Annual Variations of Environmental Conditions in Naturally Ventilated Classrooms in a Tropical Environment: Comparison with Proposed Guidelines

Internal classroom conditions are important aspects of the learning environment of students. A suite of relevant guidelines for acoustic, visual and thermal comfort parameters in naturally and/or mechanically ventilated classrooms in tropical environments is proposed. Data measured during winter and rainy seasons in a typical provincial school in central Thailand were then compared. Only thermal parameters, viz. wet bulb globe temperature, air temperature and relative humidity met the proposed guidelines values at all times during the school year. Mean sound levels and signal-to-noise ratios did not meet the requirements at some time during this period. Mean illuminance in classrooms only reached proposed guideline values when all internal lights were operating which occurred mainly during the rainy season. Illuminance in front of blackboards and whiteboards never reached proposed thresholds at any time.