How to calculate timber round timber in cubes calculator. Several ways to calculate the cubic capacity of timber

For many builders, the topic of calculating the number of logs in a cube is familiar. But for an unprepared person, this may seem not only very distant, but also incomprehensible. And very often there are disagreements between the builders themselves, as well as between the builders and the customer about how many logs should be in a cube.

In order to deal with this problem, a mathematical method is usually used, which in a few minutes can give a clear answer about how many logs are needed for a certain number of cubic meters.

As a rule, rounded logs are used in the construction of wooden buildings. But this material may differ in size, that is, in length and diameter. The unit of measurement is taken to be centimeters. There are one million centimeters in one cubic meter. Thus, first you need to decide on the size of the logs.

In order to measure the size of the logs, you will need a regular centimeter tape measure. All logs, as a rule, should initially be of the same size, and later, depending on the project, they are sawn into the necessary elements.

So, having measured the size of the log with a tape measure, we get the values ​​\u200b\u200bof the length and diameter in centimeters. For example, let's try to calculate how many logs are needed for one cubic meter if the logs are six meters long and eighteen centimeters in diameter.

The following formula is required for the calculation:

Volume = Pi * Radius * Radius * Length.

Six meters in this case equals six hundred centimeters. Pi is always 3.14. We get the radius by dividing the diameter by two. Thus, our formula takes the following form: Volume \u003d 3.14 * (18: 2) * (18: 2) * 600 \u003d 3.14 * 9 * 9 * 600 \u003d 152604 centimeters. To convert to cubic meters, divide the resulting number by one million: 152604: 1000000 = 0.1526. This result tells us that one log of this size will take up only 0.15 with a small cubic meter.

Now you need to figure out how many logs are in a meter. This is our main task. To do this, we will divide one cubic meter by the result of our calculations - 0.1526. It turns out: Quantity = 1: 0.1526 = 6.55 logs. It turns out that for one cubic meter we need to take about seven logs of a given size.

If we consider logs of a larger diameter, for example, twenty-four centimeters, then the calculation results will be different:

Volume = 3.14 * 12 * 12 * 600 = 271296 cubic centimeters = 0.2713 cubic meters.

This means that in one cubic meter there will be: 1: 0.2713 \u003d 3.69 logs. In this case, there will be fewer logs in one cubic meter.

To calculate the number of logs per cubic meter, a very simple formula is used, which allows you to calculate the result in a matter of minutes. For calculations, of course, it is better to arm yourself with a tape measure and a calculator.

Timber is often used for construction: log cabins, bathhouses, gazebos, and other buildings. But then, in order to make a purchase, initially preparing a real amount of materials, you need to know their volumes (cubic capacity). How to calculate the volume of a log?

Traditionally, it is measured in cubic meters, and all this is called cubic capacity. Let's see how to calculate it correctly. There are methods that are used to determine the volumes of round timber and other timber required for the purchase / sale.

This method is to measure the volume of space where the building material is located. As a rule, this is a warehouse or a barn, a woodpile or a truck body, other containers of conditionally rectangular shapes. And in order to calculate the volume of a log in a certain room, you need:

1. Measure the volume of this space (cubic). To do this, we measure the width, length and height of the place for storage or transportation. We multiply the measured dimensions. The resulting will be the volume.
2. Of course, it should be taken into account: logs stored, for example, indoors, or transported in a truck, will not occupy the entire space, layers are formed between them, and they should be excluded from the calculated volume. Experts say: such segments can occupy up to 20 percent of the total space. Accordingly, 80 - the wood itself will take. That is, the emptiness coefficient, which is used in this formula, will be 0.8. To calculate the cubature of a log, it will be necessary: ​​multiply the volume of the warehouse by the appropriate coefficient (0.8). The figures obtained will be the cubic capacity of the log we need.

Method two: formula

This calculation method is most suitable for timber that is approximately the same in length and has a diameter similar to each other. The following formula is used for calculations: π *R*L, where π is equal to 3.14, R is the radius of the log, and L is its length.

Tip: building materials in the form of logs, of course, have a similar diameter, but still, they are slightly different from each other. And in order to get the most accurate result, it is necessary to measure the volume of any three units from the batch - according to the above formula. And then these parameters are summed up and divided by 3. We have an average number. We multiply the figures obtained by the number of logs at our disposal and get the volume.

Method three: tables

This technique is used by craftsmen quite often in determining the volume of logs necessary for the construction of the calculation. These are ready-made tables, which show the already calculated figures that have been developed empirically. So, we measure the diameter of the log and its length, substitute these values ​​in the table (see below) and get what we are looking for at the intersection of the columns.

Also, in order to correctly calculate these values, a cube is used according to GOST 2708-75, where, according to generally accepted construction conditions, the required numbers are also indicated, depending on the 2 initial ones: the length and diameter of the log.

For example, here are the following tables:

And for calculations, they use an online kubaturnik, for example, of the following plan: http://www.enerteh.ru/news/kubaturnik.html

Calculation algorithm example

The algorithm for obtaining data is practically simple to implement. For example:

1. According to the drawing of the premises, we consider the total amount of lumber (round timber) that will be used in the construction of the planned building.
2. When determining the quantity, we take into account the required (or desired) thickness of timber (that is, their diameter).
3. We measure the average volume of the log. Knowing the total amount that is available, we get the final volume of round timber, which is necessary for construction. We calculate the approximate volume of a log using the formula (see above) or according to the table.

Building material is often not perfectly round

To use this algorithm, it is necessary that round lumber meet certain criteria:

• the shape should be conditionally cylindrical;
• logs should be approximately the same length and diameter.

The matter becomes more complicated if it is necessary to calculate the cubic capacity of building materials of various formats. Therefore, the methods for calculating the cubic capacity for rounded and unprocessed logs are somewhat different.

Even at the stage of thinking about your own house made of wood, the owner of a private plot comes to the question - how much wood will be needed for construction. And this is not an idle interest. For example, if there is not enough lumber for construction or there is an excess of it, then in both cases you will have to overpay. How to correctly calculate the cubic capacity of a log house, so that at the same time it is enough for a residential building completely, but without a large amount of excess wood?

Simple calculation

It would seem, based on school knowledge, there is nothing easier. Having found out the length, height and width of a log or beam, you can simply multiply and get the result of the dimensions of a wooden box. However, the diameter of the material should not be overlooked, it directly affects the final figure and the width of the compensation cut, which leaves the original size of the logs, but significantly reduces the amount of wood.

It becomes clear that calculating the volume of a log house is not a very simple matter, especially taking into account the ways of connecting the corners - with and without the remainder. But still doable. So, we have the desired size 6 × 6 and in this example we will analyze the required amount:

• First of all, you need to learn that the larger diameter of the logs will ultimately come out as a plus in the overall cost of money. After all, a built house will cost a smaller layer of insulation, or even without it at all.

Thus, it becomes clear that the construction must be carried out with a log with a diameter of 26 cm and above. So - the first known size - diameter = 0.26 mm.

• Next, the height of the log house. It is impossible to calculate a log house for a house without taking into account the height. Usually it is 2.4 m per floor in a pure internal version.

But let's take an external height of 3 m as the required amount. Now it will not be difficult to calculate logs for one wall - 3 / 0.26 = 11.5 pcs. Round up to 12 and add the base crown element. The total number of logs per wall = 13 pcs.

• Now let's make a calculation for all the walls of the log house. Let's take a five-wall as an example, since the lengths of the sides are the same, then it is not difficult to calculate a log house by the number of logs - 13 × 5 = 65 pcs. That is, to build a house 6 × 6 with a log diameter of 26 cm, 65 logs will be required.

But the material is not bought by the piece. For this, there is such a measure as volume. Of course, you can go to the sawmill and poke your finger into the logs to indicate what material is needed, but it will look more than strange.

• According to the well-known school formula - π * R² * L, we will find the volume of one log. Multiplying the data - where R is the radius of the deck, and L is the length, we get the result 0.32 m³.

Now, evaluating the offers on the market of sawn timber companies, one can realize whether the average family will pull the wooden construction from the array. The proposed option is a large house, even one floor high.

To this it is worth adding the costs of the foundation, truss system and finishing, which together can give an increase in the project amount by more than 2 times. By the way, you can calculate a log house from a bar using the example given, and its cost is lower than a log.

Table of cubature calculations for material of various diameters

To facilitate complex calculations for users, here is a table of ready-made cubature calculations for a certain array diameter:

It is important that everything in excess of the presented length and volume should be left to specialists, because the construction of such whips will not do without the use of special equipment, which means that it is much cheaper and faster to entrust the work to professionals by ordering a turnkey log house from the company. Before concluding an agreement, you can ask the manager of the company how the cubic capacity is calculated.

Answering all the questions of interest to the client is his sacred duty. Perhaps the knowledge gained will serve as a support for the independent construction of an object other than a residential building.

Calculation for a bath

To build your own steam room, you do not need to resort to the services of specialists - it will not be difficult to independently calculate the log cabin of the bath.

A typical 3 × 5 project will take a little time to build and such a structure will consist of functional premises - nothing superfluous, but convenience is not lost.

So this is:

1. Steam room.
2. Washing room.
3. Dressing room.

Based on the wishes of all households, the steam room and washing room can be combined. Thus, the need for one wall is eliminated.

But you should take into account the health features of all visitors to the bath - perhaps someone does not tolerate steam. Yes, and washing at a constant temperature is not a very pleasant experience even for avid lovers of the Russian bath.

Solving the problem - how to calculate a log house for a house, can be quite easy using the above material and formulas. But do not flatter yourself and talk about the figures received as specific - you will have to take into account window and door openings, but not immediately, in order to subtract from the total, but to accept them as a due expense. Otherwise, it will turn out that the array will have to be purchased again.

There is also a risk of purchasing substandard raw materials - spoilage, knots, wormholes - all this will further affect the amount of money spent. Remember that even rich and wealthy clients cannot afford to throw money away, so they use a working rule - you can not save on quality.

It makes no sense to make the same calculations several times if the original data does not change. A rounded log with a diameter of 20 cm and a length of 6 meters will always have the same volume, regardless of who and in which city conducts the count. Only the formula V=πr²l gives the correct answer. Therefore, the volume of one OCB will always be V=3.14×(0.1)²×6=0.1884 m³. In practice, in order to exclude the moment of carrying out standard calculations, cubes are used. Such useful and informative tables are created for various types of lumber. They help to save time and find out the cubic capacity of round timber, boards, CBM, and timber.

The name of this building guide is due to the fact that the volume as a physical quantity is measured in cubic meters (or cubic meters). For a simpler explanation, they say "cubature", respectively, the table was called "cubature". This is an ordered matrix, which contains data on the volume of one product for various initial parameters. The base column contains sections, and the row contains the length (molding) of the material. The user only needs to find the number located in the cell at their intersection.

Let's consider a specific example - a cubic yard of roundwood. It was approved in 1975, is called GOST 2708-75, the main parameters are diameter (in cm) and length (in meters). Using the table is very simple: for example, you need to determine the V of one log having Ø20 cm with a length of 5 m. At the intersection of the corresponding row and column, we find the number 0.19 m³. A similar cube for round timber exists according to another standard - ISO 4480-83. Reference books are very detailed in increments of 0.1 m, as well as more general, where the length is taken in 0.5 m.

little secrets

The very use of the cube is not difficult, but the main nuance is the correct data. Round wood is not a cylinder, but a truncated cone, in which the lower and upper cuts are different. One of them can be 26 cm, and the other - 18. The table assumes an unambiguous answer for a particular section.

Various sources suggest doing it in two ways: calculate the average value and take the volume from the reference book for it, or take the size of the upper cut as the main section. But if the tables were compiled according to certain standards, then they must be used in accordance with the accompanying instructions. For a cubature GOST 2708-75, the diameter of the upper saw cut of the log is taken. Why is the raw data moment so important? Because with a length of 5 meters for Ø18 cm we get 0.156 m³, and for Ø26 cm - 0.32 m³, which is actually 2 times more.

Another nuance is the correct cubes. If complex formulas for truncated cones were used in the GOST 2708-75 table, calculations were carried out, and the results were rounded to thousandths, then modern companies that make up their own cubes allow themselves “liberties”. For example, instead of 0.156 m³, there is already the number 0.16 m³. Often, frankly erroneous cubic meters are posted on Internet sites, in which the volume of a log 5 meters long with Ø18 cm is indicated not 0.156 m³, but 0.165 m³. If an enterprise uses such directories, selling roundwood to consumers, then it makes a profit, in fact deceiving customers. After all, the difference in 1 product is significant: 0.165-0.156=0.009 or almost 0.01 m³.

The main problem of round timber is a different section. Sellers offer to resolve issues with calculations in the following ways:

• calculation of the volume of each unit and summation of the obtained values;
• storage method;
• finding the average diameter;
• method based on the density of the wood.

1. It must be said right away that the first of the indicated options gives the correct results. Only the calculation of the volume of each log and the subsequent addition of the numbers ensures that the buyer will pay for the timber that he will receive from the company. If the length is the same, then it is enough to find the cross-sectional areas of all the trunks, add them up, and then multiply by the length (in meters).

2. Warehousing method.

It is assumed that the stored round timber occupies a part of the space that has the shape of a rectangular parallelepiped. In this case, the total volume is found by multiplying the length, width and height of the figure. Given that there are voids between the stacked trunks, 20% is subtracted from the resulting cubic capacity.

Minus - the acceptance as an indisputable fact that the tree occupies 80% of the total space. After all, it may well happen that the bars are folded inaccurately, thereby the percentage of voids is much greater.

3. Density based method.

In this case, you need to know the mass of the forest and the density of the wood. The cubature is easily found by dividing the first number by the second. But the result will be very inaccurate, since a tree of the same species has a different density. The indicator depends on the degree of maturity and humidity.

4. Average method.

If the trunks of harvested trees are almost the same in appearance, then any 3 of them are chosen. Measure the diameters, and then find the average value. Further, according to the cubature, the parameter for 1 product is determined and multiplied by the required amount. Let the results show: 25, 27, 26 cm, then the average is Ø26 cm, since (25 + 26 + 27) / 3 = 26 cm.

Given the disadvantages of the considered methods, the only correct way to calculate the cubature can be considered to be the volume of each log using the cubature GOST 2708-75 or ISO 4480-83 and summing up the data obtained.

In the industrial harvesting of roundwood, it is quite difficult to determine its cubic capacity. To accurately calculate the volume of each log, you can use the truncated cone volume formula, which takes into account the main diameters of both cuts and the length of the log itself.

Round wood is very convenient and practical for building houses, baths and other residential and non-residential premises.

In fact, the cubic size of the roundwood is not calculated in such a complicated way. It is accepted all over the world to count it in a faster way. Special tables are used for this.

How to calculate the cubic capacity of a single tree without additional measurements?

A few years ago, to calculate the volume of a single tree, they used the product of the arithmetic mean of the areas of saw cuts and the length of the tree. With the help of a meter (reminiscent of an ordinary caliper), the diameter of the tree in its middle part was determined. Then it was multiplied by 3 and the cross-sectional area was obtained.

Further, the resulting number was multiplied by the length of the workpiece, and a volumetric result was obtained. This method of calculation is inaccurate, since the thickness of the bark is not taken into account. The number Pi was taken with a large deviation from the real one, and the formula in its distorted form gave large errors.

The formula itself looks like this: the diameter of a rounded log is divided by 2 and squared, then multiplied by Pi and the length of the log.

Even if we measure the thickness of the bark and take this into account to determine the diameter of the tree itself, then deviations from these indicators will be inaccurate, although with a smaller error. More accurate calculations showed that the actual deviations in the calculations of the cubature of a round log with primitive measurements have a certain dependence on the parameters of the tree, which was taken into account when compiling the corresponding tables to determine the volumetric parameter. Let's try to figure out how to calculate the cubic capacity of the forest. This will require:

• roulette;
• the corresponding calculation tables, where there is a final cubature.

Back to index

?
Peculiarities .
How much does a board cube weigh?

Technology for calculating the volume of a single log

First you need to use a tape measure to measure the length of the tree and its diameter on the cut in the upper part (excluding the bark). After that, let's look at the tabular parameters: at the intersection of the line, where the length of the tree is indicated, and the column indicating the corresponding diameter, we find the volume of the measured body. Everything is simple and reliable.

Such calculations also cannot be called absolutely accurate, since the features in which the forest was grown and the shape of the trunk were not taken into account. But it is customary not to pay attention to such trifles with large volumes of workpieces.

Back to index

Calculation of volume of cubic capacity of stockpiled timber

With industrial volumes of harvesting round logs, other methods and tabular data are used. In essence, a round forest in a stored state has the shape of a rectangular parallelepiped. Calculations of its volume are familiar to everyone from school. But it is impossible to use this method, since the dimensions of the voids between the logs will not be taken into account. By the way, they also directly depend on the diameter of the logs, which can be calculated mathematically.

Through numerous calculations, the coefficient was determined, with the help of which a special table was compiled. It works similarly to the previously described table, with the only difference that the volume of the mentioned parallelepiped and the average thickness of the upper cut are taken into account. The cubic capacity of the forest can be calculated with great accuracy.

But one cannot hope for good accuracy of calculations with inaccurate stacking of forest products. This procedure is not used in the warehouse storage of timber, since in this case the volume that the round timber occupies directly in the warehouse is estimated.

It is very easy to calculate the cubic capacity after preliminary weighing the forest.

Next, you need to calculate the volume by dividing the mass of the forest by the density, which corresponds to the type of wood. Such a calculation cannot be considered ideal either, since the forest in different degrees of maturity has a deviation in density. The humidity of the wood can also play a special role here.