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IS 3513:2000 (Part 3) is the Indian Standard (BIS) for resin treated compressed wood laminates (compregs) - specification, part 3: for general purposes. This standard lays down the specification and requirements for resin treated compressed wood laminates (compregs) used for general engineering and architectural purposes. It defines parameters like materials, manufacturing methods, dimensions, and critical physical and mechanical properties.
Resin Treated Compressed Wood Laminates (Compregs) - Specification, Part 3: For General Purposes
Overview
Status
Current
Usage level
Specialized
Domain
Materials Science — Wood and Other Lignocellulosic Products
! Compregs are highly dense and heavy due to resin impregnation and high-pressure compression; standard woodworking tools may wear out faster.
! Do not confuse Part 3 (General Purposes) with Part 1 (Electrical) or Part 2 (Chemical), which have specialized resin formulations and testing requirements.
! Storage should be in a dry, well-ventilated area to prevent surface moisture absorption before machining or finishing.
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 Values5
Quick Reference Values
Specific Gravity (Minimum)1.10
Moisture Content (Maximum)8%
Tensile Strength, Along the Grain (Minimum)100 N/mm²
Compressive Strength, Perpendicular to Laminae (Minimum)120 N/mm²
Water Absorption (24 hrs)Depends on thickness, typically up to 5%
Tables & Referenced Sections
Key Tables
Table 1 - Physical and Mechanical Properties of Compregs for General Purposes
A high-density composite material made by impregnating wood veneers with synthetic resin (like phenol formaldehyde) and compressing them under heat and high pressure.
Can IS 3513 Part 3 compregs be used for electrical insulation?+
No, IS 3513 Part 1 specifically covers compregs intended for electrical purposes and testing for dielectric strength.
What resins are typically used in manufacturing compregs?+
Synthetic resins such as phenol formaldehyde (BWP grade) conforming to IS 848 are generally used.