a. It is the intent of this standard to recommend the size, thickness, and length of ferrous and nonferrous tubes most commonly used in conventional shell and tube refinery heat exchangers.
b. This standard applies to tubes made by any manufacturing process excluding those of the extended surface type.
c. This standard does not cover tubes for exchangers in package-type commercial units such as refrigeration, . compressor, or steam boiler units. Examples of such exchangers are lubricating-oil or jacket-water heaters and coolers.