Before revision: The addition of a concrete coating is also useful to compensate for the pipeline's negative buoyancy when it carries lower density substances.Ramakrishnan, p. 186 The pipeline's inside wall is not coated for petroleum service.
After revision: The addition of a concrete coating is also useful to compensate for the pipeline's positive buoyancy when it carries lower density substances.Ramakrishnan, p. 186 The pipeline's inside wall is not coated for petroleum service.