Biological safety cabinets are glass chambers for the operation, research and testing of hazardous objects, chemical reagents and various materials that contain harmful microorganisms. Such cameras are used in technical, chemical, biological, microbiological and medical centers and companies; the work is done by an operator who must have the necessary skills and certificate.
There are some features that need to consider when company choose and use this camera:
- HEPA filters play a key role in bsc. The purity of air in microbiological safety cabinets depends on its quality and also on the quality of its installation to protect the object, operator and the environment from external contamination.
- The chambers are divided into types A and B. This is the division by the proportion of air recycled back to the chamber and the installation room. Only one part of the air from the chamber of the box is removed through the filter. Another part continues to be recycled in the box, for example, the recirculation rate is 70% in boxes of type A, while it is 30% in the box of type B1.
- An important role is played by the smoky test. Smoky tests allow knowing the nature of the movement of air currents, highly prone to external influences, in the box and around it. For example, the use of heating equipment inside the box can lead to destabilization of downward flow, thereby increasing the probability of cross contamination.
Microbiological safety cabinet purpose
The main purpose of biosafety cabinets is the reliable protection of the operator and the environment from contaminated and dangerous air that enters the camera through the front window with the object under investigation. Harmful air is captured in the box by a stream from the front working window and goes directly to the filtration system. The working material is protected from external and cross contamination, because some kinds of such cabinets have closing window or a window with a sealed seam.
There are many requirements and certain international standards if laboratory wants to buy such a cabinet for research, tests and analyses. It is necessary to know that boxes of biological safety have classification. There are 3 different kinds of cameras with different levels of protection. Cabinets differ in appearance and offer different types of studies, depending on the level of threat of the material or object that is being inspected. Class 2 has a different name and performs the same function as the conventional laminar flow model.
The filtration system in three types of cameras is the same, it is the operation of the vertical airflow, which rises from the bottom to the top and enters the filter. At the top of the chamber, clean air leaves the cabinet and goes into the room without harm to the environment. This is the basic principle of the work of air cleaning, but the supply of incoming air is different in different types of chambers.
Biological safety cabinet classes
There are 3 classes of cabinets, each performs its functions and has its own construction. The third class is the most reliable and safe and allows working even with radiation materials, toxic substances and dangerous viruses in microbiology.
These boxes provide protection for the operator, but not for his operation. The tested material or object is inside the glass chamber; the operator opens the window and performs manipulations before the operation. The window closes when the work is complete or is in the standby mode, so the harmful components of the object do not get outside, but go to the upper filter for cleaning. Operator can open the window again and continue working; the incoming air takes away harmful components from the material under investigation and carries it to the cleaning system. Working process with two objects and its cross contamination is eliminated by creating an upward flow of air. This biosafety cabinet was made for work with any hazardous substances, except for materials that belong to the Hazard Group 4.
This kind of cabinet can be called biological safety hood, where the work is done through the open front window. The camera protects the tested material, operator and the environment from harmful fume. The principle of the box is based on the forced recirculation of a part of the air in a closed volume through the main filter. Incoming air passes through the filter, is cleared of inhalable contaminations and is fed unidirectional down into the working zone, thereby creating clean air environment and preventing cross-contamination in the chamber box. There are small grills opposite the front window, where outside air enters and interacts with the incoming air from the window and rises up. Part of the air with the fan goes at high pressure chamber (about 30%); it is ejected in lab through the outlet filter. This class of biological safety cabinet is more reliable than a first-class model.
This biohazard safety cabinet provides reliable protection for the operator from the investigated object or material because the process of operation is through the glass shield. There is a fan inside the camera that takes air into the main HERA filter. The operator works with special gloves, which are connected to the chamber by sealed seams. The principle of the box is based on the supply of cleaned air into the working zone with subsequent removal of harm air through a cleaning system. Air that passes through the filter is cleaned of aerogenic pollutants and supplied to the working zone by a unidirectional downward flow. Air from the working chamber is removed into the working room or exhaust ventilation system, after having passed a two-step system of cleaning. Manipulations with working material, objects or other dangerous components are carried out only with gloves in biocontainment. Such bsc allow operators to work with Group 4 hazards because it provides the highest protection.