API MPMS 6.2 2004 pdf free download

API MPMS 6.2 2004 pdf free download.Manual of Petroleum Measurement Standards Chapter 6—Metering Assemblies Section 2—Loading Rack Metering Systems.
1 Introduction This standard serves as a guide in the selection, installation and operation of loading rack metering systems for petroleum products, including liquefied petroleum gas. This standard does not endorse or advocate the preferential use of any spe- cific type of metering system or meter. In general, metering system installations must meet certain fundamental requirements, including those that ensure proper meter type, size, installation and adequate protective and read- out devices (such as presets, registers [counters], strainers, relief valves, pressure and flow control valves, and air elimi- nators, where required). Descriptions of these and other sys- tem components are covered elsewhere in this standard or other API standards. Also, to ensure compliance with state laws and regulations the latest editions of NIST Handbook 44, Handbook 12, as well as specific local weights and measures requirements, should be considered. 2 Scope of Application This standard offers guidance on the design, selection, and operation of loading rack metering systems and associated equipment where liquid hydrocarbons are loaded into vehicle tanks. 3 Pertinent Publications 3.1 REFERENCED PUBLICATIONS The most recent editions of the following standards, recom- mended practices, and handbooks are cited in this standard. API Manual of Petroleum Measurement Standards ( MPMS ) Chapter 4.2, “Pipe Provers” Chapter 4.4, “Tank Provers” Chapter 4.5, “Master Meters” Chapter 4.6, “Pulse Interpolation” Chapter 4.7, “Field-Standard Test Measures” Chapter 5.1, “General Considerations for Measure- ment by Meters” Chapter 5.2, “Measurement of Liquid Hydrocar- bons by Displacement Meter” Chapter 5.3, “Measurement of Liquid Hydrocarbons by Turbine Meters” Chapter 5.6, “Measurement of Liquid Hydrocarbons by Coriolis Force-Flow Meters” Chapter 6.6, “Pipeline Metering Systems” Chapter 7, “Temperature Determination”
4 Loading Rack Metering Systems The loading rack metering systems described in this stan- dard are those that apply to transport-type truck facilities. The rack may be of a single-product/single-meter, single- product/multi-meter, or multi-product/multi-meter design. The design of the rack should allow one meter to be proved without interfering with the other meters involved in the loading operations. 4.1 LOADING RACK METERING SYSTEM INSTALLATION Loading rack metering systems are designed to deliver accurate quantities of products into transport trucks for the subsequent delivery to remote locations. The metering config- urations may consist of single tally meters, single product meters, blend meters and additive meters. Since rack delivery meter volumes are considered in the terminal loss/gain deter- mination, the design, installation and operation of the meters is extremely important. It must be noted that the loading rack is usually the final opportunity to measure accurately, i.e., after the product leaves the loading rack, measurement errors are difficult to correct.
4.2 TOP LOADING Since State and Federal regulations govern the release of hydrocarbon emissions to the atmosphere, some forms of top loading may not be acceptable. Top loading (see Figure 1) requires the use of an overhead- loading arm to reach the loading dome hatches on the trucks. Loading arms should be designed to reach all domes on a sin- gle-bottom truck to avoid moving the truck. They should be equipped with an extended drop tube and either a deflector end or a 45º cut C tube end that will reach to the bottom of the truck and provide submerged filling. The loading arm should be in the same state of fill—either void or full—at the begin- ning and end of the loading operation to ensure measurement consistency.