The Influence of Office Furniture, Workstation Layouts, Diffuser Types and Location on Indoor Air Quality and Thermal Comfort Conditions at Workstations

Abstract

Many factors affect the airflow patterns, contaminant removal efficiency and the indoor air quality at individual workstations in office buildings. The effects of office furniture design and workstation layouts on ventilation performance, contaminant removal efficiency and thermal comfort conditions at workstations were studied. The range of furniture configurations and environmental parameters investigated included: 1) partition heights, 2) partition gap size, 3) diffuser types, 4) supply air diffuser location relative to the workstation, 5) return air grill location relative to the workstation, 6) heat source locations, 7) presence of furniture, 8) supply air temperatures, 9) adjacent workstations, 10) contaminant source locations, 11) supply air flow rates, and 12) outdoor air flow rates. The tracer gas technique was used to study experimentally the relative impact of these parameters on the air distribution and ventilation performance, as well as contaminant removal efficiency. Thermal environmental parameters such as air velocity and temperature were monitored at several locations to characterize the impact of these parameters on the thermal comfort conditions. The results showed that the outdoor air flow rate had a significant influence on the mean age of air. The air distributions at all the workstations were good even when the supply air flow rate was relatively low (i.e 5 L/s). At the same time, most of the parameters tested had a significant influence on contaminant removal efficiency when there was a contaminant source present somewhere in the office.

Integrating IAQ control strategies to reduce the risk of asymptomatic SARS CoV-2 infections in classrooms and open plan offices

“…Semi-open partitions between occupants can be used to form a personal cubical around each occupant to change the air distribution pattern and reduce the cross contamination (Shaw et al 1993a&b, Zhang et al 1994, Haghighat et al 1996, Kong, Zhang, and Wang 2014, and Kong 2019. Concentrations in a non-source containing cubical can be reduced by a factor of 1.1 to 3.6 in mixing type ventilation system with square or linear ceiling air diffusers except for the workstations located far away from the air supply or right under the exhaust grills (Haghighat et al 1996). Underfloor ventilation with a swirl air diffuser on the floor has the potential to reduce the exposure of a manikin inside an office cubical to the pollutant emitted outside the cubical by a factor of 2-3 (Kong, Zhang, and Wang 2014).…”

Mitigating COVID-19 infection disease transmission in indoor environment using physical barriers

“…In this sense, proper distribution of airflow and use of physical barriers can decrease the spreading of aerosol particles, thus further reducing the risk of human infection (Xu et al 2020). The critical factors impacting indoor airflow distribution include ventilation mode (location and design of air diffusers) as well as supply airflow rate (Bjorn and Nielsen 2002) (Lv et al 2019) (Haghighat et al 1996). In case of physical barrier and air deflectors, the focus will be on large and open space (Lv et al 2019) (Dominguez Espinosa and Glicksman 2017).…”

Comparative research on the air pollutant prevention and thermal comfort for different types of ventilation

“…31 Another study showed that the contaminant removal effectiveness (CRE) was similar for the floor pollutant source and the desktop pollutant source under MV. 32 However, with the occurrence of the airflow short-circuiting, the CRE with the floor pollutant source was higher than with the desktop pollutant source under MV. 33 For displacement ventilation (DV), a peak of contaminant concentration at the breathing level was found when the contaminant was exhaled by the source manikin.…”