precaution and control may be required to prevent aerosol production and reduce vessel pressurization.


The electrical outlet of BSC plugs must have a dedicated circuit breaker to prevent accidental shutdowns and overload. Some of the larger cabinet models operating at 115V will require a circuit rated for 20 Amp service. 15 and 20 Amp are different configurations. Usually, the electrical requirements for biological safety cabinets are:

  • 115 VAC, 60 Hz, 12 Amps
  • 115 VAC, 60 Hz, 16 Amps
  • 230 VAC, 50/60 Hz, 6 Amps
  • 230 VAC, 50/60 Hz, 8 Amps

Keep in mind that individual models may have varying electrical requirements, depending on the cabinet’s size.

Budget Considerations

Since BSCs are long-term investments for your lab, make sure to carefully review your budget and spend some time comparing the prices among other distributors to identify the average approximate cost for the equipment. To ensure you are investing an appropriate amount, don’t rely solely on what you see on tag prices of the BSCs, take into account the lifetime cost of operating the cabinet as this may also vary depending on the model and your application.

  At the same time, you can also request suppliers to provide a detailed price quote for the entire package, including the BSC Model number, canopy exhaust connection, optional equipment, and more. Plus work out the details about shipping and delivery with the manufacturer's representative at the time of purchase.

Biological Safety Cabinet Services And Maintenance

When selecting a Biological Safety Cabinet supplier, make a qualified, manufacturer-compliant engineer who is around to repair the BSC when the need arises. In addition, to get the most out of your purchase, look for Biological Safety Cabinet providers that can guarantee a fair warranty period or multi-year service agreement options to save time from troublesome and time-consuming product returns.

Lastly, ensure that your provider offers the appropriate parts for your biological safety cabinet in case you need to have it serviced back to factory settings. Several third-party equipment repair service providers have limited availability to parts, which may cause downtime and affect your laboratory’s overall productivity.

Back To Top
We are fully compliant with the GDPR laws. We promise to safeguard your data and protect your privacy rights.