Модуль 11. СТРОИТЕЛЬНЫЕ МАТЕРИАЛЫ И ИЗДЕЛИЯ ИЗ ДРЕВЕСИНЫ

Задание 1. На основе информации, данной в переводе, и текста, представленного после таблицы, дайте развернутое толкование понятия. Используйте следующие выражения:

измельчение и расщепление древесины – timber grinding and splitting волокнистая масса – fiber, pulp

отливка плит – slab casting

с последующим прессованием и сушкой – with following moulding and drying для внутренней отделки – for interior trim

перфорированные и изоляционные плиты – pegboards and lith boards особо высокие акустические свойства – particular acoustic properties

Definition Translation

Древесно-волокнистые плиты (ДВП) – тепло-, звукоизоляционный и конструктивный древесный материал; изготавливается путём измельчения и расщепления древесины (или другого растительного сырья) в волокнистую массу, отливки из неё плит с последующим прессованием и сушкой. Различают по твёрдости: сверхтвёрдые, твёрдые и полутвёрдые. В зависимости от отделки (окрашивание эмалями, облицовка бумажными пластиками, полимерными плёнками и т.п.) и твёрдости плиты находят применение в строительстве. Твёрдые и сверхтвёрдые плиты используются для внутренней отделки жилых и общественных зданий, полутвердые и твердые находят применение в отделке потолков и панелей, сверхтвердые плиты и плиты, пропитанные смолами, применяют для полов. В ряде случаев применяются двухслойные и многослойные плиты, склеенные из твёрдых перфорированных (лицевой слой) и изоляционных (внутренний слой) плит. Изоляционноотделочные плиты служат для отделки помещений, требующих особо высоких акустических свойств. Изоляционные плиты используются для тепло- и звукоизоляции стен, перегородок, полов и потолков в жилых помещениях, а также для утепления кровельных покрытий

Fiberboard

Fiberboard is a type of engineered wood product that is made out of wood fibers. Types of fiberboard (in order of increasing density) include particle board, mediumdensity fiberboard, and hardboard. Fiberboard is sometimes used as a synonym for particle board, but particle board usually refers to low-density fiberboard. Plywood is

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not a type of fiberboard, as it is made of thin sheets of wood, not wood fibers or particles. Fiberboard, particularly medium-density fiberboard (MDF), is heavily used in the furniture industry. For pieces that will be visible, a veneer of wood is often glued onto fiberboard to give it the appearance of conventional wood.

Fiberboard is also used in the auto industry to create free-form shapes such as dashboards, rear parcel shelves, and inner door shells. These pieces are usually covered with a skin, foil, or fabric such as cloth, suede, leather, or polyvinyl chloride.

Urea-formaldehyde (UF) resins are dominantly used in the medium density fiberboard (MDF) industry because of their low cost and fast curing characteristics. However, pressures on the use of UF resins are mounting steadily due to potential problems associated with formaldehyde emission. On the other hand, phenolformaldehyde (PF) resins are more durable and do not emit formaldehyde after cure. But the Industry has traditionally shied away from using PF resins due primarily to their higher cost and much slower curing rate than UF resins. However, the press times PF-bonded fiberboard can be substantially reduced by manipulating the fiber mat temperatures, molecular weight distribution of PF resins and pressing parameters. As a result, the press times for PF-bonded fiberboard can be made comparable to those for UF-bonded fiberboard. Also, the resin content required for PF-bonded fiberboard is less than 5% to achieve a good board quickly. This is considerably lower than that required for UF-bonded fiberboard.

Certain types of fiberboard can be considered "green" building products. Consisting of bio-based, secondary raw materials (wood chip or sugarcane fibers) recovered from within 100 miles (160 km) of manufacturing facilities, the binding agent used in this type of fiberboard is an all-natural product, consisting of vegetable starch containing no added formaldehydes.

Fiberboard, classified by ASTM C208, Standard Specification for Cellulosic Fiber Insulating Board, has many benefits and is used in residential and commercial construction. Different uses and applications include:

sound proofing/deadening, structural sheathing, low-slope roofing,

sound deadening flooring underlayment,

High density coated wood fiber is an ideal cover board, and the industry apparently agrees. More than two billion square feet of this product have already been installed in the U.S. roofing market. In terms of cost and availability, wood fiber is hard to beat.

Задание 2. Сопоставьте толкование с переводом, дополните информацию, где необходимо. Используйте следующие выражения:

деревянная щепа – refuse wood, chip, cliff, cleft, shaving

предшественница черепицы – predecessor of tile

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Задание 3. Прочитайте текст, организуйте информацию, представленную в тексте, в виде опорной схемы. Перескажите текст, опираясь на полученную схему.

Lath

A lath is a thin, narrow strip of straight-grained wood. A lattice, or lattice-work, is a criss-crossed or interlaced arrangement of laths, or the pattern made by such an arrangement. Lath is the basic material used in the formerly common building technique known as lath and plaster, which was used to make interior walls.

Lath may also refer to wire mesh, typically with a paper backing, that is applied to a wood or metal framework as matrix over which stucco is applied. One of the key elements of lath, whether wooden slats or wire mesh, are the openings or gaps that allow plaster or stucco to ooze behind and form a stronger bond to the lath itself.

Today, wooden-slat laths are still used in building construction to form a base or groundwork for plaster (modern lath and plaster applications are mostly limited to conservation projects), tiles, slates, and other coverings (such as roofing). Such strips of wood are also employed to form lattice-work, or are used as the bars of venetian blinds or shutters. Riven lath is the stronger forerunner to sawn lath, as it was traditionally split with the grain from chestnut, oak, or similar hardwoods. Laths were also used to fix reed to a timber structure before plastering.

Wire-mesh lath is used extensively with stucco in home and commercial construction. In these applications the lath adds strength and rigidity in addition to providing a matrix to which the stucco can adhere. (This is similar to the way rebar is used to strengthen some concrete and masonry appications.)

Lath cut from spruce or balsam fir trees are used for building wooden lobster traps. Lath is also used on many tobacco farms in the Connecticut Valley as a means to carry and hang the plant in barns. This is achieved by using one of two methods, hooking or spearing. A "spear" lath is just a regular lath that is held in an upright position, the worker then mounts a spear on top and "spears" the tobacco onto the lath. The other form of lath is called Hook Lath, which just has small hooks attached

that allows a worker to hook the stems of tobacco plants onto the lath.

Задание 4. Сопоставьте толкование с переводом, дополните информацию, где необходимо. Используйте следующие выражения:

горячее прессование – hot pressing

измельчённые древесные стружки – ground wood chips синтетическое связующее – synthetic binding agent

отходы деревообработки – woodworking waste productions

неделовая древесина – refuse wood

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отходы сельского хозяйства – farm waste акустические прослойки – acoustic interlayers

чистые полы – wearing floors

подшивка потолков – covering of ceilings

Задание 5. Прочитайте текст, организуйте информацию, представленную в тексте, в виде опорной схемы. Перескажите текст, опираясь на полученную схему.

Particle board

Particle board, also known as particleboard and chipboard, is an engineered wood product manufactured from wood chips, sawmill shavings, or even saw dust, and a synthetic resin or other suitable binder, which is pressed and extruded. Particleboard is a composite material.

Particleboard is cheaper, denser and more uniform than conventional wood and plywood and is substituted for them when appearance and strength are less important than cost. However, particleboard can be made more attractive by painting or the use of wood veneers that are glued onto surfaces that will be visible. Though it is denser than conventional wood, it is the lightest and weakest type of fiberboard, except for insulation board. Medium-density fibreboard and hardboard, also called high-density fiberboard, are stronger and denser than particleboard. Different grades of particleboard have different densities, with higher density connoting greater strength and greater resistance to failure of screw fasteners.

A major disadvantage of particleboard is that it is very prone to expansion and discoloration due to moisture, particularly when it is not covered with paint or another sealer. Therefore, it is rarely used outdoors or places that have high levels of moisture, with the exception of some bathrooms, kitchens and laundries, where it is commonly used as an underlayment beneath a continuous sheet of vinyl flooring. It does, however, have some advantages when it comes to constructing the cabinet box and shelves. For example, it is well suited for attaching cabinet door hinges to the sides of frameless cabinets. Plywood has the potential to feather off in sheaves when extreme weight is placed on the hinges. In contrast, particle board holds the screws in

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place under similar weight. Additionally, particleboard is favored for cabinet shelves that need to span a long width (30"or more) since it will not bow under the weight like plywood.

Particleboard or chipboard is manufactured by mixing wood particles or flakes together with a resin and forming the mix into a sheet. The raw material to be used for the particles is fed into a disc chipper with between four and sixteen radially arranged blades. The particles are first dried, after which any oversized or undersized particles are screened out.

Resin, in liquid form, is then sprayed through nozzles onto the particles. There are several types of resins that are commonly used. Amino, formaldehyde based resins are the best performing when considering cost and ease of use. Urea Melamine resins are used to offer water resistance with increased melamine offering enhanced resistance. Phenol formaldehyde is typically used where the panel is used in external applications due to the increased water resistance offered by phenolic resins and also the colour of the resin resulting in a darker panel. Melamine Urea phenolic formaldehyde resins exist as a compromise. To enhance the panel properties even further the use of resorcinol resins typically mixed with phenolic resins are used, but this is usually used with plywood for marine applications and a rare occasion in panel production.

Panel production involves various other chemicals – including wax, dyes, wetting agents, release agents – to make the final product water resistant, fireproof, insect proof, or to give it some other quality.

Once the resin has been mixed with the particles, the liquid mixture is made into a sheet. A weighing device notes the weight of flakes, and they are distributed into position by rotating rakes. In graded-density particleboard, the flakes are spread by an air jet that throws finer particles further than coarse ones. Two such jets, reversed, allow the particles to build up from fine to coarse and back to fine.

The sheets formed are then cold-compressed to reduce their thickness and make them easier to transport. Later, they are compressed again, under pressures between two and three megapascals and temperatures between 140 °C and 220 °C. This process sets and hardens the glue. All aspects of this entire process must be carefully controlled to ensure the correct size, density and consistency of the board.

The boards are then cooled, trimmed and sanded. They can then be sold as raw board or surface improved through the addition of a wood veneer or laminate surface.

Задание 6. Дайте дефиницию понятия древесина.

Задание 7. Прочитайте текст, организуйте информацию, представленную в тексте, в виде опорной схемы. Перескажите текст, опираясь на полученную схему и схемы «Древесные породы» и «Изделия из древесины».

Wood

Wood has been used as a building material for thousands of years in its natural state. Today, engineered wood is becoming very common in industrialized countries.

Wood is a product of trees, and sometimes other fiberous plants, used for construction purposes when cut or pressed into lumber and timber, such as boards, planks and similar materials. It is a generic building material and is used in building

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just about any type of structure in most climates. Wood can be very flexible under loads, keeping strength while bending, and is incredibly strong when compressed vertically. There are many differing qualities to the different types of wood, even among same tree species. This means specific species are better suited for various uses than others. And growing conditions are important for deciding quality.

"Timber" is the term used for construction purposes except the term "lumber" is used in the United States. Raw wood (a log, trunk, bole) becomes timber when the wood has been "converted" (sawn, hewn, split) in the forms of minimally-processed logs stacked on top of each other, timber frame construction, and light-frame construction. The main problems with timber structures are fire risk and moisturerelated problems.

Схема 23. Древесные породы

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