Conversion of units

After the SI (International System of Units) units of physical quantities should preferably be used in this unit system. But has other, explained in the following units use.

• 2.1 surface
• 2.2 mass
• 2.3 Pressure
• 2.4 Energy
• 2.5 performance
• 2.6 power of optical systems
• 2.7 Length-related mass
• 2.8 Dimensionless variables
• 2.9 Exceptions in the UK and Ireland 2.9.1 length
• 2.9.2 volume
• 2.9.3 mass

• 3.1 surface
• 3.2 mass
• 3.3 Sound pressure level

• 4.1 length
• 4.2 Area
• 4.3 volume
• 4.4 mass
• 4.5 Time and time-related variables
• 4.6 temperature
• 4.7 energy
• 4.8 performance
• 4.9 Dimensionless variables

For use with the SI -approved non-SI units

Chapter 4 of the so-called SI brochure lists units that are not part of the SI, but can be used together with him. The following examples of such units are arranged according to the respective associated magnitude. Some of these units can be used together with SI prefixes ( such as " kilo" or " milli ").

Surface

• Hectares ( ha):

The ( or hectares) is in Germany, Austria and Switzerland - there with the unit name " hectares " - a legal unit for specifying the area of land and parcels, so no general statutory unit area. According to the EEC Directive ( 80/181/EEC ) on the other hand is " hectare" is merely a specific name for a hundred times the Ar. According to the general rules for the formation of multiples of units with SI prefixes the name of this unit " Hektoar " would be. From Ar more decimal multiples and parts with the help of SI intentions may be formed.

Volume

• Liters ( l or L):

Mass

• Ton ( t):

Time

• Minutes (min), hour (h) and days (d):

The use of SI prefixes with these three time units is not permitted by SI brochure. The year is not mentioned in the SI brochure as an accepted unit, but is in general use, even in legal texts, such as when specifying time runs for dates and deadlines.

Dimensionless variables

• Degrees (°) with angular minute (') and arcsecond ( " ), as well as the Gon (formerly grads) ( gon) for the plane angle:

Other legal non-SI units in the European Union

Other units outside the SI are according to Directive 80/181/EEC by the unit and Regulation in Austria dimensions and measures legislation was implemented in Germany by that legal units.

Surface

• Ar ( a):

• Barn (b):

Mass

• Atomic mass unit ( u)

• Metric carat = 0.2 g

Pressure

• Bar (bar) and millimeters of mercury - (mmHg ):

Energy

• Electron volt (eV ):

Performance

• Volt-amperes (VA) and Var ( var):

Power of optical systems

• Diopters ( dpt ):

Length-related mass

• Tex ( tex):

Dimensionless variables

• Full angle:

• Cable ( B) and Napier (Np)

• Phon and Sone ( sone )

Exceptions in the UK and Ireland

Other non-SI units are consistently valid for specific uses in those EU Member States where they were authorized on 21 April 1973. These are some Anglo-American units in the UK and Ireland:

Length

For lengths on road signs and in the distance and speed measurement:

• Mile ( mile):

• Yard (yd ):

• Foot (ft):

• Inch ( in ):

Volume

For volume details the serving of beer and cider on tap as well as for milk in returnable containers:

• Pint (pt):

Mass

For mass information in the trading of precious metals:

• Troy ounce, troy ounce (oz tr):

Other legal non-SI units in Switzerland

Largely Swiss units Ordinance of 23 November 1994 following the European regulation. However, there are the following differences:

Surface

• Are ( a) and hectare (ha):

Mass

• Metric carat (ct):

SPL

Non-SI units is discouraged their use

In general, but also in the technical language usage, partly some units or unit characters are used that are not or only partially compliant with the International System of Units. Therefore, the SI brochure advises against their use. Some sorted by size associated Examples of such units are:

Length

• Inches ( " ), eg, for specifying the diagonal of screens or the diameter of car or bike rims as well as hard drives and storage media, often in the context of American products:

• Astronomical unit ( abbreviated AU, internationally for AU Astronomical Unit)

• Light-year ( ly, ly ) with light second light minute light-hour light-day and

Surface

• Square place m² (abbreviation for square feet, out of date)
• Square inch, Square foot and Acre in Anglo-Saxon

Volume

• Cc instead of cc ( abbreviation for cubic centimeter, obsolete)
• Cbm instead m³ (abbr. for cubicmeter, obsolete)
• Cubic meters (Fm ) and cubic meters (Rm) instead of m3, the volume of long wood or plywood ( legal units to 1977 )
• Gallon and barrel in Anglo-Saxon countries, especially in gasoline and petroleum

Mass

• Kilos instead of pounds
• Hekto instead of Hg (especially in Italy)
• Deka instead decagram (especially in Austria, Hungary and the Czech Republic )
• Further use of the pound and the hundredweight (in the sense of 0.5 kg and 50 kg, the latter in Switzerland, Austria and Russia, 100 kg)

Time and time-related variables

• Superscript h, m and s for the specification of time points in hours, minutes and seconds (from midnight) in a time scale; this spelling was in DIN 1355 period, output in January 1943 recommended.
• M instead of minutes for the unit of time minute; also this spelling was from 1943 to recommended in DIN 1355, " when there is no confusion with m (meters ) is possible."
• Mph instead of km / h (speed unit )
• Kilometers per hour instead of kilometers per hour km / h
• " Auxiliary word / time unit " instead of specifying frequencies in the unit 1 / s or s -1 Umin, rpm, rpm, but also V / min, instead of " speed in 1/min or min-1 "
• Flops, but also flop / s ( floating-point operations per second )
• Mips, but also Wed / s ( mega instructions per second ), would correct " number of instructions in 10-6 seconds "

Temperature

• Shortening of " degrees Celsius" to " degrees "; the degree (° ) is a unit of plane angle and the old unit degrees ( deg ) for temperature differences.
• The obsolete term " degree Kelvin " for " Kelvin ".

Energy

• In the food sector, the calorific value of food still in calories ( cal) or kilocalories ( kcal) is specified.

Performance

• The use of HP ( horsepower ) is spread instead of watt (kilo ) particularly in motor vehicles. In the SI, however, the PS unit signs of Petasiemens.

Dimensionless variables

• Generally accepted is the indication of pieces (pcs, pcs. ) In terms of a dimensionless size quantities.
• Other pieces Measures such as the dozen = 12 pieces
• Ppb for "parts per billion" and ppt for " parts per trillion " or "parts per thousand ". Since the significance of the number and name trillion trillion is not the same in all languages ​​, it is inadvisable to use these terms or abbreviations.