By: Nicole Imeson
Infection prevention and control (IPAC) measures play critical roles in healthcare facilities, particularly in those housing operating rooms, airborne infection isolation (AII) rooms, and protective environment (PE) rooms for immunocompromised patients. Numerous factors contribute to IPAC, including mechanical, electrical, and architectural elements and systems. The Commissioning Provider (CxP), acting as the owner's representative, enhances the functionality and operation of IPAC systems throughout the commissioning process.
The American Society of Healthcare Engineering (ASHE) provides several guides and toolkits to assist construction teams in assessing and preventing the risk of infection. ASHRAE Standard 170 Ventilation of Healthcare Facilities details the requirements for filtration, air changes per hour, outdoor air, pressure relationships to adjacent spaces, design temperatures, and relative humidity for various patient and service spaces throughout a healthcare facility. These guidelines and standards establish crucial parameters for maintaining a safe and hygienic environment, with additional contributions from passive measures such as controlling traffic flow, door swing orientation, and selecting appropriate finishes to minimize the spread of pathogens.
Operations and Maintenance
Larger hospitals incorporate interstitial floors to create a buffer between patient floors for mechanical and electrical systems. This setup enables operations staff to conduct maintenance without disturbing patients below, and healthcare staff can navigate freely without encountering obstacles such as ladders. Placing mechanical and electrical equipment within patient areas is critical in hospitals without interstitial floors.
For example, a large hospital project faced height limitations due to a nearby regional airport, which prevented the incorporation of interstitial floors. During the design phase, the question arose: is it preferable to place the VAV boxes inside the patient rooms or outside the hallway? Placing the VAV box in the hallway would disrupt healthcare staff during servicing and heighten the risk of bacterial transmission. Conversely, locating it in a patient's room would disturb the patient and their family. Following collaboration with the owner, it was decided to "put the VAV box in the patient room because if servicing is required, the patient and their family would be moved to another space while the work is undertaken," explained John McFarland, a Principal at WorkingBuildings in Atlanta. This decision minimizes disturbance in the hallway, enhancing overall functionality and comfort within the hospital. Consulting with the owner provided the design team with a better understanding of maintenance procedures concerning patients. This enabled them to adapt the design to meet all necessary requirements.
This hospital also chose dual HEPA filters for critical areas, installing one at the air handling unit and the second at the diffusers in specific patient rooms. HEPA filters can remove over 99.97% of particles sized 0.3 microns or larger, ensuring high air quality. Analysis showed that adding a second HEPA filter in series minimally affected air quality since most particles had already been removed. However, due to the lower face velocity, the diffuser filter adds minimal pressure drop to the system and allows maintenance staff to replace air handling unit filters without shutdowns. Although the room-side diffusers were costlier, their infrequent need for replacement and pressure drop indicators ensured efficient maintenance.
Life Safety
IPAC serves as a safety aspect, but life safety operations like fire alarm, exiting, and smoke control take precedence. Pressurization is crucial in isolation rooms to prevent airborne pathogens from spreading to adjacent spaces. Shutdown requirements and sequences can vary depending on jurisdiction and Fire Marshall requirements. "Anytime you go to a life safety mode, you immediately create a non-steady state scenario, which makes things really complicated," explained McFarland.
CxPs, with their expertise in operations and functional testing, play a crucial role in evaluating and troubleshooting conflicts between IPAC and life safety operations. While the engineer of record designs the system, the CxP tests its functionality, identifying instances where scenarios were overlooked or theoretical concepts failed in practice. For instance, if air handlers shut down during a fire alarm while the exhaust fan stays running, the isolation room may become negatively over-pressurized, hindering occupants from opening the door. In such cases, adjusting the exhaust fan to a lower flow rate maintains negative pressure while enabling egress. "You can actively monitor the pressure and slow the exhaust fan down so you're still maintaining a negative when you lose supply airflow but not exhausting as much as before," explained McFarland. When everything shuts down during a fire alarm, sequencing the shutdown to stop supply airflow first and exhaust airflow second keeps the room in a negative pressure state for as long as possible until it goes neutral. Upon restarting, bringing the exhaust online before the supply and adjusting its flow to maintain constant negative pressure will limit the potential for the spread of pathogens.
Communication and Collaboration
Effective communication and alignment within the design and construction team significantly impact the success of healthcare projects due to their design complexity and the involvement of large teams. Minor changes like altering room numbers or equipment tags can significantly impact the project if made during construction or turnover. Every team member relies on room numbers to identify spaces. "Room numbering and equipment naming, equipment tag methodology, are two things that should go into an OPR (Owner's Project Requirements). They're absolutely critical that the owner has a buy-in on," explained McFarland. If the nomenclature doesn't meet the owners' requirements, they will change, leading to confusion and additional time spent deciphering room identities (i.e., determining whether it's the old or new number).
Scheduling functional testing before the construction cleaning reduces re-work to clean patient rooms before turnover. Collaborating with the construction group to functionally test systems as they are completed, rather than waiting for entire areas to be finished, identifies issues before they recur in future installations. Achieving this requires communication and mutual respect between the CxP and general contractor to ensure systems are ready for testing when the CxP arrives on site.
The commissioning of infection prevention and control (IPAC) systems in healthcare facilities is an intricate and essential process that encompasses various factors ranging from mechanical and electrical components to architectural design considerations. The CxP serves as a linchpin in the process, ensuring that IPAC systems meet the evolving needs of the facility and its occupants. By prioritizing communication, collaboration, and adherence to the owner's project requirements, healthcare facilities can effectively mitigate the risk of infections and create safer environments for patients, staff, and visitors.