Replacement Model for Street Lighting Systems

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Faculty of Engineering, University of Nigeria, Nsukka, Nigeria


Replacing failed bulbs of streetlights in a location can be very tasking and expensive if the optimal time for replacement is not determined. In this paper, a model has been developed that helps to establish the optimal time for the replacement of streetlight bulbs. Burnt-out bulbs are replaced individually when they fail, and group replacement is carried out on all bulbs after a specified time. The costs for both individual replacement and group replacement are determined. The developed model was applied to locally sourced data from a field survey of a streetlight installation at the University of Ilorin, Ilorin, North-central Nigeria. The model gave the optimum replacement time of burnt-out bulbs as the eighteenth week when applied to the data used in this work. The optimum replacement time will be dependent on the dataset used. This makes the developed model useful in establishing the optimal replacement time of any stochastically failing items that are in large quantities. The model will help to reduce maintenance costs for facility managers.


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Replacement model, Streetlights, Burnt-out bulbs, optimum replacement time


Usman, A. M., Adediran, Y. A., Otuoze, A. O., Mohammed, O. O., & Zakariyya, O. S., (2021): Replacement Model for Street Lighting Systems. Nigerian Journal of Technology (NIJOTECH), Vol. 40, No. 1; pp 49-55, Published by Faculty of Engineering, University of Nigeria, Nsukka, Nigeria. Available online at