ABSTRACT
The need for control of a health hazard created by an industrial process as found in oil refineries and petrochemical plants must be determined by a trained industrial hygienist after careful evaluation and sampling of the in-plant environment. To determine the need for and the extent of ventilation control, in addition, length of the workday, working conditions, housekeeping practices, and time of the year are factors to be considered. The air volume needed would equal the enclosure volume; one air change would be required. Thus, the effects of mechanical ventilation, window ventilation, cross currents, traffic, rotating machinery, convection currents, and heat can dwarf into insignificance the effect of specific gravity. Use the plot plan, equipment layout, and electrical data for needed information. The disposal of air exhausted from local exhaust systems can present a problem in the case of toxic substances or substances that can create a nuisance, such as dusts and odors.
