49 CFR §195.581

1. (a)You must clean and coat each pipeline or portion of pipeline that is exposed to the atmosphere, except pipelines under paragraph (c) of this section.
2. (b)Coating material must be suitable for the prevention of atmospheric corrosion.
3. (c)Except portions of pipelines in offshore splash zones or soil-to-air interfaces, you need not protect against atmospheric corrosion any pipeline for which you demonstrate by test, investigation, or experience appropriate to the environment of the pipeline that corrosion will—
   1. (1)Only be a light surface oxide; or
   2. (2)Not affect the safe operation of the pipeline before the next scheduled inspection.