Contents

• EDCS Unit Dictionary
• EDCS Scale Dictionary
• EDCS Unit Equivalence Class Dictionary

EDCS Unit Dictionary

EDCS Unit Symbolic Constant: EUC_AMP_PER_METRE

EDCS Unit Code: 1

Symbol: A/m

EDCS Unit Equivalence Class Label: LINEIC_ELECTRIC_CURRENT

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 3

• Quantity: lineic electric current (linear electric current density)
  Definition: The electric current in a conducting sheet divided by the width of the sheet.
  Reference type: PR
  Reference: I31-5, 5-16.a
  Supplemental References: none
  


• Quantity: magnetic field strength
  Definition: A vector quantity, the rotation (curl) of which is equal to the sum of the electric current density and the time derivative of the electric flux density.
  Reference type: PR
  Reference: I31-5, 5-17.a
  Supplemental References: none
  


• Quantity: magnetization
  Definition: The extent to which a magnetic material is magnetized, given by the magnetic moment per unit volume.
  Reference type: PR
  Reference: I31-5, 5-28.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_AMP_PER_SQ_M_KELVIN_SQD

EDCS Unit Code: 2

Symbol: A/(m² · K²)

EDCS Unit Equivalence Class Label: THERMION_EMISSION_CUR_DENS

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: thermionic emission current density
  Definition: A vector quantity, the integral of whose normal component over a heated surface is equal to the net number of particles (electrons or ions) emitted from that surface, as a function of the thermodynamic temperature of that surface.
  Reference type: PR
  Reference: I31-13, 13-27.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_AMP_PER_SQ_METRE

EDCS Unit Code: 3

Symbol: A/m²

EDCS Unit Equivalence Class Label: AREIC_ELECTRIC_CURRENT

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: areic electric current (electric current density)
  Definition: A vector quantity, the integral of whose normal component over a given surface is equal to the electric current flowing through that surface.
  Reference type: PR
  Reference: I31-5, 5-15.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_AMPERE

EDCS Unit Code: 4

Symbol: A

EDCS Unit Equivalence Class Label: ELECTRIC_CURRENT

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 4

• Quantity: current linkage
  Definition: The net electric conduction current through a closed loop.
  Reference type: PR
  Reference: I31-5, 5-18.a
  Supplemental References: none
  


• Quantity: electric current
  Definition: That constant electric current which, if maintained in two straight parallel conductors of infinite length, of negligible circular cross-section, and placed 1 metre apart in vacuum, would produce between these conductors a force equal to 2 x 10^-7 newton per metre of length.
  SI base unit.
  Reference type: PR
  Reference: I31-0, Table 1
  Supplemental References: I31-5, 5-1.a
  


• Quantity: magnetic potential difference
  Definition: On a given path, the magnetic potential difference between point 1 and point 2 is the line integral from 1 to 2 of the magnetic field strength along that path.
  Reference type: PR
  Reference: I31-5, 5-18.a
  Supplemental References: none
  


• Quantity: magnetomotive force
  Definition: The work required to carry a magnetic pole of unit strength once around a magnetic circuit.
  Reference type: PR
  Reference: I31-5, 5-18.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_ANGSTROM

EDCS Unit Code: 5

Symbol: Å

EDCS Unit Equivalence Class Label: LENGTH

Unit Status: Deprecated

Number of quantities which this unit of measure may represent:: 1

• Quantity: length
  Definition: ångström; 1 Å = 10^-10 m = 10^-1 nm = 10^-4 μm (exactly).
  Reference type: PR
  Reference: I31-1, 1-3.a (remarks)
  Supplemental References: I1000, Annex A, 6.3
  

EDCS Unit Symbolic Constant: EUC_ARE

EDCS Unit Code: 6

Symbol: a

EDCS Unit Equivalence Class Label: AREA

Unit Status: Deprecated

Number of quantities which this unit of measure may represent:: 1

• Quantity: area
  Definition: The product of length and width.
  1 a = 1 dam² = 10² m² (exactly).
  Reference type: PR
  Reference: I31-1, 1-5.a (remarks)
  Supplemental References: I1000, Annex A, 1-4
  

EDCS Unit Symbolic Constant: EUC_ASTRONOMICAL_UNIT

EDCS Unit Code: 7

Symbol: AU

EDCS Unit Equivalence Class Label: LENGTH

Unit Status: Deprecated

Number of quantities which this unit of measure may represent:: 1

• Quantity: length
  Definition: 1 AU = 1,495 978 7 x 10¹¹ m (approximately).
  Reference type: PR
  Reference: I31-1, 1-3.B.b
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_BAR

EDCS Unit Code: 8

Symbol: bar

EDCS Unit Equivalence Class Label: PRESSURE

Unit Status: Deprecated

Number of quantities which this unit of measure may represent:: 1

• Quantity: pressure
  Definition: The force that is exerted per unit area.
  1 bar = 10⁵ Pa (exactly).
  Reference type: PR
  Reference: I31-3, 3-15a (remarks)
  Supplemental References: I1000, Annex A, 3-15.1
  

EDCS Unit Symbolic Constant: EUC_BARN

EDCS Unit Code: 9

Symbol: b

EDCS Unit Equivalence Class Label: AREA

Unit Status: Deprecated

Number of quantities which this unit of measure may represent:: 1

• Quantity: area
  Definition: The product of length and width.
  1 b = 100 fm² = 10^-28 m² (exactly).
  Reference type: PR
  Reference: I31-10, 10-3.a (remarks)
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_BECQUEREL

EDCS Unit Code: 10

Symbol: Bq

EDCS Unit Equivalence Class Label: RADIONUCLIDE_ACTIVITY

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: activity of a radio nuclide
  Definition: The average number of spontaneous nuclear transitions from a particular energy state occurring in an amount of a radionuclide in a small time interval, divided by that interval.
  1 Bq = 1 s^-1.
  Reference type: PR
  Reference: I31-0, Table 3
  Supplemental References: I31-9, 9-33.a; I31-10, 10-49.a
  

EDCS Unit Symbolic Constant: EUC_BECQUEREL_PER_CUBIC_METRE

EDCS Unit Code: 11

Symbol: Bq/m³

EDCS Unit Equivalence Class Label: VOLUMIC_ACTIVITY

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: volumic activity (activity concentration)
  Definition: Activity of a radionuclide divided by the total volume of the sample.
  Reference type: PR
  Reference: I31-9, 9-35.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_BECQUEREL_PER_KG

EDCS Unit Code: 12

Symbol: Bq/kg

EDCS Unit Equivalence Class Label: MASSIC_ACTIVITY

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: massic activity (specific activity)
  Definition: Activity of a radionuclide divided by the total mass of the sample.
  Reference type: PR
  Reference: I31-9, 9-34.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_BEL

EDCS Unit Code: 13

Symbol: B

EDCS Unit Equivalence Class Label: FIELD_OR_POWER_LEVEL_DIFF

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 4

• Quantity: field quantity ratio (level difference)
  Definition: Twice the common logarithm of a field quantity ratio.
  1 B is the level of a field quantity when 2 lg (F/F₀) = 1 where F and F₀ represent two amplitudes of the same kind, F₀ being a reference amplitude.
  1 B = (1/2) ln 10 Np = 1,151 293 Np (approximately).
  Reference type: PR
  Reference: I31-2, 2-9.b
  Supplemental References: none
  


• Quantity: power quantity ratio (level difference)
  Definition: The common logarithm of a power quantity ratio.
  1 B is the level of a power quantity when lg (P/P₀) = 1 where P and P₀ represent two powers, P₀ being a reference power.
  Reference type: PR
  Reference: I31-2, 2-10.b
  Supplemental References: none
  


• Quantity: sound power level
  Definition: L_W = 1/2 ln (P/P₀) = 1/2 ln 10·lg (P/P₀) where P is the root-mean-square of the sound power and the reference power p₀ = 1 x 10^-12 W.
  Reference type: PR
  Reference: I31-7, 7-22.a
  Supplemental References: none
  


• Quantity: sound pressure level
  Definition: L_p = ln (p/p₀) = ln 10·lg (p/p₀) where p is the root-mean-square value of the sound pressure and the reference pressure p₀ = 20 μPa.
  Reference type: PR
  Reference: I31-7, 7-21.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_CANDELA

EDCS Unit Code: 14

Symbol: cd

EDCS Unit Equivalence Class Label: LUMINANCE_INTENSITY

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: luminous intensity
  Definition: The luminous intensity, in a given direction, of a source that emits monochromatic radiation of a frequency 540 x 10¹² Hertz, and that has a radiant intensity in that direction of 1 / 683 watt per steradian.
  SI base unit.
  Reference type: PR
  Reference: I31-0, Table 1
  Supplemental References: I31-6, 6-29.a
  

EDCS Unit Symbolic Constant: EUC_CD_PER_SQ_METRE

EDCS Unit Code: 15

Symbol: cd/m²

EDCS Unit Equivalence Class Label: LUMINANCE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: luminance
  Definition: At a point on a surface and in a given direction, the luminous intensity of an element of the surface, divided by the area of the orthogonal projection of this element on a plane perpendicular to the given direction.
  Reference type: PR
  Reference: I31-6, 6-32.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_COULOMB

EDCS Unit Code: 16

Symbol: C

EDCS Unit Equivalence Class Label: ELECTRIC_CHARGE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 3

• Quantity: electric charge (quantity of electricity)
  Definition: The integral of electric current over time.
  1 C = 1 s · A.
  Reference type: PR
  Reference: I31-0, Table 2
  Supplemental References: I31-5, 5-2.a
  


• Quantity: electric flux
  Definition: Across a surface element, the scalar product of the electric flux density and the surface element.
  Reference type: PR
  Reference: I31-5, 5-8.a
  Supplemental References: none
  


• Quantity: elementary charge
  Definition: The electric charge of a proton.
  Reference type: PR
  Reference: I31-9, 9-6.a
  Supplemental References: I31-8, 8-43.a
  

EDCS Unit Symbolic Constant: EUC_COULOMB_METRE

EDCS Unit Code: 17

Symbol: C · m

EDCS Unit Equivalence Class Label: ELECTRIC_DIPOLE_MOMENT

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 2

• Quantity: electric dipole moment
  Definition: A vector quantity, the vector product of which with the electric field strength of a homogenous field is equal to the torque.
  1 C · m = 1 m · s · A.
  Reference type: PR
  Reference: I31-5, 5-14.a
  Supplemental References: none
  


• Quantity: electric dipole moment of a molecule
  Definition: A vector quantity, the vector product of which with the electric field strength is equal to the torque.
  Reference type: PR
  Reference: I31-8, 8-32.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_COULOMB_METRE_SQD_PER_VOLT

EDCS Unit Code: 18

Symbol: C · m²/V

EDCS Unit Equivalence Class Label: ELECTRIC_POLARIZABILITY

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: electric polarizability of a molecule
  Definition: The induced electric dipole moment divided by electric field strength.
  1 C · m²/V = 1 (s⁴ · A²)/kg.
  Reference type: PR
  Reference: I31-8, 8-33.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_COULOMB_PER_CUBIC_M

EDCS Unit Code: 19

Symbol: C/m³

EDCS Unit Equivalence Class Label: VOLUME_DENSITY_CHARGE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: volume charge (volume density of charge, electric charge density)
  Definition: The charge divided by volume.
  1 C/m³ = 1 (s · A)/m³.
  Reference type: PR
  Reference: I31-5, 5-3.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_COULOMB_PER_KG

EDCS Unit Code: 20

Symbol: C/kg

EDCS Unit Equivalence Class Label: EXPOSURE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: exposure of ionizing radiation
  Definition: The total electric charge of the ions of the same sign produced when all the electrons (negative and positive) liberated by photons in an element of air are stopped in air, divided by the mass of that element.
  1 C/kg = 1 (s · A)/kg.
  Reference type: PR
  Reference: I31-10, 10-58.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_COULOMB_PER_KG_SEC

EDCS Unit Code: 21

Symbol: C/(kg · s)

EDCS Unit Equivalence Class Label: EXPOSURE_RATE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: exposure rate of ionizing radiation
  Definition: The exposure (ionizing radiation) divided by time.
  1 C/(kg · s) = 1 A/kg.
  Reference type: PR
  Reference: I31-10, 10-59.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_COULOMB_PER_MOLE

EDCS Unit Code: 22

Symbol: C/mol

EDCS Unit Equivalence Class Label: MOLAR_CHARGE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: molar charge
  Definition: The charge carried per amount of substance.
  1 C/mol = 1 (s · A)/mol.
  Reference type: PR
  Reference: I31-8, 8-45.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_COULOMB_PER_SQ_M

EDCS Unit Code: 23

Symbol: C/m²

EDCS Unit Equivalence Class Label: SURFACE_DENSITY_CHARGE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 3

• Quantity: areic charge (surface density of charge)
  Definition: The charge divided by surface area.
  1 C/m² = 1 (s · A)/m².
  Reference type: PR
  Reference: I31-5, 5-4.a
  Supplemental References: none
  


• Quantity: electric flux density
  Definition: A vector quantity, the divergence of which is equal to the volumic charge.
  Reference type: PR
  Reference: I31-5, 5-7.a
  Supplemental References: none
  


• Quantity: electric polarization
  Definition: A vector quantity equal to the electric dipole moment per unit volume of a material.
  Reference type: PR
  Reference: I31-5, 5-13.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_CUBIC_M_PER_CUBIC_M

EDCS Unit Code: 24

Symbol: m³/m³

EDCS Unit Equivalence Class Label: VOLUME_FRACTION

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: volume fraction (of B)
  Definition: The volume of B divided by the volume of the mixture.
  1 m³/m³ = 1.
  Reference type: PR
  Reference: I31-8, 8-15.a
  Supplemental References: I31-0, 2.3.3
  

EDCS Unit Symbolic Constant: EUC_CUBIC_METRE

EDCS Unit Code: 25

Symbol: m³

EDCS Unit Equivalence Class Label: VOLUME

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 2

• Quantity: section modulus
  Definition: The section modulus of a plane area (section) about an axis in its plane is the second moment of area divided by the distance from the axis to the most remote point of the area.
  Reference type: PR
  Reference: I31-3, 3-21.a
  Supplemental References: none
  


• Quantity: volume
  Definition: The product of length, width and height.
  Reference type: PR
  Reference: I31-1, 1-6.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_CUBIC_METRE_PER_COULOMB

EDCS Unit Code: 26

Symbol: m³/C

EDCS Unit Equivalence Class Label: RECIPROCAL_VOLUMIC_CHARGE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: reciprocal volumic charge (reciprocal charge density)
  Definition: The volume divided by the charge.
  Reference type: PR
  Reference: I31-13, 13-20.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_CUBIC_METRE_PER_KG

EDCS Unit Code: 27

Symbol: m³/kg

EDCS Unit Equivalence Class Label: SPECIFIC_VOLUME

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: specific volume
  Definition: The volume divided by mass.
  Reference type: PR
  Reference: I31-3, 3-4.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_CUBIC_METRE_PER_MOLE

EDCS Unit Code: 28

Symbol: m³/mol

EDCS Unit Equivalence Class Label: MOLAR_VOLUME

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: molar volume
  Definition: The volume divided by the amount of substance.
  Reference type: PR
  Reference: I31-8, 8-6.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_CUBIC_METRE_PER_SEC

EDCS Unit Code: 29

Symbol: m³/s

EDCS Unit Equivalence Class Label: VOLUME_FLOW_RATE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 2

• Quantity: recombination coefficient
  Definition: The coefficient in the law of recombination.
  Reference type: PR
  Reference: I31-10, 10-28.a
  Supplemental References: none
  


• Quantity: volume flow rate
  Definition: The volume of matter which crosses a given surface, divided by time.
  Reference type: PR
  Reference: I31-3, 3-30.a
  Supplemental References: I31-7, 7-13.a
  

EDCS Unit Symbolic Constant: EUC_CURIE

EDCS Unit Code: 30

Symbol: Ci

EDCS Unit Equivalence Class Label: RADIONUCLIDE_ACTIVITY

Unit Status: Deprecated

Number of quantities which this unit of measure may represent:: 1

• Quantity: activity of a radio nuclide
  Definition: The average number of spontaneous nuclear transitions from a particular energy state occurring in an amount of a radionuclide in a small time interval, divided by that interval.
  1 Ci = 3.7 x 10¹⁰ Bq (exactly).
  Reference type: PR
  Reference: I31-9, 9-33.a (remarks)
  Supplemental References: I1000, Annex A, 9-33
  

EDCS Unit Symbolic Constant: EUC_DAY

EDCS Unit Code: 31

Symbol: d

EDCS Unit Equivalence Class Label: TIME

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 1

• Quantity: time
  Definition: 1 d = 24 h = 86 400 s (exactly).
  Reference type: PR
  Reference: I31-0, Table 4
  Supplemental References: I31-1, 1-7.d
  

EDCS Unit Symbolic Constant: EUC_DB

EDCS Unit Code: 32

Symbol: dB

EDCS Unit Equivalence Class Label: FIELD_OR_POWER_LEVEL_DIFF

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 2

• Quantity: field quantity ratio (level difference)
  Definition: A dimensionless quantity used to describe a comparison of field levels.
  1 dB = 10^-1 B (exactly) = 1,151 293 x 10^-1Np (approximately).
  Reference type: PR
  Reference: I31-2, 2-9.a (remarks)
  Supplemental References: none
  


• Quantity: power quantity ratio (level difference)
  Definition: A dimensionless quantity used to describe a comparison of power levels.
  1 dB = 10^-1 B (exactly) = 1,151 293 x 10^-1Np (approximately).
  Reference type: PR
  Reference: I31-2, 2-10.a (remarks)
  Supplemental References: I1000, Annex A, 7-21
  

EDCS Unit Symbolic Constant: EUC_DB_PER_METRE

EDCS Unit Code: 33

Symbol: dB/m

EDCS Unit Equivalence Class Label: POWER_LEVEL_DIFF_LEN_GRADIENT

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: power ratio (level difference) gradient
  Definition: The rate of power ratio change as a function of distance.
  Reference type: PR
  Reference: I31-0, 2.3.2.2 (derived)
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_DB_PER_METRE_KHZ

EDCS Unit Code: 34

Symbol: dB/(m · kHz)

EDCS Unit Equivalence Class Label: POWER_LEVEL_DIFF_LEN_FREQ

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: power ratio (level difference) distance and frequency gradient
  Definition: The rate of power ratio change as a function of distance and spectral frequency.
  Reference type: PR
  Reference: I31-0, 2.3.2.2 (derived)
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_DB_PER_OCTAVE

EDCS Unit Code: 35

Symbol: none

EDCS Unit Equivalence Class Label: POWER_LEVEL_DIFF_FREQ_GRADIENT

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: power ratio (level difference) frequency gradient
  Definition: The rate of power ratio change as a function of spectral frequency octave.
  Reference type: PR
  Reference: I31-0, 2.3.2.2 (derived)
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_DB_PER_SQ_METRE

EDCS Unit Code: 36

Symbol: dB/m²

EDCS Unit Equivalence Class Label: AREIC_POWER_LEVEL_DIFF

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: areic power ratio (level difference)
  Definition: The power level divided by area.
  Reference type: PR
  Reference: I31-0, 2.3.2.2 (derived)
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_DB_PER_SQ_METRE_KHZ

EDCS Unit Code: 37

Symbol: dB/(m² · kHz)

EDCS Unit Equivalence Class Label: GRAD_POWER_LEVEL_DIFF_LEN_FREQ

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: gradient of power ratio (level difference) distance and frequency gradient
  Definition: The rate of change of power ratio change as a function of distance and spectral frequency.
  Reference type: PR
  Reference: I31-0, 2.3.2.2 (derived)
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_DB_REF_ONE_MICROPASCAL

EDCS Unit Code: 38

Symbol: dB (re 1 μPa)

EDCS Unit Equivalence Class Label: PRESSURE_POWER_LEVEL

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: pressure power quantity ratio (level)
  Definition: 1 dB (re 1 μPa) is the level of a pressure power quantity when lg (P/P₀) = 0,1 where P and P₀ represent two pressure powers, P₀ being a reference power of 1 μPa.
  Reference type: PR
  Reference: I31-0, 2.3.2.2 (derived)
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_DECAY_RATE

EDCS Unit Code: 39

Symbol: %/min

EDCS Unit Equivalence Class Label: RATE

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 1

• Quantity: decay constant (disintegration constant)
  Definition: Probability of decay of an active species in a small time interval, divided by that interval.
  1 %/min = 1 / 6 x 10^-3 1/s (exactly).
  Reference type: PR
  Reference: I31-9, 9-36.a
  Supplemental References: I31-0, 2.3.2.3
  

EDCS Unit Symbolic Constant: EUC_DEGREE_ARC

EDCS Unit Code: 40

Symbol: º

EDCS Unit Equivalence Class Label: PLANE_ANGLE

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 2

• Quantity: Bragg angle
  Definition: The angle between an incident X-ray beam and a set of crystal planes for which the secondary radiation displays maximum intensity as a result of constructive interference.
  Reference type: PR
  Reference: I31-13, 13-4.b
  Supplemental References: none
  


• Quantity: plane angle
  Definition: The angle between two half-lines terminating at the same point is defined as the ratio of the length of the included arc of the circle (with its centre at that point) to the radius of that circle.
  1º = (π / 180) rad (exactly).
  Reference type: PR
  Reference: I31-0, Table 4
  Supplemental References: I31-1, 1-1.b
  

EDCS Unit Symbolic Constant: EUC_DEGREE_C

EDCS Unit Code: 41

Symbol: ºC

EDCS Unit Equivalence Class Label: THERMO_TEMPERATURE

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 1

• Quantity: thermodynamic temperature
  Definition: A special name for the kelvin for use in stating values of Celsius temperature.
  t = T - T₀ where T₀ = 273,15 K (exactly).
  Reference type: PR
  Reference: I31-0, Table 2
  Supplemental References: I31-4, 4-2.a
  

EDCS Unit Symbolic Constant: EUC_DEGREE_C_PER_HOUR

EDCS Unit Code: 42

Symbol: ºC/h

EDCS Unit Equivalence Class Label: THERMO_TEMP_CHANGE_RATE

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 1

• Quantity: thermodynamic temperature change rate
  Definition: The thermodynamic temperature change over an interval of time, divided by that time.
  1 ºC/h = 1 / 3,6 x 10^-3 K/s (exactly).
  Reference type: PR
  Reference: I31-0, 2.3.2.2 and 2.3.4 (derived)
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_DEGREE_C_PER_METRE

EDCS Unit Code: 43

Symbol: ºC/m

EDCS Unit Equivalence Class Label: LINEIC_THERMO_TEMP_GRADIENT

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 1

• Quantity: lineic thermodynamic temperature gradient
  Definition: The thermodynamic temperature change over a distance, divided by that distance.
  1 ºC/m = 1 K/m (exactly).
  Reference type: PR
  Reference: I31-0, 2.3.2.2 (derived)
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_DEGREE_C_PER_SEC

EDCS Unit Code: 44

Symbol: ºC/s

EDCS Unit Equivalence Class Label: THERMO_TEMP_CHANGE_RATE

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 1

• Quantity: thermodynamic temperature change rate
  Definition: The thermodynamic temperature change over an interval of time, divided by that time.
  1 ºC/s = 1 K/s (exactly).
  Reference type: PR
  Reference: I31-0, 2.3.2.2 (derived)
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_ELECTRONVOLT

EDCS Unit Code: 45

Symbol: eV

EDCS Unit Equivalence Class Label: ENERGY

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 12

• Quantity: alpha disintegration energy
  Definition: The sum of the kinetic energy of the alpha particle produced in the disintegration process and the recoil energy of the product atom in the reference frame in which the emitting nucleus is at rest before its disintegration.
  Reference type: PR
  Reference: I31-9, 9-38.b
  Supplemental References: none
  


• Quantity: average energy loss per ion pair formed (average energy loss per elementary charge of the same sign produced)
  Definition: The initial kinetic energy of an ionizing charged particle, divided by the total ionization produced by that particle.
  Reference type: PR
  Reference: I31-10, 10-25.b
  Supplemental References: none
  


• Quantity: beta disintegration energy
  Definition: Sum of the maximum beta particle energy and the recoil energy of the atom produced in the reference frame in which the emitting nucleus is at rest before its disintegration.
  Reference type: PR
  Reference: I31-9, 9-40.b
  Supplemental References: none
  


• Quantity: electron affinity
  Definition: The energy difference between an electron at rest at infinity and an electron at the lowest level of the conduction band in an insulator or semiconductor.
  Reference type: PR
  Reference: I31-13, 13-26.b
  Supplemental References: none
  


• Quantity: energy
  Definition: The kinetic energy acquired by an electron in passing through a potential difference of 1 volt in a vacuum. Its value is experimentally determined as 1,602 177 x 10^-19 J (approximately).
  Reference type: PR
  Reference: I31-0, Table 6
  Supplemental References: I31-9, 9-32.b
  


• Quantity: exchange integral
  Definition: The interaction energy arising from electron exchange.
  Reference type: PR
  Reference: I31-13, 13-35.b
  Supplemental References: none
  


• Quantity: Fermi energy
  Definition: In a metal, the highest energy of occupied states at zero thermodynamic temperature.
  Reference type: PR
  Reference: I31-13, 13-28.b
  Supplemental References: none
  


• Quantity: gap energy
  Definition: Difference in energy between lowest level of conduction band and highest level of valence band.
  Reference type: PR
  Reference: I31-13, 13-28.b
  Supplemental References: none
  


• Quantity: maximum beta particle energy
  Definition: Maximum energy of the energy spectrum in a beta disintegration process.
  Reference type: PR
  Reference: I31-9, 9-39.b
  Supplemental References: none
  


• Quantity: reaction energy
  Definition: In a nuclear reaction, the sum of the kinetic and photon energies of the reaction products minus the sum of the kinetic and photon energies of the reactants.
  Reference type: PR
  Reference: I31-10, 10-1.b
  Supplemental References: none
  


• Quantity: resonance energy
  Definition: Kinetic energy of an incident particle, in the reference frame of the target, corresponding to a resonance in a nuclear reaction.
  Reference type: PR
  Reference: I31-10, 10-2.b
  Supplemental References: none
  


• Quantity: work function
  Definition: The energy difference between an electron at rest at infinity and an electron at the Fermi level in the interior of a substance.
  Reference type: PR
  Reference: I31-13, 13-25.b
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_ELECTRONVOLT_M_SQD

EDCS Unit Code: 46

Symbol: eV · m²

EDCS Unit Equivalence Class Label: TOTAL_ATOMIC_STOPPING_POWER

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 1

• Quantity: total atomic stopping power
  Definition: The total linear stopping power divided by the number density of the atoms in the substance.
  1 eV · m² = (1,602 177 33 ± 0,000 000 49) x 10^-19 J · m² (approximately).
  Reference type: PR
  Reference: I31-10, 10-19.b
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_ELECTRONVOLT_M_SQD_PER_KG

EDCS Unit Code: 47

Symbol: (eV · m²)/kg

EDCS Unit Equivalence Class Label: TOTAL_MASS_STOPPING_POWER

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 1

• Quantity: total mass stopping power
  Definition: The total linear stopping power divided by the volumic mass of the substance.
  1 (eV · m²)/kg = (1,602 177 33 ± 0,000 000 49) x 10^-19 (J · m²)/kg (approximately).
  Reference type: PR
  Reference: I31-10, 10-20.b
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_ELECTRONVOLT_PER_METRE

EDCS Unit Code: 48

Symbol: eV/m

EDCS Unit Equivalence Class Label: TOTAL_LINEAR_STOPPING_POWER

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 2

• Quantity: linear energy transfer
  Definition: For an ionizing charged particle, the energy imparted locally to matter in traversing a small distance through the matter, divided by that distance.
  Reference type: PR
  Reference: I31-10, 10-54.b
  Supplemental References: none
  


• Quantity: total linear stopping power
  Definition: For an ionizing charged particle, the energy imparted locally to matter in traversing a small distance through the matter, divided by that distance; -dE/dx.
  1 eV/m = (1,602 177 33 ± 0,000 000 49) x 10^-19 J/m (approximately).
  Reference type: PR
  Reference: I31-10, 10-18.b
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_FARAD

EDCS Unit Code: 49

Symbol: F

EDCS Unit Equivalence Class Label: CAPACITANCE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: capacitance
  Definition: The charge divided by potential difference.
  1 F = 1 C/V = 1 (s⁴ · A²)/(m² · kg).
  Reference type: PR
  Reference: I31-0, Table 2
  Supplemental References: I31-5, 5-9.a
  

EDCS Unit Symbolic Constant: EUC_FARAD_PER_METRE

EDCS Unit Code: 50

Symbol: F/m

EDCS Unit Equivalence Class Label: PERMITTIVITY

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: permittivity
  Definition: The ability of a material to resist the formation of an electric field within it.
  1 F/m = 1 (s⁴ · A²)/(m³ · kg).
  Reference type: PR
  Reference: I31-5, 5-10.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_FOOT

EDCS Unit Code: 51

Symbol: ft

EDCS Unit Equivalence Class Label: LENGTH

Unit Status: Deprecated

Number of quantities which this unit of measure may represent:: 1

• Quantity: length
  Definition: 1 ft = 0,304 8 m (exactly).
  Reference type: PR
  Reference: I31-1, 1-3.A.b
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_GAL

EDCS Unit Code: 52

Symbol: Gal

EDCS Unit Equivalence Class Label: ACCELERATION

Unit Status: Deprecated

Number of quantities which this unit of measure may represent:: 1

• Quantity: acceleration
  Definition: The change in velocity divided by time.
  1 Gal = 0,01 m/s² (exactly).
  Reference type: PR
  Reference: I31-1, 1-11.B.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_GEOPOTENTIAL_METRE

EDCS Unit Code: 53

Symbol: gpm

EDCS Unit Equivalence Class Label: GEOPOTENTIAL_ENERGY_LENGTH

Unit Status: Not in the scope of SI

Number of quantities which this unit of measure may represent:: 1

• Quantity: geopotential energy height (geopotential specific energy)
  Definition: A height proportional to the potential energy of mass (geopotential) at this height relative to the geoid.
  The geopotential metre varies with geodetic latitude. On <EARTH> at mid-latitudes it equals 0,98 m (approximately).
  Reference type: IR
  Reference: [WMO182, "geopotential altitude"]
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_GON

EDCS Unit Code: 54

Symbol: gon

EDCS Unit Equivalence Class Label: PLANE_ANGLE

Unit Status: Deprecated

Number of quantities which this unit of measure may represent:: 1

• Quantity: plane angle
  Definition: The angle between two half-lines terminating at the same point is defined as the ratio of the length of the included arc of the circle (with its centre at that point) to the radius of that circle.
  1 gon = π / 200 rad = 0,015 707 96 rad (exactly).
  Reference type: PR
  Reference: I31-1, 1-1.B.a
  Supplemental References: I1000, Annex A, 1-1
  

EDCS Unit Symbolic Constant: EUC_GRAM

EDCS Unit Code: 55

Symbol: g

EDCS Unit Equivalence Class Label: MASS

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 1

• Quantity: mass
  Definition: For historical reasons the name of the base unit for mass, the kg, contains the name of the SI prefix "kilo".
  A gram is a special name given to unit kg x 10^-3 that is used instead of "millikilogram".
  Reference type: PR
  Reference: I31-0, 3.2.4
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_GRAM_PER_CUBIC_CM

EDCS Unit Code: 56

Symbol: g/cm³

EDCS Unit Equivalence Class Label: VOLUMIC_MASS

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 2

• Quantity: mass concentration (of B)
  Definition: The amount of substance of B divided by the volume of the mixture.
  Reference type: PR
  Reference: I31-8, 8-11.a
  Supplemental References: none
  


• Quantity: volumic mass (mass density)
  Definition: The mass divided by the volume.
  1 g/cm³ = 10³ kg/m³ (exactly).
  Reference type: PR
  Reference: I31-3, 3-2.b
  Supplemental References: I31-0, 2.3.2.3; I31-7, 7-8.a
  

EDCS Unit Symbolic Constant: EUC_GRAM_PER_CUBIC_M

EDCS Unit Code: 57

Symbol: g/m³

EDCS Unit Equivalence Class Label: VOLUMIC_MASS

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 2

• Quantity: mass concentration (of B)
  Definition: The amount of substance of B divided by the volume of the mixture.
  Reference type: PR
  Reference: I31-8, 8-11.a
  Supplemental References: none
  


• Quantity: volumic mass (mass density)
  Definition: The mass divided by the volume.
  1 g/m³ = 10^-3 kg/m³ (exactly).
  Reference type: PR
  Reference: I31-3, 3-2.b
  Supplemental References: I31-0, 2.3.2.3; I31-7, 7-8.a
  

EDCS Unit Symbolic Constant: EUC_GRAM_PER_GRAM

EDCS Unit Code: 58

Symbol: g/g

EDCS Unit Equivalence Class Label: MASS_FRACTION

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 1

• Quantity: mass fraction (of B)
  Definition: The mass of B divided by the mass of the mixture.
  1 g/g = 1 kg/kg = 1.
  Reference type: PR
  Reference: I31-8, 8-12.a
  Supplemental References: I31-0, 2.3.3; I31-0, 2.3.2.3
  

EDCS Unit Symbolic Constant: EUC_GRAM_PER_KILOGRAM

EDCS Unit Code: 59

Symbol: g/kg

EDCS Unit Equivalence Class Label: MASS_FRACTION

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 1

• Quantity: mass fraction (of B)
  Definition: The mass of B divided by the mass of the mixture.
  1 g/kg = 10^-3 kg/kg = 10^-3 (exactly).
  Reference type: PR
  Reference: I31-8, 8-12.a
  Supplemental References: I31-0, 2.3.3; I31-0, 2.3.2.3
  

EDCS Unit Symbolic Constant: EUC_GRAY

EDCS Unit Code: 60

Symbol: Gy

EDCS Unit Equivalence Class Label: ABSORBED_DOSE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 2

• Quantity: absorbed dose of ionizing radiation
  Definition: For any ionizing radiation, the energy imparted to an element of irradiated matter divided by the mass of this element.
  1 Gy = 1 J/kg = 1 m²/s².
  Reference type: PR
  Reference: I31-0, Table 3
  Supplemental References: I31-10, 10-51.a
  


• Quantity: kerma
  Definition: For indirectly ionizing (uncharged) particles, the sum of the initial kinetic energies of all charged particles liberated in an element of matter, divided by the mass of that element.
  Reference type: PR
  Reference: I31-10, 10-55.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_GRAY_PER_SECOND

EDCS Unit Code: 61

Symbol: Gy/s

EDCS Unit Equivalence Class Label: ABSORBED_DOSE_RATE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 2

• Quantity: absorbed dose rate of ionizing radiation
  Definition: The absorbed dose of ionizing radiation over an interval of time, divided by that time.
  1 Gy/s = 1 W/kg = 1 m²/s³.
  Reference type: PR
  Reference: I31-10, 10-53.a
  Supplemental References: none
  


• Quantity: kerma rate
  Definition: For indirectly ionizing (uncharged) particles, the sum of the initial kinetic energies of all charged particles liberated in an element of matter in a small interval of time, divided by the mass of that element and the interval of time.
  Reference type: PR
  Reference: I31-10, 10-56.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_HECTARE

EDCS Unit Code: 62

Symbol: ha

EDCS Unit Equivalence Class Label: AREA

Unit Status: Deprecated

Number of quantities which this unit of measure may represent:: 1

• Quantity: area
  Definition: The product of length and width.
  1 ha = 1 hm² = 10⁴ m² (exactly).
  Reference type: PR
  Reference: I31-1, 1-5.a (remarks)
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_HENRY

EDCS Unit Code: 63

Symbol: H

EDCS Unit Equivalence Class Label: INDUCTANCE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 2

• Quantity: magnetic inductance
  Definition: For a thin conducting loop, the magnetic flux through the loop, caused by an electric current in the loop, divided by that current.
  For two thin conducting loops (m and n), the magnetic flux through one loop, due to an electric current in the other loop, divided by that current.
  1 H = 1 Wb/A = 1 (m² · kg)/(s² · A²).
  Reference type: PR
  Reference: I31-0, Table 2
  Supplemental References: I31-5, 5-22.a
  


• Quantity: permeance
  Definition: The reciprocal of the reluctance of a magnetic circuit, determined by the magnetic flux divided by the magnetomotive force.
  Reference type: PR
  Reference: I31-5, 5-39.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_HENRY_PER_METRE

EDCS Unit Code: 64

Symbol: H/m

EDCS Unit Equivalence Class Label: MAGNETIC_PERMEABILITY

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: magnetic permeability
  Definition: The ability of a substance to acquire magnetization when placed in a magnetic field.
  1 H/m = 1 (m · kg)/(s² · A²).
  Reference type: PR
  Reference: I31-5, 5-24.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_HERTZ

EDCS Unit Code: 65

Symbol: Hz

EDCS Unit Equivalence Class Label: FREQUENCY

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 2

• Quantity: frequency
  Definition: The number of cycles divided by time.
  1 Hz = 1 s^-1.
  Reference type: PR
  Reference: I31-0, Table 2
  Supplemental References: I31-2, 2-3.a; I31-6, 6-1.a; I31-7, 7-2.a
  


• Quantity: rotational frequency
  Definition: The number of revolutions divided by time.
  1 Hz = 1 s^-1.
  Reference type: PR
  Reference: I31-5, 5-41.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_HOUR

EDCS Unit Code: 66

Symbol: h

EDCS Unit Equivalence Class Label: TIME

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 1

• Quantity: time
  Definition: 1 h = 60 min = 3 600 s (exactly).
  Reference type: PR
  Reference: I31-0, Table 4
  Supplemental References: I31-1, 1-7.c
  

EDCS Unit Symbolic Constant: EUC_INT_SOLAR_FLUX_UNIT

EDCS Unit Code: 67

Symbol: none

EDCS Unit Equivalence Class Label: FLUX_DENSITY

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 1

• Quantity: international solar flux unit
  Definition: The unit of radio emission from the <SUN>, measured at a wavelength of 10.7 cm (approximately 2 800 MHz).
  1 SFU = 10⁴ Jy = 10^-22 W/(m² · Hz) (exactly).
  Reference type: PR
  Reference: I31-0, 2.3.1 and 2.3.2 (derived)
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_INV_CUBIC_CM

EDCS Unit Code: 68

Symbol: 1/cm³

EDCS Unit Equivalence Class Label: VOLUMETRIC_ENTITY_DENSITY

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 1

• Quantity: volumetric entity density (any elementary entity: atoms, molecules, ions, electrons, other particles, or specified groups of such particles)
  Definition: The number of molecules or particles divided by volume.
  1/cm³ = 10^-6 1/m³.
  Reference type: PR
  Reference: I31-10, 10-27.a
  Supplemental References: I31-0, 2.3.2.3
  

EDCS Unit Symbolic Constant: EUC_INV_CUBIC_CM_SEC

EDCS Unit Code: 69

Symbol: 1/(cm³ · s)

EDCS Unit Equivalence Class Label: VOLUMETRIC_ENTITY_EMIT_RATE

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 1

• Quantity: volumetric entity emittance or capture rate (any elementary entity: atoms, molecules, ions, electrons, other particles, or specified groups of such particles)
  Definition: The number of molecules or particles divided by volume, per time.
  1/(cm³ · s) = 10^-6 1/(m³ · s).
  Reference type: PR
  Reference: I31-10, 10-35.a
  Supplemental References: I31-0, 2.3.2.3
  

EDCS Unit Symbolic Constant: EUC_INV_CUBIC_METRE

EDCS Unit Code: 70

Symbol: 1/m³

EDCS Unit Equivalence Class Label: VOLUMETRIC_ENTITY_DENSITY

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 4

• Quantity: electron number density (volumic electron number)
  Definition: The number density of electrons in conduction band.
  Reference type: PR
  Reference: I31-13, 13-30.a
  Supplemental References: none
  


• Quantity: ion number density (ion density)
  Definition: The number of positive or negative ions in a volume element, divided by that element.
  Reference type: PR
  Reference: I31-10, 10-27.a
  Supplemental References: none
  


• Quantity: neutron number density
  Definition: The number of free neutrons in a volume element, divided by that element.
  Reference type: PR
  Reference: I31-10, 10-29.a
  Supplemental References: none
  


• Quantity: volumetric entity density (any elementary entity: atoms, molecules, ions, electrons, other particles, or specified groups of such particles)
  Definition: The number of molecules or particles divided by their volume.
  Reference type: PR
  Reference: I31-8, 8-10.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_INV_CUBIC_METRE_EV

EDCS Unit Code: 71

Symbol: 1/(m³ · eV)

EDCS Unit Equivalence Class Label: DENSITY_STATES

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 1

• Quantity: density of states
  Definition: A function of the energy in a solid given by the number of permitted quantum states in the energy range between E and E + dE, per unit volume of the material.
  1/(m³ · eV) = (6,241 5061 4 ± 0,0001 0011 9) x 10¹⁸ 1/(m³ · J) (approximately).
  Reference type: PR
  Reference: I31-13, 13-17.b
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_INV_CUBIC_METRE_JOULE

EDCS Unit Code: 72

Symbol: 1/(m³ · J)

EDCS Unit Equivalence Class Label: DENSITY_STATES

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: density of states
  Definition: A function of the energy in a solid given by the number of permitted quantum states in the energy range between E and E + dE, per unit volume of the material.
  Reference type: PR
  Reference: I31-13, 13-17.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_INV_CUBIC_METRE_SEC

EDCS Unit Code: 73

Symbol: 1/(m³ · s)

EDCS Unit Equivalence Class Label: VOLUMETRIC_ENTITY_EMIT_RATE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 2

• Quantity: slowing-down density
  Definition: The number density of neutrons slowing down past a given energy value in a small time interval, divided by that interval.
  Reference type: PR
  Reference: I31-10, 10-35.a
  Supplemental References: none
  


• Quantity: volumetric entity emittance or capture rate (any elementary entity: atoms, molecules, ions, electrons, other particles, or specified groups of such particles)
  Definition: The number of molecules or particles divided by volume, per time.
  Reference type: PR
  Reference: I31-10, 10-34.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_INV_HENRY

EDCS Unit Code: 74

Symbol: 1/H

EDCS Unit Equivalence Class Label: RELUCTANCE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: reluctance
  Definition: The magnetic potential difference divided by magnetic flux.
  1/H = 1 A/Wb = 1 (s² · A²)/(m² · kg).
  Reference type: PR
  Reference: I31-5, 5-38.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_INV_KELVIN

EDCS Unit Code: 75

Symbol: 1/K

EDCS Unit Equivalence Class Label: LINEAR_EXPANSION_COEFF

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 3

• Quantity: cubic expansion coefficient
  Definition: The coefficient of volumic expansion divided by the thermodynamic temperature change.
  Reference type: PR
  Reference: I31-4, 4-3.a
  Supplemental References: none
  


• Quantity: linear expansion coefficient
  Definition: The coefficient of linear expansion divided by the thermodynamic temperature change.
  Reference type: PR
  Reference: I31-4, 4-3.a
  Supplemental References: none
  


• Quantity: relative pressure coefficient
  Definition: The coefficient of pressure change divided by the thermodynamic temperature change.
  Reference type: PR
  Reference: I31-4, 4-3.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_INV_METRE

EDCS Unit Code: 76

Symbol: 1/m

EDCS Unit Equivalence Class Label: INV_LENGTH

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 9

• Quantity: angular reciprocal lattice vector
  Definition: A vector whose scalar products with all fundamental lattice vectors are integral multiples of 2π.
  Reference type: PR
  Reference: I31-13, 13-2.a
  Supplemental References: none
  


• Quantity: angular repetency (angular wave number)
  Definition: The reciprocal of the wavelength or the number of waves per unit angle along the direction of propagation.
  Reference type: PR
  Reference: I31-2, 2-7.b
  Supplemental References: I31-6, 6-5.b; I31-7, 7-7.b; I31-13, 13-10.b
  


• Quantity: curvature
  Definition: The reciprocal of a radius of curvature.
  Reference type: PR
  Reference: I31-1, 1-4.a
  Supplemental References: none
  


• Quantity: fundamental reciprocal lattice vectors
  Definition: The fundamental translation vectors for the reciprocal lattice.
  Reference type: PR
  Reference: I31-13, 13-2.a
  Supplemental References: none
  


• Quantity: linear attenuation coefficient (linear extinction coefficient)
  Definition: The ratio of a quantity which is a function of distance divided by the distance between the measurements.
  Reference type: PR
  Reference: I31-6, 6-42.a
  Supplemental References: I31-10, 10-13.a
  


• Quantity: linear ionization by a particle
  Definition: The number of elementary charges of the same sign produced over an element of length of the path of an ionizing charged particle, divided by that element.
  Reference type: PR
  Reference: I31-10, 10-23.a
  Supplemental References: none
  


• Quantity: repetency (wavenumber)
  Definition: The reciprocal of the wavelength or the number of waves per unit length along the direction of propagation.
  Reference type: PR
  Reference: I31-2, 2-6.a
  Supplemental References: I31-6, 6-4.a; I31-7, 7-6.a
  


• Quantity: vergence (lens power)
  Definition: The reciprocal of the distance between a point of reference and the point at which a pair of converging or diverging light rays intersect.
  Reference type: PR
  Reference: I31-6, 6-46.a
  Supplemental References: none
  


• Quantity: volumic cross-section (macroscopic cross-section)
  Definition: Sum of the cross-sections for a reaction or process of a specified type over all atoms in a given volume, divided by that volume.
  Reference type: PR
  Reference: I31-10, 10-7.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_INV_MICRON

EDCS Unit Code: 77

Symbol: 1/μm

EDCS Unit Equivalence Class Label: INV_LENGTH

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 2

• Quantity: angular repetency (angular wave number)
  Definition: The reciprocal of the wavelength or the number of waves per unit angle along the direction of propagation.
  1 μm^-1 = 10⁶ 1/m (exactly).
  Reference type: PR
  Reference: I31-2, 2-7.b
  Supplemental References: I31-6, 6-5.b; I31-7, 7-7.b; I31-13, 13-10.b
  


• Quantity: repetency (wavenumber)
  Definition: The reciprocal of the wavelength or the number of waves per unit length along the direction of propagation.
  Reference type: PR
  Reference: I31-2, 2-6.a
  Supplemental References: I31-6, 6-4.a; I31-7, 7-6.a
  

EDCS Unit Symbolic Constant: EUC_INV_MOLE

EDCS Unit Code: 78

Symbol: 1/mol

EDCS Unit Equivalence Class Label: MOLAR_DENSITY

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: molar density (Avogadro constant)
  Definition: The number of molecules divided by the amount of substance.
  Reference type: PR
  Reference: I31-8, 8-4.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_INV_PASCAL

EDCS Unit Code: 79

Symbol: 1/Pa

EDCS Unit Equivalence Class Label: COMPRESSIBILITY

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 4

• Quantity: bulk compressibility
  Definition: The reciprocal of the bulk modulus.
  Reference type: PR
  Reference: I31-3, 3-19.a
  Supplemental References: none
  


• Quantity: compressibility
  Definition: The extent to which a material reduces its volume when it is subjected to compressive stresses.
  1/Pa = 1 (m · s²)/kg.
  Reference type: PR
  Reference: I31-3, 3-19.a
  Supplemental References: none
  


• Quantity: isentropic compressibility
  Definition: At a constant value of entropy, the extent to which a material reduces its volume when it is subjected to compressive stresses.
  Reference type: PR
  Reference: I31-4, 4-5.a
  Supplemental References: none
  


• Quantity: isothermal compressibility
  Definition: At a constant temperature, the extent to which a material reduces its volume when it is subjected to compressive stresses.
  Reference type: PR
  Reference: I31-4, 4-5.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_INV_RADIAN

EDCS Unit Code: 80

Symbol: 1/rad

EDCS Unit Equivalence Class Label: RECIPROCAL_PLANE_ANGLE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: reciprocal plane angle
  Definition: The reciprocal of the angle between two half-lines terminating at the same point is the ratio of the radius of a circle (with its centre at that point) to the length of the included arc of that circle.
  1 rad^-1 = 1 m/m = 1.
  Reference type: PR
  Reference: I31-0, 2.3.2.2 (derived)
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_INV_SEC_STERADIAN

EDCS Unit Code: 81

Symbol: 1/(s · sr)

EDCS Unit Equivalence Class Label: PHOTON_INTENSITY

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: photon intensity
  Definition: In a given direction from a source, the photon flux leaving the source, or an element of the source, in an element of solid angle containing the given direction, divided by that element of solid angle.
  Reference type: PR
  Reference: I31-6, 6-24.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_INV_SECOND

EDCS Unit Code: 82

Symbol: 1/s

EDCS Unit Equivalence Class Label: RATE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 7

• Quantity: angular frequency
  Definition: The frequency of rotation or vibration.
  Reference type: PR
  Reference: I31-2, 2-4.b
  Supplemental References: I31-5, 5-42.b; I31-7, 7-4.b
  


• Quantity: angular frequency
  Definition: The number of cycles or revolutions divided by time.
  Reference type: PR
  Reference: I31-6, 6-2.b
  Supplemental References: I31-9, 9-14.b; I31-9, 9-15.b; I31-13, 13-11.b
  


• Quantity: damping coefficient
  Definition: The factor defining the rate of exponential amplitude decay in a periodic or acoustic system.
  Reference type: PR
  Reference: I31-7, 7-23.a
  Supplemental References: I31-2, 2-11.a
  


• Quantity: decay constant (disintegration constant)
  Definition: Probability of decay in a small time interval, divided by that interval.
  Reference type: PR
  Reference: I31-9, 9-36.a
  Supplemental References: none
  


• Quantity: photon flux
  Definition: The number of photons in an incident beam of light received by a surface over a time interval.
  Reference type: PR
  Reference: I31-6, 6-23.a
  Supplemental References: none
  


• Quantity: pulsatance
  Definition: The angular velocity of a periodic quantity.
  Reference type: PR
  Reference: I31-2, 2-4.b
  Supplemental References: I31-5, 5-42.b; I31-7, 7-4.b
  


• Quantity: rotational frequency
  Definition: The number of revolutions divided by time.
  Reference type: PR
  Reference: I31-2, 2-3.b
  Supplemental References: I31-5, 5-41.b
  

EDCS Unit Symbolic Constant: EUC_INV_SQ_CM_SEC_SR_EV

EDCS Unit Code: 83

Symbol: 1/(cm² · s · sr · eV)

EDCS Unit Equivalence Class Label: PARTICLE_FLUX_DENSITY

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 1

• Quantity: particle flux density within an energy range
  Definition: At a point on a surface and in a given direction, the charged particle flux of an element of the surface within an energy range of 1 eV centered on a given particle energy, divided by the area of the orthogonal projection of this element on a plane perpendicular to the given direction, and divided by an element of solid angle containing the given direction.
  1/(cm² · s · sr · eV) = 10^-6 1/(m² · s · sr · eV) (exactly).
  Reference type: PR
  Reference: I31-0, 2.3.2.3 (derived)
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_INV_SQ_CM_SEC_SR_KEV

EDCS Unit Code: 84

Symbol: 1/(cm² · s · sr · KeV)

EDCS Unit Equivalence Class Label: PARTICLE_FLUX_DENSITY

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 1

• Quantity: particle flux density within an energy range
  Definition: At a point on a surface and in a given direction, the charged particle flux of an element of the surface within an energy range of 1 KeV centered on a given particle energy, divided by the area of the orthogonal projection of this element on a plane perpendicular to the given direction, and divided by an element of solid angle containing the given direction.
  1/(cm² · s · sr · KeV) = 10^-9 1/(m² · s · sr · eV) (exactly, assuming an even distribution of particle energies).
  Reference type: PR
  Reference: I31-0, 2.3.2.3 (derived)
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_INV_SQ_CM_SEC_SR_MEV

EDCS Unit Code: 85

Symbol: 1/(cm² · s · sr · MeV)

EDCS Unit Equivalence Class Label: PARTICLE_FLUX_DENSITY

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 1

• Quantity: particle flux density within an energy range
  Definition: At a point on a surface and in a given direction, the charged particle flux of an element of the surface within an energy range of 1 MeV centered on a given particle energy, divided by the area of the orthogonal projection of this element on a plane perpendicular to the given direction, and divided by an element of solid angle containing the given direction.
  1/(cm² · s · sr · MeV) = 10^-12 1/(m² · s · sr · eV) (exactly, assuming an even distribution of particle energies).
  Reference type: PR
  Reference: I31-0, 2.3.2.3 (derived)
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_INV_SQ_CM_SEC_STERADIAN

EDCS Unit Code: 86

Symbol: 1/(cm² · s · sr)

EDCS Unit Equivalence Class Label: PHOTON_LUMINANCE

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 1

• Quantity: photon luminance (photon radiance)
  Definition: At a point on a surface and in a given direction, the photon intensity of an element of the surface, divided by the area of the orthogonal projection of this element on a plane perpendicular to the given direction.
  1/(cm² · s · sr) = 10^-4 1/(m² · s · sr) (exactly).
  Reference type: PR
  Reference: I31-6, 6-25.a
  Supplemental References: I31-0, 2.3.2.3
  

EDCS Unit Symbolic Constant: EUC_INV_SQ_M_SEC_SR_EV

EDCS Unit Code: 87

Symbol: 1/(m² · s · sr · eV)

EDCS Unit Equivalence Class Label: PARTICLE_FLUX_DENSITY

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 1

• Quantity: particle flux density within an energy range
  Definition: At a point on a surface and in a given direction, the charged particle flux of an element of the surface within an energy range of 1 eV centered on a given particle energy, divided by the area of the orthogonal projection of this element on a plane perpendicular to the given direction, and divided by an element of solid angle containing the given direction.
  Reference type: PR
  Reference: I31-0, 2.3.2.2 (derived)
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_INV_SQ_M_SEC_STERADIAN

EDCS Unit Code: 88

Symbol: 1/(m² · s · sr)

EDCS Unit Equivalence Class Label: PHOTON_LUMINANCE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: photon luminance (photon radiance)
  Definition: At a point on a surface and in a given direction, the photon intensity of an element of the surface, divided by the area of the orthogonal projection of this element on a plane perpendicular to the given direction.
  Reference type: PR
  Reference: I31-6, 6-25.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_INV_SQ_METRE

EDCS Unit Code: 89

Symbol: 1/m²

EDCS Unit Equivalence Class Label: AREAL_ENTITY_DENSITY

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 2

• Quantity: areal entity density (any elementary entity: atoms, molecules, ions, electrons, other particles, or specified groups of such particles)
  Definition: At a given point in space, the number of particles incident on a small sphere, divided by the cross-sectional area of that sphere.
  Reference type: PR
  Reference: I31-6, 6-28.a
  Supplemental References: none
  


• Quantity: particle fluence
  Definition: At a given point in space, the number of particles incident on a small sphere, divided by the cross-sectional area of that sphere.
  Reference type: PR
  Reference: I31-10, 10-8.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_INV_SQ_METRE_SEC

EDCS Unit Code: 90

Symbol: 1/(m² · s)

EDCS Unit Equivalence Class Label: PARTICLE_CURRENT_DENSITY

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 4

• Quantity: current density of particles
  Definition: A vector quantity, the integral of whose normal component over any surface is equal to the net number of particles passing through that surface in a small time interval divided by that interval.
  Reference type: PR
  Reference: I31-10, 10-12.a
  Supplemental References: none
  


• Quantity: particle fluence rate (particle flux density)
  Definition: At a given point in space, the number of particles incident on a small sphere in a small time interval, divided by the cross-sectional area of that sphere and by the time interval.
  Reference type: PR
  Reference: I31-10, 10-9.a
  Supplemental References: I31-10, 10-31.a
  


• Quantity: photon exitance
  Definition: At a point on a surface, the photon flux leaving an element of the surface, divided by the area of that element and by the time interval.
  Reference type: PR
  Reference: I31-6, 6-26.a
  Supplemental References: none
  


• Quantity: photon irradiance
  Definition: At a point on a surface, the photon flux incident on an element of the surface, divided by the area of that element and by the time interval.
  Reference type: PR
  Reference: I31-6, 6-27.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_INV_STERADIAN

EDCS Unit Code: 91

Symbol: 1/sr

EDCS Unit Equivalence Class Label: RECIPROCAL_SOLID_ANGLE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: reciprocal solid angle
  Definition: The reciprocal of a solid angle of a cone is the ratio of the square of the radius of a sphere (with its centre at the apex of that cone) to the area cut out on a spherical surface.
  1 sr^-1 = 1 m²/m² = 1.
  Reference type: PR
  Reference: I31-0, 2.3.2.2 (derived)
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_INV_STERADIAN_METRE

EDCS Unit Code: 92

Symbol: 1/(sr · m)

EDCS Unit Equivalence Class Label: SPECTRAL_RECIPROCAL_SOLID_ANGLE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: spectral reciprocal solid angle
  Definition: The reciprocal of a solid angle of a cone is the ratio of the square of the radius of a sphere (with its centre at the apex of that cone) to the area cut out on a spherical surface, as a function of radiant wavelength.
  Reference type: PR
  Reference: I31-0, 2.3.2.2 (derived)
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_INV_STERADIAN_MICRON

EDCS Unit Code: 93

Symbol: 1/(sr · μm)

EDCS Unit Equivalence Class Label: SPECTRAL_RECIPROCAL_SOLID_ANGLE

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 1

• Quantity: spectral reciprocal solid angle
  Definition: The reciprocal of a solid angle of a cone is the ratio of the square of the radius of a sphere (with its centre at the apex of that cone) to the area cut out on a spherical surface, as a function of radiant wavelength.
  1/(sr · μm) = 10⁶ 1/(sr · m) (exactly).
  Reference type: PR
  Reference: I31-0, 2.3.2.2 (derived)
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_JANSKY

EDCS Unit Code: 94

Symbol: Jy

EDCS Unit Equivalence Class Label: FLUX_DENSITY

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 1

• Quantity: flux density
  Definition: The amount of a given type of radiation that crosses a specified area within a specified period.
  1 Jy = 10^-26 W/(m² · Hz) (exactly).
  Reference type: PR
  Reference: I31-0, 2.3.1
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_JOULE

EDCS Unit Code: 95

Symbol: J

EDCS Unit Equivalence Class Label: ENERGY

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 18

• Quantity: alpha disintegration energy
  Definition: The sum of the kinetic energy of the alpha particle produced in the disintegration process and the recoil energy of the product atom in the reference frame in which the emitting nucleus is at rest before its disintegration.
  Reference type: PR
  Reference: I31-9, 9-38.a
  Supplemental References: none
  


• Quantity: average energy loss per ion pair formed (average energy loss per elementary charge of the same sign produced)
  Definition: The initial kinetic energy of an ionizing charged particle, divided by the total ionization produced by that particle.
  Reference type: PR
  Reference: I31-10, 10-25.a
  Supplemental References: none
  


• Quantity: beta disintegration energy
  Definition: Sum of the maximum beta particle energy and the recoil energy of the atom produced in the reference frame in which the emitting nucleus is at rest before its disintegration.
  Reference type: PR
  Reference: I31-9, 9-40.a
  Supplemental References: none
  


• Quantity: electron affinity
  Definition: The energy difference between an electron at rest at infinity and an electron at the lowest level of the conduction band in an insulator or semiconductor.
  Reference type: PR
  Reference: I31-13, 13-26.a
  Supplemental References: none
  


• Quantity: energy
  Definition: The amount of work.
  1 J = 1 N·m = 1 (m² · kg)/s².
  Reference type: PR
  Reference: I31-0, Table 2
  Supplemental References: I31-3, 3-26.a
  


• Quantity: energy imparted
  Definition: The energy imparted by ionizing radiation to the matter in a given volume is the difference between the sum of the energies of all the directly ionizing (charged) and indirectly ionizing (uncharged) particles which have entered the volume and the sum of the energies of all those which have left it, minus the energy equivalent of any increase in rest mass that has taken place in nuclear or elementary particle reactions within the volume.
  Reference type: PR
  Reference: I31-10, 10-50.a
  Supplemental References: none
  


• Quantity: enthalpy
  Definition: Heat content.
  Reference type: PR
  Reference: I31-4, 4-20.a
  Supplemental References: none
  


• Quantity: exchange integral
  Definition: The interaction energy arising from electron exchange.
  Reference type: PR
  Reference: I31-13, 13-35.a
  Supplemental References: none
  


• Quantity: Fermi energy
  Definition: In a metal, the highest energy of occupied states at zero thermodynamic temperature.
  Reference type: PR
  Reference: I31-13, 13-28.a
  Supplemental References: none
  


• Quantity: gap energy
  Definition: Difference in energy between lowest level of conduction band and highest level of valence band.
  Reference type: PR
  Reference: I31-13, 13-28.b
  Supplemental References: none
  


• Quantity: heat (quantity of heat)
  Definition: Energy that is the result of the temperature difference between the boundary of a system and its surrounding environment.
  Reference type: PR
  Reference: I31-4, 4-6.a
  Supplemental References: none
  


• Quantity: level width
  Definition: The uncertainty in energy (full width at half maximum) of an unstable state due to the finite lifetime of the state.
  Reference type: PR
  Reference: I31-9, 9-32.a
  Supplemental References: none
  


• Quantity: maximum beta particle energy
  Definition: Maximum energy of the energy spectrum in a beta disintegration process.
  Reference type: PR
  Reference: I31-9, 9-39.a
  Supplemental References: none
  


• Quantity: mean energy imparted
  Definition: The expectation value of the energy imparted.
  Reference type: PR
  Reference: I31-10, 10-50.a
  Supplemental References: none
  


• Quantity: radiant energy
  Definition: The energy emitted, transferred or received as radiation.
  Reference type: PR
  Reference: I31-6, 6-7.a
  Supplemental References: none
  


• Quantity: reaction energy
  Definition: In a nuclear reaction, the sum of the kinetic and photon energies of the reaction products minus the sum of the kinetic and photon energies of the reactants.
  Reference type: PR
  Reference: I31-10, 10-1.a
  Supplemental References: none
  


• Quantity: resonance energy
  Definition: Kinetic energy of an incident particle, in the reference frame of the target, corresponding to a resonance in a nuclear reaction.
  Reference type: PR
  Reference: I31-10, 10-2.a
  Supplemental References: none
  


• Quantity: work function
  Definition: The energy difference between an electron at rest at infinity and an electron at the Fermi level in the interior of a substance.
  Reference type: PR
  Reference: I31-13, 13-25.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_JOULE_METRE_SQD

EDCS Unit Code: 96

Symbol: J · m²

EDCS Unit Equivalence Class Label: TOTAL_ATOMIC_STOPPING_POWER

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: total atomic stopping power
  Definition: The total linear stopping power divided by the number density of the atoms in the substance.
  1 J · m² = 1 (m⁴ · kg)/s².
  Reference type: PR
  Reference: I31-10, 10-19.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_JOULE_METRE_SQD_PER_KG

EDCS Unit Code: 97

Symbol: (J · m²)/kg

EDCS Unit Equivalence Class Label: TOTAL_MASS_STOPPING_POWER

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: total mass stopping power
  Definition: The total linear stopping power divided by the volumic mass of the substance.
  1 (J · m²)/kg = 1 m⁴/s².
  Reference type: PR
  Reference: I31-10, 10-20.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_JOULE_PER_CUBIC_M

EDCS Unit Code: 98

Symbol: J/m³

EDCS Unit Equivalence Class Label: ENERGY_DENSITY

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 3

• Quantity: radiant energy density
  Definition: The radiant energy in an element of volume, divided by that element.
  Reference type: PR
  Reference: I31-6, 6-8.a
  Supplemental References: none
  


• Quantity: sound energy density (volumic sound energy)
  Definition: The mean sound energy in a given volume divided by that volume.
  Reference type: PR
  Reference: I31-7, 7-15.a
  Supplemental References: none
  


• Quantity: volumic electromagnetic energy (electromagnetic energy density)
  Definition: The energy in an element of volume, divided by that element.
  1 J/m³ = 1 kg/(m · s²).
  Reference type: PR
  Reference: I31-5, 5-30.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_JOULE_PER_GRAM_K

EDCS Unit Code: 99

Symbol: J/(g · K)

EDCS Unit Equivalence Class Label: SPECIFIC_HEAT_CAPACITY

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 2

• Quantity: massic entropy (specific entropy)
  Definition: The heat entropy divided by mass.
  Reference type: PR
  Reference: I31-4, 4-19.a
  Supplemental References: none
  


• Quantity: massic heat capacity (specific heat capacity)
  Definition: The heat capacity divided by mass.
  1 J/(g · K) = 10³ J/(kg · K) (exactly).
  Reference type: PR
  Reference: I31-4, 4-16.a
  Supplemental References: I31-0, 2.3.2.3
  

EDCS Unit Symbolic Constant: EUC_JOULE_PER_KELVIN

EDCS Unit Code: 100

Symbol: J/K

EDCS Unit Equivalence Class Label: HEAT_CAPACITY

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 3

• Quantity: Boltzmann constant
  Definition: A constant equal to 1,38 x 10^-23 J/K, used in statistical physics.
  Reference type: PR
  Reference: I31-8, 8-37.a
  Supplemental References: none
  


• Quantity: entropy
  Definition: When a small quantity of heat dQ is received by a system the thermodynamic temperature of which is T, the entropy of the system is increased by dQ/T, provided that no irreversible change takes place in the system.
  Reference type: PR
  Reference: I31-4, 4-18.a
  Supplemental References: none
  


• Quantity: heat capacity
  Definition: The quantity dQ/dT, when the temperature of a system is increased by dT as a result of the addition of a small quantity of heat dQ.
  1 J/K = 1 (m² · kg)/(s² · K).
  Reference type: PR
  Reference: I31-4, 4-15.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_JOULE_PER_KELVIN_MOLE

EDCS Unit Code: 101

Symbol: J/(K · mol)

EDCS Unit Equivalence Class Label: MOLAR_ENTROPY

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 3

• Quantity: molar entropy
  Definition: The heat entropy divided by the amount of substance.
  Reference type: PR
  Reference: I31-8, 8-9.a
  Supplemental References: none
  


• Quantity: molar gas constant
  Definition: The universal constant of proportionality in the ideal gas law: pV_m = RT.
  Reference type: PR
  Reference: I31-8, 8-36.a
  Supplemental References: none
  


• Quantity: molar heat capacity
  Definition: The heat capacity divided by the amount of substance.
  1 J/(K · mol) = 1 (m² · kg)/(s² · K · mol).
  Reference type: PR
  Reference: I31-8, 8-8.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_JOULE_PER_KG

EDCS Unit Code: 102

Symbol: J/kg

EDCS Unit Equivalence Class Label: SPECIFIC_ENERGY

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: specific energy
  Definition: The energy divided by mass.
  1 J/kg = 1 m²/s².
  Reference type: PR
  Reference: I31-4, 4-21.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_JOULE_PER_KG_KELVIN

EDCS Unit Code: 103

Symbol: J/(kg · K)

EDCS Unit Equivalence Class Label: SPECIFIC_HEAT_CAPACITY

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 2

• Quantity: massic entropy (specific entropy)
  Definition: The heat entropy divided by mass.
  Reference type: PR
  Reference: I31-4, 4-19.a
  Supplemental References: none
  


• Quantity: massic heat capacity (specific heat capacity)
  Definition: The heat capacity divided by mass.
  1 J/(kg · K) = 1 m²/(s² · K).
  Reference type: PR
  Reference: I31-4, 4-16.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_JOULE_PER_KM

EDCS Unit Code: 104

Symbol: J/km

EDCS Unit Equivalence Class Label: LINEAR_ENERGY_TRANSFER

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 2

• Quantity: linear energy transfer
  Definition: For an ionizing charged particle, the energy imparted locally to matter in traversing a small distance through the matter, divided by that distance.
  1 J/km = 10^-3 J/m (exactly).
  Reference type: PR
  Reference: I31-10, 10-54.a
  Supplemental References: none
  


• Quantity: total linear stopping power
  Definition: For an ionizing charged particle, the energy imparted locally to matter in traversing a small distance through the matter, divided by that distance; -dE/dx.
  1 J/km = 1 x 10^-3 J/m (exactly).
  Reference type: PR
  Reference: I31-10, 10-18.a
  Supplemental References: I31-0, 2.3.2.3
  

EDCS Unit Symbolic Constant: EUC_JOULE_PER_M_FOURTH_PWR

EDCS Unit Code: 105

Symbol: J/m⁴

EDCS Unit Equivalence Class Label: SPECTRAL_RAD_ENERGY_DENSITY

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: spectral concentration of radiant energy density (in terms of wavelength)
  Definition: The radiant energy density in an infinitesimal wavelength interval, divided by the range of that interval.
  1 J/m⁴ = 1 kg/(m² · s²).
  Reference type: PR
  Reference: I31-6, 6-9.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_JOULE_PER_METRE

EDCS Unit Code: 106

Symbol: J/m

EDCS Unit Equivalence Class Label: LINEAR_ENERGY_TRANSFER

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 2

• Quantity: linear energy transfer
  Definition: For an ionizing charged particle, the energy imparted locally to matter in traversing a small distance through the matter, divided by that distance.
  1 J/m = 1 (m · kg)/s².
  Reference type: PR
  Reference: I31-10, 10-54.a
  Supplemental References: none
  


• Quantity: total linear stopping power
  Definition: For an ionizing charged particle, the energy imparted locally to matter in traversing a small distance through the matter, divided by that distance; -dE/dx.
  Reference type: PR
  Reference: I31-10, 10-18.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_JOULE_PER_MOLE

EDCS Unit Code: 107

Symbol: J/mol

EDCS Unit Equivalence Class Label: MOLAR_ENERGY

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 2

• Quantity: chemical potential
  Definition: A partial molar Gibbs free energy; the change in Gibbs free energy when one mole of a substance is added to a very large amount of a sample.
  Reference type: PR
  Reference: I31-8, 8-17.a
  Supplemental References: none
  


• Quantity: molar thermodynamic energy
  Definition: The thermodynamic energy divided by the amount of substance.
  1 J/mol = 1 (m² · kg)/(s² · mol).
  Reference type: PR
  Reference: I31-8, 8-7.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_JOULE_PER_SQ_METRE

EDCS Unit Code: 108

Symbol: J/m²

EDCS Unit Equivalence Class Label: RADIANT_ENERGY_FLUENCE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 2

• Quantity: energy fluence
  Definition: At a given point in space, the sum of the energies, exclusive of rest energy, of all the particles incident on a small sphere, divided by the cross-sectional area of that sphere.
  Reference type: PR
  Reference: I31-10, 10-10.a
  Supplemental References: none
  


• Quantity: radiant energy fluence
  Definition: At a given point in space, the radiant flux incident on a small sphere, divided by the cross-sectional area of that sphere.
  1 J/m² = 1 kg/s².
  Reference type: PR
  Reference: I31-6, 6-11.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_JOULE_SECOND

EDCS Unit Code: 109

Symbol: J · s

EDCS Unit Equivalence Class Label: PLANCK_CONSTANT

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: Planck constant
  Definition: 1 J · s = 1 (m² · kg)/s.
  Reference type: PR
  Reference: I31-9, 9-7.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_KELVIN

EDCS Unit Code: 110

Symbol: K

EDCS Unit Equivalence Class Label: THERMO_TEMPERATURE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: thermodynamic temperature
  Definition: The fraction 1 / 273,16 of the thermodynamic temperature of the triple point of water.
  SI base unit.
  Reference type: PR
  Reference: I31-0, Table 1
  Supplemental References: I31-4, 4-1.a; I31-13, 13-12.a; I31-13, 13-29.a; I31-13, 13-36.a
  

EDCS Unit Symbolic Constant: EUC_KELVIN_PER_KM

EDCS Unit Code: 111

Symbol: K/km

EDCS Unit Equivalence Class Label: LINEIC_THERMO_TEMP_GRADIENT

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 1

• Quantity: lineic thermodynamic temperature gradient
  Definition: The thermodynamic temperature difference divided by distance.
  1 K/km = 10^-3 K/m (exactly).
  Reference type: PR
  Reference: I31-0, 2.3.2.2 and 2.3.2.3 (derived)
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_KELVIN_PER_METRE

EDCS Unit Code: 112

Symbol: K/m

EDCS Unit Equivalence Class Label: LINEIC_THERMO_TEMP_GRADIENT

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: lineic thermodynamic temperature gradient
  Definition: The thermodynamic temperature difference divided by distance.
  Reference type: PR
  Reference: I31-0, 2.3.2.2 (derived)
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_KELVIN_PER_SEC

EDCS Unit Code: 113

Symbol: K/s

EDCS Unit Equivalence Class Label: THERMO_TEMP_CHANGE_RATE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: thermodynamic temperature change rate
  Definition: The thermodynamic temperature change over an interval of time, divided by that time.
  Reference type: PR
  Reference: I31-0, 2.3.2.2 and 2.3.4 (derived)
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_KELVIN_PER_WATT

EDCS Unit Code: 114

Symbol: K/W

EDCS Unit Equivalence Class Label: THERMAL_RESISTANCE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: thermal resistance
  Definition: The temperature difference divided by heat flow rate.
  1 K/W = 1 (m² · kg · K)/s³.
  Reference type: PR
  Reference: I31-4, 4-12.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_KG_METRE_PER_SEC

EDCS Unit Code: 115

Symbol: kg · m/s

EDCS Unit Equivalence Class Label: MOMENTUM

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: momentum
  Definition: The product of mass and velocity.
  Reference type: PR
  Reference: I31-3, 3-8.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_KG_METRE_SQD

EDCS Unit Code: 116

Symbol: kg · m²

EDCS Unit Equivalence Class Label: MOMENT_INERTIA

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: moment of inertia (about an axis)
  Definition: The sum (integral) of the products of the elements of mass of a body and the squares of their distances from an axis.
  Reference type: PR
  Reference: I31-3, 3-7.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_KG_METRE_SQD_PER_SEC

EDCS Unit Code: 117

Symbol: (kg · m²)/s

EDCS Unit Equivalence Class Label: ANGULAR_MOMENTUM

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: moment of momentum (angular momentum)
  Definition: The moment of momentum of a particle about a point is equal to the vector product of the radius vector from this point to the particle and the momentum of the particle.
  Reference type: PR
  Reference: I31-3, 3-11.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_KG_PER_CUBIC_METRE

EDCS Unit Code: 118

Symbol: kg/m³

EDCS Unit Equivalence Class Label: VOLUMIC_MASS

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 2

• Quantity: mass concentration (of B)
  Definition: The amount of substance of B divided by the volume of the mixture.
  Reference type: PR
  Reference: I31-8, 8-11.a
  Supplemental References: none
  


• Quantity: volumic mass (mass density)
  Definition: The mass divided by the volume.
  Reference type: PR
  Reference: I31-3, 3-2.a
  Supplemental References: I31-7, 7-8.a
  

EDCS Unit Symbolic Constant: EUC_KG_PER_KG

EDCS Unit Code: 119

Symbol: kg/kg

EDCS Unit Equivalence Class Label: MASS_FRACTION

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: mass fraction (of B)
  Definition: The mass of B divided by the mass of the mixture.
  1 kg/kg = 1.
  Reference type: PR
  Reference: I31-8, 8-12.a
  Supplemental References: I31-0, 2.3.3
  

EDCS Unit Symbolic Constant: EUC_KG_PER_LITRE

EDCS Unit Code: 120

Symbol: kg/l

EDCS Unit Equivalence Class Label: VOLUMIC_MASS

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 2

• Quantity: mass concentration (of B)
  Definition: The amount of substance of B divided by the volume of the mixture.
  Reference type: PR
  Reference: I31-8, 8-11.b
  Supplemental References: none
  


• Quantity: volumic mass (mass density)
  Definition: The mass divided by the volume.
  1 kg/l = 10^-3 kg/m³ (exactly).
  Reference type: PR
  Reference: I31-3, 3-2.c
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_KG_PER_METRE

EDCS Unit Code: 121

Symbol: kg/m

EDCS Unit Equivalence Class Label: LINEIC_MASS

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: lineic mass (linear density)
  Definition: The mass divided by length.
  Reference type: PR
  Reference: I31-3, 3-5.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_KG_PER_MOLE

EDCS Unit Code: 122

Symbol: kg/mol

EDCS Unit Equivalence Class Label: MOLAR_MASS

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: molar mass
  Definition: The mass divided by the amount of substance.
  Reference type: PR
  Reference: I31-8, 8-5.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_KG_PER_SECOND

EDCS Unit Code: 123

Symbol: kg/s

EDCS Unit Equivalence Class Label: MASS_FLOW_RATE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: mass flow rate
  Definition: The mass of matter which crosses a given surface, divided by time.
  Reference type: PR
  Reference: I31-3, 3-29.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_KG_PER_SQ_METRE

EDCS Unit Code: 124

Symbol: kg/m²

EDCS Unit Equivalence Class Label: SURFACE_DENSITY

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 2

• Quantity: areic mass (surface density)
  Definition: The mass divided by area.
  Reference type: PR
  Reference: I31-3, 3-6.a
  Supplemental References: none
  


• Quantity: mean mass range
  Definition: The mean linear range multiplied by the volumic mass of the substance.
  Reference type: PR
  Reference: I31-10, 10-22.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_KILOGRAM

EDCS Unit Code: 125

Symbol: kg

EDCS Unit Equivalence Class Label: MASS

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: mass
  Definition: The mass of the international prototype of the kilogram.
  SI base unit.
  Reference type: PR
  Reference: I31-0, Table 1
  Supplemental References: I31-3, 3-1.a; I31-8, 8-31.a; I31-9, 9-4.a; I31-9, 9-5.a; I31-9, 9-28.a; I31-13, 13-31.a
  

EDCS Unit Symbolic Constant: EUC_KILOPOUND

EDCS Unit Code: 126

Symbol: kp

EDCS Unit Equivalence Class Label: MASS

Unit Status: Deprecated

Number of quantities which this unit of measure may represent:: 1

• Quantity: mass
  Definition: 1 kip = 453,592 37 kg (exactly).
  Reference type: PR
  Reference: I31-3, 3-1.B.a
  Supplemental References: I31-0, 2.3.2.3
  

EDCS Unit Symbolic Constant: EUC_KM_PER_HOUR

EDCS Unit Code: 127

Symbol: km/h

EDCS Unit Equivalence Class Label: SPEED

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 1

• Quantity: velocity
  Definition: The distance divided by time.
  1 km/h = 1 / 3,6 m/s (exactly).
  Reference type: PR
  Reference: I31-1, 1-10.b
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_KNOT

EDCS Unit Code: 128

Symbol: kn

EDCS Unit Equivalence Class Label: SPEED

Unit Status: Deprecated

Number of quantities which this unit of measure may represent:: 1

• Quantity: velocity
  Definition: The distance divided by time.
  1 kn = 1 nautical mile per hour = 1,852 km/h = 0,514 444 m/s (exactly).
  Reference type: PR
  Reference: I31-1, 1-10.b (remarks)
  Supplemental References: I1000, Annex A, 1-10
  

EDCS Unit Symbolic Constant: EUC_LIGHT_YEAR

EDCS Unit Code: 129

Symbol: l.y.

EDCS Unit Equivalence Class Label: LENGTH

Unit Status: Deprecated

Number of quantities which this unit of measure may represent:: 1

• Quantity: length
  Definition: The distance travelled in 1 year by electromagnetic waves in free space.
  1 l.y. = 9,460 730 x 10¹⁵ m (exactly).
  Reference type: PR
  Reference: I31-1, 1-3.B.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_LITRE

EDCS Unit Code: 130

Symbol: l, L
(Both symbols are equally accepted.)

EDCS Unit Equivalence Class Label: VOLUME

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 1

• Quantity: volume
  Definition: The product of length, width, and height.
  1 l = 1 dm³ = 10^-3 m³ (exactly).
  Reference type: PR
  Reference: I31-0, Table 4
  Supplemental References: I31-1, 1-6.b
  

EDCS Unit Symbolic Constant: EUC_LITRE_PER_HOUR

EDCS Unit Code: 131

Symbol: L/h

EDCS Unit Equivalence Class Label: VOLUME_FLOW_RATE

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 1

• Quantity: volume flow rate
  Definition: The volume of matter which crosses a given surface, divided by time.
  1 L/h = 1 / 3,6 x 10^-6 m³/s (exactly).
  Reference type: PR
  Reference: I31-0, 2.3.2.2 (derived)
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_LITRE_PER_SECOND

EDCS Unit Code: 132

Symbol: L/s

EDCS Unit Equivalence Class Label: VOLUME_FLOW_RATE

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 1

• Quantity: volume flow rate
  Definition: The volume of matter which crosses a given surface, divided by time.
  1 L/s = 10^-3 m³/s (exactly).
  Reference type: PR
  Reference: I31-0, 2.3.2.2 (derived)
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_LONG_TON

EDCS Unit Code: 133

Symbol: ton (long)

EDCS Unit Equivalence Class Label: MASS

Unit Status: Deprecated

Number of quantities which this unit of measure may represent:: 1

• Quantity: mass
  Definition: 1 long ton (US) = 1 ton (UK) = 1 016,047 kg (exactly).
  Reference type: PR
  Reference: I31-3, 3-1.B.e
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_LUMEN

EDCS Unit Code: 134

Symbol: lm

EDCS Unit Equivalence Class Label: LUMINANCE_FLUX

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: luminous flux
  Definition: The rate of light emission.
  1 lm = 1 cd · sr.
  Reference type: PR
  Reference: I31-0, Table 2
  Supplemental References: I31-6, 6-30.a
  

EDCS Unit Symbolic Constant: EUC_LUMEN_HOUR

EDCS Unit Code: 135

Symbol: lm · h

EDCS Unit Equivalence Class Label: QUANTITY_LIGHT

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 1

• Quantity: quantity of light
  Definition: The time integral of luminous flux.
  1 lm · h = 3 600 lm · s (exactly).
  Reference type: PR
  Reference: I31-6, 6-31.b
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_LUMEN_PER_SQ_METRE

EDCS Unit Code: 136

Symbol: lm/m²

EDCS Unit Equivalence Class Label: LUMINANCE_EXITANCE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: luminous exitance
  Definition: At a point on a surface, the luminous flux leaving an element of the surface, divided by the area of that element.
  Reference type: PR
  Reference: I31-6, 6-33.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_LUMEN_PER_WATT

EDCS Unit Code: 137

Symbol: lm/W

EDCS Unit Equivalence Class Label: LUMINANCE_EFFICIENCY

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: luminous efficacy
  Definition: The luminous flux divided by power (radiant flux).
  1 lm/W = 1 (s³ · lm)/(m² · kg).
  Reference type: PR
  Reference: I31-6, 6-36.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_LUMEN_SECOND

EDCS Unit Code: 138

Symbol: lm · s

EDCS Unit Equivalence Class Label: QUANTITY_LIGHT

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: quantity of light
  Definition: The time integral of luminous flux.
  Reference type: PR
  Reference: I31-6, 6-31.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_LUX

EDCS Unit Code: 139

Symbol: lx

EDCS Unit Equivalence Class Label: ILLUMINANCE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: illuminance
  Definition: At a point on a surface, the luminous flux incident on an element of the surface, divided by the area of that element.
  1 lx = 1 lm/m².
  Reference type: PR
  Reference: I31-0, Table 2
  Supplemental References: I31-6, 6-34.a
  

EDCS Unit Symbolic Constant: EUC_LUX_HOUR

EDCS Unit Code: 140

Symbol: lx · h

EDCS Unit Equivalence Class Label: LIGHT_EXPOSURE

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 1

• Quantity: light exposure
  Definition: The time integral of illuminance.
  1 lx · h = 3 600 lx · s (exactly).
  Reference type: PR
  Reference: I31-6, 6-35.b
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_LUX_SECOND

EDCS Unit Code: 141

Symbol: lx · s

EDCS Unit Equivalence Class Label: LIGHT_EXPOSURE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: light exposure
  Definition: The time integral of illuminance.
  Reference type: PR
  Reference: I31-6, 6-35.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_METRE

EDCS Unit Code: 142

Symbol: m

EDCS Unit Equivalence Class Label: LENGTH

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 22

• Quantity: (instantaneous) sound particle displacement
  Definition: Instantaneous displacement of a particle in a medium from what would be its position in the absence of sound waves.
  Reference type: PR
  Reference: I31-7, 7-10.a
  Supplemental References: none
  


• Quantity: Bohr radius
  Definition: The radius of the electron orbit having the lowest energy in the Bohr atom; 0,5292 x 10^-10 m.
  Reference type: PR
  Reference: I31-9, 9-8.a
  Supplemental References: none
  


• Quantity: Burgers vector
  Definition: The vector characterizing a dislocation, i.e. the closing vector in a Burgers circuit encircling a dislocation line.
  Reference type: PR
  Reference: I31-13, 13-7.a
  Supplemental References: none
  


• Quantity: coherence length
  Definition: The distance in a superconductor over which the effect of a perturbation is appreciable.
  Reference type: PR
  Reference: I31-13, 13-39.a
  Supplemental References: none
  


• Quantity: Compton wavelength
  Definition: The wavelength associated with the mass of any particle.
  Reference type: PR
  Reference: I31-9, 9-27.a
  Supplemental References: none
  


• Quantity: diffusion length
  Definition: The mean distance that a particle travels before it is absorbed or recombines.
  Reference type: PR
  Reference: I31-13, 13-34.a
  Supplemental References: none
  


• Quantity: diffusion length
  Definition: The square root of the diffusion area.
  Reference type: PR
  Reference: I31-10, 10-41.a
  Supplemental References: none
  


• Quantity: electron radius
  Definition: The classical theoretical radius of an electron, 2,82 x 10^-15 m, obtained by equating the rest mass energy of an electron to the coulomb energy.
  Reference type: PR
  Reference: I31-9, 9-26.a
  Supplemental References: none
  


• Quantity: focal distance
  Definition: For a single thin lens, the distance from the centre of the lens to the focal point.
  Reference type: PR
  Reference: I31-6, 6-45.a
  Supplemental References: none
  


• Quantity: fundamental lattice vector
  Definition: The fundamental translation vectors for the crystal lattice.
  Reference type: PR
  Reference: I31-13, 13-1.a
  Supplemental References: none
  


• Quantity: half-thickness (half-value thickness)
  Definition: The thickness of the attenuating layer that reduces the current density of a unidirectional beam to one-half of its initial value.
  Reference type: PR
  Reference: I31-10, 10-17.a
  Supplemental References: none
  


• Quantity: lattice plane spacing
  Definition: The distance between successive lattice planes.
  Reference type: PR
  Reference: I31-13, 13-3.a
  Supplemental References: none
  


• Quantity: lattice vector
  Definition: The translation vector which maps the crystal lattice on itself.
  Reference type: PR
  Reference: I31-13, 13-1.a
  Supplemental References: none
  


• Quantity: length
  Definition: The length of the path travelled by light in vacuum during a time interval of 1 / 299 792 458 of a second.
  SI base unit.
  Reference type: PR
  Reference: I31-0, Table 1
  Supplemental References: I31-1, 1-3.a
  


• Quantity: mean free path
  Definition: For a molecule, the average distance between two successive collisions.
  Reference type: PR
  Reference: I31-8, 8-38.a
  Supplemental References: none
  


• Quantity: mean free path
  Definition: The average distance travelled by a particle between collisions with another particle in the system.
  Reference type: PR
  Reference: I31-13, 13-16.a
  Supplemental References: none
  


• Quantity: mean free path
  Definition: The average distance that particles travel between two successive specified reactions or processes.
  Reference type: PR
  Reference: I31-10, 10-39.a
  Supplemental References: none
  


• Quantity: mean linear range
  Definition: The distance that a particle penetrates in a given substance under specified conditions averaged over a group of particles having the same initial energy.
  Reference type: PR
  Reference: I31-10, 10-21.a
  Supplemental References: none
  


• Quantity: migration length
  Definition: The square root of the migration area.
  Reference type: PR
  Reference: I31-10, 10-41.a
  Supplemental References: none
  


• Quantity: nuclear radius
  Definition: The average radius of the volume in which the nuclear matter is included.
  Reference type: PR
  Reference: I31-9, 9-17.a
  Supplemental References: none
  


• Quantity: slowing-down length
  Definition: The square root of the slowing-down area.
  Reference type: PR
  Reference: I31-10, 10-41.a
  Supplemental References: none
  


• Quantity: wavelength
  Definition: The distance in the direction of propagation of a periodic wave between two successive points where at a given time the phase is the same.
  Reference type: PR
  Reference: I31-6, 6-3.a
  Supplemental References: I31-2, 2-5.a; I31-7, 7-5.a
  

EDCS Unit Symbolic Constant: EUC_METRE_FOURTH_POWER

EDCS Unit Code: 143

Symbol: m⁴

EDCS Unit Equivalence Class Label: SECOND_MOMENT_AREA

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: second moment of area (second axial moment of area)
  Definition: The second axial moment of area of a plane area (section) about an axis in its plane is the sum (integral) of the products of its elements of area and the squares of their distances from the axis or point.
  Reference type: PR
  Reference: I31-3, 3-20.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_METRE_KELVIN

EDCS Unit Code: 144

Symbol: m · K

EDCS Unit Equivalence Class Label: SECOND_RADIATION_CONSTANT

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 1

• Quantity: second radiation constant
  Definition: The constant c₂ in the expression for the spectral concentration of the radiant exitance of a full radiator (black body).
  Reference type: PR
  Reference: I31-6, 6-20.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_METRE_PER_HOUR

EDCS Unit Code: 145

Symbol: m/h

EDCS Unit Equivalence Class Label: SPEED

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 1

• Quantity: velocity
  Definition: The distance divided by time.
  1 m/h = 1 / 3,6 x 10^-3 m/s (exactly).
  Reference type: PR
  Reference: I31-1, 1-10.a
  Supplemental References: I31-0, 2.3.2.3
  

EDCS Unit Symbolic Constant: EUC_METRE_PER_SEC

EDCS Unit Code: 146

Symbol: m/s

EDCS Unit Equivalence Class Label: SPEED

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 4

• Quantity: group velocity
  Definition: The velocity of a packet of waves having different frequencies and phase velocities.
  Reference type: PR
  Reference: I31-2, 2-8.a
  Supplemental References: none
  


• Quantity: neutron speed
  Definition: The magnitude of the neutron velocity.
  Reference type: PR
  Reference: I31-10, 10-30.a
  Supplemental References: none
  


• Quantity: phase velocity
  Definition: In wave propagation, the velocity of a surface of constant phase; this would be the speed of the wave.
  Reference type: PR
  Reference: I31-2, 2-8.a
  Supplemental References: none
  


• Quantity: velocity
  Definition: The distance divided by time.
  Reference type: PR
  Reference: I31-1, 1-10.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_METRE_PER_SEC_SQD

EDCS Unit Code: 147

Symbol: m/s²

EDCS Unit Equivalence Class Label: ACCELERATION

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: acceleration
  Definition: The change in velocity divided by time.
  Reference type: PR
  Reference: I31-1, 1-11.a
  Supplemental References: I31-7, 7-12.a
  

EDCS Unit Symbolic Constant: EUC_MILE

EDCS Unit Code: 148

Symbol: mile

EDCS Unit Equivalence Class Label: LENGTH

Unit Status: Deprecated

Number of quantities which this unit of measure may represent:: 1

• Quantity: length
  Definition: 1 mile = 1 609,344 m (exactly).
  Reference type: PR
  Reference: I31-1, 1-3.A.d
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_MILE_PER_HOUR

EDCS Unit Code: 149

Symbol: mile/h

EDCS Unit Equivalence Class Label: SPEED

Unit Status: Deprecated

Number of quantities which this unit of measure may represent:: 1

• Quantity: velocity
  Definition: The distance divided by time.
  1 mile/h = 0,447 04 m/s (exactly).
  Reference type: PR
  Reference: I31-1, 1-10.A.b
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_MINUTE

EDCS Unit Code: 150

Symbol: min

EDCS Unit Equivalence Class Label: TIME

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 1

• Quantity: time
  Definition: 1 min = 60 s (exactly).
  Reference type: PR
  Reference: I31-0, Table 4
  Supplemental References: I31-1, 1-7.b
  

EDCS Unit Symbolic Constant: EUC_MINUTE_ARC

EDCS Unit Code: 151

Symbol: '

EDCS Unit Equivalence Class Label: PLANE_ANGLE

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 1

• Quantity: plane angle
  Definition: The angle between two half-lines terminating at the same point is defined as the ratio of the length of the included arc of the circle (with its centre at that point) to the radius of that circle.
  1' = (1 / 60)º = (π / 10 800) rad (exactly).
  Reference type: PR
  Reference: I31-0, Table 4
  Supplemental References: I31-1, 1-1.c
  

EDCS Unit Symbolic Constant: EUC_MINUTE_PER_CUBIC_METRE

EDCS Unit Code: 152

Symbol: min/m³

EDCS Unit Equivalence Class Label: VOLUMIC_DOSE

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 1

• Quantity: volumetric entity dose (any elementary entity: atoms, molecules, ions, electrons, other particles, or specified groups of such particles)
  Definition: The time integral of exposure to a number of molecules or particles divided by their volume.
  1 min/³ = 60 s/m³ (exactly).
  Reference type: PR
  Reference: I31-8, 8-10.a
  Supplemental References: I31-0, 2.3.2.2 (derived)
  

EDCS Unit Symbolic Constant: EUC_MOLE

EDCS Unit Code: 153

Symbol: mol

EDCS Unit Equivalence Class Label: AMOUNT_SUBSTANCE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: amount of substance
  Definition: The amount of substance in a system which contains as many elementary entities as there are atoms in 0,012 kilogram of carbon 12.
  When the mole is used, the elementary entities must be specified, and may be atoms, molecules, ions, electrons, other particles, or specified groups of such particles.
  SI base unit.
  Reference type: PR
  Reference: I31-0, Table 1
  Supplemental References: I31-8, 8-3.a
  

EDCS Unit Symbolic Constant: EUC_MOLE_PER_CUBIC_M

EDCS Unit Code: 154

Symbol: mol/m³

EDCS Unit Equivalence Class Label: CONCENTRATION

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: concentration (amount-of-substance concentration)
  Definition: The amount of substance divided by the volume of the mixture.
  Reference type: PR
  Reference: I31-8, 8-13.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_MOLE_PER_KG

EDCS Unit Code: 155

Symbol: mol/kg

EDCS Unit Equivalence Class Label: MOLALITY_SOLUTE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 2

• Quantity: ionic strength
  Definition: The mass concentration of ions in a solution.
  Reference type: PR
  Reference: I31-8, 8-46.a
  Supplemental References: none
  


• Quantity: molality of solute
  Definition: The amount of substance of solute in a solution divided by the mass of the solvent.
  Reference type: PR
  Reference: I31-8, 8-16.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_MOLE_PER_LITRE

EDCS Unit Code: 156

Symbol: mol/l, mol/L

EDCS Unit Equivalence Class Label: CONCENTRATION

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 1

• Quantity: concentration (amount-of-substance concentration)
  Definition: The amount of substance divided by the volume of the mixture.
  1 mol/l = 10³ mol/m³ (exactly).
  Reference type: PR
  Reference: I31-8, 8-13.b
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_MOLE_PER_MOLE

EDCS Unit Code: 157

Symbol: mol/mol

EDCS Unit Equivalence Class Label: MOLE_FRACTION

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: mole fraction (of B)
  Definition: The ratio of the amount of substance of B to the amount of substance of the mixture.
  1 mol/mol = 1.
  Reference type: PR
  Reference: I31-8, 8-14.a
  Supplemental References: I31-0, 2.3.3
  

EDCS Unit Symbolic Constant: EUC_NAUTICAL_MILE

EDCS Unit Code: 158

Symbol: none

EDCS Unit Equivalence Class Label: LENGTH

Unit Status: Deprecated

Number of quantities which this unit of measure may represent:: 1

• Quantity: length
  Definition: 1 nautical mile = 1 852 m (exactly).
  Reference type: PR
  Reference: I31-1, 1-3.a (remarks)
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_NEPER

EDCS Unit Code: 159

Symbol: Np

EDCS Unit Equivalence Class Label: FIELD_OR_POWER_LEVEL_DIFF

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 3

• Quantity: field quantity ratio (level difference)
  Definition: Twice the natural logarithm of a field quantity ratio.
  1 Np is the level of a field quantity when ln (F/F₀) = 1 where F and F₀ represent two amplitudes of the same kind, F₀ being a reference amplitude.
  Reference type: PR
  Reference: I31-2, 2-9.a
  Supplemental References: none
  


• Quantity: logarithmic decrement
  Definition: The product of damping coefficient and period.
  Reference type: PR
  Reference: I31-7, 7-25.a
  Supplemental References: I31-2, 2-12.a
  


• Quantity: power quantity ratio (level difference)
  Definition: The natural logarithm of a power quantity ratio.
  1 Np is the level of a power quantity when 1/2 ln (P/P₀) = 1 where P and P₀ represent two powers of the same kind, P₀ being a reference power.
  Reference type: PR
  Reference: I31-2, 2-10.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_NEPER_PER_SECOND

EDCS Unit Code: 160

Symbol: Np/s

EDCS Unit Equivalence Class Label: DAMPING_COEFFICIENT

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: damping coefficient
  Definition: The factor defining the rate of exponential amplitude decay in a periodic or acoustic system.
  Reference type: PR
  Reference: I31-7, 7-23.b
  Supplemental References: I31-2, 2-11.b
  

EDCS Unit Symbolic Constant: EUC_NEWTON

EDCS Unit Code: 161

Symbol: N

EDCS Unit Equivalence Class Label: FORCE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: force
  Definition: An external agent that causes a change in the motion of a free body, or that causes stress in a fixed body; proportional to the rate of change in momentum.
  1 N = 1 (m · kg)/s².
  Reference type: PR
  Reference: I31-0, Table 2
  Supplemental References: I31-3, 3-9.a
  

EDCS Unit Symbolic Constant: EUC_NEWTON_M_SQD_PER_KG_SQD

EDCS Unit Code: 162

Symbol: (N · m²)/kg²

EDCS Unit Equivalence Class Label: GRAVITATIONAL_FORCE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: gravitational force between two particles
  Definition: The force of attraction between massive bodies due to gravitation.
  1 N · m²/kg² = 1 m³/(kg · s²).
  Reference type: PR
  Reference: I31-3, 3-14.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_NEWTON_METRE

EDCS Unit Code: 163

Symbol: N · m

EDCS Unit Equivalence Class Label: MOMENT_FORCE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: moment of force
  Definition: Torque, the tendency of a force to cause an object to rotate about a given point.
  1 N · m = 1 (m² · kg²)/s².
  Reference type: PR
  Reference: I31-3, 3-12.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_NEWTON_METRE_SECOND

EDCS Unit Code: 164

Symbol: N · m · s

EDCS Unit Equivalence Class Label: ANGULAR_IMPULSE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: angular impulse
  Definition: The integral over time of all torques applied.
  1 N · m · s = 1 (m² · kg²)/s.
  Reference type: PR
  Reference: I31-3, 3-13.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_NEWTON_PER_METRE

EDCS Unit Code: 165

Symbol: N/m

EDCS Unit Equivalence Class Label: SURFACE_TENSION

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: surface tension
  Definition: The stretching force required to form a liquid film, tending to minimize the area of a surface; equal to the surface energy of the liquid per unit length of the film at equilibrium.
  1 N/m = 1 kg/s².
  Reference type: PR
  Reference: I31-3, 3-25.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_NEWTON_PER_SQ_M

EDCS Unit Code: 166

Symbol: N/m²

EDCS Unit Equivalence Class Label: PRESSURE

Unit Status: Accepted

Number of quantities which this unit of measure may represent:: 8

• Quantity: fugacity (in a gaseous mixture)
  Definition: A function substituting for pressure, allowing a real gas system to be considered by the same equations that apply to an ideal gas.
  Reference type: PR
  Reference: I31-8, 8-20.a
  Supplemental References: none
  


• Quantity: instantaneous sound pressure
  Definition: The difference between the instantaneous total pressure and the static pressure.
  Reference type: PR
  Reference: I31-7, 7-9.a
  Supplemental References: none
  


• Quantity: modulus of elasticity
  Definition: The stress per unit elastic strain, expressed as a ratio between the stress placed on a material and the strain, or dimensional response to stress.
  Reference type: PR
  Reference: I31-3, 3-18.a
  Supplemental References: none
  


• Quantity: osmotic pressure
  Definition: The excess pressure required to maintain osmotic equilibrium between a solution and the pure solvent separated by a membrane permeable only to the solvent.
  Reference type: PR
  Reference: I31-8, 8-26.a
  Supplemental References: none
  


• Quantity: partial pressure (of B, in a gaseous mixture)
  Definition: For a gaseous mixture, p_B = x_B·p, where p is the pressure.
  Reference type: PR
  Reference: I31-8, 8-19.a
  Supplemental References: none
  


• Quantity: pressure
  Definition: The force divided by the area over which it is applied.
  Reference type: PR
  Reference: I31-3, 3-15.a
  Supplemental References: none
  


• Quantity: pressure
  Definition: The force that is exerted per unit area.
  1 N/m² = 1 Pa = 1 kg/(m · s²).
  Reference type: PR
  Reference: I31-0, Table 2
  Supplemental References: none
  


• Quantity: static pressure
  Definition: The pressure that would exist in the absence of sound waves.
  Reference type: PR
  Reference: I31-7, 7-9.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_NEWTON_SECOND

EDCS Unit Code: 167

Symbol: N · s

EDCS Unit Equivalence Class Label: IMPULSE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: impulse
  Definition: A vector quantity given by the integral over time of the force acting on a body, usually in a collision in which the time interval is very brief; it is equal to the change in the momentum of the body.
  1 N · s = 1 (m · kg)/s.
  Reference type: PR
  Reference: I31-3, 3-10.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_NEWTON_SECOND_PER_METRE

EDCS Unit Code: 168

Symbol: (N · s)/m

EDCS Unit Equivalence Class Label: MECHANICAL_IMPEDANCE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: mechanical impedance
  Definition: At a surface (or at a point), the complex representation of total force divided by the complex representation of average particle velocity at that surface (or of particle velocity at that point) in the direction of the force.
  1 (N · s)/m = 1 kg/s.
  Reference type: PR
  Reference: I31-7, 7-19.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_OCTAVE

EDCS Unit Code: 169

Symbol: none

EDCS Unit Equivalence Class Label: FREQUENCY_INTERVAL

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: frequency interval
  Definition: The numerical value of a frequency interval in octaves is given by lb (f₂/f₁), when f₂ is greater than f₁.
  Reference type: PR
  Reference: I31-7, 7-3.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_OHM

EDCS Unit Code: 170

Symbol: Ω

EDCS Unit Equivalence Class Label: RESISTANCE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: electrical resistance
  Definition: The electric potential difference divided by current when there is no electromotive force in the conductor.
  1 Ω = 1 V/A = 1 (m² · kg)/(s³ · A²).
  Reference type: PR
  Reference: I31-0, Table 2
  Supplemental References: I31-5, 5-33.a; I31-5, 5-44.a
  

EDCS Unit Symbolic Constant: EUC_OHM_METRE

EDCS Unit Code: 171

Symbol: Ω · m

EDCS Unit Equivalence Class Label: RESISTIVITY

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 2

• Quantity: residual resistivity
  Definition: For metals, the resistivity extrapolated to zero thermodynamic temperature.
  Reference type: PR
  Reference: I31-13, 13-18.a
  Supplemental References: none
  


• Quantity: resistivity
  Definition: The inherent ability of a material to resist current flow.
  1 Ω · m = 1 (m³ · kg)/(s³ · A²).
  Reference type: PR
  Reference: I31-5, 5-36.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_PARSEC

EDCS Unit Code: 172

Symbol: pc

EDCS Unit Equivalence Class Label: LENGTH

Unit Status: Deprecated

Number of quantities which this unit of measure may represent:: 1

• Quantity: length
  Definition: The distance at which 1 astronomical unit subtends an angle of 1 second of arc.
  1 pc = 206 264,8 AU = 30,856 78 x 10¹⁵ m (exactly).
  Reference type: PR
  Reference: I31-1, 1-3.B.c
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_PASCAL

EDCS Unit Code: 173

Symbol: Pa

EDCS Unit Equivalence Class Label: PRESSURE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 8

• Quantity: fugacity (in a gaseous mixture)
  Definition: A function substituting for pressure, allowing a real gas system to be considered by the same equations that apply to an ideal gas.
  Reference type: PR
  Reference: I31-8, 8-20.a
  Supplemental References: none
  


• Quantity: instantaneous sound pressure
  Definition: Difference between the instantaneous total pressure and the static pressure.
  Reference type: PR
  Reference: I31-7, 7-9.a
  Supplemental References: none
  


• Quantity: modulus of elasticity
  Definition: The stress per unit elastic strain, expressed as a ratio between the stress placed on a material and the strain, or dimensional response to stress.
  Reference type: PR
  Reference: I31-7, 7-9.a
  Supplemental References: none
  


• Quantity: osmotic pressure
  Definition: The excess pressure required to maintain osmotic equilibrium between a solution and the pure solvent separated by a membrane permeable only to the solvent.
  Reference type: PR
  Reference: I31-8, 8-26.a
  Supplemental References: none
  


• Quantity: partial pressure (of B, in a gaseous mixture)
  Definition: For a gaseous mixture, p_B = x_B·p, where p is the pressure.
  Reference type: PR
  Reference: I31-8, 8-19.a
  Supplemental References: none
  


• Quantity: pressure
  Definition: The force divided by the area over which it is applied.
  Reference type: PR
  Reference: I31-3, 3-18.a
  Supplemental References: none
  


• Quantity: pressure
  Definition: The force that is exerted per unit area.
  1 Pa = 1 N/m² = 1 kg/(m · s²).
  Reference type: PR
  Reference: I31-0, Table 2
  Supplemental References: I31-3, 3-15.a
  


• Quantity: static pressure
  Definition: The pressure that would exist in the absence of sound waves.
  Reference type: PR
  Reference: I31-7, 7-9.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_PASCAL_PER_KELVIN

EDCS Unit Code: 174

Symbol: Pa/K

EDCS Unit Equivalence Class Label: PRESSURE_COEFFICIENT

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: pressure coefficient
  Definition: The fractional change in the pressure of a gas sample divided by the fractional change in the temperature under specified conditions, such as constant volume.
  1 Pa/K = 1 kg/(m · s² · K).
  Reference type: PR
  Reference: I31-4, 4-4.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_PASCAL_PER_SEC

EDCS Unit Code: 175

Symbol: Pa/s

EDCS Unit Equivalence Class Label: PRESSURE_CHANGE_RATE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: pressure change rate
  Definition: The rate of change in force is exerted per unit area.
  1 Pa/s = 1 kg/(m · s³).
  Reference type: PR
  Reference: I31-0, 2.3.2.2 (derived)
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_PASCAL_SEC

EDCS Unit Code: 176

Symbol: Pa · s

EDCS Unit Equivalence Class Label: DYNAMIC_VISCOSITY

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: dynamic viscosity
  Definition: The constant of proportionality of the rate of deformation of a Newtonian fluid, directly proportional to the applied shear stress.
  1 Pa · s = 1 kg/(m · s).
  Reference type: PR
  Reference: I31-3, 3-23.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_PASCAL_SEC_PER_CUBIC_METRE

EDCS Unit Code: 177

Symbol: (Pa · s)/m³

EDCS Unit Equivalence Class Label: ACOUSTIC_IMPEDANCE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: acoustic impedance
  Definition: At a surface, the complex representation of sound pressure divided by the complex representation of volume flow rate.
  1 (Pa · s)/m³ = 1 kg/(m⁴ · s).
  Reference type: PR
  Reference: I31-7, 7-18.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_PASCAL_SEC_PER_METRE

EDCS Unit Code: 178

Symbol: (Pa · s)/m

EDCS Unit Equivalence Class Label: SURFACE_DENSITY_MECH_IMPED

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: characteristic impedance of a medium
  Definition: At a point in a medium and for a plane progressive wave, the complex representation of sound pressure divided by the complex representation of particle velocity.
  1 (Pa · s)/m = 1 kg/(m² · s).
  Reference type: PR
  Reference: I31-7, 7-20.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_PERCENT

EDCS Unit Code: 179

Symbol: %

EDCS Unit Equivalence Class Label: PURE_NUMBER

Unit Status: Deprecated

Number of quantities which this unit of measure may represent:: 1

• Quantity: special (pure number)
  Definition: 1% = 0,01 x 1 (often omitted).
  Reference type: PR
  Reference: I31-0, 2.3.3
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_PHON

EDCS Unit Code: 180

Symbol: none

EDCS Unit Equivalence Class Label: LOUDNESS_LEVEL

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: loudness level
  Definition: 1 phon is the loudness level when 2 lb (p_eff/p₀)_{1 kHz} = 0,1, where p_eff is the root-mean-square value of the sound pressure of a pure tone of 1 kHz, which is judged by a normal observer under standardized listening conditions as being as loud as the sound under investigation, and where p₀ = 20 μPa.
  Reference type: PR
  Reference: I31-7, 7-31.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_PPB_MASS_FRACTION

EDCS Unit Code: 181

Symbol: none

EDCS Unit Equivalence Class Label: MASS_FRACTION

Unit Status: Deprecated

Number of quantities which this unit of measure may represent:: 1

• Quantity: mass fraction (of B)
  Definition: The mass of B divided by the mass of the mixture.
  1 x 10^-9 kg/kg (exactly).
  Reference type: PR
  Reference: I31-8, 8-12.a
  Supplemental References: I31-0, 2.3.3
  

EDCS Unit Symbolic Constant: EUC_PPM_MASS_FRACTION

EDCS Unit Code: 182

Symbol: none

EDCS Unit Equivalence Class Label: MASS_FRACTION

Unit Status: Deprecated

Number of quantities which this unit of measure may represent:: 1

• Quantity: mass fraction (of B)
  Definition: The mass of B divided by the mass of the mixture.
  1 x 10^-6 kg/kg (exactly).
  Reference type: PR
  Reference: I31-8, 8-12.a
  Supplemental References: I31-0, 2.3.3
  

EDCS Unit Symbolic Constant: EUC_PPT_MASS_FRACTION

EDCS Unit Code: 183

Symbol: none

EDCS Unit Equivalence Class Label: MASS_FRACTION

Unit Status: Deprecated

Number of quantities which this unit of measure may represent:: 1

• Quantity: mass fraction (of B)
  Definition: The mass of B divided by the mass of the mixture.
  1 x 10^-12 kg/kg (exactly).
  Reference type: PR
  Reference: I31-8, 8-12.a
  Supplemental References: I31-0, 2.3.3
  

EDCS Unit Symbolic Constant: EUC_PPTH_MASS_FRACTION

EDCS Unit Code: 184

Symbol: none

EDCS Unit Equivalence Class Label: MASS_FRACTION

Unit Status: Deprecated

Number of quantities which this unit of measure may represent:: 1

• Quantity: mass fraction (of B)
  Definition: The mass of B divided by the mass of the mixture.
  1 x 10^-3 kg/kg (exactly).
  Reference type: PR
  Reference: I31-8, 8-12.a
  Supplemental References: I31-0, 2.3.3
  

EDCS Unit Symbolic Constant: EUC_RAD

EDCS Unit Code: 185

Symbol: rd

EDCS Unit Equivalence Class Label: ABSORBED_DOSE

Unit Status: Deprecated

Number of quantities which this unit of measure may represent:: 1

• Quantity: absorbed dose of ionizing radiation
  Definition: For any ionizing radiation, the energy imparted to an element of irradiated matter divided by the mass of this element.
  1 rad = 1 cGy = 10^-2 Gy (exactly).
  Reference type: PR
  Reference: I31-10, 10-51.a (remarks)
  Supplemental References: I1000, Annex A, 10-51.2
  

EDCS Unit Symbolic Constant: EUC_RADIAN

EDCS Unit Code: 186

Symbol: rad

EDCS Unit Equivalence Class Label: PLANE_ANGLE

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 3

• Quantity: angle of optical rotation
  Definition: Angle through which plane-polarized light is rotated clockwise, as seen when facing the light source, in passing through an optically active medium.
  Reference type: PR
  Reference: I31-8, 8-51.a
  Supplemental References: none
  


• Quantity: phase difference
  Definition: The relative angular displacement between a periodic quantity and a reference angle or between two sinusoidally varying quantities of identical frequencies.
  Reference type: PR
  Reference: I31-5, 5-43.a
  Supplemental References: none
  


• Quantity: plane angle
  Definition: The angle between two half-lines terminating at the same point is defined as the ratio of the length of the included arc of the circle (with its centre at that point) to the radius of that circle.
  1 rad = 1 m/m = 1
  A complete angle (full circle) is 2π rad.
  Reference type: PR
  Reference: I31-0, Table 2
  Supplemental References: I31-1, 1-1.a
  

EDCS Unit Symbolic Constant: EUC_RADIAN_PER_METRE

EDCS Unit Code: 187

Symbol: rad/m

EDCS Unit Equivalence Class Label: ANGULAR_REPETENCY

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: angular repetency (angular wave number)
  Definition: The reciprocal of the wavelength or the number of waves per unit angle along the direction of propagation.
  Reference type: PR
  Reference: I31-2, 2-7.a
  Supplemental References: I31-6, 6-5.a; I31-7, 7-7.a; I31-13, 13-10.a
  

EDCS Unit Symbolic Constant: EUC_RADIAN_PER_SEC

EDCS Unit Code: 188

Symbol: rad/s

EDCS Unit Equivalence Class Label: ANGULAR_VELOCITY

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 4

• Quantity: angular frequency
  Definition: The frequency of rotation or vibration.
  Reference type: PR
  Reference: I31-2, 2-4.a
  Supplemental References: I31-5, 5-42.a; I31-7, 7-4.a
  


• Quantity: angular frequency
  Definition: The number of cycles or revolutions divided by time.
  Reference type: PR
  Reference: I31-6, 6-2.a
  Supplemental References: I31-9, 9-14.a; I31-9, 9-15.a; I31-13, 13-11.a
  


• Quantity: angular velocity
  Definition: The change in angular position divided by time.
  Reference type: PR
  Reference: I31-1, 1-8.a
  Supplemental References: none
  


• Quantity: pulsatance
  Definition: The angular velocity of a periodic quantity.
  Reference type: PR
  Reference: I31-2, 2-4.a
  Supplemental References: I31-5, 5-42.a; I31-7, 7-4.a
  

EDCS Unit Symbolic Constant: EUC_RADIAN_PER_SEC_SQD

EDCS Unit Code: 189

Symbol: rad/s²

EDCS Unit Equivalence Class Label: ANGULAR_ACCELERATION

Unit Status: Recommended

Number of quantities which this unit of measure may represent:: 1

• Quantity: angular acceleration
  Definition: The change in angular velocity divided by time.
  Reference type: PR
  Reference: I31-1, 1-9.a
  Supplemental References: none
  

EDCS Unit Symbolic Constant: EUC_REM

EDCS Unit Code: 190

Symbol: rem

EDCS Unit Equivalence Class Label: DOSE_EQUIVALENT

Unit Status: Deprecated

Number of quantities which this unit of measure may represent:: 1

• Quantity: dose equivalent of ionizing radiation
  Definition: The product of D, Q and N, at the point of interest in tissue, where D is the absorbed dose, Q is the quality factor and N is the product of any other modifying factors.
  1 rem = 1 cSv = 10^-2 Sv (exactly).
  Reference type: PR
  Reference: I31-10, 10-52.a (remarks)
  Supplemental References: I1000, Annex A, 10-52
  

EDCS Unit Symbolic Constant: EUC_ROENTGEN

EDCS Unit Code: 191

Symbol: R

EDCS Unit Equivalence Class Label: EXPOSURE

Unit Status: Deprecated

Number of quantities which this unit of measure may represent:: 1