What is the difference between IS 2408 and IS 1708?

IS 2408 is for testing full structural sizes which include natural defects, while IS 1708 is for testing small, clear specimens devoid of defects.

What are the primary properties evaluated under this code?

Flexure (bending) characteristics, compression parallel to the grain, and modulus of elasticity for full-size structural members.

Why is moisture content important in this test?

Timber strength is inversely proportional to its moisture content below the fiber saturation point; thus, testing requires correlating strength to a standard moisture level (usually 12%).

IS 2408

: 1963

Methods of static tests of timber in structural sizes

CurrentSpecializedTesting MethodMaterials Science · Timber and Timber Stores

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This standard outlines the methods for conducting static tests on timber members in structural sizes. It is used to evaluate mechanical properties such as flexural strength and compressive strength on full-scale sections, accounting for natural defects (like knots and shakes) that small clear specimens do not capture.

Methods of static tests of timber in structural sizes

Quick Reference Values

standard testing temperature27 ± 2 °C

standard relative humidity65 ± 5 %

reference moisture content12 %

Key Formulas

Modulus of Rupture (MOR) = 3PL / (2bd²) — Flexural strength of rectangular beams

Practical Notes

Test specimens must include natural defects typical of their grade to accurately reflect real-world structural capacity.

Moisture content must be recorded immediately after testing, as the structural strength of timber varies significantly with moisture levels.

Loading rates must be strictly controlled to ensure static loading conditions, avoiding dynamic or impact effects.