A Field Investigation of Thermal Comfort Parameters in Green Building Index (GBI)-Rated Office Buildings in Malaysia

Field investigation; GBI; Office building; Thermal comfort

Malaysia is classified as having tropical atmospheric conditions that are for the most part consistently hot and humid. The first half of the year is typically sunny while the remaining six months are wet. This hot and humid tropical climate is widely acknowledged as presenting particular challenges for building design (Szokolay, 2008). As a consequence of global warming, the world is facing an increase in outdoor and indoor temperatures. Although climates, living conditions, and societies differ widely across the world, the temperatures that individuals find comfortable in terms of dress, activity, moisture, and air are known to be very similar. To date, however, the construction industry’s idea of green building seems to have focused only on finding the “right mechanism” for an environmentally sustainable “final result” (such as energy efficiency or water conservation), with no provision for subsequent appraisal of building execution (Yang, 2012).

The essential purpose of a building is to provide a safe and comfortable place for people to live, work, and communicate (Bessoudo et al., 2010). On that basis, it is appropriate to consider the building façade not just as a “wrapper” but as a boundary with fundamental capacities that impact indoor environmental quality and comfort (Drake, 2007). As indoor thermal comfort is commonly determined by the façade’s thermal performance (Gratia & Herde, 2004; Liping & Hien, 2007), it seems important to ask how this factor is addressed in the design of mechanical ventilation structures in hot and humid climates like Malaysia. Previous studies have explored this issue from various perspectives. Gagge et al. (1986) discovered that thermal comfort is influenced by the relation between the building and outside conditions. More recently, Cheung et al. (2005) examined the impacts of architectural components on energy consumption in mechanically ventilated buildings and the effects on occupants’ performance.

However, despite numerous analyses of how the building envelope affects indoor air quality, few studies have explored the effectiveness of façade structures in hot and humid climates as compared to those in cold climates (Ochoa & Capeluto, 2008). While a range of green building certification systems have been introduced worldwide, one question in particular remains to be clarified: are green building certification schemes as currently applied producing levels of Indoor Environmental Quality that satisfy their occupants (Liang et al., 2013)? In this regard, Gou et al. (2013) called for more research to identify the factors affecting indoor air quality in tropical locations.

It is generally accepted that green building techniques can provide superior indoor conditions that enhance wellbeing, prosperity, and efficiency. When properly applied, these techniques ensure more comfortable and advantageous working conditions. For that reason, the present study investigates the execution of NRNC GBI-rated buildings in Malaysia and the effects on indoor thermal comfort. While the study does not question GBI accreditation, it seeks to evaluate the execution of these provisions in the post occupancy period in terms of how green façade-shading devices help to fulfill criteria for indoor thermal comfort.

Based on these findings, it may be concluded that Buildings A and B have achieved the requisite IEQ thermal comfort criteria for recertification after five years. Buildings C and D were found worthy of conclusive accreditation from GBI Malaysia. These findings also confirm that IEQ falls within the stipulated GBI range for green office buildings in a hot and humid climate like Malaysia thanks to various double-glazing provisions for façade shading. While a couple of parameters were not fully met, indoor conditions in these buildings are nevertheless considered adequate as benchmarks for green office buildings in Malaysia and South-East Asia.

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