Seminar “Efficient pellet production”

How to measure how many cubic meters of firewood are in a car?

If the volume of the body (width * length * height) is 10 cubic meters. m, and the length of the logs is 50 cm, then in the machine there are 10 * 0.75 = 7.5 “folded” cubic meters of firewood. To convert folded cubic meters into real ones, we multiply the volume by a factor of 0.7 (see above).

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Mass calculation

The calculation instructions are quite simple.
This is done as follows:

• The weight of one beam is equal to the weight of a cube of lumber/divided by its quantity.
• To determine the number of pieces in a cube, you need to know its dimensions. For example, you need to find out the weight of a beam is 100x150x6000, first we find out the amount of material: 1: 0.100: 0.150: 6 = 11.1 pcs.
• Knowing the mass of the cube and the number of pieces, it is not difficult to calculate how much a 100x150 beam weighs: 860/11.1 = 78 kg

Below is the weight of pine beams of different sections:

• 150x150x6000 mm - 7.4 pieces fit in one cubic meter, its weight is 860 kg. Weight 1 pc. section 150x150 is 116 kg.
• Weight1 pcs. cross section 150x100 equals 78 kg, 11.1 pieces fit in one cubic meter.
• Weight 1 pc. cross section 100x100 equals 52 kg, 16.6 pieces fit in one cubic meter.

Approximate price for timber

A solid beam is a regular log, processed along four edges to give the correct geometric shape. Even despite the far from the most advanced technology for its production, it is quite possible to build from such material not only a budget bathhouse, but also a decent country house for permanent residence. In any case, it will be several times cheaper than a house made of laminated veneer lumber.

We analyzed the current state of affairs on the Russian building materials market and compiled a small table that reflected the average price range per cubic meter and linear meter of solid timber.
Below are the most popular sizes of non-profiled material, both natural moisture and dried to optimal humidity. Indicative data on prices for non-profiled solid timber (2013)

Prices may vary from company to company. Much depends on the quality of the lumber, compliance with the declared dimensions, and production technology.

What is the best firewood for burning?

Oak firewood is considered the most optimal in terms of calorific value, followed by birch, aspen and pine.

• Oak contains few resins, but emits a lot of carbon monoxide. The tart aroma of burning oak logs tones the body.
• Birch firewood burns for a long time and evenly, but has a lot of resinous substances and deposits soot in the chimney.
• Conifers are also used less frequently due to their high resin content.
• It is not recommended to use firewood from poplar, as it emits an unpleasant, bitter odor and produces little heat.

It is best to use hardwood firewood, which has a high specific gravity. It is advisable that the firewood be dry and not freshly cut. Let us remind you that when buying wet firewood, you pay more for weight, but get less heat.

Computing problems

To calculate a screw foundation - the number and type of supports, we need the following information:

• Total volume of wooden structures.
• The average specific weight of wood is kg:m3 or t/m3.
• Load-bearing capacity of one screw pile.

There are two obvious problems here:

1. Calculating the volume and weight of walls is relatively simple, but calculating the total load on the foundation is much more difficult. It includes at a minimum the weight of floors, roofing, household items, snow on the roof and the occupants of the house.
2. The design load on a pile is determined not only by the diameter of its shaft and blades, but also by the type of soil: different soils have different bearing capacity.

The first problem is solved simply and elegantly: it has long been noted that with a balanced structure, the mass of the external walls is approximately 50% of the total mass of the house. Accordingly, an approximate calculation of the weight of a wooden house can be done by finding the weight of the vertical enclosing structures and doubling it.

The walls of the log house provide half the mass of the house.

The calculated load-bearing capacity of piles for different soils is a little more complicated: here you will have to operate exclusively with reference data. We will try to make life easier for the reader and present them here.

Types of timber

The timber is made solid, glued, profiled.

Solid is made from the whole core of a log. It has sufficiently high strength and high thermal insulation properties. Compared to other types, it has a lower cost.

Glued laminated timber consists of well-dried boards glued together. The boards are pre-processed thoroughly. Bonding occurs using water- and air-tight glue. It has a low degree of shrinkage, excellent thermal insulation properties, and is resistant to deformation. According to the standard, the surface of the laminated timber should be perfectly flat.

Important! Angara pine has the greatest strength and durability. Releases substances that have a beneficial effect on the human respiratory system. Profiled material has a fairly high cost, but has the greatest strength

Thanks to the system of grooves and tenons, it has the greatest thermal insulation properties and is easily joined together. No moisture will penetrate into the joints, even in heavy rain. Therefore, mold will not grow between the joints. Guaranteed not to be subject to deformation during the entire service life

Profiled material has a fairly high cost, but has the greatest strength. Thanks to the system of grooves and tenons, it has the greatest thermal insulation properties and is easily joined together. No moisture will penetrate into the joints, even in heavy rain. Therefore, mold will not grow between the joints. Guaranteed not to be subject to deformation during the entire service life.

Planed timber is used not only in construction, but also for making furniture. Only dried material is used. It has four high-quality processed planes. Due to the low moisture content, the service life is significantly increased.

Properly selected timber for a certain type of work will serve for a long time, creating coziness and comfort in the house.

How much will a log house for a house weigh?

When building a wooden house, you must know the weight of the log house in order to prepare for the construction of walls, pour the foundation, and order transport for transportation. The total weight of the structure depends on the choice of lumber, drying method, and wood density. There is a table with the weight of 1 cube of profiled lumber:

Glued material has its own weight indicators, which depend on many criteria: the method of making wood, the profile, the type of lumber, the mixture used for coupling, the processing method, etc. Therefore, its weight needs to be checked with the manufacturer, usually it ranges from 400 to 600 kg/m3 .

Let's take an average of 500 kg and calculate the weight of the above-mentioned 8x8 log house. We multiply the mass of one cube by the number of cubes:

We get the result: 18,000 kg or 18 tons - the net weight of the log house without taking into account insulation and other structures that can also be taken into account.

Dependence of board weight on moisture

If you need a board with natural moisture, the price depends on the weight of the cube of material and its moisture saturation:

• semi-dry products have a moisture content of 18 to 23 percent;
• a raw product with a moisture content of more than 23% is the cheapest - from $30 per cubic meter;
• dry edged board with a moisture content in the range of 12-18 percent costs $40-50 per cubic meter;
• dry lumber with a moisture content of 6-12 percent is the most expensive - from $60 per m³.

Depending on the dampness, the weight of the material also changes. For example, a cube of wet oak floorboards weighs 990 cwt. If the material is dried to a moisture content of 10%, then the mass of the cube will decrease to 0.67 tons. But the price for dried lumber will increase.

The increase in price depending on moisture saturation is justified by the fact that the characteristics of the product also increase:

• dried wood has stable geometric dimensions;
• it is resistant to rotting;
• the material is durable and flexible;
• wood is quickly and easily processed;
• ensures strong fixation by adhesive method;
• the product will last longer.

Heat transfer from wood

In addition, there is another indicator - heat transfer. It will come to the aid of those who use wood as firewood for heating. The higher the hardness, i.e. The density of the wood species, the higher its calorific value. Of course, no one will heat a room with boxwood, but when choosing between linden and pine or birch and acacia, you can get much more heat if you know which of these species is the hardest. Information about the density of each tree can be gleaned from the tables, since all this information is systematized for ease of use.

Weight of a dense cubic meter, kg

The table shows average mass values. Possible maximum and minimum mass values ​​are 1.3 and 0.7, respectively, from its average value

Wood quality.

Deciduous wood is divided into three grades, coniferous - into five.

The best grade lumber is called selected ( marked with a horizontal stripe or the letter “O”

), the remaining varieties are designated by numbers 1-4 (
marked with the corresponding number of dots, vertical stripes, or simply a number
).

The quality of lumber is assessed based on the worst side or edge.

The grade is determined by the presence/absence of knots, rot, cracks, warping and deformation, wormholes, the degree of precision of machining ( non-parallelism of planes and edges is regulated by GOST 24454-80

).

Wood 1st grade

used for the manufacture of elements of building structures, windows, doors, stairs (
for standard sizes of elements of stairs, see
), finishing of floors and walls.

2nd grade

goes to flooring, load-bearing building structures (
category II
), formwork, lathing and planed parts (
GOST 8442-75 and GOST 475-78
).

3rd grade

used for the manufacture of load-bearing structures (
category III
).

4th grade

Suitable for the manufacture of containers and small workpieces.

The permissible humidity of the 4th grade is not standardized. The humidity of other varieties should not exceed 22%.

If this value is exceeded, the lumber is called “raw” - a significant loss of its strength occurs.

Classification

For the production of various wooden products, round timber is used that meets the specified requirements and corresponds to the established classification. Types of timber are divided according to the following indicators:

• purpose;
• method of mechanical processing;
• appearance;
• assortment;
• grades;
• tree species;
• resistance to natural pests and climatic factors.

For further purposes, sawn wood is used for:

• sawing into various lumber (edged and unedged boards, timber, rounded logs);
• external processing (planing and peeling);
• processing into wood pulp (sawdust, shavings, chips) and cellulose;
• used in round form (construction of houses and utility buildings).

According to the method of mechanical processing, they are divided into classes:

• round logs (obtained by sawing a log into pieces of a certain size. A high-quality log is sawed lengthwise into logs measuring 6 m or 3 m, depending on further use);
• sawn - obtained by transverse division on special machines;
• planed - obtained as a result of processing on veneer cutting machines;
• peeled;
• chopped;
• crushed.

Based on their appearance, the timber obtained by sawing a tree cane is divided into the following products:

• round logs (round timber);
• construction products and structural elements (beams, rafters, floors, etc.);
• lumber and blanks for various purposes;
• particle boards, wood fiber boards, OSB boards;
• granules and pellets.

The class of planed timber includes boards, beams, rafters and ceilings, and furniture blanks.

The grade of round timber is determined by the requirements of current standards and technical specifications.

For each assortment, requirements are defined, which include the following parameters:

• nominal geometric dimensions (length, crown diameter);
• permitted tolerances and allowances;
• permissible humidity level;
• wood class;
• the estimated volume of each product (based on these data, the total volume upon shipment is obtained).

Based on the cutting diameter, timber is divided into three categories:

• logs with a diameter of at least 12 cm at the top of the cut;
• sub-product with a cut diameter from eight to eleven centimeters;
• poles with a diameter of 3 cm to 7 cm.

Each size is determined taking into account the purpose of the future final product. For example, for round timber whose thickness does not exceed 13 cm, a diameter gradation of 1 cm is accepted. For a cut diameter of more than 14 cm, it is 2 cm. Rounding occurs to the nearest even diameter value.

Allowances are understood as the amount of mandatory addition to the length of the assortment. They ensure further production of lumber of the required sizes (taking into account drying processing). The usual size of allowances is from three to six millimeters. The dimensions of the allowances are determined separately for coniferous and deciduous species and are determined by the relevant standard.

The grade of timber determines its quality and physical and mechanical properties. According to this indicator, wood is divided into four grades:

• 1st grade is large-sized wood without knots or a small number of them (used for the manufacture of parts in ship and aircraft construction, parts for which there are increased requirements for reliability and aesthetics);
• 2nd grade – logs from the middle part of the log (they make construction and finishing materials, various moldings, used in a round shape after external processing);
• 3rd grade is obtained from the central part of the whip with a certain number of knots;
• Grade 4 is used for the manufacture of containers and individual furniture elements. The main requirement for this variety is the absence of rot, internal rot, and deep surface blue.

Based on resistance to fungi and external parasites, timber is divided into two classes. The first class is resistant timber, the second is not resistant.

What does mass depend on?

The mass of the timber is determined, like the weight of any wood, by the following factors:

• dimensions, length of the timber board;
• dried - dry wood contains no more than 18% water, wet wood - more than 45%;
• the type and structure of the tree - for example, oak and pine have different densities, even when extremely dried;
• the presence of impregnation, which makes the wooden material somewhat heavier, even after the coating composition has completely dried.

The moisture content of wood is determined based on its storage conditions. After a year of storage in a warehouse, where precipitation (rain, snow, fog) and splashes of water are completely excluded, the wood dries out to an average of 21%. To reduce the humidity percentage to a minimum of 17%, dry and hot conditions are created in the room. In a hangar with steel walls and a roof, in the summer heat the temperature reaches +55, which speeds up the drying process; in winter, under Russian conditions, the warehouse is additionally maintained at an elevated temperature. The boards and beams are placed on spacers, and air circulates in the resulting cracks. Silica gel can be used to absorb moisture; In order to maximize the effectiveness of desiccant absorbers, the warehouse is tightly closed after ventilation. Conditions artificially created for dehydrating wood will prevent unnecessary idleness of wood and the appearance of mold and mildew on their surface.

Raw wood contains 24–45% moisture content. It is dried from the moment of cutting down (the workpiece itself) to a balanced (natural moisture) state. But wet (freshly cut), including floatable (downstream of the river), can contain up to half (by weight) of water: it is abundantly saturated with it. And for proper drying it may take up to a year of storage. The total weight of the cargo requested by the customer is the weight of each stack (or boards from a stack) multiplied by the number of units (stacks, boards, respectively). The mass of cubic meters of wood is a secondary factor for the user. First of all, the actual cubic meters taken from the warehouse after payment for the order are taken into account. But the total weight is important to the manager and the delivery driver: the more “cubes” of timber the client orders, the higher the fuel costs for the truck. Unlike slabs or other boards of unusual shape, as well as wood chips, shavings, sawdust, wood dust, bark, laminated veneer lumber, like a simple board or composite wood board, is simplified in calculating the mass of a cubic meter (and an individual instance of the material).

Sawdust weight

Sawdust remaining after sawing firewood or processing wood blanks on a circular saw is considered a very useful consumable material used for both household and construction purposes.

Since they belong to the category of waste, their quality and other characteristics are not subject to regulation and are not specified in the provisions of the current standards (GOST). To determine the weight of edged sawdust (birch, pine and any other), empirical methods (experimental, practical) are usually used, and in some cases tabular data is taken to find this parameter.

So, the main factor determining the density or weight characteristics of lumber, raw wood or sawdust is their moisture content. Strict and accurate accounting of this parameter makes it possible to calculate specific indicators with a sufficient degree of accuracy.