A study of various public lighting maintenance practices and the development of a locally applicable maintenance model in line with international trends.
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Public lighting is seen as a non-core function by many municipalities and therefore does not always receive the necessary management attention. As a result the provision of public lighting maintenance differs substantially between Local Authorities; in some instances public lighting is in a state of disrepair and in other instances the service delivery is excellent. One of the major problems identified is the lack of information with regard to the number and types of fittings installed and also the number of failures that occur. As a consequence many municipalities cannot provide accurate costs to enable comparison with other Local Authorities. There is also a general lack of consensus as to what constitutes appropriate service delivery in terms of system availability and failure response times. This results in large differences in terms of costs, which range from R11.50 to R26.60 per fitting per month and system availability, which ranges from less than 70% to better than 99%. To establish appropriate service levels responses were obtained from the general public and two groups more directly involved with streetlight maintenance namely, public officials and street lighting experts. This data together with the evaluation of historical data collected over the last 16 months on the Benoni network allows the formulation of appropriate cycle times in order to achieve the expected service delivery in terms of system availability and response times. A holistic literature survey is presented covering the major aspects which impact on service delivery such as the restructuring of the electricity distribution industry and local authority transformation. The aspects of energy efficiency and equipment life expectancy are covered in detail and recommendations are made as to the appropriate replacement cycles. The different lamp replacement policies are also discussed and cost comparisons made. Recommendations made are that a system availability of 98% is both acceptable and achievable with a moderate budget. Response times of less than 24 hours would be ideal but this does not optimise the utilisation of resources, budget constraints may dictate a longer response time. Response times of more than 5 days would generally be unacceptable. Optimal fitting replacement age is between 19 and 23 years. Under normal circumstances the introduction of energy efficient luminaires is the most cost effective when inefficient fittings have reached their optimal replacement age. Changes in energy costs, tax concessions or cost subsidisation will however impact on the appropriate replacement strategy.