API MPMS 17.11 2009 pdf download.Measurement and sampling of cargoes on board tank vessels using closed and restricted equipment.
2 Normative References This document should be used in conjunction with the following referenced documents. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. API Manual of Petroleum Measurement Standards (MPMS) Chapter 1, Vocabulary API MPMS Chapter 2, Tank Calibration API MPMS Chapter 2.8B, Establishment of the Location of the Reference Gauge Point and the Gauge Height of Tanks on Marine Tank Vessels API MPMS Chapter 3, Tank Gauging API MPMS Chapter 3.1A-2005, Manual Gauging for Petroleum and Petroleum Products API MPMS Chapter 7, Temperature Determination API MPMS Chapter 8.1, Manual Sampling of Petroleum and Petroleum Products API MPMS Chapter 17.2, Measurement of Cargos on Board Tank Vessels API MPMS Chapter 17.4, Method of Quantification of Small Volumes on Marine Vessels (OBQ/ROB) API MPMS Chapter 17.12/EI HM 51, Procedures for Bulk Liquid Chemical Cargo Inspection by Cargo Inspectors API Recommended Practice 2003, Protection Against Ignitions Arising out of Static, Lightning and Stray Currents EI HM 28, Procedures for Oil Cargo Measurement by Cargo Inspectors EI HM 29, Procedures for Oil Product Cargo Measurements by Cargo Inspectors, Section 1, Crude Oil ISO 3170:2004 1 , Petroleum liquids—Manual sampling
3.12 stand pipe A vertical section of pipe extending from the top of a marine vessel tank through which measurements and samples of tank contents can be obtained. NOTE Stand pipes are frequently fitted with vapor control valves to allow closed or restricted operation. The pipe should extend to the floor of the tank with the internal part (also called “stilling well” or “still pipe”) slotted to allow free flow of tank contents while providing guidance for gauging and sampling equipment. 3.13 static accumulator oils Oils having a conductivity of less than 50 pS/m; these oils relax (dissipate charge) slowly. 3.14 UTI Ullage, temperature and interface 3.15 vapor control valve VCV Valve fitted on a stand pipe, expansion trunk or the deck that permits use of the portable hand-held gauging instruments while restricting the release of vapors into the atmosphere. 3.16 vapor pressure RVP, TVP Reid vapor pressure (RVP): The vapor pressure of a liquid at 100 °F (37.8 °C, 311 °K) as determined by ASTM D323. True vapor pressure (TVP): The pressure at which the fluid is in equilibrium between its liquid and gas state. 3.17 volatile organic compounds VOCs Organic chemicals that have a high vapor pressure and easily form vapors at normal temperature and pressure. 3.18 washing, crude oil COW Use of a high pressure stream of the crude oil cargo to dislodge or dissolve clingage and sediment from the bulkheads, bottom, and internal tank structures of a vessel during the discharge operation. 4 Health and Safety Precautions 4.1 General Personnel involved with the gauging and sampling of petroleum and petroleum-related substances should be familiar with their physical and chemical characteristics, including potential for fire, explosion, and reactivity, and with the appropriate emergency procedures as well as potential toxicity and health hazards.
4.2 Static Electricity Hazards If the tank is in a non-inert condition, specific precautions will be required with regard to safe measurement and sampling procedures when handling static accumulator oils. These are generally as follows. During loading, and for 30 minutes after the completion of loading, metallic equipment for dipping (gauging), ullaging or sampling shall not be introduced into or remain in the tank. Examples of equipment include manual steel ullage tapes, portable gauging devices mounted on deck stand pipes, metal sampling apparatus and metal sounding rods. Non-conducting equipment with no metal parts may, in general, be used at any time. However, ropes or tapes used to lower equipment into tanks shall not be made from synthetic materials. After the 30-minute waiting period, metallic equipment may also be used for dipping (gauging), ullaging and sampling but it is essential that it is effectively bonded and securely earthed to the structure of the ship before it is introduced into the tank and that it remains earthed until after it has been removed. Operations carried out through stand pipes are permissible at any time because it is not possible for any significant charge to accumulate on the surface of the liquid within a correctly designed and installed stand pipe. A stand pipe should extend the full depth of the tank and be effectively bonded and earthed to the tank structure. 4.3 Health Hazards Petroleum vapor dilutes oxygen in the air and may also be toxic. Hydrogen sulfide vapors are particularly hazardous. Petroleum vapors with relatively low concentrations of hydrogen sulfide may cause unconsciousness or death. During and after the opening of a VCV, personnel should position themselves to avoid any gas which may be released. Harmful vapors or oxygen deficiency cannot always be detected by smell, visual inspection, or judgment. Appropriate precautions should be used for the protection against toxic vapors or oxygen deficiency.