Home » Applying Engineered Infection Prevention (EIP) Strategies in Commercial and Institutional Buildings
With the onset of the COVID-19 pandemic and the identification of airborne droplets as the primary path of infection transmission, professionals designing, operating, and maintaining all types of facilities are focusing on the importance of indoor air quality (IAQ). The quality of the indoor environment, and air quality in particular, has always been a top priority in health care, where people responsible for designing and operating facilities work to address the potential for infection transmission and prevent nosocomial infections, or health care associated infections (HAI), that cause a substantial number of illnesses and deaths every year. As the COVID-19 pandemic continues to evolve, and our understanding of the disease and the behavior of the virus that causes it develops, the focus on IAQ and its role in infection transmission has expanded to all types of facilities, including schools and other public buildings.
In general, we know IAQ has a major impact on occupant health, comfort, productivity, and quality of life. Occupants take an average of 20 breaths every minute. Each breath contains more than life-sustaining oxygen. Occupants also inhale aerosols and particles, spores, dust, and allergens.
Unfortunately, viruses and bacteria are present among the airborne matter that gets circulated through buildings and transferred from occupant to occupant through breathing and other forms of contact.
A range of solutions and technologies, many already common in health care environments, are being adapted and implemented in buildings elsewhere. Such pathogen mitigation solutions and technologies fall under the umbrella of Engineered Infection Prevention (EIP). EIP mitigation strategies usually include dilution (ventilation), filtration, humidification, and air cleaning and disinfection. Filtration is the most prevalent method employed by straining the air and capturing particles. Filtration has its place in an EIP and IAQ strategy but only treats air that moves through the filter media. In order for pathogens to be captured by the filters in an HVAC system, they must get entrained in the return airstream and find their way to the filter banks. Filtration also adds a restriction (static pressure) that must be overcome through additional fan energy. Along with proper filtration, it is important to address the risk of infection transmission directly in the space where occupants work, learn, play, and live. Therefore, EIP strategies incorporating a mix of technologies are most effective in mitigating the risk of infection transmission.
Any EIP solution, whether consisting of one technology or a mix of technologies, comprises a risk mitigation strategy. With each element of the strategy, risk of infection is reduced but not eliminated. Combined with proven basic personal measures of masks and social distancing, and with careful application, EIP strategies can make indoor environments safer, and, in general, address both airborne and surface transmission, where examples are listed in the table below. For the purposes of our discussion here, we are going to focus on the EIP strategies that address the potential for airborne infection transmission. Think of them as building blocks in an overall airborne EIP strategy. Fundamental building blocks include ventilation, filtration, and humidity. Supplemental building blocks address additional air cleaning and disinfection with ionization and ultraviolet germicidal irradiation.