What is Building Pressurization?

The Value of Managing Commercial Building Pressurization

Poor indoor air quality is a major concern for both building managers and occupants. However, have you considered that building pressurization could be the underlying cause of these unhealthy conditions?

Building pressurization is the relationship between the air pressure inside and outside of a building. It plays a crucial role in maintaining a healthy and comfortable environment. When a building is pressurized correctly, it helps prevent the infiltration of outdoor air pollutants, dust, and contaminants. Most properties should have a slightly positive building pressure.

On the other hand, an improperly balanced relationship between indoor and outdoor pressure can lead to several issues: moisture intrusion, air leakage, and increased energy consumption. It is essential for building managers to understand and monitor building pressurization to ensure optimal indoor air quality (IAQ) and occupant comfort.

Watch the short video below to learn the most important thing you can do to maintain proper pressurization in your building.

Building pressurization ensures proper airflow and an optimal balance of pressure between the interior and exterior of a facility. This requires careful design and operation of HVAC systems, including the selection and placement of air handling units, exhaust systems, ductwork design, and appropriate control strategies.

Different interior spaces within a building can have pressure differences in relation to other spaces. In a hospital setting, an isolation room maintains negative pressure to prevent the escape of air into adjacent spaces, while an operating room is kept at positive pressure to prevent the infiltration of external air. Achieving the right indoor pressure is also important in scientific research for contamination-free cleanrooms.

In this blog, we will look at the overall pressurization of the entire building, which refers to the pressure relationship between the interior and exterior environments.

Why Building Pressurization Matters in Commercial Buildings

• Moisture Control

  Adequate building pressurization serves as a barrier against outdoor humidity, safeguarding against condensation, mold growth, and moisture damage. These factors not only compromise the structural integrity of the building but also pose risks to the wellbeing of its occupants. By maintaining proper pressurization, the building can mitigate these concerns and ensure healthier indoor air quality.

• Ventilation

  Pressurization is the net result of the flow of fresh outside air into a building and the removal of inside air via exhaust systems. This is particularly important for occupant health and comfort, as poor indoor air quality can lead to various respiratory issues and discomfort.

• Energy Efficiency

  In a properly pressurized building, outside air is conditioned through the mechanical units, which are optimized for energy efficiency. Meanwhile with negative building pressure, outside air infiltrates the building envelope and bypasses these mechanical units. It’s important to maintain proper building pressurization in order to achieve lower operating and energy costs in commercial buildings.

The Fundamental Cause of Inadequate Building Pressurization

We can achieve proper pressurization by maintaining an offset between the flow rate of outside air introduced through the HVAC units and the flow rate of air being exhausted from the building. That’s why the operation of HVAC systems, including the way they handle air, is the primary driver of building pressurization. When these systems are improperly designed or malfunctioning, they can cause air imbalances that result in areas of over- or under-pressurization. Issues such as incorrectly sized air handling units, faulty control system mechanisms, and alterations to mechanical systems can significantly impact the overall pressurization of a building.

How Can You Maintain Building Pressure Control?

• HVAC

  Heating, ventilation, and air conditioning systems play a crucial role in maintaining building pressurization. These systems are equipped with dampers that regulate the flow of outside air into different zones of the building. You can adjust the dampers based on numerous factors to achieve the desired pressurization levels. By creating a controlled supply airflow, outside air is conditioned optimally through the mechanical units, resulting in greater energy efficiency.

• Building Automation System (BAS)

  A properly maintained BAS provides greater control for facility management and leads to energy efficiency. Various differential pressure and static pressure sensors throughout the building and within the HVAC units optimize HVAC operation. The BAS allows facility management to set occupancy schedules and create scenarios in which the HVAC systems will automatically adjust airflow rates and damper positions based on input from the sensors. It can also provide real-time alerts in case of any anomalies that may occur during normal operation.

• Professional Consultation

  HVAC technicians, building automation specialists, and specialized consultants can assist with controlling building pressurization in a commercial building. They can analyze space utilization according to design and from sensor feedback, adjust HVAC system settings accordingly, and optimize the building automation system for efficient pressurization and energy utilization. They provide valuable insights and recommendations for maintaining proper building pressurization by conducting audits, performing airflow analysis, and suggesting improvements to optimize the building’s HVAC system performance.

Strategies for Achieving Proper Building Pressurization

Building pressurization starts with the design of the spaces and the HVAC systems. Without a proper design, it can be difficult to achieve the desired building pressurization. This includes not just the original design of the building, but any time a renovation occurs or the functionality of a space within the building is altered. Whenever adjustments to a building function are made, it is important to include an HVAC design professional in the conversation prior to making those changes.

Another important step for proper pressurization is regular maintenance of HVAC systems, both to the units themselves and the various sensors within the system. This can include:

• Inspecting and maintaining HVAC equipment, including dampers, filters, ventilation systems, air handlers, exhaust fans, and economizers

• Inspecting and maintaining sensors, plus replacing as appropriate to ensure proper operation

• Training building operators on how to monitor the BAS for any anomalies so that issues can be addressed before they cause significant damages

By implementing these strategies and following regular maintenance practices, owners and operators can achieve and maintain proper building pressurization. This work ensures a healthy and comfortable indoor environment for building occupants.