Piles of different types are constructed for open-air storage and drying of sawn timber. The type of pile depends on:
- the type of sawn timber,
- the dimensions,
- the moisture content,
- the intended period of storage
of the sawn timber to be stored.
The construction of the pile must guarantee storage and drying of the sawn timber free from damage and meet the requirements of labour safety. Therefore, the following rules must be observed:
- Sawn timber of equal type, equal thickness, equal type of wood and, if possible, equal length only should be stored in each pile.
- When horizontally storing sawn timber of different length, the longest timbers should be stored at the bottom and the shortest timbers on the top of the pile.
- The outsides of the piles should be vertical.
- Boards should be stored with the wide face near the heart showing upwards.
Figure 7 Storage of boards in piles of sawn timber 1 correct storage, 2 wrong storage
- The lateral distance between edged boards and frame timbers should be at least 30 mm.
- Piles with high-quality sawn timber should be covered on top to protect the wood against detrimental weather influences. The covering plates must be firmly secured.
- For identification of the stored timber, identification plates should be fixed to sawn-timber piles showing features like:
· type of wood,
· board thickness,
· pile volume in m3,
· date of storage...
Wet timber is stored and dried in the following types of piles: box-type piles, package-type piles and block-type piles using pile strips. Pile strips of equal length only are to be used for this purpose.
The pile strips at the bottom are to be put directly on the pile supports, the next strips are to be put exactly in vertical alignment with the pile strips beneath and between the layers of sawn timber.
Figure 8 Position of pile strips in piles of sawn timber 1 correct position, 2 wrong position
Moreover, it is important that the edges of the pile strips, at least at one wide side of the pile, are in alignment or slightly projecting only with respect to the gross-grained faces of the sawn timber (except for package-type piles).
Figure 9 Position of pile strips at the wide side of piles 1 edges in alignment, 2 projecting
At least at one longitudinal side of the pile, the pile strips must be arranged so as to end or be in alignment with the sawn timber.
Why must the pile strips be arranged exactly vertically above the pile supports and above each other?
If no pile strips are used, wet and dry sawn timber is stored in the following types of piles: cross-type piles, triangular piles, shear-type piles.
Dry sawn timber is stored without pile strips in closed, dry rooms.
The different types of piles are constructed, as follows:
- Box-type pile
Edged or unedged-sawn boards or frame timbers of equal thickness and approximately the same length are well arranged side by side and piled up in layers in a box-type form using pile strips. The dimensions are:
· pile height = 4000 mm
· pile width = 1000 mm
· lateral distance to the next pile = 300 mm
- Package-type pile
Edged or unedged-sawn timbers of equal thickness and approximately the same length are tied up in packages or piled up with intermediate pile strips. This is done by means of stacker trucks.
Moreover, 60 mm to 80 mm thick spacers are used. The pile height is in accordance with internal works' rules and with the labour safety requirements.
Figure 11 Construction of a package-type pile 1 boards, 2 pile strips, 3 spacers
- Block-type pile
Unedged-sawn boards, arranged ace. to their origin of trunks, are piled up in blocks using pile strips. The width of the bottom board must be one third of the trunk diameter. Neighbouring blocks are connected with common pile strips.
Figure 12 Construction of a block-type pile 1 unedged-sawn boards, 2 pile strips, 3 bottom boards, 4 common pile strips of neighbouring blocks
- Cross-type pile
Edged boards or squared timbers of equal length are piled up at right angles to each other without any pile strips.
- Triangular pile
Edged or unedged-sawn boards of equal length are piled up in the form of equilateral triangles without any pile strips.
- Shear-type pile
Edged boards or squared timbers are erected with their gross-grained ends standing on the ground of the pile area. They are supported by a frame in a shear-type arrangement.
Figure 15 Shear-type pile 1 edged boards, 2 pile area, 3 frame, 4 securing of boards from slipping off
The timbers must be secured from slipping off on the ground.