Wood - most friendly in relation to person an everyday material. Any dwelling does not manage while products from wood.
If to replace wooden window frames, doors and plinths, tables and chairs, cases and shelfs on plastic, glass or metal (and such
The tendency, in view of lack of wood and labour input of its(her) processing, becomes more and more obvious), from a house there will leave habitual and necessary heat which is radiated with wood. Probably, interior will be more graceful, but is colder.
Low heat conductivity and электропроводность, high chemical stability(resistance), beautiful and natural appearance do(make) wood by an effective building and finishing material.
Электропроводность wood considerably raises at saturation by its(her) moisture.
But wood has also some lacks with which it is necessary to be considered at its(her) use in dwelling.
Much of us annoying sensations connected to a creaking wooden floor, inflating doors and коробящимися panels from древесностружечных plates are familiar.
Density of wood. Humidity of wood Bangladesh
The major physical properties of wood define(determine) its(her) value and suitability as a building and finishing material. To them concern: density (in a dry condition), humidity, durability, heat conductivity, permeability for liquids and gases, a smell, a structure, shine.
The density of wood of different tree species depends on its(her) structure, humidity, maturity and other factors. Average density of wood with natural humidity recalculate for density at standard humidity of 12 % appropriate to a dry condition of wood. least average density - at wood of a fir (375 kg / a cube, м), greatest - at wood of an oak and a maple (690). At a pine this parameter is equal 550 kg / cubes, m, at fur-trees - 450, at an aspen - 495, at a birch - 630, at a larch - 660, at ясеня - 680 kg / cube, m.
On a degree of humidity wood divide(share) on wet, long taking place in water (humidity of 100 %), newly felled (35-100), air - dry (15 - 20), комнатно - dry (8 - 8) and absolutely dry (0). moisture influences various properties of wood. So, shrinkage and swelling occur at change of its(her) humidity. With increase of humidity of wood its(her) durability decreases. In
Quality of protective actions warning negative influence of a moisture, wood impregnate with antiseptics&, and products from it(her) cover with varnishes, paints, thin polymeric пленками.
Wooden window blocks and basic parts of furniture from wood - are most subject for destroying influence of a moisture.
At full removal(distance) of a moisture from wooden products (shrinkage) may take place them растрескивание and loss of form.
Wood of different breeds of trees differs from each other on hardness and on durability.
Hardness of wood is defined(determined) by resistibility to mechanical influences - to impacts, сколам, to cutting - and represents for us interest as property determining a degree of labour input of its(her) machining. Very soft wood - at a poplar, a fir, a linden, soft - at a pine, a fur-trees and a larch, wood of average hardness - at a birch, a nut tree, a pear and a black pine, firm - at an oak, ясеня, a yew, very firm - at a beech.
The wood is drier, she(it) is firmer. Durability of wood is defined(determined) by limits of efforts and loadings which she(it) may bear(take out), not collapsing and not being deformed, at compression, a stretching, a bend. On durability of wood, as well as on its(her) hardness, significant influence renders humidity.
So, with increase of humidity of wood at 30 % durability and hardness of wood is reduced in 1,5 - 2 times.
Durability of wood is reduced at long loadings that may result in deformation changes of products from it(her).
Wood is rather steady against temperature deformations: heating or cooling does not result in significant changes of its(her) volume as factor of its(her) heat conductivity is insignificant. This one of most loved(liked) properties determining its(her) heat and friendliness: she(it) does not hasten to take away from him(it) warmly at a touch to it(her).
Sound reflecting properties of wood are insignificant; products from wood of coniferous breeds of small density (for example, from fur-trees) have ability even to resound sound.
The wooden house шумнее stone, brick or concrete.
Wood participates in теплообменных processes of a premise(room) as in greater degree reflects a little, instead of absorbs heat.
The wood not protected by paint and varnish coverings has ability to breathe - absorbing from air and to give to him(it) surpluses of a moisture, and also to accumulate smells.
Case furniture from wood of fur-trees - good resonators of a sound.
The main decorative qualities of wood - its(her) color and a structure.
Trees of a temperate climate in comparison with trees of a tropical zone have more light colouring wood.
The structure of wood is especially expressive at deciduous breeds of trees, therefore she(it) is applied to manufacturing or furnish of furniture of best models.