EXERGETIC METABOLISM OF BLOCK LAYING ACTIVITY IN AN OUTDOOR ENVIRONMENT

Musa, A. I. and Ismaila, S. O. and Waheed, M. A. and Olayanju, T.M.A. (2017) EXERGETIC METABOLISM OF BLOCK LAYING ACTIVITY IN AN OUTDOOR ENVIRONMENT. UMUDIKE JOURNAL OF ENGINEERING AND TECHNOLOGY (UJET), 3 (1). pp. 70-79.

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Abstract

This study analysed the metabolic exergy of human body during block laying in an outdoor environment. Two hundred and four masons were investigated across the three senatorial districts of Ogun State, Nigeria with distributions of 50.98, 30.88 and 18.14% for Central, West and East respectively using snowball sampling technique. This technique was used due to the inaccessible and hard to find masons that laid blocks outdoor. The meteorological (air temperature, and radiant temperature, relative humidity, wind speed and solar radiation), physiological (skin temperature, and core temperature) were measured and recorded hourly for 10 hours per day at an average of 17 masons every month from May 2013 to April 2014. Models were developed to determine the metabolic exergy, exergy in [(1-Ta/Tc) ӼM], exergy out [(1-Ta/Tsk) ӼM], exergy destroyed [(1-Ta/Tc) ӼM - (1-Ta/Tsk) ӼM], The data collected were subjected to descriptive statistics using SPSS 21.0. The mean values of air temperature, radiant temperature, relative humidity, wind speed and solar radiation were 33.13 ± 2.34 oC, 34.00 ± 2.13 oC, 55.32 ± 6.40%, 0.48 ± 0.03 m/s and 662.73 ± 100.31 W/m2 respectively. The skin temperature and core temperature were 34.02 ± 0.54, 36.39 ± 0.14 oC, respectively. The metabolic exergy ӼM, exergy in, out and destroyed by the mason were 120.62 ± 10.38, 10.25 ± 6.19, 2.38 ± 6.40 and 7.88 ± 1.99 W respectively. The study concluded that the rate and proportions of the different components in the exergy balance equation (exergy input, destroyed, and output) vary according to the outdoor temperature and humidity. The metabolic exergy of the mason was determined as 120.60 (±10.38) W which conformed to the ISO standard.

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