Coefficient of stacking of crushed firewood: calculation of loading volume

The coefficient of stacking of crushed firewood in the truck body is a critical parameter that determines the final cost of the fuel lot and the actual volume of the imported goods. When ordering wood for firewood, for example, for GAZelle or KAMAZ, the buyer often faces a situation where the visually complete body actually contains much less wood than stated by the seller in cubic meters. Understanding the principles of calculating the conversion rate allows you to avoid overpayments and controversial situations when accepting cargo, since it depends on the density of the stacking how much real fuel will get into your plywood.

The main problem is that wood is not a liquid or bulk cargo that can be compacted to a monolithic state. Between the logs inevitably formed voids, occupying up to 40-50% of the body volume. Stowage factor It is a quantity that shows how much of the total volume is occupied by wood itself, and what is air. For crushed wood, this indicator varies depending on the type of wood, the length of the logs and, most importantly, the way they are placed in the vehicle body.

What is the conversion rate and what it depends on

In the forestry industry and solid fuel trade, there are strict standards governing the conversion of a folding meter to a dense one. Conversion factor This is a numerical indicator by which the volume of the stack is multiplied (folding meter) to obtain the volume of pure wood (dense meter). For crushed firewood, which is most often transported for sale for heating, this ratio is usually lower than for neatly folded wood wood wood wood, due to the chaotic loading.

The value of the coefficient directly depends on several technical factors. First, it is the geometry of logs: long, straight churks are stacked tighter than short and curved boughs. Second, the wood species is important: heavy rocks such as oak or birch often have a smoother chip than conifers, which affects the stacking density. Third, humidity plays a role: dry wood has a smaller volume at the same weight, but when loaded "by eye" the difference in volume may not be obvious without weighing.

• 🌲 Wood species: Hard hard hardwoods (oak, beech, ash) give a lower shrinkage coefficient when peeled than soft (axis, poplar), which affects the final volume.
• 📏 Length of logs: The standard length of 25-33 cm allows you to stack firewood denser than long meter long chunks, which create large voids at the sides of the car.
• 🚛 Body type: Body with high sides (KAMAZ, ZIL) allow you to create greater pressure of the lower layers on the upper, increasing the density, unlike open sides of GAZelle.

It is important to understand that when manual loading in bulk, the coefficient can be minimal, since workers tend to throw firewood as quickly as possible, without caring about density. If mechanized bucket loading is used, the density may be higher, but the risk of damage to the body or overspray also increases. The average coefficient for crushed wood loaded in bulk is 0.7-0.75, whereas for neatly folded firewood it can reach 0.8.

Comparison of loading methods: in bulk and rows

The way of loading firewood into the car body is the first factor that catches the eye when accepting goods. There are two main methods: loading in bulk (chaotic) and stacking in rows (stalling). When delivering firewood to private individuals, the method is most often used bulkingIt requires less time and effort on the part of the supplier. However, it is this method that gives the greatest error in volume and the lowest stacking coefficient.

When stacked in rows, or stacked, the firewood is arranged in a certain order, often with cross dressing, which minimizes voids. This method allows you to achieve a stacking coefficient of up to 0.8 and above. However, in commercial delivery conditions on small trucks such as the GAZelle, stacking is practically not used due to the length of the process. In the body of KAMAZ or ZIL with high sides, partial stacking at the sides is sometimes practiced for the stability of the cargo.

The difference in volume between different loading methods can be significant. If you ordered 5 cubic meters of wood, then when loaded in bulk you will actually get about 3.5-3.75 cubic meters of dense wood. With careful laying, this volume can grow to 4 cubic meters or more. For the consumer, this means that when buying in bulk, the price per cubic meter should be lower to compensate for the smaller actual mass of the fuel.

⚠️ Attention: If the seller claims that the stowage coefficient for bulk loading is 0.9 or 1.0, this is clearly fraud. It is physically impossible to fill 100% of the body volume with crushed wood without pressing.

Calculation of the volume of wood in different types of cars

To accurately understand how much firewood will enter the car, it is necessary to take into account not only the stacking coefficient, but also the geometry of the body. Different models of trucks have different capacity and configuration of the sides, which affects the final loading volume. Below is a table with indicative data on popular truck models used for the transportation of firewood.

Type of vehicle	Body volume (m3)	Coef. laying	Actual volume of wood (m3)
GAZelle (board 3m)	4.0 - 5.0	0.65 - 0.70	2.6 - 3.5
ZIL-130 (dump truck)	5.0 - 6.0	0.70 - 0.75	3.5 - 4.5
KAMAZ (timber truck/dump truck)	10.0 - 12.0	0.75 - 0.80	7.5 - 9.6
Ural (logging truck)	12.0 - 14.0	0.75 - 0.80	9.0 - 11.2

In calculating the volume for GAZELES It is worth considering that often the wood is loaded with a slide, which visually increases the volume, but physically it is only a mound that quickly crumbles during transportation. Therefore, the real coefficient for GAZelle is often in the lower limit of the range - about 0.65. For heavy duty trucks, such as KAMAZ or uralDue to the height of the sides and the possibility of tamping the lower layers, the coefficient is higher.

It is also worth remembering the bulk density. One folding meter of birch wood weighs about 500-600 kg, while oak wood weighs up to 700-800 kg. Knowing the load capacity of the car, you can easily check the honesty of the seller. If a 5-ton ZIL loaded a “full body” of light aspen firewood, and the car barely bent the springs, then the volume there, and the density (mass) – no.

The influence of humidity and wood on styling

The humidity of wood is a hidden parameter that significantly affects the volume and weight of firewood. Freshly cut wood contains a large amount of water, which evaporates when drying, reducing the mass, but practically not changing the geometric volume of the log. However, when peeling raw firewood, they can cut less smoothly, forming more chips and small fractions that fill the voids, artificially increasing the stacking rate, but reducing the quality of the fuel.

Different types of wood behave differently when peeled and stacked. Birch and oak when splitting give a smooth chip, which allows the logs to fit closer to each other. Aspen and alder often have a fibrous structure, which is why the peg forms "shaggy" edges that interfere with dense stacking and create additional voids. Pine and spruce containing a lot of resin, when drying, can crack along the fibers, which also changes the geometry of the log.

When buying, it is important to consider that wood-wood They are the same size as dry ones, but they weigh much more. If the calculation is carried out in cubic meters, then it is more profitable for you to buy dry firewood, since in the same volume they will be more in weight (energy intensity). If the sale is by weight (tonnage), then the difference in humidity does not play a role for the wallet, but plays for logistics.

How to determine humidity in the eye

Dry wood has cracks on the ends, make a ringing sound when hitting each other and do not leave traces of moisture on the hands. Raw wood is heavier, have a darker color on the cut and when burning, hiss strongly.

GOST regulations and legal aspects of the purchase

In the Russian Federation, the main document regulating the accounting of timber products is GOST 3243-88 "Wound." Technical specifications”. According to this standard, wood is measured in folding meters. The conversion of the folding meter into a dense one is carried out using coefficients approved for different types of wood and methods of laying. For wood chipped with a length of up to 0.25 m and 0.33 m conversion coefficients in dense cubic meters are 0.72 and 0.76, respectively (when laid in a pulp).

However, when delivered in bulk in the back of the car, these standards are often ignored by both parties, which leads to conflicts. Legally, if the check or contract indicates “piercing wood, volume 5 m3”, the seller is obliged to bring 5 cubic meters measured by the dimensions of the body (length, width and height of the embankment). If the firewood is with a large slide or with huge voids, this is a violation of the terms of delivery.

The buyer has the right to demand recalculation or re-weighing of the cargo if there is suspicion of fraud. In the case of a trial, the court will rely on the act of measurement and data of GOST. Therefore, the presence of photofixation of the unloading process and measurement of body dimensions is an important insurance for the consumer.

⚠️ Attention: Oral agreements on a “full machine” have no legal effect. The consignment note must indicate the exact volume in cubic meters or the weight in tons/kilograms.

Practical advice on the reception of wood

To minimize the risks and get exactly the amount of fuel you paid for, you should adhere to a certain algorithm of actions when accepting firewood. Do not rely on the honesty of the seller, especially if the transaction is made with an individual or through an intermediary without documents. Control begins even before the arrival of the car - with the clarification of the model of the car and the type of body.

At the time of unloading, care must be taken not to scatter firewood over a large area, which will make subsequent measurement difficult. If possible, it is better to take firewood in an already prepared container or container, the volume of which you know. This is the most reliable way to check.

• 📸 Photos: Take photos of the machine before unloading, during the process and the empty body to capture the load level.
• 📏 Measurements: Use the roulette to measure the length, width and height of the layer of wood in the body immediately after arrival, before unloading.
• ⚖️ Weighing: If the volume is doubtful, offer to weigh the machine on the nearest scales (before and after unloading) - this is the most objective method.

It is also worth paying attention to the presence of large-sized logs ("churok") that have not been punctured. They take up a lot of space, but in fact are a marriage, as they can not be used normally without additional preparation. The presence of a large percentage of such logs should be the basis for recalculating the volume or reducing the price.

Frequently Asked Questions (FAQ)

How to convert cubic meters of wood into tons?

To translate, you need to know the density of wood. The average density of birch wood is about 600-700 kg / m3 (in a dense body). For crushed firewood in the machine, multiply the volume by the stacking coefficient (for example, 0.7), and then by the density. Example: 5 m3 × 0.7 × 650 kg/m3 ≈ 2275 kg (2.2 tons).

What is the coefficient to use to calculate firewood in GAZelle?

For GAZelle with sides loaded with crushed wood in bulk, it is recommended to use a coefficient of 0.65-0.7. This means that out of 4-5 cubic meters of the body volume of really useful wood will be about 2.6-3.5 cubic meters.

Why do wood brought in the car take up less space in the woodwork?

It's because of the sealing. In the body of wood lie chaotic with a lot of voids. When you lay in a slab, you manually remove these voids, placing logs closer to each other. The volume is visually reduced, but the amount of wood remains the same.

Can I ask for a recount if the wood is wet?

Yes, you can. Humidity affects weight, but not volume. However, if the wood is so raw that it is rotten or has a non-standard shape that prevents stacking, this can be considered a quality violation. The contract should specify that the wood must comply with GOST 3243-88, which regulates the humidity of not more than 50% (for natural drying firewood).

Which is better: buying wood in cubes or by weight?

Buying by weight is more profitable if you can control the weighing, as the void factor is excluded. Buying in cubes is more profitable if the wood is dry and crushed finely, since more mass fits into the volume. In the market conditions, most often sold in cubes, so it is important to know the stacking ratio.