Appendix A
Metric (SI) System
A.l Introduction
The most widely used system of units for scientific and technical data and
specifications is the Système International d’Unités (International System
of Units), commonly referred to as the SI System or Metric System.
This appendix describes the metric SI System and its proper usage, and it
provides conversion factors and metric equivalents for the water properties
commonly used in coastal engineering. This appendix is intended as a guide
for those engineers who are unfamiliar with metric usage (primarily those
us who of grew up using the English system of units).
What follows is a nearly verbatim reproduction of an unpublished U.S.
Army Corps of Engineers Coastal Engineering Technical Note entitled “Metric (SI) Standard for Design” prepared by the author in 1981. The primary
reference used in the preparation of this material was the “Engineering
Design Handbook - Metric Conversion Guide” (DARCOM 1976). A more
common reference is Petersen (1980).
There are three classes of units in the SI system: base units, supplementary units, and derived units.
1. Base units are physical quantities of measurement which
are considered dimensionally independent.
2. Supplementary units are measures of plane angle and solid
angle.
3. Derived units are combinations of base units and/or supplementary units. Some derived units have special names.
Included in this appendix are only the units of measurement commonly