Geotechnical Engineering

DHARM

N-GEO\APPENDIX.PM5 904

904 GEOTECHNICAL ENGINEERING

General Rules and Conventions

Symbols

1. Full names of units, even when they are named after a person, are not written with a
   capital initial letter.


2. The symbol for a unit, named after a person, is written with a capital initial letter.


3. Symbols for other units are not written with capatal letters.


4. Symbols for units are always used in the singular.


5. No punctuation marks should be used within or at the ends of symbols for units.


6. A space is left between the numeral and the symbol.


7. A space is left between the symbols for compound units—e.g., kW h; N m. (m N would
   denote metre newton while mN would denote millinewton)


8. The denominators of compound units are expressed preferably in the base units and not
   in thier multiples or submulitples—e.g., MN/m^2 is preferred to N/mm^2.


9. The symbol of multiples and submultiples is to be used only conjointly with that of the
   unit and not with the full name of the unit—e.g., MW and not M watt.

Prefixes

Multiples or submultiples involving the factor 1000 (or 10+3n n being an integer) are preferen-
tially used for the purpose of international consistency.

Common prefixes used are:

kilo (k) 103

mega (M) 106

giga (G) 109

milli (m) 10 –3

micro (μ)10–6

nano (n) 10 –9

Normally, double prefixes are avoided.

REFERENCES

1. Ramaswamy, G.S., and Rao. V.V.L., SI Units: A Source Book, Tata McGraw-Hill Co. Ltd., 1971.


2. IS: 3616: Recommendations of the International System (SI) of Units, ISI, New Delhi.


3. IS: SP5-1969: Guide to SI Units, ISI, New Delhi.