The performance of Biological safety cabinets relies on its location. Where should be placed is an important question when designing a laboratory room.
Biological safety cabinets are work stations providing product, environment and personnel protection while infectious microorganisms are manipulated. The way you place them within the laboratory room is crucial to the health of the workers. Specific considerations need to be met ensuring maximum effectiveness of these prime barriers.
Biological safety cabinets involve contaminated and pathogenic work surfaces and their location needs to be established with the utmost care for human health and safety. Best practicing in placing and working on the biological safety cabinets will minimize health risks and air or surface contamination.
The ideal location of biological safety cabinets is as far from the laboratory entry as possible. Biological safety cabinets need to be located away from:
• laboratory equipment that creates air movement
• portable fans
• air supply registers
• chemical fume hoods
• open windows
• foot traffic
Clearance
Above the cabinet, there needs to be clearance providing accurate measurements for air velocity across the surface of the exhaust filter for changes in the exhaust filter.
There needs to be enough clearance on each side and behind the cabinet to allow ease of access for maintenance, ensuring that the air in the cabinet is re-circulated into the lab with no hindrance.
When your biological safety cabinet is connected or hard-ducted by a canopy unit to the system of ventilation, there needs to be enough provided space so that the duct work configurations won’t interfere with airflow.
Around Biological Safety Cabinets, minimum work zone dimensions include forty inches in the cabinet front and twelve inches on either side. Around the cabinet, clear zones need to include an eighty-inch minimum from the opposite walls and traffic areas and the opposite bench areas, sixty inches away. There need to be forty inches between the bench tops and biological safety cabinets along a wall perpendicular.
• Along a perpendicular wall, biological safety cabinets need to be spaced forty-eight inches apart.
• When two Bio-safety cabinets are side by side, there needs to be a minimum of forty inches between them.
• When there are many biological safety cabinets in one room, ideally, the placement should be staggered. If this is not possible, not less than one hundred-twenty inches need to be between two facing cabinets within a space.
• Biological Safety Cabinets need to be located away from windows and doors that can be opened. They need to be placed away from potentially disrupted equipment including ventilation systems, air conditioners, and fans. They also need to be away from heavily-traveled lab areas. The way they are installed needs to be in a way that the exhaust air fluctuations and room supply don’t cause cabinets to operate outside of its parameters of containment.
Also known as a microbiology safety cabinet, a biological safety cabinet or biological safety cabinets is a ventilated, enclosed works pace laboratory for being able to work with pathogens or contaminated materials safely. A defined level of bio-safety is required. Different biological safety cabinets types are classified depending on their degree of bio-contaminants.
The main purpose of biological safety cabinets is to protect the worker and the lab as well as the environment surrounding pathogens. All the air circulating needs to be filtered with high-efficiency particulate air or HEPA as it exits the bio-safety cabinet to remove harmful viruses and bacteria. This is the opposite of a clean bench laminar flow which blows exhaust unfiltered air towards the user and is not safe for working with pathogenic agents. Most biological safety cabinets are not safe for use as fume hoods. In the same way, the fume hood does not provide environment protection that the high-efficiency particulate air filter provides in a biological safety cabinet. Many biological safety cabinets classes have a second purpose to maintain the materials’ sterility within the cabinet.
Within a biological safety cabinet work needs to be safely and carefully performed, just as with work on open-top benches. To avoid personnel exposure and contamination, it is recommended that best practices be followed to control and reduce aerosol and splatter generation. This includes keeping materials clean at least a foot away from activities involving aerosols and arranging the flow of work from clean to contaminated. Open flames, in particular, can cause airflow disruption within. Decontaminate every biological safety cabinet surface once work is completed, along with all the materials and lab equipment. When relocating or servicing a biological safety cabinet, there needs to be gas decontamination, usually from formaldehyde. Also, high-efficiency particulate air filters need to be replaced.
Used daily and for hours on end, biological safety cabinets protect the sample material and the user. Ergonomics and factors of human design become important. this includes a reduced noise level for a more conducive atmosphere to work. It also requires optimized sitting positions such as a stool or stand with adjustable height. It also requires more light within the cabinet from panoramic windows if possible and a ten-inch angled front sash for better sitting positions. Light sources also help the conditions of working tremendously.
However, UV lamps and other ultraviolet light sources are not recommended. The frequent need for bulb replacement, shallow penetrative light, and reduced effectiveness in high humidity poses a safety risk to personnel. Lamps that use ultraviolet light should not be the main source of decontamination surfaces within a biological safety Cabinet.
Biosafety cabinets types
The Three Classes Of Biological Safety Cabinets
There are three classes of Biological Safety Cabinets. These are distinguished by the level of product protection provided and the level of environmental and personnel protection provided.
Class 1
Cabinets that are classified as class 1 offer environment and personnel protection but no protection of the product. Inward airflow contributes to sample contamination. These types of Biological Safety Cabinets are used commonly for enclosing specified procedures or equipment that generates aerosols. In this class, biological safety cabinets are either connected to the exhaust system of the building with ducts or recirculating exhaust filtration back into the lab without ducts.
Class 2
This category of Biological Safety Cabinets provides sample protection and environment protection. The air within is filtered with high-efficiency particulate air Almost ninety percent of Biological Safety Cabinets are type A2 cabinets. Each type is defined by Standard 49 of the NSF International Standard.
Operation principles use a blower that is motor-driven and mounted on the cabinets to draw in mass directional airflow into the air grill and around a user. This protects the operators. The air is then drawn back beneath the surface of work and back up to the cabinet top, passing through the high-efficiency particulate air filter. Sterile, filtered air is then blown downwards over processes and products to avoid contamination. Through the high-efficiency particulate air filter, the air is exhausted and pulled by exhaust fans or recirculated back into the lab through ducts where it is expelled out of the building.
Class 3
Cabinets categorized as class 3 are only installed generally in maximum labs for containment. These are designed specifically for work with pathogenic BSL-4 agents and maximize protection. The gas-tight enclosure and the double door autoclave or dunk tank is where all materials leave or enter. The front includes attached gloves to prevent contact directly with hazard materials. Also known as glove boxes, Class 3 cabinets are built customized and attached to a line. The installed lab equipment inside it is normally also custom-built.
Service And Maintenance
There needs to be a regular schedule for cabinet maintenance. During this check certification, there is a verification of the filter and airflow capacity. There are limited lifespans on filters that determine the quality of air within the lab space and the number of aerosols and particles generated within the work zone of the BSC. The fan within the walls works harder with the same volume of air to push or pull these as the filters load with dust and particulates. Filter changes need to be done by trained personnel as this is considered a contaminated object. When ultraviolet light is used within the BSC, the lamps need to be changed and checks as over time, these decrease in power, resulting in less disinfection of the work space.
Remember
When working with your biological safety cabinet for carrying out experiments, remember to know your airflow. Knowing your air flow maximized potential protection from contaminated air. Work at the proper sash height levels. Most cabinets indicates where windows need to be located when working. Know the correct height of the window sash to balance and maintain air flow. Don’t block the grill for air flow. Use good techniques in microbiological work to reduce risks of generating aerosols or creating splatters. Most cabinets are designed so that spores nebulized horizontally get captured by the down ward flowing air of the cabinet within fourteen inches of travel. Avoid covering the grill for air even with your hands, elbows and arms. Doing so will compromise the integrity of the air flow. Less movement is more when walking around your cabinet or when closing or opening doors. Near the biological safety cabinet, rapid movement may disrupt the air barrier.