Table 7.1 -- Table of contents
This International Standard uses EDCS units to characterize the values of physical quantities and conforms to the International System of Units as defined in [I31]. Within the EDCS Unit Dictionary, each EU has a unique definition and is denoted by both a unique EUL and a unique EUC.
The EDCS Unit Dictionary is presented in four tables: two tables of EUs derived from SI (ordered alphabetically by EUL), one table of EUs outside the scope of SI, and one table of deprecated EUs. Within each table, the EUs are ordered alphabetically by the EUL.
This International Standard uses EDCS unit scales to provide scaling information for use in conjunction with EUs. Within the EDCS Unit Scale Dictionary, each ES has a unique definition and is denoted by both a unique ESL and a unique ESC.
The EDCS Unit Scale Dictionary is presented in two tables with the ESs ordered by the value of the multiplicative constant (scale factor).
This International Standard defines EDCS unit equivalence classes that are sets of units of measure that are equivalent in the sense that they characterize the same physical quantity. Within the EDCS Unit Equivalence Class Dictionary, each EQ has a unique definition and is denoted by both a unique EQL and a unique EQC.
The EDCS Unit Equivalence Class Dictionary is presented in three tables ordered alphabetically. Within each table, the EQs are ordered alphabetically by the EQL.
The EDCS Unit Dictionary is presented in Table 7.5 through Table 7.7, and in Table B.1. The specification of each field of an EDCS Unit Dictionary entry is presented in Table 7.3. Units of measure whose use is deprecated are presented separately in Table B.1. All references in the EDCS Unit Dictionary are prescriptive references except for those in Table 7.7, therefore the reference type field is omitted in these EDCS dictionary entries.
An EU may have more than one quantity. When this is the case, the quantity, definition, and references fields are repeated for each quantity.
Table 7.3 -- EDCS Unit Dictionary entry fields
Field | Specification | Location |
Label |
The EUL (see 4.3.2 Label). | Clause 7 |
Symbol |
The symbol for the EU. If an EU has no symbol, "none" is entered in this field. | Clause 7 |
Quantity | The quantity associated with the EU; additional synonymous quantities may be included parenthetically. | Clause 7 |
Definition | The definition of the EU, including any value in terms of SI base units if the symbol is not already in terms of SI base units. | Clause 7 |
EQ label |
The EQL (see 4.10 EDCS unit equivalence classes). | Clause 7 |
Code |
The EUC (see 4.3.3 Code). | Clause 7 |
References |
The references for this EU (see 4.3.4 References and reference type). For EUs within the scope of SI, either this field contains a reference to the part of [I31] where this unit is defined or this field contains an explanation of its derivation from units defined in [I31]. | Clause 7 |
In Table 7.5 through Table 7.7 and in Table B.1, the notation "re" means "referenced to." For example: "dB (re 1 μPa)" means "decibels referenced to one (1) microPascal."
Table 7.4 -- EDCS Unit Dictionary tables
The EDCS Unit Scale Dictionary is presented in Table 7.9 and Table 7.10 with its EDCS dictionary entries ordered by the value of the multiplicative constant (scale factor). The specification of each field of an EDCS Unit Scale Dictionary entry is presented in Table 7.8. All references in the EDCS Unit Scale Dictionary are prescriptive references, therefore the reference type field is omitted in these EDCS dictionary entries.
Table 7.8 -- EDCS Unit Scale Dictionary entry fields
Field | Specification | Location |
Label |
The ESL (see 4.3.2 Label). | Clause 7 |
Symbol |
The symbol for the ES. | Clause 7 |
Definition | The multiple or submultiple factor of the ES. | Clause 7 |
Code |
The ESC (see 4.3.3 Code). | Clause 7 |
All entries in Table 7.9 are normatively referenced to [I31-0, Table 4].
Table 7.9 -- Unit Scale Dictionary for powers of 10
Label | Symbol | Definition | Code |
YOTTA | Y | 1024 | 1 |
ZETTA | Z | 1021 | 2 |
EXA | E | 1018 | 3 |
PETA | P | 1015 | 4 |
TERA | T | 1012 | 5 |
GIGA | G | 109 | 6 |
MEGA | M | 106 | 7 |
KILO | k | 103 | 8 |
HECTO | h | 102 | 9 |
DECA | da | 101 | 10 |
UNI | 1 | 100 | 11 |
DECI | d | 10-1 | 12 |
CENTI | c | 10-2 | 13 |
MILLI | m | 10-3 | 14 |
MICRO | μ | 10-6 | 15 |
NANO | n | 10-9 | 16 |
PICO | p | 10-12 | 17 |
FEMTO | f | 10-15 | 18 |
ATTO | a | 10-18 | 19 |
ZEPTO | z | 10-21 | 20 |
YOCTO | y | 10-24 | 21 |
All entries in Table 7.10 are normatively referenced to [I60027].
Table 7.10 -- Unit Scale Dictionary for powers of 210
Label | Symbol | Definition | Code |
KIBI | Ki | 210 | 22 |
MEBI | Mi | 220 | 23 |
GIBI | Gi | 230 | 24 |
TEBI | Ti | 240 | 25 |
PEBI | Pi | 250 | 26 |
EXBI | Ei | 260 | 27 |
The EDCS Unit Equivalence Class Dictionary is presented in Tables 7.13 through 7.15. The specification of each field of an EDCS Unit Equivalence Class Dictionary entry is presented in Table 7.11. All references in the EDCS Unit Equivalence Dictionary are dictionary references, therefore the reference type and references fields are omitted in these EDCS dictionary entries.
Table 7.11 -- EDCS Unit Equivalence Class Dictionary entry fields
Field | Specification | Location |
Label |
The EQL (see 4.3.2 Label). | Clause 7 |
Definition | The definition of the quantity of which the members of this EQ are called "quantities of the same kind" [I31-0]. | Clause 7 |
Equivalence class membership |
The list of EULs that are members of the EQ. The labels of EUs that are part of the International System of Units are shown in bold. The labels of EUs that are deprecated units (see Annex B) are shown in italics. The remaining EUs are those based on units used with the SI. |
Clause 7 |
Code |
The EQC (see 4.3.3 Code). | Clause 7 |
Table 7.12 -- EDCS Unit Equivalence Class Dictionary tables
http://www.iso.ch/iso/en/ittf/PubliclyAvailableStandards/ISO_IEC_18025_Ed1.html