Structure and design
One of the added challenges facing a return to the office today is addressing the trend towards collaborative workspaces and larger, open-air industrial type settings with higher structural ceilings exposing duct and pipe work. This is possibly the least optimal environment to prevent transmission. The installation of a suspended ceiling allows for the easy configuration of permanent or modular individual offices, helping employees maintain social distance and lowering the potential spread of pathogens.
A metric used to measure the amount of air entering and exiting a room is air changes per hour (ACH). It is calculated based on the height of the structural ceiling in an open-air model. The incorporation of a suspended ceiling has the effect of reducing the ceiling height, and thus the volume of air needing to be exhausted. Installation of a suspended ceiling reduces room volume, effectively increasing ACH, and lowers the time it takes to clear a space of airborne contaminates.
Leakage control
Specially engineered suspended ceilings are a proven technology in patient rooms, clean rooms, and laboratories to help prevent the spread of contaminants. Today, acoustical suspended ceiling panels are available with a gasket in their design. When placed in a standard ceiling suspension system, the panels improve indoor air quality by forming a tight seal with the grid, to reduce airflow leakage through the ceiling plane and the potential spread of infectious particles into the plenum and other areas of the building.
Easily retrofitted into existing grids, these systems provide even more control over the volume of air in a room and have been proven to increase the effectiveness of in-ceiling air filtration by up to 40 percent. Increasing the effectiveness of HVAC systems is one of the keys to controlling the transmission of viruses such as COVID-19 and other airborne pathogens.
Some acoustical ceiling systems integrate an ultraviolet (UV) air purification system with their panels. The air panel purifier design uses UV light to deactivate pathogens. Test results show the system neutralizes 97 percent of infectious pathogens in aerosols during the first pass of air through the system. Each unit provides continuous air cleaning safely and directly from the ceiling plane through a shielded UV-C chamber. It also increases the number of air changes in the space.
Case study
The difference a gasketed ceiling tile system can make was recently demonstrated at
the Encompass Health Rehabilitation Hospital of Middletown, Delaware. The hospital is a provider of inpatient rehabilitation, contains 40 beds, and includes one patient room that functions as a negative pressure infection isolation room. The room is 5.79 x 5.79 m (19 x 19 ft) and conditioned using one constant volume supply box and one dedicated exhaust fan.
The room was designed to operate at a minimum differential pressure of -0.508 mm (-0.020 in.) w.c. (water column) in relation to the adjacent corridor. However, the exhaust fan for the space could not always achieve the required pressure, which caused nuisance alarms, and in some instances, a reversal of the room pressure when its doors opened. The actual exhaust air from the space was increased to the maximum extent possible for the exhaust fan.
Instead of replacing the exhaust fan to achieve the required room differential pressure and help eliminate the pressure variability, the facility replaced the existing ceiling panels with recently introduced gasketed ceiling panels. When placed in a standard ceiling suspension system, these panels form a tight seal and can reduce airflow leakage through the ceiling plane over four times more than panels without this newer feature.
