Positive pressure and negative pressure are relative to the pressure in the surrounding space.
 
Positive pressure: the air supply volume is greater than the exhaust volume. The indoor air is under positive pressure. Combined with the air conditioning unit, the cleanliness of the air sent into the container can be guaranteed.
Positive pressure is preferentially applied to containers where the external environment is harsh (such as ZONE 0, ZONE 1, and ZONE 2) and the internal environment is secure.
Please download the A60 offshore pressurised container product brochure for reference. 
 
Negative pressure: the air supply volume is less than the exhaust air volume, and the room is under negative pressure. The surrounding air flows into the space and is discharged through the exhaust outlet for unified treatment.
Negative pressure is preferred in containers where the external environment is safe but the interior will produce toxic and harmful gases.
​Please download laboratory container brochure for reference.