(a) This part applies to tank vessels that use a vapor control system (VCS) to collect vapors emitted to or from a vessel's cargo tanks while operating in the navigable waters of the United States, except—

(1) Tank vessels with an operating vapor collection system approved by the Coast Guard prior to July 23, 1990, for the collection and transfer of cargo vapor to specific facilities. Such tank vessels are only subject to 46 CFR 39.1013, 39.3001, and 39.4005; and

(2) A tank barge that collects vapors emitted from its cargo tanks during gas-freeing or cleaning operations at a cleaning facility. This type of tank barge is only subject to 46 CFR part 39, subparts 39.1000 and 39.6000, and must comply with requirements of these two subparts at the time of its next inspection for certification required by 46 CFR 31.10-15, but no later than August 15, 2018.

(b) This part does not apply to the collection of vapors of liquefied flammable gases as defined in 46 CFR 30.10-39.

(c) In this part, regulatory measurements, whether in the metric or English system, are sometimes followed by approximate equivalent measurements in parentheses, which are given solely for the reader's convenience. Regulatory compliance with the regulatory measurement is required.