Journal of Applied Sciences1812-56541812-5662Asian Network for Scientific Information10.3923/jas.2011.1612.1617WoldeyohannesA.D.MajidM.A.A.92011119The development of steel pipes allowed greater quantities of gas to be transported to satisfy the ever growing demand. However, as the age of the pipe increases the roughness of the pipe tends to increase due to the accumulation of various elements around the internal surface of the pipe, which results a decrease in performance of the pipeline network systems. This paper discusses the use of simulation model for the analysis of the effect of age of pipes on the performance of the pipeline network system of natural gas. The flow equations which govern the simulation were modified to take into account the effect of the age of pipes. Analysis was made based on branched pipeline network system serving five power plant customers. The performance of three groups of pipes i.e., new, 10 and 20 years old were evaluated and compared. The results of the simulation analysis showed that a decrease in flow capacity of 2.16 and 4.35% were observed for the 10 and 20 years old pipes, respectively. To certain extent the model is capable of evaluating the effect of the age of pipe on the performance of the gas transmission system. In order to establish firm relationships between the age of the pipes and performance of the pipeline network system, further research is required.]]>Revie, R.W. and H.H. Uhlig,2008Worthingham, R.G., B. Asante, G. Carmichael and T. Dunsmore,1993Menon, E.S.,2005Ferrira, P.A., M.F.C. Bezerra and R. Loschiavo,2004Riemer, D.P.,2000Zhou, X.,1993Nestic, S., S. Wang, J. Cai and Y. Xiao,2004Woldeyohannes, A.D. and M.A. Abd Majid,2008Nimmanonda, P., V. Uraikul, C.W. Chan and P. Tontiwachwuthikul,2002Abbaspour, M.,2005Hoeven, T.V.D.,2003Abdolahi, F., A. Mesbah, R.B. Boozarjomehry and W.Y. Svrcek,2007Osiadacz, A.J.,1987Woldeyohannes, A.D. and M.A. Abd Majid,2009Letniowski, F.W.,1993Nimmanonda, P.,2003Gresh, M.T.,2000Wu, S., R.Z. Rios-Mercado, E.A. Boyd and L.R. Scott,2000Kurz, R. and S. Ohanian,2003