Board grade 0. Softwood lumber grades. General technical requirements

Real Specifications determine: quality requirements for lumber and furniture boards for valuable breeds wood used in the trade turnover of the company "ORIS TRADE".

Grade AA requirements (grade 0).

Requirements for grade AB (grade 1).

UPPER LAYER
- requirements as for grade AA (grade 0).

LOWER LAYER
- one-sided non-through healthy knots up to 12 mm in diameter are allowed, no more than two on one face of the board.
- Eyes (live light knots "in color" no more than 5 mm in diameter), except for group ones (" cat paw") without Borders.
- Sapwood without limits

QUALITY REQUIREMENTS FOR BEECH Lumber

Requirements for grade "AA"

UPPER LAYER and LOWER LAYER (variety-determining defects):
- The presence of one mineral inclusion up to 7 mm per linear meter
- Capturing a false core is NOT ALLOWED.

Requirements for grade "AB"

UPPER LAYER
- Like in grade AA

LOWER LAYER
- False core allowed without restriction
- No more than 3 live knots with a diameter of no more than 10 mm per layer are allowed
- Dead and rotten edge, edge and end knots “for processing” are allowed (for cutting or trimming - on the end or on the edge of the board)
- Mineral inclusions up to 10 mm are allowed 1 piece per linear meter

Requirements for grade "SS"

UPPER LAYER and LOWER LAYER (variety-determining defects):
- requirements as for grade B plate

NOT ALLOWED on all classes
- core, rot in all forms (tobacco, etc.), rotten falling knots, wormholes
- mushroom stains (blue and colored sap stains), gasket stains

For a beech board, the following variety-forming features are additionally distinguished:
- steamed beech - lumber that has undergone special processing ("steaming") and has a specific reddish color (the degree of color can vary from "pink" to "red" depending on the degree of steaming).
- unsteamed beech - lumber that has not undergone special processing ("steaming"), and has a natural color characteristic of beech lumber (white).

QUALITY REQUIREMENTS FOR ASH Lumber

Requirements for grade "AA"

UPPER LAYER and LOWER LAYER (variety-determining defects):
- The presence of one one-sided live knot with a diameter of not more than 7 mm on one layer
- Core capture is NOT ALLOWED.

Requirements for grade "AB"

UPPER LAYER
- Like in grade AA
LOWER LAYER
- One-sided non-through healthy knots up to 12 mm in diameter are allowed, no more than two on one face of the board.
- Dead and rotten edge, edge and end knots “for processing” are allowed (for cutting or trimming - on the end or on the edge of the board)

Requirements for grade "SS"

UPPER LAYER and LOWER LAYER (variety-determining defects):
- Unrestricted kernel allowed
- Allowed no more than 2 live knots with a diameter of no more than 10 mm per face
- Dead and rotten edge, edge and end knots “for processing” are allowed (for cutting or trimming - on the end or on the edge of the board)

NOT ALLOWED on all classes
- core, rot in all forms (tobacco, etc.), rotten falling knots, wormholes
- mushroom stains (blue and colored sap stains), gasket stains

Quality requirements for furniture boards

Definition of quality (grade):

For all types of furniture boards:

humidity no more than 8% +/-2%;
dead (black) knots are not allowed;
lamella width 40-50mm
PVA glue D-4 (KLEIBERIT);
polishing not less than 120 units;
thickness tolerance +0.1mm; width tolerance +/-1mm;
packaging in shrink film.

Requirements for oak shields

AA - Both faces are clean, without sapwood (squirrel). Knots no more than 2 mm in diameter, not through, "live" no more than 1 piece per linear meter are allowed on one layer. Both layers are selected according to texture (radial and tangential cut lamellas are glued into different shields) and color (lack of sharp color transitions on one layer )
AB - The upper surface is clean, without sapwood, without knots. The lower (2nd layer) is allowed to have sapwood (squirrel) without restrictions, as well as live knots in color with a diameter of not more than 20 mm. One face (front) is matched with color (lack of sharp color transitions on one face)
SS Sapwood without restrictions is allowed on both layers, live knots up to 20 mm in diameter. Rotten knots, rot are not allowed. Selection by color and texture is not carried out

Requirements for beech boards

AA - Both faces are clean, without false core capture. On one layer, knots are allowed no more than 2 mm in diameter, not through, "live" no more than 1 piece per linear meter. Mineral inclusions are allowed up to 7 mm. Both layers are selected according to texture (radial and tangential cut lamellas are glued into different boards) and color (absence of sharp color transitions on one layer)
AB - The upper surface is clean, without the capture of a false nucleus. On the upper (front) layer, knots are allowed no more than 2 mm in diameter, not through, "live" no more than 1 piece per linear meter. Mineral inclusions are allowed up to 7 mm. The lower (2nd layer) is allowed a false core without restrictions, as well as live knots “in color” with a diameter of not more than 20 mm, mineral inclusions up to 15 mm. One face (front) is matched by color (lack of sharp color transitions on one face)
SS On both layers it is allowed to capture a false core without restrictions, live knots up to 20 mm in diameter, mineral inclusions up to 15 mm. Rotten knots, rot are not allowed. Selection by color and texture is not carried out.

All photos from the article

The assortment is understood as a set of types and standard sizes of a particular type of product, that is, with regard to the board, the most important criteria are the grade and size range. It is for these factors that all products of this type are subdivided, we will consider the basic information that every developer who selects the lumber of the group in question should know.

Product types

As for the main types of products shown in the diagram above, the following can be said about each of them:

Unedged board	This option is distinguished by the fact that only two sides are cut off, and the ends are not processed. Such elements are most often used for framing and other structures where the appearance does not really matter, the main advantage of this solution is the affordable price, which is why it is the most affordable
Semi-edged board	In this type of product, two sides and one of the ends are most often processed, but at the same time, bevels and bark residues may be present on the edge. In general, this solution is of higher quality, but nevertheless it cannot be used on visible structures, where aesthetic appeal is important.
Edged board	The highest quality type of products, in which all sides are processed, therefore geometric parameters elements are the same, but the strength indicators are much higher. This group of products is used most often and is much more in demand among developers than other types.

Important! According to the scientific definition, a board is a type of lumber, the thickness of which does not exceed 100 m, and the width is at least twice the thickness. Elements up to 32 mm thick in hardwood and up to 40 mm in conifers ah refer to a thin board, the remaining options - to a thick one.

Basic design parameters

Assortment wooden planks includes requirements for grade and size, we will consider the first criterion in more detail in the next section, and in the table below we denote the generally accepted sizes of elements:

As for the length, the generally accepted options range from 1 to 6 meters, other standard sizes can be produced by agreement.

Product grade

The grade of edged board directly depends on the quality of the element and its strength characteristics, this parameter is applicable only to edged elements and is designed to simplify the choice of a specific type of product for certain works, we will consider the main options, and the photo below shows all the defects that must be taken into account when variety definition.

The right choice of grade of edged board or edged timber has big influence not only on the quality of the final product, but also on its final price.

Legal framework

Currently, the criteria and indicators of lumber quality are regulated by the current state standards and take into account several factors:

In one article, we decided to briefly combine all the characteristics of lumber - this is something that is important to understand and needs to be known to the ordinary consumer. We will talk about the main factors and criteria that affect the grade, as well as methods for their visual definition. Our methodology is based on the above state standards and is as close as possible to the concepts of lumber grade existing on the market today. Yes, indeed, some rules state standards, adopted in the 80s, today differ from the real properties offered for sale on the lumber market. The main thing remains the fact that, in fact, lumber has not changed in its physical properties: pine and spruce are out of politics, despite the fact that years have passed since the adoption of GOSTs, and they can and should be used in general construction activities with confidence and without fear. Currently, there are unwritten standards on the market for determining the grade of coniferous wood species, and in most regulated parameters they differ from generally accepted standards GOST. Also, deviations from GOST may be according to the classification of natural defects, taking into account their biological features, meaning knots - the shape and their number, the size of the wane part. Be sure to read the article Classification of wood defects, find out what is an important and unacceptable defect, and what is not important. Don't be fooled when buying lumber.

General technical requirements

Softwood lumber is made from spruce, fir, pine, cedar and larch. The most common and affordable is pine or spruce lumber. Typically for making edged lumber, round timber raw materials are not sorted and spruce and pine are offered for sale in a mixed form, since they also grow together in the forest. Sorting is not economically viable - in other words, sorting will increase the cost of the final cost of the material, but it is important to understand that the quality of pine and spruce boards is the same in its technical specifications. That is, this aspect can be ignored - their physical characteristics are very close, and for most construction tasks, the quality and strength characteristics of spruce and pine will be identical.

According to the quality of the structure and the quality of processing, the edged board can be of five grades. Edged timber of coniferous species has four grades. The relative humidity of sawn timber of selected and 1-3 grades cannot exceed 22%, in agreement with the customer, the indicators may change. The fourth grade has no restrictions on humidity. Grade evaluation is carried out taking into account the state of the edge or face, only the worst part is taken into account when measuring. The surface roughness for the selected and 1-3 grades should be less than 1250 microns, the fourth grade has no restrictions on this parameter. This is just very important. Often, cheaper lumber is sold under the guise of a higher grade.

Edged timber, size according to GOST

Also, the lumber grade is influenced by the criterion for limiting the natural defects of wood, we will talk about common approaches standard for determining the class of wood. There are many articles on our site that explain narrowly professional terms, methods that do not say anything to an ordinary person. But, even having studied the materials, experience is needed, it is difficult for the layman to distinguish dozens of types of knots and violations of the structure of wood “by eye”. Most The best way not to be a victim of fraud is to buy edged boards or edged beams, relying on a trusted supplier. Our Elka-Palka company is always ready to help you. We are honest about sorting. Let us briefly consider the main differences between the varieties of edged boards and edged timber. The criteria by which it is worth distinguishing the varieties and quality of boards and timber is the presence of defects or defects.

Norms and limitations of natural vices

Choice variety. Sound intergrown knots, layer, rib, edge and partially intergrown knots are allowed, the number is indicated in the tables of the standard. The presence of rotten and shriveled knots is prohibited. end cracks(deep and shallow) can be no more than 10% and 16%, respectively. All signs of the presence of fungal diseases of wood are prohibited, warping and non-parallelism of the faces is set within 0.2-1.0%.
Board first class. This is sawn timber of the correct geometric shape, with dimensional tolerances within the framework of GOST. If it is compared with a selected variety, then the following indicators will slightly change: the number of healthy knots increases various kinds, by about 10%, the number of shallow end cracks can reach 25%. Rolling is allowed no more than 20% of the area of the material layer. Mushroom heartwood stains (stripes), sapwood fungal stains and mold are allowed with a total area of the lumber area - no more than 10%. Rot is not allowed. These figures are typical for summer period and do not affect the quality of lumber in any way, as they are natural and do not lead to the destruction of the wood structure. Look to understand the article The defects of wood on our website. The wane is allowed to be blunt, on edges and faces measuring in fractions of the width of the corresponding sides of the edged sawn timber without length restrictions, not more than 1/6. Such a wane is also called - "pencil" wane. Basically, edged board of the 1st grade is used for general construction work - installation truss systems roofing, bearing structures, construction of a house, interfloor beams and ceilings, rough hemming and rough floors, fences.

Board second grade. The advantage is mainly low price. The main differences from grade 1 lumber are that products can have large fiber inclinations, resin pockets are allowed. The lumber may have more but slight fungus staining and small bluish spots. Significant wane is allowed. The main use of edged boards of the second grade is the use in construction, in the manufacture of formwork, lathing on pitched roofs, it is also used for the manufacture of forests.
Third grade. Significant roll is allowed, the presence of resin pockets, can increase up to 4 pieces / m. etc., a double core is allowed. Sprouting can be only one-sided, the number of heart spots can increase up to 20%. A wormhole is allowed in any area. Decayed rotten and tobacco knots allowed in total number partially fused and unjoined healthy knots of the same size and not more than half of their number. Formation and through cracks are allowed, including those facing the end. In connection with the above symptoms physical properties wood deteriorate sharply and it is possible to use such material in limited use - the construction of temporary buildings or sheds, the manufacture of containers and pallets.
Fourth grade. A wormhole is allowed up to 6 pcs/m. etc., rot can only be sieve variegated, the total area of rot is not more than 10% of the area of lumber. It may have a blunt and sharp wane, transverse and longitudinal warping along the face and edge, including winging.

These are the "scientific" characteristics of lumber, depending on their class. Now we consider it necessary to give you practical advice, with the help of which lumber should be selected, for this it is not necessary to study the provisions of state standards

We deeply doubt that the majority of buyers, before purchasing lumber, measure various defects and compare their appearance with an album of diseases and defects of wood. It is for them that we will give some simple and understandable criteria for choosing high-quality wood.

The more annual rings are visible in a vertical section and the closer they are to each other, the better the quality of the lumber. If there are many rings, radial sawing was performed, and these are the highest quality boards. The closer the rings are to each other, the smaller the annual growth of wood, the stronger it is, the better it resists moisture, etc. This indicator largely depends on climate zone tree growth, the colder the climate, the better the tree.

One more thing. It is very common to see the difference in wood quality different varieties even professionals cannot, these estimates are quite subjective. No one examines every board for hours. And the price difference between them is significant. What are we getting at? Purchase lumber from a trusted supplier and there will be no unpleasant "surprises". The Elka-Palka company always has edged timber and edged board best quality, which you can buy in one call. Such a purchase will allow you, without overpaying and without wasting extra time, to get the desired result. Buy edged board can be inexpensive and excellent appearance, with remarkable properties.