Appendix 4: SI Units and Basic Conversion Factors
SI BASE UNITS
Quantity/dimension | SI unit and symbol |
---|---|
Length | metre (m) |
Mass | kilogram (kg) |
Time | second (s) |
Temperature | kelvin (K) |
Electric current | ampere (A) |
Amount of substance | moles (mol) (need also to specify associated atoms, molecules, or whatever) |
Light intensity | candela (cd) |
SOME SI-DERIVED UNITS WITH SPECIAL NAMES
Quantity/dimension | SI unit | Symbol | Dimensions |
---|---|---|---|
Force | newton | N | kg m/s 2 |
Pressure | pascal | Pa | N/m 2 |
Energy, work | joule | J | Nm |
Power | watt | W | J/s |
ADDITIONAL UNITS RELEVANT TO WATER TREATMENT
Unit | Symbol |
---|---|
Area | m 2 |
Concentration (of amount of substance) | mol/m 3 |
Density | kg/m 3 |
Surface tension | N/m |
Velocity | m/s |
Viscosity (dynamic) | Pa s |
Viscosity (kinematic) | m 2/s |
Volume | m 3 |
CONVERSION FACTORS
Mass | 1kg = 2.2 lb |
Length | 1m = 3.208 ft |
25.4 mm = 1 in | |
Volume | 1 m 3 = 35.3ft 3 |
Liquid measure | 1 m 3 = 220 imp. gal = 263.7 US gal |
Force | 1N = 0.225 lb f |
Pressure | 1 N/mm 2 = 145 lb f/in 2 |
1 Pa = 1 N/m 2 = 0.000145 lb f/in 2 | |
Power | 1 kW = 1.341 HP |
Volume flows | 1 m 3/s = 220.4 imp. gal/s = 19.04 Mgal/day |
Energy | 1J = 0.732 ft lb f |
1 kJ = 0.948 Btu |