ISO 2848

International standard ISO 2848 (Building construction – Modular coordination – Principles and rules, International Organization for Standardization, 1984) is an ISO standard used by the construction industry. It is based on multiples of 300 mm and 600 mm

While those dimensions equate to 30 cm and 60 cm respectively, it is the use of millimetres which is significant.

The numbers 300 and 600 were chosen because they are preferred numbers due to their large number of divisors – any multiple can be evenly divided into 2, 3, 4, 5, 6, 10, 12, 15, 20, 25, 30, etc., making them easy to use in mental arithmetic. This system is known as "modular coordination". A related standard is British Standard 6750.

Basic module

The standard unit of ISO 2848 is a basic module, a length of 100 millimetres (3.937 in) which is represented in the standards by the letter M. Adherence to the standard means that major dimensions such as grid lines on drawings, distances between wall centres or surfaces, widths of shelves and kitchen components are multiples of the basic module. As dimensions increase, preference is given to lengths which are multiples of 3 (see metric foot), 6, 12, 15, 30 and 60 basic modules. For smaller dimensions, the submodular increments ​14 M (see metric inch) and ​12 M are preferred.

Metric foot

A metric foot[1][2] is only a nickname for a preferred number length of 3 basic modules (3 M), or 300 millimetres (11.811 in). The 300 mm (30 cm) metric rule is of a similar length to the traditional imperial one-foot rule. A metric foot is 4.8 millimetres (0.189 in) shorter than an imperial foot.

Although the term "metric foot" is still occasionally used in the United Kingdom, in particular in the timber trade, dimensions are most likely to be quoted exclusively in metric units today.

The sizes of the studios at BBC Television Centre in London, which opened in 1960, are specified and measured in metric feet, in contrast to film stages where imperial feet and inches prevail.

Metric inch

A metric inch[1][2] is a nickname for a preferred ​14 subdivision of an ISO 2848 basic module, or ​112 of a metric foot measuring 25 millimetres (0.984 in). A metric inch is 0.4 millimetres (0.016 in) shorter than an inch, since the inch is defined as 25.4 millimetres.

The term was similarly used to refer to the historical Soviet Bloc practice of spacing integrated circuit pins at ​110 of a 25 mm "metric inch" length, instead of the western practice of ​110 of an imperial inch.

Further reading

References

  1. ^ a b Timber and Plywood Annual, Middlesex Publishing Company, 1969, p. 26
  2. ^ a b Encyclopedia of Distances, Springer, 2014, p. 597, ISBN 3662443422
Foot (unit)

The foot (pl. feet; abbreviation: ft; symbol: ′, the prime symbol) is a unit of length in the imperial and US customary systems of measurement. Since 1959, both units have been defined by international agreement as equivalent to 0.3048 meters exactly. In both systems, the foot comprises 12 inches and three feet compose a yard.

Historically the "foot" was a part of many local systems of units, including the Greek, Roman, Chinese, French, and English systems. It varied in length from country to country, from city to city, and sometimes from trade to trade. Its length was usually between 250 mm and 335 mm and was generally, but not always, subdivided into 12 inches or 16 digits.

The United States is the only industrialized nation that uses the international foot and the survey foot (a customary unit of length) in preference to the meter in its commercial, engineering, and standards activities. The foot is legally recognized in the United Kingdom; road signs must use imperial units (however distances on road signs are always marked in miles or yards, not feet), while its usage is widespread among the British public as a measurement of height. The foot is recognized as an alternative expression of length in Canada officially defined as a unit derived from the meter although both the U.K. and Canada have partially metricated their units of measurement. The measurement of altitude in international aviation is one of the few areas where the foot is used outside the English-speaking world.

The length of the international foot corresponds to a human foot with shoe size of 13 (UK), 14 (US male), 15.5 (US female) or 46 (EU sizing).

List of International Organization for Standardization standards, 1-4999

This is a list of published International Organization for Standardization (ISO) standards and other deliverables. For a complete and up-to-date list of all the ISO standards, see the ISO catalogue.The standards are protected by copyright and most of them must be purchased. However, about 300 of the standards produced by ISO and IEC's Joint Technical Committee 1 (JTC1) have been made freely and publicly available.

Metrication in Australia

Metrication in Australia effectively began in 1966 with the conversion to decimal currency under the auspices of the Decimal Currency Board. The conversion of measurements—metrication—commenced subsequently in 1971, under the direction of the Metric Conversion Board and actively proceeded until the Board was disbanded in 1981.

Before 1970, Australia mostly used the imperial system for measurement, which the Australian colonies had inherited from the United Kingdom. Between 1970 and 1988, imperial units were withdrawn from general legal use and replaced with SI metric units, facilitated through legislation and government agencies. SI units are now the sole legal units of measurement in Australia. Australia's largely successful transition to the metric system contrasts with the ongoing opposition to metrication in the United States, Canada and the United Kingdom.

Preferred metric sizes

Preferred metric sizes are a set of international standards and de facto standards that are designed to make using the metric system easier and simpler, especially in engineering and construction practices. One of the methods used to arrive at these preferred sizes is the use of preferred numbers and convenient numbers such as the Renard series, the 1-2-5 series to limit the number of different sizes of components needed.

One of the largest benefits of such limits is an ensuing multiplicative or exponential reduction in the number of parts, tools and other items needed to support the installation and maintenance of the items built using these techniques. This occurs because eliminating one diameter fastener will typically allow the elimination of a large number of variations on that diameter (multiple thread pitches, multiple lengths, multiple tip types, multiple head types, multiple drive types, and the tools needed for installing each, including multiple drill bits (one for each different thread pitch, material, and fit combination).

Tape measure

A tape measure or measuring tape is a flexible ruler and used to measure distance.

It consists of a ribbon of cloth, plastic, fibre glass, or metal strip with linear-measurement markings. It is a common measuring tool. Its design allows for a measure of great length to be easily carried in pocket or toolkit and permits one to measure around curves or corners. Today it is ubiquitous, even appearing in miniature form as a keychain fob, or novelty item. Surveyors use tape measures in lengths of over 100 m.

ISO standards by standard number
1–9999
10000–19999
20000+

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