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What is an Isolation Room?

Isolation rooms are used in hospital and healthcare facilities as a means of controlling the spread of contagious diseases (e.g. Covid 19, Smallpox and Ebola virus) from a patient to other patients, healthcare workers and visitors. They are also used as a protective measure for patients with a low immune system.

Hospital Isolation Room Pressure Monitoring
Visio-4 Touchscreen Brochure
Design considerations for Isolation Rooms

All patient rooms in hospitals should provide an acceptable environment for patients to recover and a good working environment for health care professionals who attend to them. The special purpose of an isolation room is to protect health care workers, other patients and visitors in a hospital from exposure to an airborne infectious agent in the event that an infectious patient is staying in the room. A principal design goal for an isolation room, then, should be to achieve and maintain an adequate level of airborne infection protection in the environment surrounding an infectious patient. In other words, to contain the airborne infectious material in such a way that the threat of exposure to health care personnel within the isolation room and others outside of the room is minimized. Ventilation is a key component of aerosol containment in isolation rooms and also the monitoring strategy deployed to ensure compliance of the intended design.

Ventilation Strategy

The strategy in designing ventilation for an isolation room suite should be to obtain the best containment possible while maintaining an acceptable thermal comfort for the patient. The contribution of ventilation to containment can in theory be maximized within an isolation room through source removal, a high dilution rate and a directional airflow from health care personnel to the patient. It is also important that there are no stagnant, under ventilated areas in the room where infectious aerosols might be concentrated. An isolation room suite typically consists of a patient room, attached bathroom and anteroom between the patient room and corridor. Containment can in principle be maximized within an isolation suite by maximizing containment within the patient room, maintaining a directional airflow from the anteroom to the patient room at all times, maintaining a high dilution rate in the anteroom, and maintaining a directional flow from the corridor to the anteroom at all times.

Hospital Isolation Room Pressure Monitor
How do Isolation Rooms prevent cross-contamination?

Patient isolation is achieved using one or more of the following methods:

   •  Control of the quantity and quality of the intake or exhaust air.
   •  Maintain different air pressures between adjacent areas.
   •  Diluting infectious particles with large air volumes.
   •  Air filtration by using HEPA filters on the supply air.

How many types of Isolation Rooms are there?

Isolation Rooms can be designed in one of three ways with regard to pressure profiles. In some countries the isolation rooms are multifunctional whereby the pressure profiles can be altered to suit the specific requirements at the time. The various configurations are described below.

This is where the patient’s bedroom is maintained at a higher pressure than the adjoining anteroom or ensuite. The patient here would typically have a low immune system and is extremely vulnerable to infection from contaminated airborne particles.

Positively Pressurised Isolation Room

This is where the patient’s bedroom is maintained at a lower pressure than the adjoining anteroom. The patient here would typically have a contagious disease or condition that may infect healthcare workers or visitors.

Negatively Pressurised Isolation Room

This is where the patient’s bedroom is maintained at the same pressure as the adjacent corridor and is separated by a positively pressurised lobby. This type of isolation room is becoming more common because it achieves the same as the Positive and Negative type.

Equal Pressure Isolation Room
Monitoring of ventilation performance

There are a number of different ways of monitoring the performance of the ventilation installation to ensure that the design criteria is met.

Room Pressure Differential Monitoring.

The traditional method was to install magnahelic gauges which had the advantage of not requiring power but in many other ways lacked the functionality available on modern devices like the Visio-3 and Visio-4 touchscreens.

Supply & Extract Air Volume Monitoring

This method used air volume transmitters fitted to the supply and extract ductwork to ensure that the minimum air changes for the isolation room is achieved. These transmitters can be connected to a Building Management System or connected to the Visio-3 & Visio-4 touchscreen.

Hepa Filter Monitoring

As a HEPA filter collects particulate matter and gets clogged over time, the pressure drop across the filter will increase. When the predetermined HEPA filter pressure drop limit is reached, the filter element must be changed. A clogged HEPA filter on the exhaust side can, for example, result in a dramatically reduced exhaust airflow rate that can compromise isolation room suite containment performance.

Useful References
& Downloads

Isolation facilities for infectious patients in acute settings (NHS)
Infection Control Guiding Principles for Buildings (HSE)
Infection control in the built environment (NHS)
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