- In June 2011, the Burmese government's Ministry of Commerce began discussing proposals to reform the measurement system in Burma and adopt the metric system used by most of its trading partners.
The "Big-Bang" way is to simultaneously outlaw the use of pre-metric measurement, metricate, reissue all government publications and laws, and change education systems to metric. India's changeover lasted from 1 April 1960, when metric measurements became legal, to 1 April 1962, when all other systems were banned. The Indian model was extremely successful and was copied over much of the developing world.
The phase-in way is to pass a law permitting the use of metric units in parallel with traditional ones, followed by education of metric units, then progressively ban the use of the older measures. This has generally been a slow route to metric. The British Empire permitted the use of metric measures in 1873, but the changeover was not completed in most Commonwealth countries until the 1970s and 1980s when governments took an active role in metric conversion. Japan also followed this route and did not complete the changeover for 70 years. In the United Kingdom, the process is still incomplete. By law, loose goods sold with reference to units of quantity have to be weighed and sold using the metric system. In 2001, the EU directive 80/181/EEC stated that supplementary units (imperial units alongside metric including labelling on packages) would become illegal from the beginning of 2010. In September 2007,[16] a consultation process was started which resulted in the directive being modified to permit supplementary units to be used indefinitely.
The third method is to redefine traditional units in terms of metric values. These redefined "quasi-metric" units often stay in use long after metrication is said to have been completed. Resistance to metrication in post-revolutionary France convinced Napoleon to revert to mesures usuelles (usual measures), and, to some extent, the names remain throughout Europe. In 1814, Portugal adopted the metric system, but with the names of the units substituted by Portuguese traditional ones. In this system, the basic units were the mão-travessa (hand) = 1 decimetre (10 mão-travessas = 1 vara (yard) = 1 metre), the canada = 1 litre and the libra (pound) = 1 kilogram.[27] In the Netherlands, 500 g is informally referred to as a pond (pound) and 100 g as an ons (ounce), and in Germany and France, 500 g is informally referred to respectively as ein Pfund and une livre ("one pound").[55] In Denmark, the re-defined pund (500 g) is occasionally used, particularly among older people and (older) fruit growers, since these were originally paid according to the number of pounds of fruit produced. In Sweden and Norway, a mil (Scandinavian mile) is informally equal to 10 km, and this has continued to be the predominantly used unit in conversation when referring to geographical distances. In the 19th century, Switzerland had a non-metric system completely based on metric terms (e.g. 1 Fuss (foot) = 30 cm, 1 Zoll (inch) = 3 cm, 1 Linie (line) = 3 mm). In China, the jin now has a value of 500 g and the liang is 50 g.
It is difficult to judge the degree to which ordinary people change to using metric in their daily lives. In countries that have recently changed, older segments of the population tend to still use the older units. Also, local variations abound in which units are round metric quantities or not. In Canada, for example, ovens and cooking temperatures are usually measured in degrees Fahrenheit and Celsius. Except for in cases of import items, all recipes and packaging include both Celsius and Fahrenheit, so Canadians are typically comfortable with both systems of measurement. This extends to manufacturing, where companies are able to use both imperial and metric units, since the major export market is the U.S., but metric is required for both domestic use and for nearly all other export. This may be due to the overwhelming influence of the neighbouring United States; similarly, many English Canadians[citation needed] (unlike most French Canadians[citation needed]) still often use non-metric measurements in day-to-day discussions of height and weight, and for clothing sizes, which are invariably measured in inches, though most driver's licences and other official government documents record weight and height only in metric (Saskatchewan driver licences, prior to the introduction of the current one-piece licence, indicated height in feet and inches but have switched to centimetres following the new licence format[citation needed]). In Canadian schools, however, metric is the standard, except when it comes up in recipes, where both are included, or in practical lessons involving measuring wood or other materials for manufacturing. In the United Kingdom, degrees Fahrenheit are seldom encountered (except when some people talk about hot summer weather), while other metric units are often used in conjunction with older measurements, and road signs use miles rather than kilometres. Another example is "hard" and "soft" metric. Canada converted liquid dairy products to litre, 500 mL, and 250 mL sizes, which caused some complaining at the time of the conversion, as a litre of milk is slightly over 35 imperial fluid ounces, while the former imperial quart used in Canada was 40 ounces. This is an example of a "hard" metric conversion. Conversely, butter in Canada is sold primarily in a 454 g package, which converts to one Imperial pound. This is considered a "soft" metric conversion. Such countries could be said to be "semi-metric". However, unlike in the rest of Canada, metrication in the Francophone province of Quebec has been more implemented and metric measures are more consistently used in Quebec than elsewhere in Canada.
Exceptions
As of 2015, in most countries of the world, the metric system officially predominates; traditional units, however, are still used in many places and industries. For example:- Photo and video cameras are standardized to mount to tripods using 1/4-20 and 3/8-16 screws, which are dimensioned in inches, as per ISO 1222:2010,[56]
- Automobile tyre pressure is commonly measured in units of psi in several countries including Brazil, Peru, Argentina, Australia, and Chile, the UK and the US.
- Automotive engine power is usually measured in horsepower (rather than in kilowatts) in Russia, most other ex-USSR countries and German-speaking countries (note that this is typically "metric horsepower" rather than imperial horsepower), although in the EU from 2010 the horsepower is permitted only as a supplementary unit.[57]
- In Hong Kong, traditional Chinese and British imperial units are normally used instead of metric units in particular types of trade.
- Amongst construction workers in Northern Europe, planks and nails are often called by their old inch-based names.
- The length of small sail boats is often given in feet in popular conversation.
- Office space is often rented in traditional units, such as square feet in Hong Kong and India, tsubo/pyeong/"ping" in Japan, Korea and Taiwan.
- In plumbing, some pipes and pipe threads are still designated in inch sizes due to historic international acceptance of particular sequences of pipe sizes and pipe threads, such as BSP / ISO 7 / EN 10226 threads.
- In the United Kingdom and some Commonwealth countries, temperatures of domestic gas ovens are often specified using gas marks.[citation needed]
- Automotive wheel diameters are still usually but not always set as whole inch measurements (although tyre widths are measured in millimetres).
- Dots per inch and pixels per inch continue to be used in describing graphical resolution in the computer and printing industry.
- Television and monitor screen diagonals are still commonly cited in inches in many countries; however, in countries such as Australia, France and South Africa, centimetres are often used for television sets, whereas CRT computer monitors and all LCD monitors are measured in inches.
- Many large format computer printers, commonly known as plotters, have carriage widths measured in inches. Common widths are 24 in (610 mm), 36 in (910 mm), 44 in (1,100 mm) and 60 in (1,500 mm). While metric media sizes are often quoted (e.g. A0, A1), rolls of film, plain paper or photographic paper are normally sold in these widths, giving rise to wastage when they are trimmed. Rolls lengths are variously quoted in feet or metres.
- In the electronic industry, the dominant spacing for components is based on intervals of 1⁄10 in (2.54 mm), and a change would lead to compatibility issues, e.g., for connectors.
- Within the mechanical industry, inch-based spare parts can occasionally be kept, e.g., to service American or pre-World War II machines, but at maintenance, screws may be exchanged to metric thread.
- In Ireland, the only legal exception to the metrication process was the pint in bars, pubs, and clubs (although alcohol sold in any other location is in metric units (usually 330 ml (bottled beer), 500 ml (canned beer), 750 ml (wine), or 1 L or 700 ml (spirits))).
- In Australia, a pint of beer was redefined to 570 ml (see Australian beer glasses).
- In both metric and non-metric countries, racing bicycle frames are generally measured in centimetres, while mountain bicycle and other frames are measured in either or both.
- In the sport of surfing, surfboards are usually designed, constructed, and sold in feet and inches.
- In Spain and former colonies i.e. Americas and Philippines certain
pre-metric units are still used, e.g., the quiñón for land measurement
in the Philippines, the fanega, ferrado and atahúlla to name three used
in Spain and other former possessions.
- The pulgada (inch) is 23 mm, 2 mm shorter than the English inch.
- In many long-time metric countries, when non-metric units are used, it is often to give rough estimates in a short form, while accurate measures always are metric, e.g., "6 feet" may feel less exact and shorter to say than "1.8 metres" or "180 cm".[citation needed] Measurement tools for inches are generally rare to find there, only on the other side of some carpenter's rulers, and may present a variation between national legacy inches and British/US inches, easily causing significant measurement errors if used.
- The Imperial gallon is used as a unit of measure for fuel in Anguilla, Antigua and Barbuda, Burma, the Cayman Islands, Dominica, Grenada, Montserrat, St Kitts and Nevis and St Vincent and the Grenadines. In the United Kingdom fuel efficiency is officially recorded in miles per imperial gallon although fuel is sold in litres. [58]
- The US gallon is used in the Bahamas, Belize, British Virgin Islands, Colombia, Dominican Republic, Ecuador, El Salvador, Guatemala, Haiti, Honduras, Liberia, Peru, Turks and Caicos Islands, and the US, especially for pricing.[58]
- In Latin America, as SI units are standard, litres are used as well, e.g., often regarding fuel economy (km per litre), and the Spanish word galón may occasionally refer to a portable fuel container, often 5-20 L.
- Road distances and speed limits are still displayed in miles and miles per hour respectively in the USA, UK, Burma, and various Caribbean nations.[59]
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