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IS 15491:2004 is the Indian Standard (BIS) for medium density coirboards for general purposes. This standard specifies the requirements for medium density coirboards made from coir fibres and synthetic resins. It covers the material composition, dimensions, tolerances, and essential physical and mechanical properties like density, strength, and water resistance for boards used in general purposes like furniture, partitions, and panelling. The standard also details the testing methods, sampling procedures, and marking criteria for conformity.
Medium Density Coirboards for General Purposes
Overview
Status
Current
Usage level
Specialized
Domain
Materials Science — Wood and Other Lignocellulosic Products
! These boards are not intended for primary structural or load-bearing applications.
! Verify the binder type (e.g., PF for boiling water resistance vs. UF for interior use) based on the intended application's moisture exposure.
! Always check for the ISI mark and manufacturer's batch number on the board as per marking requirements in Clause 7 to ensure product quality and traceability.
EN 622-5:2009CEN (European Committee for Standardization), European Union
MediumCurrent
Fibreboards. Specifications. Part 5: Requirements for dry process boards (MDF)
Specifies requirements for Medium Density Fibreboard (MDF), which has a similar density, manufacturing process, and application range, but is based on wood fibre.
ANSI A208.2-2016ANSI/CPA (American National Standards Institute / Composite Panel Association), USA
MediumCurrent
Medium Density Fiberboard (MDF) for Interior Applications
Covers property requirements for MDF panels for interior use, analogous to Grade II coirboard, but specifies wood fibre as the raw material.
ISO 16895:2020ISO (International Organization for Standardization), International
MediumCurrent
Wood-based panels — Dry-process fibreboard
Provides a global classification system and requirements for dry-process fibreboards (MDF), aligning on process and density but not raw material.
Key Differences
≠The primary raw material in IS 15491 is coir fibre derived from coconut husks, an agro-residue, whereas equivalent MDF standards (like EN 622-5) specify wood fibres.
≠IS 15491 classifies boards into Grade I (exterior, using Phenol Formaldehyde resin) and Grade II (interior, using Urea Formaldehyde resin). MDF standards like EN 622-5 have a more detailed classification based on use in dry, humid, or load-bearing conditions (e.g., MDF, MDF.H, MDF.LA).
≠Mechanical property requirements, such as Modulus of Rupture (MOR) and Internal Bond strength, are generally lower for coirboard in IS 15491 compared to the minimums specified for general purpose MDF in standards like EN 622-5, reflecting the different characteristics of coir vs. wood fibre.
≠Test durations for water resistance can differ. IS 15491 specifies limits for both 2-hour and 24-hour water immersion, while EN 622-5 primarily uses a 24-hour immersion test for thickness swelling.
Key Similarities
≈Both coirboard and MDF are manufactured using a similar dry process, where fibres are blended with a synthetic resin binder, formed into a mat, and consolidated under heat and pressure.
≈The target density range is analogous. IS 15491 specifies 600 kg/m³ to 800 kg/m³, which aligns with the typical density of Medium Density Fibreboard (MDF).
≈The intended general-purpose applications are largely the same, including furniture manufacturing, cabinetry, interior partitions, wall panelling, and ceilings.
≈Many fundamental test methods used to determine physical and mechanical properties (e.g., density, bending strength, screw withdrawal) are based on the same principles, often referencing common ISO testing standards.
Parameter Comparison
Parameter
IS Value
International
Source
Primary Raw Material
Coir fibre (from coconut husks)
Wood fibres
EN 622-5:2009
Density
600 - 800 kg/m³
Not specified as a requirement; defined by the manufacturer, but typically in the same range.
EN 622-5:2009
Modulus of Rupture (MOR) for 12-18mm board
≥ 15 N/mm²
≥ 20 N/mm² (for general purpose use in dry conditions)
EN 622-5:2009
Internal Bond Strength
≥ 0.40 N/mm²
≥ 0.55 N/mm² (for general purpose use, 12-19mm)
EN 622-5:2009
Thickness Swelling (Water Immersion)
≤ 12% (Grade II, after 2 hours)
≤ 12% (General purpose MDF, 12-19mm, after 24 hours)
EN 622-5:2009
Screw Withdrawal Strength (Face, ≥12mm board)
≥ 800 N
No minimum value specified; characteristic values are provided by manufacturer based on EN 320 test method.
EN 622-5:2009
Moisture Content
5% to 15%
4% to 10% (at time of dispatch from factory)
EN 622-5:2009
⚠ Verify details from original standards before use
Key Values6
Quick Reference Values
Density Range600 to 900 kg/m³
Minimum Modulus of Rupture (MOR) up to 12mm thickness15.0 N/mm²
Minimum Modulus of Elasticity (MOE) up to 12mm thickness2000 N/mm²
Maximum Water Absorption (24h immersion)25 % by mass
Maximum Thickness Swelling (24h immersion)15 %
Minimum Screw Withdrawal Strength (Face)800 N
Tables & Referenced Sections
Key Tables
Table 1 - Tolerances on Nominal Thickness, Length and Width
Table 2 - Physical and Mechanical Properties of Medium Density Coirboards
Key Clauses
Clause 3 - Terminology
Clause 4 - Requirements
Clause 6 - Tests
Clause 7 - Marking
Annex A - Method for Determination of Resistance to Steam
What is the specified density range for medium density coirboard?+
The density must be between 600 kg/m³ and 900 kg/m³ (Clause 4.3).
What is the maximum allowed water absorption after 24 hours of soaking?+
The maximum water absorption is 25 percent by mass (Table 2).
What is the minimum bending strength (Modulus of Rupture) for a 10mm thick board?+
For boards up to 12mm thick, the minimum MOR is 15.0 N/mm² (Table 2).
Are these boards suitable for exterior use?+
Generally no, unless specified as Exterior Grade (bonded with Phenol Formaldehyde resin) and adequately protected. They are mainly for interior applications.