Estimating ventilation and replacance needs based on sensory pollution load to improve perceived air quality in therapeutic spaces - Case study: inpatient wards of a hospital

Document Type : Research Paper


1 Department of Architecture, Faculty of Art and Architecture, Shiraz Branch, Islamic Azad University, Shiraz, Iran

2 Department of Mechanical Engineering, Shiraz Branch, Islamic Azad University, Shiraz, Iran

3 Department of occupational health engineering, school of health, Shiraz University of medical sciences, Shiraz, Iran


Background and objectives: The study of the sensory pollution load and perceived air quality has been introduced as one of the methods of evaluating indoor air quality in non-industrial environments. This method is also used to estimate ventilation needs. This study aims to recommend the required ventilation rate according to the SPL to improve the PAQ in a therapeutic space.
Methods: Ventilation rate and time which is required for 98% of the old air to be exhausted at that rate were calculated in 9 rooms in inpatient wards of a hospital. High dissatisfaction had been reported from these spaces. The SPL of individuals, building materials, and ventilation systems were estimated using the Fanger model. The required ventilation rate was recommended and compared with the existing ventilation rate, WHO, AIA, and ASHRAE standards.
Results: In the studied spaces, the measured flow rates and air changes per hour were from 28 (minimum) to 178 (maximum) l/s and 2 to 7 ACH. These values were in accordance with the AIA standard, less than the values calculated through the ASHRAE (39-117 l/s) and WHO (80-560 l/s) standards, and Fanger model (51-393 l/s & 3-13 ACH).
Conclusion: It seems that considering sensory pollution loads is a practical, simple, and fast method for estimating ventilation needs to improve perceived air quality and users’ satisfaction and performance while reducing the energy consumption required to meet the ventilation rate. It does not have some shortcomings and limitations of other standards and methods. In existing hospitals, it can be used as a method to evaluate the effectiveness of the ventilation systems as well as the perceived air quality. Besides, the importance of adopting some strategies to reduce the sensory pollution load was emphasized.