API MPMS 11.1.7-1980 (R1987)

FOREWORD

The Objectives

The complete collection of the jointly issued API/ASTM-IP tables of
which this volume is a part is the result of close cooperation between
the American Petroleum Institute (API), the Institute of Petroleum
(London) (IP), and the American Society for Testing and Materials
(ASTM). The overall objective of this effort was to meet the worldwide
need for a uniform and authoritative publication, based on the most
accurate information available. This publication serves as a basis for
standardized calculations of measured quantities of petroleum fluids
regardless of point of origin, destination, or units of measure used
by custom or statute. To meet the objective of worldwide standardized
measurement practices, the American National Standards Institute
(ANSI) and the British Standards Institute (BSI) have also been
closely involved nationally, resulting in the acceptance of the
revised tables as an American National Standard and as a British
Standard. In addition, in their respective capacities as Secretariat
of the International Organization for Standardization TC/28 and of
TC/28 SC3, ANSI and BSI have been instrumental in progressing the
revised tables towards their adoption as an international standard by
the International Organization for Standardization.

Historical Notes

The present collection supersedes all previous editions of the
petroleum measurement Tables ANSI/ASTM D1250, IP200, and API Standard
2540. Action is being taken in ISO/TC 28 for the corresponding tables
listed in ISO R91 and the tables in the addendum to R91 to be
superseded by the present revised collection.

In view of the progress of metrication in countries formerly using the
British system of weights and measures, demand for the revision of the
British edition does not justify the considerable work involved. The
present edition will therefore be withdrawn on the same date as the
corresponding metric and American editions are published and will not
be replaced.

For the metric edition the new standard covers products with densities
in the range 610.0 to 1076.0 kg/m3 (0.610 to 1.076 g/mL). The tables
for densities below this range, covering liquefied petroleum gases,
have not been revised.

The original tables, which were developed in the late 194Os, were
based on the 1916 data of Bearce and Peffer (1916) and represent
thirty years of evolution. The history of this evolution is summarized
by Hall et al. (1975).

Present Development

Downer and Inkley (1972) demonstrated that the original tables were
not satisfactory representations of many petroleum fluids of current
importance. In 1974 the American Petroleum Institute (API) and the
United States National Bureau of Standards (NBS) initiated a research
program funded by the API which intended to provide the solid
scientific base for the development of more accurate, consequently
more equitable, measurement tables. The result of this program was
precise density data on 349 different fluids representing a wide
variety of refined products and 66.8 percent of the world crude
production in 1974. The completion of this five-year, $500,000 project
in March 1979 opened the way for modernizing the tables. Using the NBS
density data and taking advantage of publications of outstanding
technical authorities, a Joint API-ASTM Physical Properties Working
Group produced this present collection of the Petroleum Measurement
Tables. The development and results of the work are described by
Hankinson et al. (1979).

Conceptual Departure

A major conceptual departure from previous versions is inherent in the
recognition of the present and future position of computers in the
petroleum industry. The actual Standard represented by this volume and
the companion volumes is neither the hardcopy printed tables nor the
set of equations used to represent the density data but is an explicit
implementation procedure used to develop computer subroutines. The
standardization of an implementation procedure implies the
standardization of the set of mathematical expressions, including
calculational sequence and round-off procedures, used within the
computer code. Absolute adherence to the outlined procedures will
ensure that all computers and computer codes of the future, meeting
the stated specifications and restrictions, will be able to produce
identical results. Hence, the published implementation procedures are
the primary Standard, the distributed subroutines are the secondary
standard, and the published tables are produced for convenience.

Acknowledgments

The task of completing this project could not have been accomplished
without many substantial contributions by a considerable number of
individuals and companies. It is impossible to single out any specific
individuals for special mention. However, included in the introductory
material are lists of the officers of the API's Committee on Petroleum
Measurement (COPM), the officers of the Joint API/ASTM Committee on
Static Petroleum Measurement (COSM), the major contributors from the
Institute of Petroleum, and the members of the COSM Physical
Properties Working Group.