This biosafety level requires at least two-door separation between the area where biohazards are used and the personnel not associated with the research, requires inward inflow into the lab and must have a visual mechanism to verify that air is flowing in the appropriate direction.

Biosafety level 3 requires at least two-door separation between the area where biohazards are used and the personnel not associated with the research, requires inward inflow into the lab and must have a visual mechanism to verify that air is flowing in the appropriate direction

Explanation:

Biosafety level 3 is required for clinical, diagnostic, teaching, researching or production laboratories working with microbes that are also following BSL-1 and BSL-2 but as these pathogenic agent can lead to life-threatening disease by inhaling it, besides other contaiment precautions, the BSL-3  facilities must have a separated entrance to laboratory door with unrestricted traffic flow and the lab must be behind two sets of self-closing doors and windows must be sealed, with a ventilation system properly directioned installed.

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