The quality of the indoor environment has become a vital component for buildings due to the time spent indoors. To this extent, the performance of the indoor environment is considered as part of the greenery criteria by green rating schemes such as the Green Building Index in Malaysia. This study aims to investigate and assess the quality of the indoor environment of Platinum-certified office buildings in a tropical climate. This research applied a case study approach over two Platinum-certified office buildings. Post-occupancy evaluation is employed integrating full-scale measurement with an occupants’ survey. The measurement was carried out from May to August, and 112 questionnaires were retrieved to evaluate occupants’ satisfaction with aspects of the indoor environment. Thermal comfort, indoor air quality, acoustic, lighting, furniture, and cleanliness are considered as the main study variables. The findings of full-scale measurement indicated high relative humidity, and low air velocity and illuminance. While occupants reported overall indoor environment quality (IEQ) comfort, a significant correlation of variables was observed. The main sources of dissatisfaction were identified as overcooling around 24 °C, high relative humidity (RH), around 70% RH, glare, and background noise around 51.9 dB. Statistically, a significant difference between occupants’ responses to IEQ of two cases was identified, although both buildings are labelled with a Platinum certificate.

Natural ventilation has been used widely in buildings to deliver a healthy and comfortable indoor environment for occupants. It also reduces the consumption of energy in the built environment and dilutes the concentration of carbon dioxide. Various methods and techniques have been used to evaluate and predict indoor airspeed and patterns in buildings. However, few studies have been implemented to investigate the relevant methods and tools for the evaluation of ventilation performance in indoor and outdoor spaces. The current study aims to review available methods, identifying reliable ones to apply in future research. This study investigates scientific databases and compares the advantages and drawbacks of methods including analytical models, empirical models, zonal models, and CFD models. The findings indicated the computational fluid dynamics (CFD) model is the most relevant method because of cost-effectiveness, informative technique, and proficiency to predict air velocity patterns and ratios in buildings. Finally, widely used CFD codes and tools are compared considering previous studies. It is concluded the application of codes for research is subject to the complexity and characteristics of a studied model, the area and field of study, the desired turbulence model, and the user interface.

The indoor environmental quality of a library greatly affects the comfort and productivity of its users while preserving the materials. Despite the high energy consumption of HVACs in libraries, achieving acceptable thermal conditions, acceptable acoustics, and sufficient daylight levels for users remains a challenge. There are limited studies on the IEQ of educational buildings, especially regarding the current situation of libraries. It is important to conduct further studies to define design guidelines promoting indoor environmental conditions. The main objectives of this study were to investigate the IEQ of a campus library to recommend retrofitting strategies. The IEQ parameters in the rare collection room, which houses special collections, and in the library hall were assessed using a full-scale measurement, with eight HOBO data loggers and sensors deployed in various locations to monitor IEQ. A comparison of the results with the standards revealed that rare collection room was unsuitable for maintaining rare collections, as the average indoor air temperature exceeded 21.2 °C, which is beyond the threshold limit. Additionally, the relative humidity ranged from 51.3% to 55.8%, which is marginally high. To provide acceptable indoor conditions, this study recommends retrofitting strategies for the exterior walls, such as using cement plaster with a low thermal conductivity. In the library hall, the reading zone was found to be thermally uncomfortable. The air velocity was below the range of 0.15 ms⁻¹ to 0.50 ms⁻¹ recommended by MS 1525. The average CO₂ level was 479.5 ppm, with some points registering an increase of up to 588 ppm. The noise level in the library hall ranged between 43 dB(A) and 61 dB(A), while the light intensity was below 300 lux in the reading area, which is not within the acceptable range. This study suggests improvement solutions, such as implementing an air temperature between 24.5 and 26.5 °C for higher thermal comfort and increasing the window-to-wall ratio to utilize natural daylight. These findings provide insights into the design of new libraries and the renovation of existing ones, ensuring that libraries continue to serve as vibrant centers of knowledge and learning for generations to come.