Biological Safety Cabinet

Biological Safety Cabinet-An Ultimate Buying Guide by Sunnyda.

A Biological Safety Cabinet is the equipment most commonly present in the biological laboratories to protect the operator, product, and the environment against contamination.

It uses HEPA filters, having 99.99% filter efficiency in removing the contaminants, resulting in filtered supply and exhaust air.

These HEPA filters mainly consist of a metal or wooden body between which borosilicate glass fiber or cellulose strip is present, secured with epoxy sealing at the edges.

Sometimes, it is also known as a ductless fume hood, but always consider that this cabinet is not beneficial for achieving protection against chemical vapors.

A vertical unidirectional airflow is established and maintained within the working area to provide a controlled environment for various applications.

A raised airflow grill, vacuum tap, and an extra ultraviolet lamp are some of the commonly used accessories with this equipment.

This buying guide contains extensive information regarding the features, specifications, uses, and operation of the Biological Safety Cabinet, along with different safety guidelines for your protection.

Ductless Fume Hood

What is a Biological Safety Cabinet?

Biological Safety Cabinet is common containment equipment available in industries dealing with different biological processes and materials.

It consists of HEPA filtered air, which can effectively remove biological contaminants from the working environment.

On the basis of the levels of protection provided, it is majorly classified into three major types; Class I, Class II, and Class III.

The efficient HEPA filters and the air curtain collectively work together to provide protection to the operators against aerosols formed inside this environment that can be hazardous to human health.

To protect the samples from contamination the unidirectional and recirculating air supplied after filtering through the clean room HEPA filter is used.

For protecting the environment, the HEPA filtered exhaust present in the upper part of this cabinet is used to remove contaminants and hazardous aerosols present in this controlled room.

For the maintenance of suitable pressure levels, a pressure gauge is also pre-installed in the Biological Safety Cabinet.

Biological Safety Cabinet

What are the Basic Features of the Biological Safety Cabinet? 

The prominent features of the Biological Safety Cabinet include:

• Allows the manufacturer to construct side panel design

• Direct current motor saves you 70%energy consumption

• You can add multiple-piece or one-piece work trays as per your need

• The self-compensating airflow fights against sudden voltage changes or extreme filter load condition

• Extensive size range options are available

• To monitor the airflow, an airflow sensor is installed inside it

• To decontaminate the working area of the entire body, the UV lamp is present

• It has an alarm to notify about unsuitable sash conditions

• To prevent microbial growth, it is powder-coated

• To allow the smooth entrance of grilles, a raised armrest is attached; it also ensures the comfort of the operator

Airflow Velocity and Temperature Sensor of Biological Safety Cabinet

What are the Common Specifications of the Biological Safety Cabinet?

The technical specifications of this Biological Safety Cabinet are given as follows:

• 30 m/s Downflow Velocity

• 3-Micron Size Particle Retention

• 53 m/s Inflow Velocity

• High Illumination Fluorescent Light

• ≥65 dBA Noise Level

• 999% Efficient HEPA Filter

• 304 Stainless Steel Working Table

• 304 or 316 Stainless Steel or Wooden Body Designing

• Microprocessor Control System

• Single-Phase 1/3 HP Blower Assembly With 1000 CFM Capacity

• Accessories Include a Vacuum Tap and Raised Airflow Grill

• Extra UV Lamp

• Tempered Glass Auto Sliding Front Door

Stainless Steel Construction Material of Biological Safety Cabinet

What are the Applications of the Biological Safety Cabinet?

The common applications of the Biological Safety Cabinet are given below:

• Dumping processes within animal laboratories

• Aerosols elimination

• For studying multiple microbial diseases

• Dealing with chemical carcinogens

• Studying highly risky agents

• Involved in microbial research units

• Deal with materials concerned with infection and biological hazard

Applications of Biological Safety Cabinet

What are Some Accessories Compatible with your Biological Safety Cabinet?

Using accessories that are compatible with your Biological Safety Cabinet will increase its effect with lesser time consumption:

• Base Stand

• Stainless Steel Casters

• Ultraviolet Lamp

• Service Fixtures

• Thermal Anemometer

• Magnehelic Gauge

Magnehelic Gauge of Biological Safety Cabinet

What are the Types of the Biological Safety Cabinet?

There are three types of Biological Safety Cabinets.

Class I Biological Safety Cabinet:

It is used to protect the environment and the operator but doesn’t protect the product.

It works with the help of recirculated airflow. It resembles a fume hood in design but the presence of a HEPA filter at its exhaust terminal is unique in both.

It is available in ducted or non-ducted. Using this cabinet, you can handle contaminants from biosafety levels 1, 2, and 3.

Class II Biological Safety Cabinet:

It protects the product, people, and the environment. In this, the downward HEPA filtered laminar airflow protects the product, the inward flow protects the user, while the safety of the surrounding environment is achieved by the HEPA filtered exhaust air.

On the basis of design, exhaust system, and airflow, it is further subdivided into A1, A2, B1, B2 categories. Biosafety cabinet class 2 type a2 is the most commonly used type in various industries.

It can easily deal with the contaminants at biosafety levels 1, 2, and 3.

Class III Biological Safety Cabinet:

The biosafety cabinet class 3 saves the user, product, and the surrounding environment from harmful contamination.

Before substances leave this controlled area, they have to pass the transfer chamber for sterilization purposes.

Class III Biological Safety Cabinet

What are the Uses of the Biological Safety Cabinet?

A Biological Safety Cabinet can be used to deal with different biological agents such as:

• Parasites

• Fungi

• Bacteria

• Animal Tissue

• Prions

It traps different parasites that can reside in this area to create trouble for the users. Biological Safety Cabinet gets rid of fungi as it doesn’t allow the flow of contaminated particles.

It filters the dirt and dust particles to allow filtered airflow in the internal and outside surroundings. Prions which can be a major cause of contamination, cannot stay in this clean area.

But don’t use this equipment with the listed substances:

• Volatile Nucleotides

• Toxic Chemicals

• Flame

• Flammable Chemicals

• Volatile Chemicals

What is the Difference Between a Biological Safety Cabinet and a Fume Hood?

A fume hood is equipment used for the removal of aerosols and chemical fumes from the work area.

Whereas a Biological Safety Cabinet is for protecting employees and a clean work environment from the harmful particulate agents produced while working with toxins or infectious agents.

A chemical fume hood is only for the protection of the user whereas a Biological Safety Cabinet offers three types of protection: one for the user, one for the material, and the last for the environment.

It has HEPA (High-Efficiency Particulate Air) filter which is missing in a fume hood. The presence of a HEPA filter helps in the efficient trapping of infectious agents (of size 0.3 microns or higher) and ensures the discharge of only microbe-free exhaust air.

Mild Steel Chemical Fume Hood

What Makes the Biological Safety Cabinet Better than Laminar Flow Cabinet?

A laminar flow cabinet functions in maintaining a clean and sterile environment for the safety and protection of the material but it discharges the air toward the worker.

As a result when carrying out work processes with the involvement of infectious agents, cultures, or toxins a laminar flow hood might allow the exposure of the worker to the biological material.

While, in the normal functioning Biological Safety Cabinet, this is not the case under-maintained airflow direction.

Laminar Flow Cabinet

What is the Working Principle of a Biological Safety Cabinet?

A Biological Safety Cabinet is constructed using high-efficiency HEPA filters to achieve a controlled environment free from contamination.

The contaminated air enters the front section of this cabinet and combines with the air of the chamber which is also contaminated.

Now, the contaminated air strikes the working area, from where it moves in an upward direction by the plenum, and then crosses the HEPA filters via the blower motor action

Around 30% of the air passes through the primary filter located at the upper portion of the cabinet and then recirculates inside the controlled room.

The leftover 70% air crosses the supply HEPA filter and reaches the working area of the Biological Safety Cabinet in a unidirectional airflow manner.

The biological materials are separated from the air with the action of the fibrous materials. These fibers trap the dust or dirt particles, resulting in the release of clean and filtered air into or out of this Biological Safety Cabinet.

The higher the surface area of the filter, the greater will be the filtration efficiency.

Some procedures followed by this filter to deal with the filtration of the air include:

• For large-sized particles, two fibers trap the particulates between them using the straining effect.

• For very small-sized particles, diffusion serves as a basis for their removal on collision with the filter’s fibers.

• The direct impact removes the contaminating particles moving at a high speed.

• The electrostatic forces of attraction eliminate the particles possessing negative charges.

• The interception mechanism of these filters removes the small size of contaminating particles.

Working Principle of Biological Safety Cabinet

What is a Non-Ducted Biological Safety Cabinet?

It is designed to work independently from the room exhaust or the building. Biological material is removed from the Biological Safety Cabinet by moving through the exhaust HEPA filter.

During the handling of biological substances at BL 1 or BL 2, exhaust air can recirculate back into the controlled environment safely.

A canopy-connected cabinet is required by explosive nucleotides, toxic and volatile chemicals, and by most activities at BL 2 containment as an extra precaution.

Ductless Biological Safety Cabinet

What is a Thimble Connected Biological Safety Cabinet?

By adding a thimble or canopy you can connect your Biological Safety Cabinet to the building exhaust.

Due to this, a small gap is formed between the exhaust of the cabinet and the exhaust of the building. This is helpful in inhibiting the reverse airflow issues in hard ducted cabinets

For trace quantities of toxic chemicals, volatile compounds, and volatile radio nucleotides you can use a canopy.

The HEPA filter is not responsible for the removal of chemicals so these particles are sent out of the building via the building exhaust.

If the exhaust of the building is not working, to direct the exhaust air into the room, a canopy is present. It will protect the user’s face from unfiltered air.

You can also add a canopy airflow alarm to alert the user regarding the insufficient efficiency of the building exhaust for removal of the exhaust air via the canopy.

Thimble Connected Biological Safety Cabinet

What are the Different States of Alarms in the Biological Safety Cabinet?

Three different states of an alarm which consist of the normal, alarm, and the error states are explained below:

Normal or Ready State:

It refers to a properly functioning alarm and an appropriate building exhaust for capturing canopy exhaust.

Green indicator for rooster with LED flashes after every two seconds. If the airflow goes below the threshold reading for 5 seconds the alarm will enter the alarm state

The Alarm State:

The alarm state is an indication of low building exhaust airflow. This state is followed by quick red light flashes and audio alarm sounds.

You can press the mute or reset button for silencing the audio alarm, but the red light flashing will continue.

On the re-establishment of proper airflow, the alarm will return to its normal operation state automatically (this setting is the default for rooster alarms but can vary depending on the setting and style of the alarm).

Error State:

The yellow caution light indicates an error state in some alarms as in the rooster alarm.

This is an indication that there is some fault in the alarm probably because of the power failure. This is the stage where you need to make a particular decision to resolve this error.

Sash Alarm of Biological Safety Cabinet

How to Respond to the Alarm Alerts in your Biological Safety Cabinet?

Your response to different alarm alerts depends upon the type of alert, and the materials causing this alarm alert.

The appropriate responses to some alarm alerts are given as:

• In case of radioactive materials or volatile chemicals are involved, immediately stop the procedure you are performing and close the sash of your cabinet. Simultaneously, press the mute or reset option to turn off this alarm.

• In case the audible alarm is activated by the biological materials, where no radioactive or toxic chemicals are involved, you can simply press the mute or reset button to silent it. The best thing is that you can safely continue your procedure after this.

If any of the above cases occurs, inform your environment, health, and safety concerned personnel and display a warning label on your cabinet.

Then, contact the technicians to check and correct the fault in the system. You may also contact the building service providers to check the condition of the building’s exhaust system.

Why is the Class 2 Type A2 Hard Ducted Biological Safety Cabinet Not Safe?

There are several reasons for declaring the Class 2 type A2 hard ducted Biological Safety Cabinet directly with the exhaust of the building, such as:

• In case the exhaust system of the building becomes non-functional, the inner motors of this cabinet will still be working; this will lead to elevated pressurization inside this ducting.

• This pressurization is not enough to throw the exhaust air towards the exhaust vent via the ducts.

• This will result in the reversing of the airflow direction, so the unfiltered air will strike the face of the operator, which is unsafe and harmful.

Class 2 Type A2 Hard Ducted Biological Safety Cabinet

What are the Reasons for Preferring the Hard Ducted Connection in your Biological Safety Cabinet?

Some major reasons that persuade the manufacturer to provide hard ducted connections in your Biological Safety Cabinet include:

• It possesses an alarm to instruct the operator about the immediate closing of the sash and emergency contact with the maintenance service providers.

• In case of faulty exhaust fans in the room, this type of cabinet switches off the blower motor operation with the help of an interlock system.

• Due to its construction and beneficial features, it can deal with high radionucleotide or volatile toxic chemicals content.

Explosion-Proof Blower of Biological Safety Cabinet

Which Parameters are Tested in the Biological Safety Cabinet?

In testing the Biological Safety Cabinet, several parameters are tested for ensuring maximum performance and efficiency of the cabinet. These parameters include:

• A particle is used for testing the HEPA filters and then for ensuring filter integrity the penetration levels are measured.

• All the flow rates and airflow patterns are tested and adjusted accordingly to satisfy the manufacturer’s parameters.

• The airflow alarms installed on the canopy are also tested followed by their calibration.

HEPA Filter of Biological Safety Cabinet

What are Different Procedures for Gaseous Decontamination of your Biological Safety Cabinet?

Two common methods for performing gaseous decontamination of your Biological Safety Cabinet before the HEPA filters replacement are:

Formaldehyde Gas Method:

It consumes more time, and the scrubbing of gas after decontamination is essential. During this procedure, you can’t enter the lab, due to the high level of risk associated with the chemical’s safety.

Vaporous Hydrogen Peroxide Method:

This procedure takes lesser time and can be finished within hours.

Even after the completion of this decontamination in your Biological Safety Cabinet, you can’t enter the lab and the chemical safety risks are lower as compared to the formaldehyde gas decontamination.

Bio Decontamination of Biological Safety Cabinet

What are the Reasons for Not Recommending UV Lights in the Biological Safety Cabinet?

Here are listed some reasons why using ultraviolet lights in your Biological Safety Cabinet is not recommended:

• It is no longer declared suitable by the NSF and American Biological Safety Association.

• The UV bulbs possess a very short shelf life, which causes inconvenience to the users.

• For sterilization, chemical cleaners and disinfectants are always the most accessible option and are proven to be advantageous for this purpose.

• It has no specific test to check whether this UV light is effective in sterilizing the system, and how much effective it is.
• It is important to clean these lights every week, and after 6 months, the old light should be replaced by a new light; this schedule was very hard for the laboratories to act upon.

How to Handle Spills in your Biological Safety Cabinet?

Often you may have to encounter situations like accidental spills when working in a bio lab. These spills are harmless usually but in some cases, they can even be toxic for your body.

This is especially observed in the chemical spillage of harmful chemicals that are volatile and biohazardous.

To handle spills in your Biological Safety Cabinet always follow these protocols:

• Do not turn off the cabinet in case of large spills into the catch basin.

• Analyze the situation and make sure you have your proper Personal Protective Equipment on.

• Choose the appropriate disinfectant and organize your biological spill kit.

• Make sure that the drain valve is properly closed.

• Wet the surface with the appropriate disinfectant and pour it through the grills also.

• Wait for at least 10 minutes to provide enough contact time between the disinfectant and the surface.

• Absorb the disinfectant left on the surface of the Biological Safety Cabinet using paper towels.

• Then with the help of the tongs pick up the debris and paper towels and dispose of them in the biowaste

• If any broken glass pieces are present, dispose of them in the sharps container.

• Building flexible tubing connected to the drain valve.

• You should always then drain the basin into a suitable disinfectant-filled container.

• Lift the work surface of your Biological Safety Cabinet followed by the decontamination of the catch basin using a suitable disinfectant.

• Wait for about 5 to 10 minutes for disinfection activity.

• Using 70% ethanol rinse the area for removing the residual disinfectant. You can also use sterile water in place of 70% ethanol if you are using 10% bleach.

• Dispose of all the paper towels from your Biological Safety Cabinet in a biowaste container.

• Finally, remove your gloves following the correct glove removal procedure and wash your hands.

Cleaning of Spills in Biological Safety Cabinet

How to Safely Use your Biological Safety Cabinet?

For maximum safety of your Biological Safety Cabinet, always consider the following instructions:

• Before starting the experiment place all the material in the chamber.

• Keep a distance of 4 to 6 inches (at least) from the front grille for ensuring efficient unidirectional airflow and containment.

• Use controlled and slow inwards and outwards movements for bringing things into or out of the chamber.

• Always avoid side-to-side movements of your hands for preventing traffic when working in the cabinet.

• The air curtains should not be disrupted by walking near the Biological Safety Cabinet.

• Keep the waste inside the cabinet and remove all the waste after the completion of the experiment. As a result, frequent disruption of the air curtain is avoided.

• Store clean (sterile) equipment on the side of the work area.

• For manipulation, the center of the work area is used for preventing cross-contamination.

• Keep the dirty (contaminated) materials on the opposite side of the Biological Safety Cabinet and dispose of them in the biohazardous waste container.

• Before the vacuum line, place the HEPA filter or any hydrophobic filter in a direction that it faces the overflow flask.

• For disinfecting the final volume of the liquid adds a sufficient quantity of disinfectant to the primary flask.

• A solution of 1:10 (volume/volume) household bleach dilution is used because it has great disinfecting properties.

• Refresh the bleach every week for ensuring maximum disinfecting effectiveness.

• Put the flasks in a secondary container if they are on the floor. You can use plastic bins as secondary containers for collecting spills in case of flasks break.

• Label the primary collection flask with a biohazard sticker.

• Never perform open flame experiments inside this cabinet.

• A good sterile environment is maintained in the chamber so no heat source is required for meeting sterility demands.

• In replacement to using flame sterilization of metal/glass plate spreaders or metal, loops use autoclaving or disposable loops or spreaders.

• The heat coming from an open flame is a cause of disruption to unidirectional air currents inside the Biological Safety Cabinet that may result in the cross-contamination of samples.

Wear PPE Before Using Biological Safety Cabinet

Conclusion.

A Biological Safety Cabinet should be your ultimate choice if you want to protect the operator, product, and the environment present inside or around your working area.

Always consider that the safety cabinet is strictly not compatible with processes dealing with the handling or formation of toxic chemicals and fumes.

To maintain its life and efficiency pay good attention to the maintenance, cleaning, and servicing schedules as suggested by your manufacturer.

Make sure that the cleaning products you are using are suitable, and not harmful to its construction. Also, minimize the corrosion and rusting by selecting stainless steel construction.

As there are multiple types of the Biological Safety Cabinet available, carefully select the one appropriate for your usage, on the basis of its airflow pattern and the level of protection it provides.

ISO approved and High-Quality Biological Safety Cabinet