DURABILITY OF GLASS Float glass is highly durable in most environments encountered in construction applications, and it does not degrade or change over time, other than the accumulation of microscopic surface damage, which reduces the strength of new glass but tends to stabilise after several years. Therefore monolithic single glazing can usually be regarded as …
Design of Glass DESIGN OF GLAZING AND SELECTION OF TYPE OF GLASS The selection of type of glass involves consideration of a range of factors and combination of a number of processes to achieve the required set of properties. In some cases the design will be constrained by the limits of one or more processing …
PHYSICAL PROPERTIES OF GLASS Density, Thermal Expansion Coefficient, Thermal Conductivity, Emissivity and Selectivity of Coated Glasses The physical properties of float glass produced in Europe do not vary significantly between manufacturers and can be taken as standard values according to BS EN 572-2. Float glass produced in other parts of the world may vary in …
Manufacturing of Glass MANUFACTURING OF FLAT GLASS Flat glass manufacturing is a key industrial process and has been subject to continuous development to achieve lower cost and higher quality since its transition from the craft of mouth-blown glass. Float glass is the dominant process for flat glass, while rolled plate remains in use for patterned …
CHEMICAL PROCESSING OF TIMBER Treatability The ease with which a timber can be impregnated with liquids, especially wood preservatives, is generally referred to as its treatability. Treatability is related directly to the permeability of timber. The permeability is a function not only of moisture content and temperature, but also of grain direction, sapwood/heartwood, earlywood/latewood and …
MECHANICAL PROCESSING OF TIMBER Solid Timber Sawing and planing: The basic requirement of these processes is quite simply to produce as efficiently as possible timber of the required dimensions having a quality of surface commensurate with the intended use. Such a requirement depends not only on the basic properties of the timber, but also on …
Performance of Timber in Fire The performance of materials in fire is an aspect of durability that has always attracted much attention, not so much from the research scientist, but rather from the material user who has to conform with the legislation on safety and who is influenced by the weight of public opinion on …
FACTORS AFFECTING DURABILITY OF TIMBER Photochemical Degradation On exposure to sunlight the coloration of the heartwood of most timbers – e.g. mahogany, afrormosia and oak – will lighten, though a few timbers will actually darken, e.g. Rhodesian teak. Indoors the action of sunlight will be slow and the process will take several years, but outdoors …
STRENGTH, TOUGHNESS, FAILURE AND FRACTURE MORPHOLOGY There are two fundamentally different approaches to the concept of strength and failure. The first is the classical strength of materials approach, attempting to understand strength and failure of timber in terms of the strength and arrangement of the molecules, the fibrils, and the cells by thinking in terms …
FACTORS AFFECTING STRENGTH IN TIMBER Many of the variables influencing modulus of elasticity also influence the various strength properties of timber. Once again, these can be regarded as being either material dependent or manifestations of the environment. Anisotropy and Grain Angle The marked difference between the longitudinal and transverse planes in both shrinkage and modulus …