What is a Negative Pressure Room? Understanding the Basics (2024)

10 Jun What is a Negative Pressure Room? Understanding the Basics

Posted at 11:50hin BlogbyAdam Peithman0 Comments

Have you ever wondered how hospitals prevent infectious diseases from spreading patient to patient, despite being filled with germs? The secret lies in negative pressure rooms, which were used extensively during the COVID-19 pandemic. In hospitals, they help isolate patients, but they are also used in pharmaceuticals, research labs, and other places that need to control the spread of contaminants. But what exactly is a negative pressure room, and how do they work? In this article, we’ll explore their definition, applications, benefits, and more.

What is a Negative Pressure Room?

A negative pressure room is a controlled environment where the air pressure inside is lower than the surrounding areas. This difference in pressure creates inward airflow into the room, and prevents airborne particles, viruses, and bacteria from escaping. They have many applications, but they are mostly known for being used in hospitals to isolate contagious patients.

How Do Negative Pressure Rooms Work?

Negative pressure rooms work by creating a lower pressure inside the space compared to the outside. They use special ventilation systems to do this, and these systems include exhaust fans, air pressure monitors, and intake vents.

To create a negative air pressure space, exhaust fans pull air out of the room to create a vacuum effect. As a result, when a door opens or there is a breach, air from the surrounding areas flows into the room to balance the pressure, and this is precisely what prevents the contaminants from escaping.

Applications of Negative Pressure Rooms


Negative pressure rooms are important in many medical settings, especially for isolating patients with airborne infectious diseases like COVID-19 or tuberculosis. By keeping pathogens within the room, they protect hospital staff as well as patients. During the COVID-19 pandemic, for example, many hospitals used these rooms to both isolate and treat infected patients.

Pharmaceutical Industry

In the pharmaceutical industry, they are used to contain hazardous compounds, especially those that need to comply with USP 800 standards. Negative air pressure spaces are often necessary to reach regulatory compliance.

Research Laboratories

Research laboratories deal with biohazards that require strict containment protocol. As a result, these rooms provide the necessary environment to safely study pathogens that may become dangerous if spread. These spaces protect both researchers and the public at large.

What is a Negative Pressure Room? Understanding the Basics (1)

Industrial Applications

In factories or industrial zones, they may be used to control the spread of dust, fumes, or chemicals. In short, they help protect workers from exposure to harmful substances. Industries like manufacturing, chemical processing, and food production commonly use negative pressure rooms for this purpose.

Design Features of Negative Pressure Rooms

Air Pressure Monitoring Systems

Many controlled environments and cleanrooms use air pressure monitoring to maintain the right pressure levels within a space. They continuously measure and display the differential between the room and its surroundings.

HEPA Filtration

High-efficiency particulate air (HEPA) filters are also used in many of these spaces. They capture airborne particles, including bacteria and viruses, preventing them from leaving through the exhaust air. These filters are very efficient, and they trap at least 99.97% of particles that are 0.3 micrometers or larger in size.

Sealing and Structural Considerations

Additionally, to maintain low pressure, these rooms must be sealed tight, or else all the efforts are in vain. Doors, windows, and other openings must be secure. Other considerations involve using materials and construction methods that support the integrity of the room.

What is a Negative Pressure Room? Understanding the Basics (2)

Benefits of Negative Pressure Rooms

Safety for Workers

Negative air pressure rooms provide a safer environment for anyone looking to stay away from dangerous compounds. This is especially important in hospitals and clinics where the risk of cross-infection is high.

Compliance with Regulations

Further, these spaces help businesses comply with relevant health and safety regulations that require the containment of dangerous materials and pathogens. Compliance is important for running any legal operation and keeping public trust.

The Bottom Line

Negative pressure rooms have proven to be important in preventing the overall spread of infectious diseases in hospitals, protecting staff from dangerous compounds in pharmaceuticals, preventing the outbreak of dangerous pathogens in research labs, and much more. These rooms, which were widely used during the COVID-19 pandemic, isolate harmful particles and ensure a safer environment for both patients and workers. If you’re looking to isolate dangerous materials from the rest of your staff, consider building a negative pressure cleanroom. Contact Allied Cleanrooms today to get a free quote and take the first step towards a safer, more controlled environment.

What is a Negative Pressure Room? Understanding the Basics (2024)


What is a Negative Pressure Room? Understanding the Basics? ›

They are called negative pressure rooms because the air pressure inside the room is lower than the air pressure outside the room. This means that when the door is opened, potentially contaminated air or other dangerous particles from inside the room will not flow outside into non-contaminated areas.

What is negative pressure in simple terms? ›

: pressure that is less than existing atmospheric pressure.

What is the difference between positive pressure room and negative pressure room? ›

Ordinarily, negative air pressure isolation rooms are used as prevention rooms, while positive air pressure isolation rooms are used for protection. Therefore, negative air pressure keeps pathogens in, and positive air pressure is intended to keep pathogens out.

What are the criteria for a negative pressure room? ›

Negative pressure rooms must undergo at least 12 total room air changes every hour. They need to maintain a negative pressure differential of at least 0.01''. Exhaust from these rooms and any connected anterooms or toilet rooms needs to travel directly outdoors with no chance of contaminating exhaust from other spaces.

How do I know if my negative pressure room is working? ›

Hold a small piece of tissue in front of the door approximately 1 inch above the floor outside of the room. If room has a glass door, slightly crack the glass sliding doors for testing. 3. If air pressure is appropriately negative, the tissue will be pulled TOWARDS the room.

How to maintain negative pressure in a room? ›

Negative Pressure Environment
  1. The air entering the room should be filtered with a HyperHEPA filter.
  2. An adequate number of room air changes per hour has to be achieved.
  3. The door of the isolation room should be self-closing.
  4. Windows, floors and ceilings should all be well sealed.
Feb 3, 2021

Is negative air pressure bad for you? ›

In homes that do not have airtight envelopes, higher negative air pressures will lead to the infiltration of airborne particles and gaseous contaminants. When negative air pressure is present, carbon monoxide can be produced by fuel-burning appliances such as furnaces, boilers, and water heaters used indoors.

Why would you need a negative pressure room? ›

Negative pressure rooms, also called isolation rooms, are a type of hospital room that keeps patients with infectious illnesses, or patients who are susceptible to infections from others, away from other patients, visitors, and healthcare staff.

Why is it called negative pressure ventilation? ›

Negative pressure ventilation is mechanical ventilation in which negative pressure is generated on the outside of the chest and transmitted to the interior to expand the lungs and allow air to flow in.

How many cfm to create negative pressure? ›

Typically, a minimum airflow difference of 150 to 200 cubic feet per minute (CFM) is adequate to maintain pressure differential in a well-sealed room. “ During the building process of negative pressure rooms it is extremely important to consider the overall integrity of the room.

Is a negative pressure room a clean room? ›

In today's fast-paced world of technology, pressurized cleanrooms are being utilized in more and more industries and applications. Two main types of cleanrooms are negative pressure rooms and positive pressure rooms. The level of pressure determines the way air naturally moves in a space.

Is negative pressure a vacuum? ›

Negative pressure, also known as a vacuum, is a process that reduces the air pressure inside a container to a level that is lower than the outside atmospheric pressure. Negative pressure is created using a mechanical device, such as a vacuum pump, that removes the air molecules from the container.

What is negative air pressure in a home? ›

What is negative air pressure? Negative air pressure occurs when the pressure inside your home is lower than the pressure outside. We've talked about the importance of insulation for an energy efficient home. However, over-insulating may restrict fresh air from entering the home.

What is the meaning of negative pressure? ›

Negative pressure is also known as vacuum negative pressure. The vacuum pressure is also known as the vacuum level. Negative pressure is calculated in many different types of units such as: Torr, Pa, mBar, mmHg [abs] … this is a measure of the pressure of the amount of matter present in a certain space.

What does negative pressure mean in HVAC? ›

Essentially, negative air pressure is when there is less air flowing into your home than being drawn out. Negative air pressure is frequently used in hospital settings to help keep contaminant levels low, but it isn't an intentional state for most homes.

What are the 4 types of isolation? ›

Fundamental principles of isolation are (i) Standard precautions (ii) droplet precautions (iii) Airborne precautions and (iv) contact precautions.

What does negative pressure in the lungs mean? ›

Inhalation: During inspiration, intrapulmonary pressure is negative, allowing outside air to enter, and during expiration, intrapulmonary pressure becomes positive due to a decrease in pulmonary volume. This forces the air out into the lungs.

What is positive pressure vs negative pressure? ›

When intake fans' combined airflow is greater than exhaust, a positive pressure is created inside the chassis. Conversely, when the airflow is greater for exhaust than it is for intake, a negative pressure is created.

Is negative pressure the same as vacuum? ›

Negative pressure, also known as a vacuum, is a process that reduces the air pressure inside a container to a level that is lower than the outside atmospheric pressure. Negative pressure is created using a mechanical device, such as a vacuum pump, that removes the air molecules from the container.

What does negative total pressure mean? ›

Pressure readings often find the "gauge" pressure, which is the difference between the absolute current pressure and absolute ideal atmospheric pressure. So a negative pressure reading on your gauge is really measuring "this much less than atmospheric pressure".

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