FIRE RESISTING PROPERTIES OF COMMON BUILDING MTERIALS Fire resisting properties of common building materials such as stone, brick, timber, cast-iron, glass, steel and concrete are mentioned below. 1. STONE The stone is a bad conductor of heat. But it suffers appreciably under the effects of fire. The stone is also liable to disintegrate into small … Read more
TYPES OF DEFECTS IN TIMBER Types of Defects in timber are grouped into the following divisions. 1. Defects due to conversion During the process of converting timber to commercial form, the following defects may occur. Chip mark: mark or sign placed by chip on finished surface of timber Diagonal grain: Due to improper sawing of … Read more
Qualities of Good Timber Good timber should have the following qualities 1. Hardness A good quality timber should be hard enough to resist deterioration. 2. Strength It should have sufficient strength to resist heavy structural loads. 3. Toughness It should have enough toughness to resist shocks due to vibrations. It should not break in bending … Read more
Timber Classification The terms timber and wood are often used synonymously, but they have distinct meanings in the building industry. Wood is the hard, fibrous material that makes up the tree under the bark, whereas timber may be defined as a wood which retains its natural physical structure and chemical composition and is suitable for … Read more
Seasoning of Timber When a tree is newly felled, it contains about 50% or more of its own weight as water. This water is in the form of sap and moisture. The water is to be removed before the timber can be used for any engineering purpose. In other words, the timber is to be … Read more
Storing of Timber on Site Store the timbers in stacks upon well treated and even surfaced beams sleepers or brick pillars so as to be above the ground level by at least 150 mm. Store members of different length and material separately. Materials of equal length are piled together in layers with wooden batters, called … Read more
The trees are the tallest living things and the man chops down forests without replanting for tomorrow. The forests are vital for the economic prosperity of land. The man and trees are closely linked and without trees, the life on our planet would be endangered. Importance of Trees It conserves soil moisture It precipitates rainfall … Read more
Objective For determination of specific gravity of timber. Reference Standards IS : 1708 (Part 2)-1986 Equipment & Apparatus Balance(0-10kg) Oven(3000C) Preparation of sample The dimension of sample to be tested is 6 cm in length and 2 x 2 cm in cross-section or 15 cm in length and 5 x 5 cm in cross-section. Procedure … Read more
Objective For determination of moisture content of timber. Reference Standards IS : 1708 (Part 1)-1986 Equipment & Apparatus Balance(0-10 kg) Oven (3000c) Preparation of sample: The dimension of sample to be tested is 2.5 cm in length and 2 x 2 cm or 5 x 5 cm in cross-section. Procedure The sample is weighed (W1) … Read more