This Standard is concerned with the regulations for industrial plants where the use of flammable or combustible liquids is incidental to the principal business, or where flammable or combustible liquids are handled or used only in unit physical operations such as mixing, drying, evaporating, filtering, distillation, and similar operations which do not involve chemical reaction. This Standard shall not apply to chemical plants, refineries or distilleries and where portions of such plants involve chemical reactions such as oxidation, reduction, halogenation, hydrogenation, alkylation, polymerization, and other chemical processes, those portions of the plant shall be in accordance with the Gulf Standard mentioned in item 2.3.