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KVH quality

Grading criterion Requirements to be met by KVH® Remarks
Exposed areas (KVH®-Si) Non-exposed areas (KVH®-NSi
Grading class compliant with DIN 4074-1 Min. S10TS; C24 in accordance with DIN 1052 The decisive strength and stiffness properties are given in DIN 1052.
Moisture content 15% ± 3% The specified moisture content is a precondition for dispensing for the most part with preservative treatment and can also be the precondition for finger joint assembly.
Type of cutting Split-heart, free-of-heart on request Split-heart Split-heart:
Given that the pith does not always automatically run through the middle of the log, split-heart is defined as follows: For a log with an ideal growth form, the pith would be cut through in two-strand cutting.
Free-of-heart: Heart plank with d ≥ 40 mm is removed
Wane Not permitted Measured at an angle ≤ 10% of the smaller cross-section side
Dimensional stability of the cross-section DIN EN 336 Dimensional stability class 2:
w ≤ 100 mm:           ± 1 mm
w > 100 mm:           ± 1,5 mm
The dimensional stability for the longitudinal dimensions must be agreed between the customer and supplier.
Knot condition Loose knots and dead knots not permitted. Occasional faulty knots or parts of knots up to max. 20 mm in diameter are permitted DIN 4074-1
Grading class S10
Replacement with natural wood dowels is permitted.
Maximum of 2 adjacent to each other permitted for Si.
Knot diameter ratio S 10: A ≤ 2/5
S 13: A ≤ 1/5
not exceeding 70 mm
Knot diameter ratio A is determined in accordance with DIN 4074-1.
The following applies for mechanical grading:
- Knot sizes are not taken into consideration for KVH®-NSi - A ≤ 2/5 applies for KVH® -Si
Ingrown bark Not permitted DIN 4074-1
Cracks, radial cracks caused by shrinking (shrinkage shakes) Width of the crack w must be ≤ 3% dof the respective cross-section width DIN 4074-1 For Si the requirements are higher than those applicable to grading class S10 in accordance with DIN 4074-1.
Pitch pockets Width ≤ 5 mm - Additional criterion
Discoloration Not permitted DIN 4074-1 For Si the requirements are higher than those applicable to grading class S10 in accordance with DIN 4074-1
Insect attack Not permitted DIN 4074-1 For Si the requirements are higher than those applicable to grading class S10 in accordance with DIN 4074-1
Twisting - - The permissible extent of twisting is not specified in further detail because no unacceptable twisting is to be expected if all the other criteria are complied with.
Longitudinal warping for split-heart cutting ≤ 8 mm/2 m
for heart-free cutting ≤ 4 mm/2 m
for split-heart cutting ≤ 8 mm/2 m In comparison:
In accordance with DIN 4074-1 S10 und S13: ≤ 8 mm/2 m
Finishing of the ends Trimmed perpendicular
Surface quality Planed and chamfered Leveled and chamfered
Finger-jointing DIN EN 385

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