US lawFederal (United States)RegulationsTitle 46 CFR — ShippingChapter I — COAST GUARD, DEPARTMENT OF HOMELAND SECURITYPart 64 — MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMSSubpart B — Standards for an MPT64.4946 C.F.R. § 64.49Labeling openings.Last amended: 2016Year: 2026Length: 18 wordsOfficial source Cite as 46 C.F.R. § 64.49 (2026)Each opening of a tank must be labeled to identify the function such as “suction”, “discharge”, “heating coil”.Previous46 C.F.R. § 64.47Next46 C.F.R. § 64.51