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.
Food and Beverages
Liquor Bottle Sizes
International agreements, including 75/106/EEC, specify 0.1, 0.25, 0.375, 0.5, 0.75, 1, 1.5, 2, 3, and 5 litres as the capacities of liquor bottles allowed in international commerce. 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 sizes:
is a standard for the design and manufacture of furniture, most commonly used in the design of cabinets, wherein the major parts are available in increments of 32 mm, and shelf supports consist of columns of 5 mm holes on 32 mm centers.
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.
A standard metric block is 190 mm wide, 390 mm long, and 190 mm high, which allows for 10 mm mortar joints in between bricks, giving a standard unit size of 200 mm square by 400 mm long.
A standard metric brick is 90 by 57 by 190 mm; with 10 mm of mortar, that produces a standard unit of 100 mm x 200 mm.
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, which results in all sizes of paper having the same aspect ratio. Also related is the set of pen thicknesses for technical drawings.
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. For each size bolt or screw and type of head, there is a corresponding size driver prescribed by various ISO standards, including:
Internal hex drive: ISO 2936:2001 "Assembly tools for screws and nuts—Hexagon socket screw keys"
External hex drive: ISO 4014, 4015, 4015, 4017, and 4018.
For each size bolt or screw and type of head, there is a corresponding size driver prescribed by Acument, the designer of the Torx drive system., there are no ISO standards for hexalobular drive sizes. For each size bolt or screw and type of head, there is a corresponding size driver prescribed by Acument, the designer of the Torx Plus drive system., there are no ISO standards for hexalobular drive sizes. If using just the 1st choice bolt sizes, the list of drivers and wrenches needed for all hex and Torx sizes are:
Allen key
Torx
Torx Plus
Hex wrench
External Torx
External Torx Plus
2 mm
T8
8IP
5 mm
E5
4EP
2.5 mm
T15
15IP
7 mm
E8
7EP
3 mm
T20
20IP
10 mm
E12
10EP
3.5 mm
T25
27IP
16 mm
E20
16EP
4 mm
T27
30IP
24 mm
E32
26EP
5 mm
T30
45IP
36 mm
40EP
6 mm
T45
50IP
8 mm
T50
60IP
10 mm
T60
70IP
14 mm
T70
100IP
19 mm
T100
ISO 1307 Plastic Hose Sizes
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.
ISO 6708 Nominal Diameter
Nominal diameter, abbreviated DN, 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. 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:
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, and if the DN value is related to the outside diameter, the size should be represented by DN/OD. The relationship between DN and NPS pipe sizes are as follows. Note that the actual internal diameter varies depending on the pipe wall thickness.
