Considerable effort and expense have been devoted to the estimation and acquisition of the amounts of VOCs released from thousands of the fugitive emission sources installed in chemical processes. In order to reduce the effort required on the estimation of VOC release, a methodology using a computational fluid dynamics (CFD) was proposed. The estimated values were compared with the experimental data obtained using a designed experimental apparatus that was composed of fugitive emission sources such as valves, pump, and flange. The emissions were sampled in sampling tedlar bags for a variety of volatile compounds at different pressures. The components were analyzed by a portable gas chromatograph. In conclusion, the amounts of benzene and toluene released from fugitive emission sources could be successfully estimated using the CFD technique.