VENTILATION
Key steps for infection-free, energy-efficient buildings
Josiah Padget, Lead consultant and Healthcare manager of CETEC Pty in Australia, highlights some of the key ventilation, building fabric, and airflow requirements to minimise the risk of infection in hospitals and other healthcare environments, while maximising energy efficiency and thus reducing energy costs.
Since the advent of COVID-19, and the established link with respiratory virus airborne transmission, indoor air quality has become especially topical. Earlier this year, the Australian Government held a Clean Air Forum at Parliament House. Australia’s Chief Medical Officer, Professor Paul Kelly, announced that he would be setting up a committee to improve the nation’s indoor air quality over the next 12 months. The absence of clear indoor air quality legislation and Government guidelines have come at a cost. For example, data from the UK shows that more than 11,600 people died after catching COVID in NHS hospitals. In Australia one jurisdiction reported that 1 in 9 COVID infections were hospital acquired in 2020. It’s terrible to think that thousands of patients who went into hospital for unrelated illnesses contracted the disease, with fatal consequences. The risk of compromising the health of patients and staff due to transmission of other airborne disease, ingress of contaminants, and the impact on efficiency – both in financial and productivity terms, is significant.
Review of HVAC systems During the pandemic healthcare Estates and Facilities managers from around the country reviewed their HVAC systems
The built environment is an essential component of a hospital’s infection control strategy, as this influences airflow, and ingress of contaminants and moisture, and impacts energy consumption.
Australia’s Chief Medical Officer, Professor Paul Kelly.
30 Health Estate Journal November 2023
to determine if air exchange rates met basic hospital engineering requirements. However, of course, air exchange rates for fresh air are only part of the picture. Airtightness of the building’s external envelope may influence airflow leakage just as much as the intra-building barriers separating CSSD, operating theatres, and isolation rooms/wards. Air barriers are the starting aspect to consider, and vital to achieve the goal of reducing the prevalence of hospital-acquired infections. The built environment is an essential component of a hospital’s infection control strategy, as this influences airflow, and ingress of contaminants and moisture, and impacts energy consumption. Internal air flows are a critical aspect for good infection control. The correct flow and control of air from clean to dirty areas is required to prevent hospital-acquired infections. Hospitals are designed to take advantage of positive and negative airflows, in key areas such as the CSSD. The Australian Commission on Safety and Quality in Healthcare mandatory Advisory AS18/07: reprocessing of reusable medical devices in health service organisations requires compliance to AS
4187 for accreditation. Building airtight sterilisation departments is critical to ensure unidirectional airflow. However, building and ward air permeability is rarely validated, which can greatly impact upon the risk of cross-contamination, and increase the risk of hospital-acquired infections.
Unintentional cross-contamination Unintentional cross-contamination can occur when excessive uncontrolled air leakage arises between clean and dirty areas, and from one patient or ward to the next. HVAC design and operation, exterior wind speed and direction, building stack effect, and building airtightness, all influence airflow and leakage inside a hospital. To protect occupants from unintentional air leakage, air barriers must be designed and tested to ensure that the construction is fit for purpose. Airtightness testing should be considered in a detailed risk analysis of the facility to reduce the risk of cross-contamination and increase wellness outcomes. In addition to internal cross-contamination, air leakage into the building envelope can cause issues related to moisture and contaminant ingress.
Courtesy of Australian Government Department of Health and Aged Care
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