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IS 3513:2000 (Part 4) is the Indian Standard (BIS) for resin treated compressed wood laminates (compregs) - specification, part 4: sampling and tests. This standard covers the methods of sampling and testing for resin-treated compressed wood laminates (compregs) to evaluate their mechanical, physical, and electrical properties.
Resin Treated Compressed Wood Laminates (Compregs) - Specification, Part 4: Sampling and tests
Overview
Status
Current
Usage level
Specialized
Domain
Materials Science — Wood and Other Lignocellulosic Products
! Test specimens must be properly conditioned to equilibrium moisture content before mechanical or electrical testing to ensure consistent and valid results.
! Sampling should be strictly random from boards of the same grade, type, and thickness manufactured under similar conditions.
! Edges of test specimens must be cut cleanly to prevent micro-cracks from causing premature failure during tensile or flexural testing.
Specification for non-impregnated densified laminated wood for electrical purposes - Part 3-1: Specifications for individual materials - Sheets
Provides specific property requirements for sheet-form densified wood, directly comparable to IS 3513's grades.
EN 61061-1:2004European Committee for Electrotechnical Standardization (CENELEC), Europe
HighCurrent
Specification for non-impregnated densified laminated wood for electrical purposes - Part 1: Definitions, designation and general requirements
The European regional adoption of the IEC 61061-1 standard, making it the equivalent for the European market.
Key Differences
≠IS 3513 uses a simple three-grade system (CEW 1, CEW 2, CEW 3), whereas the IEC 61061 series uses a more detailed designation based on wood type (e.g., Beech 'B', Hornbeam 'F') and property profiles.
≠The minimum flexural strength required by IEC 61061-3-1 for its comparable types (e.g., ≥250 MPa) is significantly higher than that for the highest IS grade, CEW 1 (≥175 MPa).
≠IS 3513 specifies a more stringent requirement for insulation resistance after water immersion (≥ 1 x 10³ MΩ) compared to the IEC standard (≥ 1 x 10² MΩ for similar types).
Key Similarities
≈Both standards define materials made from wood veneers (typically beech) bonded under high pressure and heat with thermosetting phenolic resins, intended for electrical insulation.
≈The requirements for electric strength perpendicular to laminations when tested in hot oil (90 °C) are virtually identical, with both standards specifying values around 4.0 kV/mm for a 3mm thickness.
≈Both standards specify similar testing regimes and property requirements for dimensional stability, including comparable limits for water absorption and oil absorption.
≈The primary application specified in both standards is for manufacturing insulating components in oil-filled electrical equipment like transformers, such as clamping rings, spacers, and lead supports.
Parameter Comparison
Parameter
IS Value
International
Source
Density
1.25 to 1.35 g/cm³
1.30 to 1.40 g/cm³ (for Type DW-B)
IEC 61061-1:2004
Flexural Strength (Flatwise, highest grade)
≥ 175 MPa (Grade CEW 1)
≥ 250 MPa (Type DW-B 203.1)
IEC 61061-3-1:2006
Compressive Strength (Perpendicular to laminations)
≥ 250 MPa (Grade CEW 1)
≥ 250 MPa (Type DW-B 203.1)
IEC 61061-3-1:2006
Electric Strength (Perpendicular, 3mm thick, in oil @ 90°C)
≥ 4.0 kV/mm (Grade CEW 1)
≥ 4.0 kV/mm (Type DW-B 203.1)
IEC 61061-3-1:2006
Insulation Resistance (after 24h water immersion)
≥ 1 x 10³ MΩ
≥ 1 x 10² MΩ (Type DW-B 203.1)
IEC 61061-3-1:2006
Water Absorption (3mm thick, 24h immersion)
≤ 30 mg for 25x25mm specimen (approx. 1.2% by mass)
≤ 1.5% by mass
IEC 61061-3-1:2006
⚠ Verify details from original standards before use
Key Values2
Quick Reference Values
standard testing temperature27 ± 2°C
standard relative humidity65 ± 5%
Key Formulas
Moisture Content (%) = [(W1 - W0) / W0] x 100
Tables & Referenced Sections
Key Tables
Table 1 - Number of Boards to be Selected for Sampling