{"data":{"id":"us/46-cfr-39.1003","jurisdiction":"us","citation":"46 CFR 39.1003","heading":"Definitions—TB/ALL.","body":"As used in this part only:\nBarge vapor connection means the point in a barge's piping system where it connects to a vapor collection hose or arm. This may be the same as the barge's cargo connection while controlling vapors during tank barge cargo tank-cleaning operations.\nCargo deck area means that part of the weather deck that is directly over the cargo tanks.\nCargo tank venting system means the venting system required by 46 CFR 32.55.\nCertifying entity means a certifying entity accepted by the Coast Guard as such pursuant to 33 CFR part 154, subpart P.\nCleaning facility means a facility used or capable of being used to conduct cleaning operations on a tank barge.\nCleaning operation means any stripping, gas-freeing, or tank-washing operation of a barge's cargo tanks conducted at a cleaning facility.\nCommandant means the Commandant (CG-ENG), U.S. Coast Guard, 2100 2nd St. SW., Stop 7126, Washington, DC 20593-7126.\nFacility vapor connection means the point in a facility's fixed vapor collection system where the system connects with the vapor collection hose or the base of the vapor collection arm.\nFixed stripping line means a pipe extending to the low point of each cargo tank, which is welded through the deck and terminated above deck with a valve, and plugged at the open end.\nFlammable liquid means a liquid as defined in 46 CFR 30.10-22.\nFluid displacement system means a system that removes vapors from a barge's cargo tanks during gas freeing through the addition of an inert gas or other medium into the cargo tank.\nFluid injection connection means the point in a fluid displacement system at which the fixed piping or hose that supplies the inert gas or other medium connects to a barge's cargo tanks or fixed piping system.\nGas freeing means the removal of vapors from a tank barge.\nIndependent as applied to two systems means that one system will operate when there is a failure of any part of the other system.\nInerted means the oxygen content of the vapor space in a cargo tank is reduced in accordance with the inert gas requirements of 46 CFR 32.53 or 33 CFR 153.500. If a cargo vapor in a cargo tank that is connected to the vapor collection system is defined as inerted at the start of cargo transfer, the oxygen content in the vapor space of the cargo tank must not exceed 60 percent by volume of the cargo's minimum oxygen concentration for combustion, or 8 percent by volume for vapor of crude oil, gasoline blends, or benzene.\nMarine Safety Center (MSC) means Commanding Officer, Marine Safety Center, U.S. Coast Guard, 2703 Martin Luther King Jr. Avenue SE., Washington, DC 20593 for visitors. Send all mail to Commanding Officer (MSC), Attn: Marine Safety Center, U.S. Coast Guard Stop 7430, 2703 Martin Luther King Jr. Avenue SE., Washington, DC 20593-7430.\nMaximum allowable gas-freeing rate means the maximum volumetric rate at which a barge may be gas-freed during cleaning operations.\nMaximum allowable stripping rate means the maximum volumetric rate at which a barge may be stripped during cleaning operations prior to the opening of any hatch and/or fitting on the cargo tank being stripped.\nMaximum allowable transfer rate means the maximum volumetric rate at which a vessel may receive cargo or ballast.\nMinimum oxygen concentration for combustion (MOCC) means the lowest level of oxygen in a vapor or vapor mixture that will support combustion.\nNew vapor collection system means a vapor collection system that is not an existing vapor collection system.\nService vessel means a vessel that transports bulk liquid cargo between a facility and another vessel.\nSet pressure means the pressure at which the pressure or vacuum valve begins to open and the flow starts through the valve.\nStripping means the removal, to the maximum extent practicable, of cargo residue remaining in the barge's cargo tanks and associated fixed piping system after cargo transfer or during cleaning operations.\nVacuum displacement system means a system that removes vapors from a barge's cargo tanks during gas-freeing by sweeping air through the cargo tank hatch openings.\nVapor balancing means the transfer of vapor displaced by incoming cargo from the tank of a vessel or facility receiving cargo into a tank of the vessel or facility delivering cargo via a vapor collection system.\nVapor collection system means an arrangement of piping and hoses used to collect vapor emitted to or from a vessel's cargo tanks and to transport the vapor to a vapor processing unit or a tank.\nVapor control system (VCS) means an arrangement of piping and equipment used to control vapor emissions collected to or from a vessel. It includes the vapor collection system and vapor processing unit or a tank.\nVapor processing unit means the components of a VCS that recover, destroy, or disperse vapor collected from a vessel.\nVessel-to-vessel transfer (direct or through a shore loop) means either—\n(1) The transfer of a bulk liquid cargo from a tank vessel to a service vessel; or\n(2) The transfer of a bulk liquid cargo from a service vessel to another vessel in order to load the receiving vessel to a deeper draft.\nVessel vapor connection means the point in a vessel's fixed vapor collection system where the system connects with the vapor collection hose or arm.","path":["Title 46—Shipping","CHAPTER I—COAST GUARD, DEPARTMENT OF HOMELAND SECURITY","SUBCHAPTER D—TANK VESSELS","PART 39—VAPOR CONTROL SYSTEMS","Subpart 39.1000—General"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-46.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:26:22Z","sha256":"2aab3967581db14c43a16372031d689422e98dbcc2ef4b303d49e27d71302d8e","source_id":"us-cfr","stale":true,"prev":"us/46-cfr-39.1001","next":"us/46-cfr-39.1005"},"notice":"GroundRules: Original legal text. Not legal advice."}