If you handle biohazards in a lab, you’re probably familiar with a biological safety cabinet (BSC). These cabinets protect you from infectious agents like bacteria and viruses while preventing contamination of your samples and the environment.
Just like you wouldn’t drive a car with faulty brakes, you shouldn’t work with a BSC that isn’t certified.
But what exactly is BSC certification? Why does it matter? What does the process involve, and how often is it needed? Let’s break it down.”
BSC Certification
Put simply, a biological safety cabinet (BSC) certification is a routine check-up, ensuring your cabinet functions as designed—containing hazardous microbiological agents and preventing cross-contamination.
A qualified technician conducts the certification by testing key components, including:
- Airflow: Is the air going in the right direction? Does it flow in the defined space at the correct speed?
- HEPA filters: Are they filtering out dangerous particles properly?
- Cabinet integrity: Are there leaks or any issues that could compromise safety?
It’s important to have this done by an accredited field certifier. To be accredited, a certifier must pass both a written and practical test administered by NSF.
BSC Certification Requirements
According to OSHA (Occupational Safety and Health Administration), BSCs should be tested and certified:
- When a new cabinet is installed
- When a cabinet is relocated
- After any major repairs (like replacing a HEPA filter)
- At least once a year for compliance (some labs require it twice a year)
In the US, the NSF/ANSI Standard 49 sets the bar for how Class 2 BSCs (more on this below) should function. Under this guidance, BSC testing ensures cabinets meet requirements for:
- Cleanliness
- HEPA filter integrity
- Motor/blower efficiency
- Noise levels
- Lighting
- Vibration
US health agencies like NIH and CDC, in particular, have super strict protocols for certification and decontamination of BSCs.
But what if a cabinet fails certification?
In that case, the questionable BSC must be decontaminated, repaired, and recertified before being used again. Research shows defective HEPA filters are the primary cause of such failures.
Types of Biological Safety Cabinets
Before we get into the different BSC classes, let’s cover the basics: What is a biological safety cabinet?
A BSC is a specialized, ventilated piece of equipment used in labs handling biological hazards like bacteria, viruses, parasites, toxins, bodily fluids, and plant or animal matter. It controls airflow to contain these contaminants inside.
Next: What is the purpose of a biological safety cabinet?
A BSC prevents the spread of harmful microbes, protecting the user (lab personnel), the product (sample or research material), and the surrounding environment.
The type of BSC you need depends on the work you do. Each class provides a different level of protection, which we’ll break down below:
Class 1 Biosafety Cabinet
Class I Biosafety Cabinets protect personnel and the environment, but not the sample. They’re mostly used for procedures that generate aerosols, such as working with centrifuges.
Class 2 Biosafety Cabinet
Class 2 Biosafety Cabinets are the most common, used in microbiology and pharmaceutical labs. They offer protection for all three: user, product, and environment.
Their design includes:
- An open front with inward airflow for personnel protection
- A downward HEPA-filtered laminar airflow for product protection
- HEPA-filtered exhaust air for environmental protection
There are several Class 2 cabinet subtypes, each with a slightly different way of moving air around. Let’s examine each:
- Type A1
- Recirculates a significant amount of air in the cabinets
- Suitable for work in biosafety agents 1, 2, and 3, but not ideal for volatile or toxic chemicals
- Type A2
- Recirculates a large portion of air (like Type A1) but also exhausts a percentage of it
- Suitable for biosafety agents 1, 2, and 3 and can be used with small amounts of chemical vapors if properly exhausted
- Type B1
- Exhausts a larger portion of the air than Type A cabinets
- Suitable for work with biological agents and trace amounts of volatile toxic chemicals (or VOCs) and radionuclides (radioactive materials)
- Must be hard-ducted to a dedicated exhaust system
- Type B2
- Used in toxicology labs
- Offers the highest level of protection among Class 2 BSCs
- Total exhaust cabinets, meaning no air is recycled
- Requires a separate exhaust system like Type B2
- Type C1
- Newest classifications of Class 2 BSC
- Combines the best features of Type A2 and Type B cabinets
- Can operate in different airflow modes
Class 3 Biosafety Cabinet
Class 3 Biosafety Cabinets are fully enclosed and airtight, designed specifically for working with highly infectious pathogens (biosafety agents 4).
Operators work through built-in gloves (hence the nickname “glove boxes”) to maintain complete separation from the materials inside.
How Often Should Biological Safety Cabinets Be Certified?
If you’re responsible for a BSC, keeping up with certification is extremely important. According to OSHA and NSF standards, certification should be done at least once a year. However, some industries require certification every six months.
For example, pharmaceutical compounding standards like USP 797 (sterile preparations) and USP 800 (hazardous drugs handling) recommend that a Class 2 cabinet be certified at least twice a year.
Even with strict lab protocols, an uncertified, malfunctioning BSC puts everyone at risk. Regular certification ensures that your cabinet is performing optimally and catches any potential issues before they become a serious problem.
BSC Decontamination
A biological safety cabinet (BSC) must be decontaminated before servicing, moving, or certification. This crucial step involves disinfecting the cabinet with gaseous agents like chlorine dioxide, vaporous hydrogen peroxide, or formaldehyde.
Even if a BSC looks clean, harmful pathogens may still be present. Proper BSC decontamination is essential to protect technicians replacing filters or performing repairs from contracting disease.
If your BSC is due for certification, don’t wait—schedule an inspection with a qualified technician to ensure it’s functioning safely and effectively.