Standard Numbering System. Building measurements. Standard measurements

Metric units of linear measurement were first defined in France in 1790, although official recognition did not take place until 1840. The metre was established as the new decimal unit of length on a scientific basis, defined as the length of a simple pendulum having a swing of one second at sea level on latitude 45°. A standard numbering system was devised in Germany, shortly after World War I, to achieve uniformity and standardisation in the measurement of machines and technical equipment - a system also used in France and the USA. The starting point for measurement is the Continental unit of measurement: the metre. In the Imperial system (used in the UK, USA and elsewhere), 40 inches = 1.016m = 1.00m.

The requirement of building technology for geometrical subdivisions precluded the use of the purely decimal subdivision of the metre, so the Standard Numbering System, based on the structure of 2s, was introduced into the decimal structure: 1, 2, 4, 8, 16, 31.5, 63, 125, 250, 500, 1000 - (2). (The coarser 5-part division and the finer 20- and 40-part division series are inserted appropriately with their intermediate values.)

The geometrical 10-part division of the standard number series was formed from the halving series (1000, 500, 250, 125, ...) and from the doubling series (1, 2, 4, 8, 16, ...). Because n = 3.14 and V10 = 3.16, the number 32, following 16 in the series, was rounded down to 31.5. Similarly, in the halving sequence, 62.5 was rounded up to 63.

Standard numbers offer many advantages in calculations:
1 - the product and quotient of any two standard numbers are standard numbers
2 - integer powers of standard numbers are standard numbers, and
3 - double (or half) a standard number is a standard number.

Building measurements. In contrast to engineering, in building construction, there is little requirement for a geometric division as opposed to the prevailing arithmetic addition of identical structural components (e.g. blocks, beams, joists, girders, columns and windows). Routine measurements for standard components must, therefore, comply with these requirements. However, they should also conform to concepts of technical standardisation and the standard numbering system. A standard system of measurement for building construction was based on the standard numbering system, and this is the basis for many further building standards and of measurement for design and construction, particularly in building construction above ground.

Standard measurements. The controlling dimensions are dimensions between key reference planes (e.g. floor-to-floor height); they provide not only a framework for design but also a basis which components and assemblies may refer to - (3).

Standard dimensions are theoretical but, in practice, they provide the basis for individual, basic structural and finished measurements; thus all building components are linked in an organised way (e.g. standard building brick length = 250mm (225mm in UK), in situ concrete wall thickness = 250mm.).

For any construction project, completed standard description forms give the most valuable and clearest information, and are ideal for estimating, for the construction supervisor and as a permanent reference in the site office. Any time-consuming queries based on false information are virtually eliminated; the time gained more than compensating the effort involved in completing the record book. At the top of the form, there are columns for entering relevant room dimensions, in a way easily referred to. The inputs are most simply made using key words. The column 'size' should be used merely for entry of the necessary dimensions of the items, e.g., the height of the skirting board or the frieze, the width of the window sill, etc. Finally, several spaces are provided for special components.

A space should be left free under each heading, so that the form can easily be extended for special cases. The reverse side of the form is best left free so that drawings may be added to elaborate on the room description on the next sheet. The A4 format pages are duplicated, each position containing exactly the same text; the sheets are kept up to date and eventually bound together. At the conclusion of the building work, the record book is the basis for the settlement of claims, using the dimensions at the head of the room pages. Later, the record book provides an objective record of progress, and is available for those with specialist knowledge.