2.1 This standard covers a. refrigerating and air-conditioning systems that are an integral part of the main mechanical plant of merchant, fishing, and seafood-processing ships and b. refrigerated seawater and brine-chilling systems that air condition and dehumidify passenger and cargo spaces, chill or freeze perishable cargoes, or maintain storage of chilled or frozen cargo.2.2 This standard does not cover a. details of system designs or applications; b. small, self-contained units that are not an integral part of the ship’s main mechanical plant, such as electric water coolers, reach-in refrigerators, and room air conditioners;c. cargo containers with self-contained refrigerating systems; or d. liquefied gas ships. 2.3 Exceptions to the literal details of this standard may be used when approved by the authorities having jurisdiction when equivalent safety, efficiency, and reliability are achieved