API MPMS 17.2:1999(R2011) pdf download.Manual of Petroleum Measurement Standards Chapter 17—Marine Measurement
Based on present technology, careful manual gauging, tem- perature measurement and sampling are the most accurate overall methods for measuring quantities of cargo, free water, and on-board quantity (OBQ) and/or remaining on board (ROB) on marine tank vessels. Automatic gauging may be as accurate as manual gauging for measuring overall volumes if the manufacturerÕs instructions are followed and equipment is periodically calibrated and checked using manual gauging as a reference. Safety and environmental regulations by all levels of gov- ernment and other regulatory agencies worldwide, are limit- ing and/or prohibiting the release of hydrocarbons to the atmosphere with regard to tank vessel operations. This has resulted in the restriction and, in some cases, the prohibition of traditional methods of obtaining cargo measurements through open gauge hatches. Consequently, numerous mea- surement methods and devices are now being used and addi- tional ones developed that allow the necessary cargo measurements and samples to be taken without opening the vesselÕs gauge hatches. The objective of this publication is to provide guidance to vessel and shore personnel on the generally accepted methods of determining cargo quantities on board marine tank vessels using open, closed, and restricted methods. This publication describes suggested techniques and procedures for measur- ing, calculating, reporting, and keeping records of quantities of crude oils and petroleum products transported in marine tank vessels.
1 Scope
To determine the quantity and quality of cargo on board marine tank vessels, it is necessary to accurately gauge, ascer- tain the temperature, collect a representative sample, and cal- culate the amount of all materials contained in the vesselÕs lines, cargo tanks, and slop tanks. Any void spaces that may contain cargo, such as permanent ballast tanks, double bot- toms, and cofferdams, must also be checked, and any vol- umes contained in these spaces must be calculated. This publication describes the appropriate methods of performing these procedures for crude oils and petroleum products nor- mally carried on board marine tank vessels. This standard covers the use of manual and automatic mea- surement systems commonly used on marine tank vessels. It establishes the procedures for obtaining the level measure- ments of cargo, free water, and OBQ/ROB as well as taking the temperatures and samples required for the marine custody transfer of most bulk liquid petroleum cargoes. It does not address in detail the technologies of the equipment used. This standard is not intended for use with pressurized or refriger- ated cargoes such as liquid petroleum gas (LPG) and liquid natural gas (LNG).
API MPMS 17.2:1999(R2011) pdf download
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