GDI 302: Fiber Failures

Use the following guidelines to determine how to classify a check that occurs within a knot:

• A check in a knot is considered a defect if it extends outside the knot, OR if it is open more than 1/16”.
• If a check extends outside of a Spike Knot and into the board face, it is evaluated as an edge break, see para. 810 in the General Definitions and Instructions.
• If a check within any knot is open more than 1/16”, it is evaluated as a hole.
• For checks extending outside of knots that are located away from the edge (Typically Round and Oval Knots), check provisions for the corresponding grade of the piece would apply.  For example, in the grade of Premium a check extending outside of a knot could be 10″ long, provided the opening of the check is open no greater than a medium check (1/32″), and the check does not extend through the edge of the board.

The following limitations and allowances are used to determine the grade when splits are present:

• The allowable split is permitted on both ends of the piece.
• Split limitations apply to the longest split present.
• A check on the end less than 1/2 the thickness is limited as a surface seasoning check.
• A check on the end more than 1/2 the thickness is limited as a split.

Limitations apply to the longest or widest shake present in the board.

The edge break allowed in Standard grade may penetrate no more than 1/3 the width from the edge of the board. The length of the break is limited to the width of the piece.

Compression Failures are checks that occur within compression wood, typically caused during the drying process.

The following interpretations apply to checks that may be found in compression wood in a board:

• If the Compression failure (checks found within the compression wood) is open 1/16” or less, the width of the affected area is limited to the maximum red knot size listed for the corresponding grade of the board.
• If the Compression failure (check found within the compression wood) is open greater than 1/16”, the width of the affected area is limited to the maximum allowable hole size listed for the corresponding grade of the board.

Refer to the image to determine the measurement of the affected area. Note: “Affected Area” refers to the area in which the failure (check) extends across the width of the board