Section 39.1009 - Additional tank vessel vapor processing unit requirements-TB/ALL(a) Vapor piping, fitting, valves, flanges, and pressure vessels comprising the construction and installation of a permanent or portable vapor processing unit onboard a tank vessel must meet the marine engineering requirements of 46 CFR chapter I, subchapter F.(b) Electrical equipment comprising the construction and installation of a permanent or portable vapor processing unit onboard a tank vessel must meet the electrical engineering requirements of 46 CFR chapter I, subchapter J.(c) In addition to complying with the rules of this part, tank vessels with a permanent or portable vapor processing unit must comply with applicable requirements of 33 CFR part 154, subpart P.(d) When differences between the requirements for vessels contained in 46 CFR chapter I, subchapters F and J and requirements for facilities contained in 33 CFR part 154, subpart P need to be resolved, the requirements of 46 CFR chapter I, subchapters F and J apply, unless specifically authorized by the Marine Safety Center.