Insulation of traditional Indian clothing: estimation of climate change impact on productivity from phs (predicted heat strain) model

Major databases on western clothing and their thermal properties are available, but information on non-western clothing is lacking. A recent ASHRAE project 1504-TRP, Extension of the Clothing Insulation Database for Standard 55 and ISO 7730 dealt with the issue. Simultaneously, a co-operation study at Indian workplaces allowed us to acquire some sets of the traditional clothes used at construction sites in Chennai area. The work was related to mapping of present work conditions in order to allow predictions and measures to be taken if the mean temperature of the work environment would rise. We selected ISO 7933 on predicted heat strain (PHS) as a tool to estimate productivity loss in physical work. PHS criteria are related to reaching safe body core temperature limit of 38 °C or excess water loss. 3 sets of clothing were investigated: 2 female sets of traditional clothes (churidar and saree) modified as used at construction site (added shirt and towel to protect traditional clothes and hair), and a male set commonly used at the construction sites. The clothing insulation and evaporative resistance were measured on thermal manikins. The climatic conditions were based on weather statistics, and metabolic heat production was based on field observations at work places and the ISO 8996:2004 tables (Ergonomics of the thermal environment — Determination of metabolic rate). For the future scenarios all basic parameters were left the same except the air temperature was increased by 2 °C. Adding the protective layer on female clothing did increase clothing insulation by 25-31 % and evaporative resistance by 10-18 % respectively. This affected the performance showing lower capacity to maintain work pace already under present climatic conditions. Further increase in mean air temperature may decrease the productivity by 30-80 % depending on the parameter that is observed (limited exposure time or lower work load), and on the earlier capacity to carry out the tasks. The present evaluation may have several limitations related to the PHS model's boundaries, and validation of the presented method application is needed.