What is the purpose of this standard?

To provide a uniform and systematic basis for grading and inspecting timber based on its natural defects and characteristics (Clause 1.1).

Does this standard give specific allowable knot sizes for grading?

No, it outlines the principles for how to set those limits, but does not provide the specific values. These are found in standards for specific timber products or species.

What are the main types of defects considered for grading?

Defects include knots, cross grain, checks, splits, shakes, insect attack, decay, and warp, among others (Clause 3).

What is 'cutting' in the context of timber grading?

A hypothetical rectangular portion of a piece of timber, free from defects, used to assess the grade of the timber piece (Clause 2.3).

IS 6534

: 1971

Guiding principles for grading and inspection of timber

CurrentFrequently UsedGuidelinesBIMMaterials Science · Timber and Timber Stores

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This standard lays down the guiding principles for the grading and inspection of timber. It defines common defects and establishes a framework for creating specific grading rules based on the intended end-use of the wood.

Guiding principles for grading and inspection of timber

Practical Notes

This is a foundational document; it provides the principles for creating grading rules, not the specific rules for a particular timber species (which are in other standards).

The standard emphasizes visual inspection, so understanding how to identify and measure defects like knots, slope of grain, and checks is critical.

Grading is essential for determining the suitability of timber for structural versus non-structural (joinery, furniture) applications.