Preferred metric sizes

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Use of preferred metric sizes is common in engineering designs Engineering design drawings.jpg
Use of preferred metric sizes is common in engineering designs

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 and 1-2-5 series, to limit the number of different sizes of components needed.

Contents

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).

Food and beverages

Champagne bottles in various sizes, probably 200 ml, 375 ml, 750 ml, 1.5 L, 3 L, 6 L, 9 L, 12 L and 18 L. Moet & Chandon in different sizes.jpg
Champagne bottles in various sizes, probably 200 ml, 375 ml, 750 ml, 1.5 L, 3 L, 6 L, 9 L, 12 L and 18 L.

Liquor bottle sizes

International agreements, including 75/106/EEC, [1] specify the capacities of liquor bottles allowed in international commerce as the following 10 sizes:

In the United States, the alcohol industry switched to metric bottle sizes on October 1, 1976, abandoning the existing 38 sizes of bottles and instead adopting the following 6 sizes: [2]

Building construction

System 32 furniture

Shelf where the shelf bearing holes are placed with 32 mm distances from center to center, giving flexible choices for shelve positioning. 2017 UEF Joensuu library 06 shelf.jpg
Shelf where the shelf bearing holes are placed with 32 mm distances from center to center, giving flexible choices for shelve positioning.

System 32 is a standard for the design and manufacture of furniture, most commonly used in the design of cabinets, wherein the major parts (sides, doors, etc.) are available in increments of 32 mm, and shelf supports consist of columns of 5 mm holes on 32 mm centers.

ISO 2848 basic module

Cross section of a wooden joist layer, where 6 M (or 6 modules) indicates a distance of 600 mm. Bjelkelag illustrasjon P1.png
Cross section of a wooden joist layer, where 6 M (or 6 modules) indicates a distance of 600 mm.

The ISO 2848 basic module is a unit of 100 mm, often represented by a single capital "M", along with 300 mm and 600 mm groupings, that is widely used for the widths of furniture in Europe.

Office equipment and supplies

A-series paper sizes. A size illustration2.svg
A-series paper sizes.

ISO 216 paper sizes

ISO 216 standard specifies the A sizes of paper, including the very common A4, wherein the base size of A0 is one square meter, and the ratio between the height and width is 2, which results in all sizes of paper having the same aspect ratio.

Also related is the set of pen thicknesses for technical drawings (0.13, 0.18, 0.25, 0.35, 0.50, 0.70, 1.00, 1.40, and 2.00 mm).

Manufacturing

ISO 261 and 262 fastener diameters

ISO 261 defines a set of preferred metric machine screw/bolt sizes, and ISO 262 defines a subset of those; both are based roughly on Renard series as defined in ISO 3, ISO 17, and ISO 497. Given that even ISO 262 specifies a fairly large set of diameters, a much simplified set of preferred diameters was developed by one of the lead designers of ASME Z17.1 and ANSI B4.2, Knut O. Kverneland, to reduce the list to 6 preferred sizes, and another 6 intermediate supplementary sizes. [4]

Machine screws with different thread diameters Aneka Macam Mur dan Baut.jpg
Machine screws with different thread diameters
Hex key set with metric sizes from 2 mm to 10 mm according to sizes for use with ISO 262 screw sizes (except 3.5 mm for M6 internal set screw) 1st choice metric hex key set.jpg
Hex key set with metric sizes from 2 mm to 10 mm according to sizes for use with ISO 262 screw sizes (except 3.5 mm for M6 internal set screw)

For each size bolt or screw and type of head, there is a corresponding size driver prescribed by various ISO standards, including:

ISO 262 sizesInternal hex
cap head
Internal hex
button head
Internal hex
flat head screws
Internal hex
set screws
External hex
ISO standard
External hex
DIN standard
M2.52.0 mm2.0 mm5 mm5 mm
M32.5 mm2.0 mm2.0 mm2.0 mm5.5mm5.5mm
M43.0 mm2.5 mm2.5 mm2.5 mm7 mm7 mm
M54.0 mm3.0 mm3.0 mm3.0 mm8 mm8 mm
M65.0 mm4.0 mm4.0 mm3.5 mm10 mm10 mm
M86.0 mm5.0 mm5.0 mm5.0 mm13 mm13 mm
M108.0 mm6.0 mm6.0 mm6.0 mm16 mm17 mm
M1210.0 mm8.0 mm8.0 mm8.0 mm18 mm19 mm
M1614.0 mm10.0 mm10.0 mm10.0 mm24 mm24 mm
M2017.0 mm12.0 mm12.0 mm30 mm30 mm
M2419.0 mm36 mm36 mm
M3022.0 mm46 mm46 mm

For Torx bolts, there is a corresponding size driver prescribed by Acument, the designer of the Torx drive system. As of 2018, there are no ISO standards for hexalobular drive sizes. [7]

ISO 262 sizesPan headFlat headSocket headSocket ButtonTrussExternal Torx
M2.5T8T8T8
M3T10T10T10T8E4
M4T20T20T25T15T15E5
M5T25T25T27T25T20E6
M6T30T30T30T27T30E8
M8T40T40T45T40T40E10
M10T50T50T50T45T50E12
M12T55T55T55E14
M16T70T60E20
M20T90E24
M24T100E32
M30E36

Similarly, for Torx Plus bolts, there is a corresponding size driver prescribed by Acument, the designer of the Torx Plus drive system. As of 2018, there are no ISO standards for hexalobular drive sizes. [8]

ISO 262 sizesPan headFlat headSocket headSocket ButtonTrussExternal Torx
M2.58IP8IP8IP4EP
M310IP10IP10IP8IP5EP
M420IP15IP20IP15IP15IP7EP
M525IP20IP27IP25IP20IP8EP
M630IP27IP30IP27IP30IP10EP
M845IP30IP45IP40IP40IP14EP
M1050IP50IP50IP45IP50IP16EP
M1255IP55IP55IP55IP55IP20EP
M1670IP60IP26EP
M2090IP32EP
M24100IP40EP
M30

ISO 1307 plastic hose sizes

Garden hose with mouthpiece Garden hose pistol.JPG
Garden hose with mouthpiece

See also:

ISO 1307:2006, Rubber and plastics hoses—Hose sizes, minimum and maximum inside diameters, and tolerances on cut-to-length hoses specifies nominal diameters for four different types of plastic hoses, including "Type C", which includes the typical garden hose. Each nominal diameter specifies different ID minimum and maximum values. The nominal size is a Renard series.

Nominal Size

ID

Type C

Non-mandrel-built

ID range

Inch

equivalent

ID

minmax
3.2n/an/a
43.44.6
54.25.4
6.35.67.218 in
87.28.814 in
108.710.338 in
12.511.913.512 in
1615.116.758 in
1918.319.934 in
2019.320.9
2524.226.61 in
31.530.233.41+14 in
3836.539.71+12 in

ISO 6708 nominal pipe diameter

Butterfly valve in a large DN-size. Butterfly-valve--The-Alloy-Valve-Stockist.JPG
Butterfly valve in a large DN-size.

Nominal diameter, abbreviated DN (diamètre nominal/Durchmesser nach Norm), is the designation system specified by ISO 6708 for specifying the diameter of trade sizes of metric pipework components, and is the metric equivalent to Nominal Pipe Size. [9] It is among several ISO specifications that formalize preferred numbers, and is referred to by numerous other international standards, including ISO 7598 and EN 10255. The complete set of DN values allowed by the standard are:

DN designationDN designationDN designation
DN 10DN 250DN 1 500
DN 15DN 300DN 1 600
DN 20DN 350DN 1 800
DN 25DN 400DN 2 000
DN 32DN 450DN 2 200
DN 40DN 500DN 2 400
DN 50DN 600DN 2 600
DN 60DN 700DN 2 800
DN 65DN 800DN 3000
DN 80DN 900DN 3200
DN 100DN 1 000DN 3 400
DN 125DN 1 100DN 3 600
DN 150DN 1 200DN 3 800
DN 200DN 1 400DN 4 000

The number following the DN is a nominal value that is roughly the number of millimeters of a circular feature on the connection point of the pipe, fitting, coupling, etc., but often differing by a noticeable amount. If the DN value is related to the internal bore diameter of the feature, the size should be represented by DN/ID (for Inside Diameter), and if the DN value is related to the outside diameter, the size should be represented by DN/OD (for Outside Diameter).

The relationship between DN and NPS pipe sizes are as follows. Note that the actual internal diameter varies depending on the pipe wall thickness. [10]

DNActual ODNPS [11]
designationmmdesignation
DN 1017.238
DN 1521.312
DN 2026.934
DN 2533.71
DN 3242.41+14
DN 4048.31+12
DN 5060.32
DN 6576.12+12
DN 8088.93
DN 100114.34
DN 125139.7-
DN 150168.36
DN 200219.18
DN 25027310
DN 300323.912
DN 350355.614
DN 400406.416
DN 45045718
DN 50050820
DN 60061024
DN 70071128
DN 75076232
DN 80081334
DN 90091436
DN 1 000101640
DN 1 200122048

See also

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References

  1. "Application of Directives 75/106/EEC and 76/211/EEC concerning the marking and quantity control of e-marked prepackages" (PDF). Retrieved 2017-10-17.
  2. Cherry, Rona (11 October 1976). "Liquor Industry Converts to Metric System". The New York Times. Retrieved 2018-11-29.
  3. 1 2 "Another Brick in the Wall". 10 June 2017.
  4. Kverneland, Knut O. (1996). Metric Standards for Worldwide Manufacturing. Amer Society of Mechanical Engineers. ISBN   978-0791800416.
  5. "ISO 2936:2014 Assembly tools for screws and nuts — Hexagon socket screw keys". International Standards Organisation . Retrieved 2023-01-24.
  6. "ISO Hex Head Screw Per. ISO 4014 DIN 931 ISO 4014, ISO 4016, ISO 4017, ISO 4018". Engineers Edge. Retrieved 2023-01-24.
  7. "Torx Drive System" (PDF).
  8. "Torx Plus Drive System" (PDF).
  9. "ISO 6708:1995: Pipework components -- Definition and selection of DN (nominal size)" . Retrieved 2017-10-13.
  10. "Tube Sizes - ISO" (PDF). Retrieved 2017-10-13.
  11. "ISO 17292:2004, Metal ball valves for petroleum, petrochemical and allied industries" . Retrieved 2017-10-16.