Benchmarking is an important step in implementing energy conservation in a semiconductor fabrication plant (hereafter referred to as "fab"). A semiconductor cleanroom facility system is complicated, usually comprised of several sub-systems, such as a chilled water system, a make-up system, an exhaust air system, a compressed air system, a process cooling water (PCW) system, a nitrogen system, a vacuum system, and an ultra-pure water (UPW) system. It is a daunting task to allocate energy consumption and determine an optimum benchmark. This study aims to establish the energy benchmark of a typical 8-in. DRAM semiconductor fab through field measurement data. Results of the measured energy consumption index were: chilled water system (including chiller, chilled water pump and cooling tower): 0.257 kW/kW (=0.9 kW/RT) in summer and 0.245 kW/kW (=0.86 kW/RT) in winter air recirculation air system: 0.00018 kWh/m(3) make-up air system: 0.0042 kWh/m(3) general exhaust air system: 0.0007 kWh/m(3) solvent exhaust air system: 0.0021 kWh/m(3) acid exhaust air system: 0.0009 kWh/m(3) alkaline exhaust air system: 0.0025 kWh/m(3) nitrogen system: 0.2209 kWh/m(3) compressed dry air system: 0.2250 kWh/m(3) process cooling water system: 1.3535 kWh/m(3) and ultra-pure water system: 9.5502 kWh/m(3). These data can tie used to assess the efficiency of different energy-saving schemes and as a good reference for factory authorities. The PCW system's status before and after implementing energy conservation is discussed. (C) 2008 Elsevier B.V. All rights reserved.