Negative room pressure

This technique is used to isolate patients with airborne contagious diseases such as: influenza (flu), measles, chickenpox, tuberculosis (TB), severe acute respiratory syndrome (SARS-CoV), Middle East respiratory syndrome (MERS-CoV), and coronavirus disease 2019 (COVID-19).

Leakage from these sources can make it more difficult and less energy efficient to maintain room negative pressure.

However, in some cases, such as with highly infectious microorganisms in biosafety level 4 rooms, the air must first be mechanically filtered or disinfected by ultraviolet irradiation or chemical means before being released to the surrounding outdoor environment.

[citation needed] In 2003, the CDC published guidelines on infection control, which included recommendations regarding negative pressure isolation rooms.

The advantages of this type of monitoring are that the test is continuous and an alarm will alert staff to undesirable pressure changes.

The internal air is forced out so that negative air pressure is created pulling air passively into the system from other inlets.
Inside view of a negative pressure isolation chamber for patients with contagious diseases.
Schematic of a network of rooms where air (shown in blue) flows in one direction from the corridor into the negative pressure room (green). Exhaust air is safely removed from the area through a ventilation system.