SI Units and Conversion Formulas A Table 1: SI Base Units Table 4: SI Prefixes B Quantity Name Symbol Factor Name Symbol 18 E Length meter m 10 exa 15 P Mass kilogram kg 10 peta 12 T Time second s 10 tera C 9 G Electric Current ampere A 10 giga 6 M Thermodynamic Temperature kelvin K 10 mega 3 k Amount of Substance mole mol 10 kilo 2 h Luminous Intensity candela cd 10 hecto D 101 deka da 10-1 deci d 10-2 centi c Table 2 : SI Derived Units 10-3 milli m Quantity Name Symbol 10-6 micro μ E -9 Plane Angle radian rad 10 nano n -12 Solid Angle steradian sr 10 pico p 10-15 femto f 10-18 atto a F Table 3: Derived SI Units with Special Names and Symbols Table 5: SI Derived Units whose Names and Symbols Include SI Quantity Name Symbol Derived Units with Special Names and Symbols G Frequency hertz Hz Quantity Name Symbol Force newton N Pressure, stress pascal Pa Dynamic Viscosity pascal second Pa·s Energy, Work, Quantity of Heat joule J Moment of Force newton meter N·m H Power, Radiant Flux watt W Surface Tension newton per meter N/m Electric Charge, Quantity of Electricity coulomb C Heat Flux Density, Irradiance watt per square meter W/m2 Electric Potential Difference, Electromotive Force volt V Heat Capacity, Entropy joule per kelvin J/K Capacitance farad F Specific Heat Capacity,Specific Entropy* joule per kilogram kelvin J/(kg·K) Electric Resistance ohm Ω Thermal Conductivity watt per meter kelvin W/(m·K) I Electric Conductance siemens S Permittivity farad per meter F/m Magnetic Flux weber Wb Permeability henry per meter H/m Magnetic Flux Density tesla T *Also called weight entropy. Inductance henry H J Celsius Temperature degree Celsius* °C Table 6: Units Outside the SI but Accepted for Use with the SI Luminous Flux lumen lm Name Symbol Value in SI Units *t°C=(t+273.15)K Minute (Time) min 1min=60s K Hour h 1h=60min=3,600s Day d 1d=24h=86,400s Degree ° 1°=(π/180)rad Minute (Angle) ' 1'=(1/60)°=(π/10,800)rad Second (Angle) " 1"=(1/60)'=(π/648,000)rad L Liter ℓ 1ℓ=1dm3=10-3m3 Ton t 1t=103kg M N Technical data Technical O N-7 Force Torque N dyn kgf N·m kgf·m gf·cm A 1 1×105 1.020×10-1 1 1.020×10-1 1.020×104 1×10-5 1 1.020×10-6 9.807 1 1×105 9.807 9.807×105 1 9.807×10-5 1×10-5 1 (Note) 1dyn=10-5N B Pressure 2 Pa MPa bar kgf/cm atm mHg mH2O C 1 1×10-6 1×10-5 1.019×10-5 9.869×10-6 7.501×10-6 1.020×10-4 1×106 1 1×10 1.019×10 9.869 7.501 1.020×102 1×105 1×10-1 1 1.020 9.869×10-1 7.501×10-1 1.020×10 9.807×104 9.807×10-2 9.807×10-1 1 9.678×10-1 7.356×10-1 1×10 D 1.013×105 1.013×10-1 1.013 1.033 1 7.60×10-1 1.033×10 1.333×105 1.333×10-1 1.333 1.360 1.316 1 1.360×10 9.807×103 9.807×10-3 9.807×10-2 1×10-1 9.678×10-2 7.355×10-2 1 (Note) 1Pa=1N/m3 E Work, Energy, Quantity of Heat Heat Transfer Coefficient J kgf·m kW·h kcal W/m2·K kcal/m2·h·°C cal/cm2·s·°C F 1 1.02×10-1 2.778×10-7 2.389×10-4 1 8.60×10-1 2.389×10-5 9.807 1 2.724×10-6 2.343×10-3 1.163 1 2.778×10-5 3.60×106 3.671×105 1 8.60×102 4.186×104 3.60×104 1 4.186×103 4.269×102 1.163×1-3 1 (Note) 1J=1W·s. 1kgf·m=9.807J. 1W·h=3600W·s. 1cal=4.186J G Thermal Conductivity W/m·K kcal/m·h·°C J/cm·s·°C Power, Radiant Flux 1 8.60×10-1 1×10-2 H W kW kgf·m/s kcal/s 1.163 1 1.163×10-2 2 1 1×10-3 1.020×10-1 2.389×10-4 1×10 8.60×10 1 1×103 1 1.020×102 2.389×10-1 9.807 9.807×10-3 1 2.343×10-3 I 4.186×103 4.186 4.269×102 1 Dynamic Viscosity (Note) W=1J/s. 1kgf·m/s=9.807W Pa·s P (Poise) cP 1 1×10 1×103 1×10-1 1 1×102 Flow rate J 1×10-3 1×10-2 1 m3/s m3/h ℓ/min gal(US)/min 1 3.6×103 6×104 1.585×104 2.778×10-4 1 1.667×10 4.403 Kinematic viscosity K 1.667×10-5 6×10-2 1 2.642×10-1 m2/s St cSt 6.304×10-5 2.271×10-1 3.782 1 1 1×104 1×106 1×10-4 1 1×102 L 1×10-6 1×10-2 1 (Note) 1cSt=1mm2/s M N Technical data Technical O N-8 Item SI units Power (engineering) units A P·Q P·Q P.Q = = L 60×η L 612×η L : Power Requiement [kW] L : Power Requirement [kW] P : Discharge Pressure [MPa] P : Discharge Pressure [kgf/cm2] B Requirement Q : Discharge Rate [ℓ/min] Q : Discharge Rate [ℓ/min] η : Pump Efficiency η : Pump Efficiency C ∆P·q ∆P·q L = ×η L = ×η 2π 200×π D ∆P T T : Output Torque [N·m] T : Output Torque [kgf·m] ∆P : Inlet/Outlet Pressure Differential [MPa] ∆P : Inlet/Outlet Pressure Differential [kgf/cm2] q : Volume per Oil Motor Turn [cm3] q : Volume per Oil Motor Turn [cm3] η : Torque Efficiency η : Torque Efficiency E Oil Motor Output Torque Output Motor Oil F F = 100 × P × A × η F = P × A × η F : Cylinder Output [N] F : Cylinder Output [kgf] F P : Working Presure [MPa] P : Working Presure [kgf/cm2] P 2 2 G A A : Cylinder Contact Area [cm ] A : Cylinder Contact Area [cm ] Cylinder Output Cylinder η : Cylinder Efficiency η : Cylinder Efficiency H ∆P H = 60 × P × Q H = 1.4 × P × Q I H : Heat Release [kJ/h] H : Heat Release [kcal/h] P : Pressure Loss [MPa] P : Pressure Loss [kgf/cm2] ‾Q Q : Flow Rate [ℓ/min] Q : Flow Rate [ℓ/min] Valve, piping, etc. J Pressur Loss Conversion Energy Conversion Loss Pressur 2∆P 2g·∆P Q = CA × 6000 Q = CA × 0.06 K √ ρ √ γ Q : Flow Rate [ℓ/min] Q : Flow Rate [ℓ/min] C : Compressibile Flow Coefficient C : Compressibile Flow Coefficient . A Q [Dimensionless] [Dimensionless] ( =. 0.6) A : Passage Area [cm2] A : Passage Area [cm2] L Orifice Flow Orifice ∆P : Pressure Differential [MPa] g : Gravitational Acceleration [980cm/s2] ρ : Density [kg/m3] ∆P : Pressure Differential [kgf/cm2] . γ : Specific Gravity [kgf/cm3] ( =. 0.87×10–3) M ∆P = ρ × g × H × 10-6 ∆P = γ × g × H × 10-4 N ∆P : Pressure Loss [MPa] ∆P : Pressure Loss [kg/m2] ρ : Density [kg/m3] γ : Specific Gravity [kgf/cm3] data Technical H g : Gravitational Acceleration [9.8m/s2] H : Height [m] Pressure Loss H : Height [m] O (Note) When performing calculations, make sure that you first convert values correctly. Cutting off and rounding up values can cause differences in calculation results. N-9.