The purpose of this recommended practice is to classify areas for electrical installations at production facilities. Production areas and facilities to which this publication applies are those where flammable petroleum gases and volatile liquids are produced, processed, stored, transferred, or otherwise handles. This publication does not apply to special areas defined in par. 10. Hazardous areas to be classified within the scope of this Recommended Practice occur around the following specific lease production equipment of facilities: a. Producing oil and gas wells. b. Tank batteries and auxiliary equipment. c. Lease automatic custody transfer assemblies. d. Equipment where flammable gas blankets, gas knockouts, etc., are used. e. Gas compressors and pumps handling gases or volatile liquids at leases and gas processing plants. f. Equipment for field processing gas, including: 1. Units for multistage separation of gas. 2. Units for low temperature extraction. 3. Stabilizers. 4. Dehydration units. 5. Hydrocarbon recovery units. Special Areas. Special areas including drilling rigs, marine production facilities on platforms, etc., are excluded from the scope of this Recommended Practice, and each installation of this kind should be considered on an individual basis by a competent engineering staff. Special conditions. Factors such as environment, weather, corrosion, interchangeability, standardization, and projected growth frequently dictate the use of special enclosures or installation of special electrical equipment. Such factors are outside the scope of this publication, which is concerned entirely with the proper application of electrical equipment to avoid ignition of inflammable vapors andgases.