API MPMS 15 2019 pdf free download

API MPMS 15 2019 pdf free download.Manual of Petroleum Measurement Standards Chapter 15 Guidelines for the Use of Petroleum Industry- specific International System (SI) Units.
1 Scope and Field of Application This publication specifies the API-preferred units for quantities involved in petroleum industry measurements, and indicates factors for conversion of quantities expressed in customary units to the API-preferred SI units not covered in ASTM/IEEE SI-10. The quantities that comprise the tables are grouped into convenient categories related to their use. They were chosen to meet the needs of the many and varied aspects of the petroleum industry, but also should be useful in other, similar process industries. 2 References This publication emphasizes the practical application of SI to the petroleum industry. For a complete, detailed presentation of SI and the metric practice on which this publication is based, the reader should consult ASTM/IEEE SI-10. 3 The International System of Units (SI) 3.1 General SI is the official abbreviation, in all languages, for the International System of Units (Le Système International d’Units). The International System is not the old centimeter-gram-second (cgs) system of metric units but is based on the meter, kilogram, and second as the fundamental quantities. SI is considered to be an improvement over the centimeter-gram-second metric system and is used currently or is being adopted by most nations of the world. There are two classes of units in SI. The first consists of base units which, by convention, are dimensionally independent. The second class consists of derived units that are formed by combining base units according to the algebraic relations linking the corresponding quantities. Special names and symbols have been assigned to the commonly used units in this class. The coherent nature of SI is preserved by defining all derived combinations in terms of unity, thus eliminating conversion factors within the system. As an example, the derived unit of power, with its special name (“watt”), is defined as 1 joule of work completed in 1 second of time.
4.2 Preferred Units The metric units recommended for general use are shown under the heading “API-preferred.” In most but not all cases, these conform to SI practice. The major exceptions are listed in 4.10. Where conversion factors for the quantity expressed in inch-pound units are shown with more than 1 metric unit, the unit in the “API-preferred” column is expected to have more general application; other units that also may be needed are shown in the “Other Allowable” column. API-preferred units do not preclude the use of other multiples or submultiples, as the choice of such unit- multiple is governed by the magnitude of the numerical value. 4.3 Equivalent Units Where units appear side-by-side in the “API-preferred” and “Other Allowable” columns, they are equivalent, and the latter unit is an acceptable alternative designation. 4.4 Significant Digits Most of the conversion factors are shown to six or seven significant digits, which are more than adequate for most applications. Those shown to fewer than six significant figures are limited by the precision of the known or determinable value of a physical property. The subjects of precision and round-off procedures are covered in references 2, 3, 14, and 17. 4.5 Calorie & Btu Calorie in the MPMS refers to the thermochemical calorie; British thermal unit (Btu) refers to the International Steam Tables (IT) Btu. Thermochemical Unit × 0.9993312 = IT Unit (Btu or Calorie) 4.6 Reference Conditions The standard conditions of pressure and temperature for use in measurements of petroleum and its products (both liquid and gaseous) are 101.325 kilopascals and 15 °C. Exceptions are liquid hydrocarbons with vapor pressure greater than atmospheric at 15 °C, in which case the standard pressure is the equilibrium pressure at 15 °C. For specialized applications in the gas industry, see reference 7. Additional exceptions can exist in reference temperature where calculations are made at 20 °C or 0 °C.