modular cleanrooms

Isolation Rooms

Types of Isolation Rooms

Positive air pressure rooms

Where a patient with a compromised immune system is protected from airborne infectious particles (Class P).

Negative Air Pressure Rooms

Where others are protected from any airborne transmission from a patient who may be an infection risk (Class N).


Negative air pressure rooms with Anterooms, with interlocked doors, which are used for quarantine isolation (Class Q).

Isolation Room Design

When designing an isolation room, make sure the anteroom has enough space for storage and application of PPE. The door into the anteroom from the isolation room should be self-closing, and should swing into the anteroom.

The anteroom provides access to the isolation room for staff and visitors. For Class N isolation rooms, due to the negative pressure relationship between the isolation room and the surrounding area, separate doors can be provided for the ingress and egress of the patient’s bed directly in and out of the isolation room. It is imperative that the isolation room keeps negative pressure to the anteroom, and the anteroom keeps negative pressure to the surrounding area, to ensure infectious particles do not escape from either room into the surrounding areas when any of the doors are open. Magnehelic gages should be installed to ensure negative pressure relationships are held.

A dedicated exhaust system should be provided from the isolation room. To maintain negative pressure, the exhaust system needs to remove more air than what is being supplied into the room. The exhaust air ducts for isolation rooms should be independent from the building’s air exhaust system. This will reduce the risk of contaminated air finding its way back into non-contaminated areas through a back-draught situation.

Negative Pressure Isolation Rooms

Negative Pressure Isolation Rooms

The intent of an isolation room is to control the airflow in a room to minimize the chance for cross-infection, of non-infected people within a facility, from airborne infectious particles.

This is accomplished by:

  • Maintaining different air pressures between adjacent rooms.
  • Air filtration, using HEPA or ULPA filters.
  • Controlling airflow patterns to best suit the application.
  • Exhausting infectious air particles from the room, diluting with large volumes of air.


An anteroom, also called a gown room or airlock, functions as:

  • A controlled area in which the transfer of supplies, equipment and people can take place without contaminating surrounding areas.
  • A controlled negative pressure room where personnel can put on or take off their personal protective equipment (PPE) prior to entering into, or exiting from, the isolation room.
  • An additional barrier against the potential loss of pressurization of the isolation room.