ISO 31 Quantities and Units

The ISO 31 standard developed by the International Standards Organization (ISO) consists of the following subsections under the main heading of "Quantities and units":

• ISO 31-0 Part 0 General principles
• ISO 31-1 Part 1: Space and time
• ISO 31-2 Part 2: Periodic and related phenomena
• ISO 31-3 Part 3: Mechanical
• ISO 31-4 Part 4: Heat
• ISO 31-5 Part 5: Electricity and magnetism
• ISO 31-6 Part 6: Light and related electromagnetic radiations
• ISO 31-7 Part 7: Acoustics
• ISO 31-8 Part 8: Physical chemistry and molecular physics
• ISO 31-9 Part 9: Atom and nuclear physics
• ISO 31-10 Part 10: Nuclear reactions and ionizing radiations
• ISO 31-11 Part 11: Mathematical signs and symbols for use in the physical sciences and technology
• ISO 31-12 Part 12: Characteristic numbers
• ISO 31-13 Part 13: Solid state physics

The ISO 31-0 standard provides general information on the principles of the international system of units (SI), including recommendations for physical quantities, equations, quantity and unit symbols, and consistent units of units, particularly the printing of symbols and numbers. Annexes to this standard include:

• A guide to terms used in names for physical quantities (Annex A)
• A guide to rounding numbers (Appendix B)
• An annex (Annex C) containing international organizations in the field of quantities and units

The ISO 31-1 standard describes symbols and definitions for 21 quantities and units for space and time. Where appropriate, conversion factors are also defined in this standard. Annexes to this standard include:

• Units in feet, pounds and seconds and some other units (Appendix A)
• Other non-SI units given specifically for information on conversion factor (Annex B)

The ISO 31-2 standard describes symbols and definitions for 17 quantities and units for periodic and related phenomena. Where appropriate, conversion factors are also defined in this standard.

The ISO 31-3 standard describes symbols and definitions for 38 quantities and units for mechanics. Where appropriate, conversion factors are also defined in this standard. Annexes to this standard include:

• Units in feet, pounds and seconds and some other units (Appendix A)
• Other units given for information specifically on conversion factor (Annex B)

The ISO 31-4 standard describes symbols and definitions for 43 quantities and units for heat. Where appropriate, conversion factors are also defined in this standard. Annexes to this standard include:

• Units with proper names in the centimeter-gram-second unit (CGS) system (Annex A)
• In feet, pounds and seconds, and some other units (Appendix B)
• Other units given for information specifically on conversion factor (Annex C)

The ISO 31-5 standard describes names and symbols for 70 quantities and units. Where appropriate, conversion factors are also defined in this standard. Annexes to this standard include:

• Three-dimensional equations and quantities (Gaussian quantities) (Appendix A)
• Examples of relationships in different systems of equations (Appendix B)

The ISO 31-6 standard describes the names, symbols and definitions of 57 quantities and units of light and related electromagnetic radiations. Where appropriate, conversion factors are also defined in this standard.

The ISO 31-7 standard describes symbols and definitions for 39 quantities and units for acoustics. Where appropriate, conversion factors are also defined in this standard.

The ISO 31-8 standard describes quantities and units in various fields of science and technology.

The ISO 31-9 standard describes the names, symbols and definitions of 51 quantities and units related to atomic and nuclear physics. Where appropriate, conversion factors are also defined in this standard. Annexes to this standard include:

• Symbol names of chemical elements (Annex A)
• Notation of symbols for chemical elements and nuclides (Annex B)
• The original names and symbols of the nuclides of the radioactive series (Annex C)
• Examples of relationships to different systems of equations using different unit systems (Annex D)

The ISO 31-10 standard describes names and symbols for 70 quantities and units related to nuclear reactions and ionizing radiations. Where appropriate, conversion factors are also defined in this standard.

The ISO 31-11 standard explains the meanings of mathematical signs and symbols used in physical sciences and technology, their verbal equivalents, printing, representation and applications of scalars, vectors and tensors.

The ISO 31-12 standard describes names, symbols and definitions for 25 selected characteristic numbers used to describe transmission phenomena.

The ISO 31-13 standard describes the names, symbols and definitions of 62 quantities and units related to solid state physics. Where appropriate, conversion factors are also defined in this standard.

The ISO 31 standard was later replaced by the "ISO 80000 Quantities and units" standard.

Our organization also provides testing services for quantities and units within the scope of ISO 31 standard, with its trained and expert staff and advanced technological equipment, among the numerous test, measurement, analysis and evaluation studies it provides for businesses in various sectors.