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Understanding Your HVAC System: Building Pressure Monitoring & Control

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Clint Bradford

Part of the job of a building automation system (BAS) involves monitoring and adjusting how a heating, ventilation, and air conditioning (HVAC) system reacts to changes in air pressure.

Modern HVAC systems use air intakes, exhaust fans, relief dampers, and other mechanical means to adjust air pressure inside or within specific portions of a building. These mechanical components create negative or positive building pressure, either throughout the building or in specific areas that require an air pressure differential. Facility managers can use a building pressure monitoring system integrated within a smart BAS to track changes in building pressure to maintain optimal conditions while improving energy efficiency and protecting human health.

Building Pressure: Monitoring Systems for HVAC

Commercial and residential buildings use pressure sensors within their HVAC systems to maintain safe and comfortable environments for their occupants. An integrated BAS can also optimize the HVAC system to improve energy efficiency and maintain a preventive approach. Facility managers who understand how these systems interact can use them to their fullest potential. 

Understanding a Building’s HVAC System

Within all the components that make up a modern HVAC system are monitoring devices called differential pressure switches. These devices measure pressure and flow rates through lines and into rooms to ensure efficient operation; they act as sensors for the HVAC system.

These sensors are already part of modern HVAC systems. Creating a building pressure monitoring system does not require upgrading since means to measure air pressure are already there. And it becomes truly meaningful when sensor data is passed onto an intelligent BAS with integrated analytics.   

Building pressure monitoring systems can: 

  • Measure the air volume that flows through the system, enabling demand-controlled ventilation and aiding with the positioning of ventilation dampers, which control airflow. 
  • Measure channel pressure changes within an HVAC system’s air ducts, which can trigger adjustments in fan power to ensure steady airflow. 
  • Monitor the condition of filters within modern HVAC systems, helping to determine when filters require replacement. 
  • Monitor room pressure to ensure consistent and appropriate conditions.
  • Measure air pressure in rooms that require differential pressure to prevent contaminated air from spreading to other rooms. 

These capabilities can have significant benefits for building occupants and play important roles in facilities management.

Why Building Pressure Monitoring Systems Matter

HVAC systems maintain air temperature by varying airflow using a variable air volume (VAV) configuration. Based on air volume measurements from pressure sensors, a smart BAS can control the airflow by opening or closing air dampers. 

A BAS can directly adjust the environment within a building and in individual rooms by using HVAC’s built-in building pressure monitoring system as a guide. Pressure sensors can also measure hydraulic or pneumatic subsystems that use liquids or gases when heating or cooling and monitor for leaks of potentially dangerous chemicals within these subsystems, such as ammonia, which is used as a coolant in many HVAC systems. As such, they play a critical role in ensuring safety and protecting the health of building occupants. 

Energy Efficiency

A building pressure monitoring system with an intelligent BAS helps the HVAC system run more efficiently. Differential pressure sensors can reduce energy consumption by: 

  • Improving the efficiency of heat exchange to control temperature and humidity in a room.
  • Maintaining relative air pressure in ducts that can otherwise cause unwanted areas of negative or positive pressure, resulting in airflows that cause the loss of cooled or heated air. 
  • Minimizing power used by fans by adjusting fan speed to regulate airflow only as needed. 

These small steps can make a big difference in energy consumption over time.

Indoor Air Quality

The data collected by a building pressure monitoring system can be used to effectively distribute air throughout a building. This improves air quality significantly, helping to create safer and healthier indoor environments. For example, ensuring enough fresh air enters a ventilation system reduces levels of carbon dioxide and other potentially hazardous airborne contaminants. At a time when indoor air quality standards are becoming more strict and public demand for safety is rising, building pressure monitoring systems add great value.

Negative or Positive Air Pressure

In some cases, differing levels of air pressure between rooms are essential for safety. These include:

For example, using built-in building pressure monitoring systems to create negative pressure rooms allows for the isolation of highly contagious airborne illnesses such as Covid-19. 

An Integrated Solution for Building Pressure Monitoring

Integrating a building pressure monitoring system with an analytics-led BAS is the best way to track sensor data and understand how air moves through a building’s ventilation system. With advanced analytics, an intelligent building automation system can continuously regulate air pressure throughout a building, using predefined parameters to improve efficiency, comfort, and safety. The result is a better, smarter, and healthier building.

Buildings IOT offers innovative products and services that help you make the most of your building pressure monitoring system. To learn more, contact our team of experts today.



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