Panahi - Power and Water Institute of Technology Tehran, I.R. of Iran P.O. BOx ۱۶۷۶۵-۱۷۱۹
Bohlool - Power and Water Institute of Technology Tehran, I.R. of Iran P.O. BOx ۱۶۷۶۵-۱۷۱۹
Farshadian - Power and Water Institute of Technology Tehran, I.R. of Iran P.O. BOx ۱۶۷۶۵-۱۷۱۹

This paper investigates the maintainability problems in different process plants, with attention concentrated on power plants. Maintenance costs are recognized as an important factor in the life-cycle cost of a process plant. There are two approaches to. improve the maintainability of a process plant. First one looks towards better maintenance management, while the objective of the second one is to achieve a more efficient design method. Both need information about different types of equipments which cause most common defects. Maintenance reports and other related documents concerning five items: valves; pumps; pipes and joints; heat exchangers; and fans in thirteen process units have been carefully studied. As a result crucial problems have been identified and presented in the paper. Conclusions have been made about the most trouble making items.