Title: An evaluation of classroom-illumination: a critical requirement for effective designing and construction of naturally-illuminated schools in Nigeria

Authors: Osagie Ibhadode; Oluseyi Olarenwaju Ajayi; Abiodun Ayodeji Abioye; Joseph Ismaila; Adebayo Abidemi Adekunle

Addresses: Building Research Department, Nigerian Building and Road Research Institute (NBRRI), Nigeria ' Department of Mechanical Engineering, Covenant University, Ota, Nigeria ' Department of Mechanical Engineering, Covenant University, Ota, Nigeria ' Building Research Department, Nigerian Building and Road Research Institute (NBRRI), Nigeria ' Building Research Department, Nigerian Building and Road Research Institute (NBRRI), Nigeria

Abstract: Indoor lighting-levels (illuminances) of 180 classrooms in 60 public [primary and secondary] schools located in all six geopolitical zones of Nigeria, were experimentally investigated 12 times under three different sky-conditions ['clear', 'partly-clear' and 'overcast'] using the Hagner digital lux-meter. The analysed empirical-data were: 'Mean indoor illuminance for tasks on desks' tops near windows exposed to direct sunlight and/or higher illumination(Ld(DSL))' ranging from 1,243 lux-4,486 lux, 'Mean indoor illuminance for tasks on desks' tops near windows exposed to indirect sunlight and/or lower illumination(Ld(ISL))' ranging from 674 lux-2,987 lux, 'Mean indoor illuminance for tasks on desks' tops at Center of Classroom(Ld(CrC))' ranging from 101 lux-449 lux and 'Mean indoor illuminance for tasks on boards(Lb)' ranging from 110 lux-494 lux. Three globally recommended standards' ['CIE-ISO', 'IESNA', and 'EN'], values [of minimal/optimal lighting-levels for classroom-activities like 'reading on the blackboard' (Lsb 500 lux) and 'writing, drawing and reading on desks' (Lsd = 300 lux)]; and the follow-up statistical-analyses reveal 'excessive solar irradiation' and/or 'inadequate illumination' in the classrooms.

Keywords: illuminance; solar irradiation; classroom lighting; naturally illuminated schools; sky condition; sunlight; luxmeter (light metre); design and construction; academic performance; Nigeria; IEQ; health condition; indoor environment; circadian system; human visual system.

DOI: 10.1504/PIE.2019.102849

Progress in Industrial Ecology, An International Journal, 2019 Vol.13 No.4, pp.342 - 372

Accepted: 13 Dec 2018
Published online: 03 Sep 2019 *

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