Guide to Building Pressure Standards for Hospitals and Medical Facilities

A heating, ventilation, and air-conditioning (HVAC) system is one of the most important components of a medical facility, and not just because of its role in indoor air quality (IAQ). Modern HVAC systems have inbuilt sensors that monitor air pressure throughout a building, including in areas in hospitals that require specific air pressure arrangements. This is critical for meeting the building pressure standards that protect the health and safety of patients and staff.

As Timothy Larson of RTM Engineering Consultants says: 

With an increased emphasis on the safety and welfare of patients, visitors, and staff, the requirements to maintain specific pressure relationships and airflow rates is the most apparent difference between health care facilities and other buildings. For example, the requirements call for a positive-pressure relationship in operating rooms and pharmacies and negative-pressure relationships for airborne-infectious isolation rooms and emergency department waiting rooms. 

The unique role of air pressure in health care facilities means proper operation of HVAC systems and compliance with building air pressure standards are imperative.

Why Building Pressure Standards Matter in Healthcare Settings

Ventilation is more than moving air throughout a building. Ventilation also involves controlling contaminants to keep building occupants safe from airborne pathogens and other dangerous materials. Physical filters are not the only way to do this; by varying air pressure in specific ways, you can manage the movement of particulate matter.

Medical facilities vary air pressure in specific areas to minimize threats to human health. These include isolation rooms requiring negative pressure, as well as operating rooms and protective environment rooms needing positive pressure.

• Negative air pressure results from air being sucked out of a room by the ventilation system to limit cross-contamination, a practice used by hospitals to prevent highly contagious infections from spreading. 
• Positive air pressure helps ensure that airborne pathogens do not infect patients or contaminate equipment and is created by moving unpolluted air into the room.

The ability to modulate air pressure and create these environments is key to safeguarding patients and healthcare workers.

Building Pressure Standards & Guidelines for Hospitals

The need for specific environmental conditions in hospitals and other medical buildings has led to the development of specific air pressure standards. In the United States, the standards established by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), the American Society for Healthcare Engineering (ASHE), and the American National Standards Institute (ANSI) provide vital guidance for healthcare facilities. Many of these standards are reviewed and modified as new information becomes available. 

Some of the most important ASHRAE building pressure standards and guidelines include: 

• ASHRAE/ASHE Standard 170-2017 represents the minimum standard for medical facilities, outlaying requirements for temperatures and humidity while providing recommendations for sterility, odor control, and comfort as they relate to patient care. Standard suggests positively pressured environments for operating rooms and sterile storage rooms to protect patients, equipment, and supplies from airborne contaminants in neighboring areas. 
• ASHRAE/ANSI Standard 90.1-2016 looks specifically at the difference between infiltration and air leakage rates within a building’s envelope. 
• ASHRAE/ANSI Standard 62.1-2016 deals with air pressure within laboratories that handle hazardous materials, looking at ventilation rates in both existing buildings and new building designs to help incorporate natural ventilation into engineered systems. 
• ASHRAE/ANSI Standard 52.2-2017 deals with air pressure in ducts containing HEPA filters used for air purification, particularly in positive pressure environments. It looks at temperature, relative humidity, and absolute pressure to calculate and test airflow through ducts.  
• ASHRAE Guideline 10-2016 provides guidance on indoor environmental quality, including indoor air quality, airborne contaminants, humidity, temperature, and sound pressure levels in buildings.  
• ASHRAE Guidelines 29-2019 looks at risk management as it applies to extraordinary incidents that can negatively affect public health and safety. This includes examining the vulnerability of a building’s envelope due to differing air pressure as it relates to windows, doors, and other building openings.  

Other building pressure standards and guidelines include: 

• NFPA (National Fire Protection Association) Standard 99 looks at how building pressure affects airflow, humidity, and temperature. It promotes requirements for the design and implementation of HVAC systems to create positive and negative pressure areas, depending on the risk of transmitting airborne infections. 
• Appendix C of the EPA’s (Environmental Protection Agency) Building Air Quality Guide looks at how vapor pressure (absolute humidity) can contribute to mold and mildew growth. It suggests directly venting areas generating moisture to a building’s exterior, diluting humid indoor air, and using dehumidification techniques. 
• The Joint Commission’s Environment of Care EC.02.05.01 Standard defines performance of mechanical ventilation systems to provide proper pressurization, changing, and filtration of air for critical areas in accordance with NFPA 99 and ASHRAE 170.

Other agencies and organizations at the local and state levels may also include building pressure standards and guidelines for healthcare facilities. 

Why Building Pressure Standards Matter in Healthcare Settings

The value of air pressure monitoring in healthcare environments is not new. But the pandemic has heightened awareness about building pressure standards and how they relate to a facility’s HVAC system. It has also spurred hospitals and medical facilities to seek better ways to comply with those standards.

Pressure measurement mechanisms are already contained within the equipment that makes up the HVAC pressure; you already have the data you need. An integrated and intelligent building management system makes that data meaningful. By unifying building systems and adding an advanced analytics system to your BMS, you get deep visibility into the pressure in your buildings and greater control over the environment. 

With a mobile-first analytics platform, like onPoint, building pressure points can be continuously monitored and you can make real-time adjustments through a centralized dashboard from anywhere. This means you no longer have to move patients, call a service provider, and disrupt the vital work that happens within these buildings. Many adjustments can even be made automatically, minimizing reliance on manual intervention and the risk of human error. The robust reporting capabilities offered by cutting-edge analytics software allow you to analyze trends, identify vulnerabilities, and easily share insights with all relevant stakeholders. 

Adhering to building pressure standards is essential to protect human health. With the right technologies, creating and maintaining safe environments is easier than ever before.

Buildings IOT offers the services, software, and support hospitals and other medical facilities need to comply with building pressure standards. Contact our expert team to learn more.