Daylighting in Isaan Sim: Case study Sim in the upper Isaan

Abstract

This work aims to present the results of field survey on daylighting inside the building of eight buildings of Sim Isan (northeast Buddhist temple) in three provinces: Nakhon Phanom, Sakon Nakhon, and Nong Khai. Data on usability, physical aspects, and factors influencing the daylight were collected. A light meter was used, and the obtained data were used for defining variables. Then daylighting simulation was performed by using

a software “DIALux 4.13” in order to analyze factors influencing the daylight quantitatively by comparing the results to the standards of eyesight and vision in Sim Isan. In the last part of this article, Sim Isan in this study is compared to (1) Sim Isan with different eave overhang length, and (2) standardized Buddhist holy temples at present replacing ancient Sim Isan in northeastern Thailand. The findings revealed that Sim Isan was both used and not used for religious rites because it was replaced by the typical modern Buddhist temples, or it was sometimes used for ceremonial purposes in Buddhist holidays. Sim Isan had openings passing through of 7-9% of four-sided wall. According to the average of daylight from the survey and illuminance values under fair and partly cloudy sky, the light in building was higher than 300 lx, which passed TIEA standard suitable for reading prayer books and performing religious activities. In a cloudy day, however, the average daylight was lower than 300 lx. In case of Sim Isan with double-layer roofs, the amount of daylight was so low that it was not enough for using. In a comparison of daylight between Sim Isan and standardized Buddhist holy temples when the sky was partly cloudy, the amount of light was higher than 300 lx, and the standardized Buddhist holy temples was lighter than Sim Isan.