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The importance of standardisation cannot be over emphasised. It requires the quality of
materials and manufactured items to be not below a specific standard level. However, the
importance of standardisation is not limited to this factor alone, since each revised standard
places higher requirements upon the products than the preceding one, with the effect that the
industry concerned has to keep up with the standards and improved production techniques.
Thus, the industry of building materials gains both in quantity and quality, so that new, more
efficient products are manufactured and the output of conventional materials is increased.
To develop products of greater economic efficiency, it is important to compare the performance
of similar kinds of materials under specific service conditions. Expenditures for running an
installation can be minimised by improving the quality of building materials and products.
Building industry economists are thus required to have a good working knowledge, first, of the
building materials, second, of their optimum applications on the basis of their principal properties,
and, third, of their manufacturing techniques, in order that the buildings and installations may
have optimum engineering, economic performance and efficiency. Having acquired adequate
knowledge, an economist specialising in construction becomes an active participant in the
development of the building industry and the manufacture of building materials.
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h 2 () is the mass of a unit volume of homogeneous material denoted by
=M
Vg/cm^3where M =mass (g)
V = volume (cm^3 )
Density of some building materials is as follows:
Material Density (g/cm^3 )
Brick 2.5–2.
Granite 2.6–2.
Portland cement 2.9–3.
Wood 1.5–1.
Steel 7.8–7.
f
2 h 2 (b) is the mass of a unit volume of material in its natural state (with pores and
voids) calculated as
b = M
Vkg/m^3where M = mass of specimen (kg)
V = volume of specimen in its natural state (m^3 )
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For most materials, bulk density is less than density but for liquids and materials like glass
and dense stone materials, these parameters are practically the same. Properties like strength
and heat conductivity are greatly affected by their bulk density. Bulk densities of some of the
building materials are as follows: