APPROPRIATE COST-SIGNIFICANT MODEL FOR MECHANICAL ENGINEERING SERVICES COST ESTIMATING

Abstract

The importance of accurate estimates has been widely recognized for many years. Efforts had been made by researchers to improve upon the cost estimates produced for general construction works with little attention given to the production of accurate cost estimates for mechanical engineering service.

This paper therefore develops a cost-significant regression cost estimating model for mechanical engineering service using tender figures, cost of cost-significant mechanical items and design variables. Cost data for 123 mechanical engineering service works for eight different types of building project awarded between 1993 and 2008 in Lagos State and Federal Capital Territory, Abuja were collected and used for the analysis.

The cost data collected were updated to 2008 using inflation rate in order to account for the effect of time on money and the changing economic condition in Nigeria. The updated data were then subjected to regression analysis to produce the cost-significant estimating model. The results of the analysis showed that there is a strong and direct relationship between cost of mechanical engineering service on one hand and design. variables and cost of cost-significant mechanical items on the other hand.

The developed model was tested with known sample data. The result of the test showed that the developed model produced estimates with co-efficient of variation (CV) of 1.33% which is an improvement on the 5-9% CV specified as being achievable in practice.