What is the definition of negative pressure in a space?

The definition of negative pressure in a space is when air is taken out of the space, creating a pressure difference where the internal air pressure is lower than the external air pressure. This condition is important in various applications, particularly in microbial remediation and containment settings, as it helps prevent the escape of airborne contaminants or spores to surrounding areas.

By maintaining negative pressure, any potential contaminants are drawn into the space rather than let out, thus protecting the environment from exposure. This technique is often used during mold remediation, where controlling air movement is crucial for achieving effective results and safeguarding both workers and occupants.

In this context, adding air or filtering it would not achieve negative pressure, as those actions would either maintain or potentially increase the air pressure inside the space. Similarly, when the air pressure equals the outside pressure, it indicates a neutral atmosphere, not a negative pressure condition.