hello everyone welcome to chemical safety and biosafety I'm Mr Gold today's video is on the various biosity level Laboratories now we shall look at the level 3 design and features of the different ball safety level Laboratories in this video I shall first explain secondary containment we have previously learned that primary containment is to protect the Personnel working in a laboratory it contains the Hazardous source can you require example of primary containment today we shall look at secondary containment secondary containment prevents The Accidental release of infectious biological agents out of the laboratory into the external environment in so doing the people outside of the lab are being protected the design of the lab provides this containment we can divide Laboratories into four while safety levels BSL one and two have similar lab design and features BSL 3 lab is a high containment lab with added lab design features bsl4 is a maximum containment lab each level of laboratory has its own lab design safety equipment practices and PPE for example the biosafety equipment practices and people use in a bowl safety level 1 Lab are applicable to a biosafety level 2 lab however they are added a laboratory design biosity equipment practices and PPE in a bio safety level 2 lab not found in above safety level 1 Lab similarly a bsl-3 lab has additional laboratory design biosity equipment practices and PPE on top of what found in a bsl2 lab in order to determine which lab to use when handling biological agents a risk assessment has to be performed usually by default a bsl2 lab is used when handling risk group 2 biological agents similarly a BSL tree lab is used when handling risk group 3 biological agents however if we are handling risk group 2 biological agents in large quantity and in high concentration we may use a BSL tree lab instead of a bsl2 Lab a risk group 3 biological agent may also be handled in a bsl2 lab with additional PPE and practices for example for the purpose of diagnostic uh uh samples harboring risk group 3 biological agents like SARS Corona virus 2 the one causing covid-19 a bsl2 lag may be used with additional PPE and more string jump practices now we call this type of lab bsl2 plus lab we have looked at the four biosafety Labs briefly and we have come to the end of this video thank you for watching bye