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IS 12896:1990 is the Indian Standard (BIS) for indian timbers for door and window shutters and frames- classification. This standard classifies Indian timber species into Class I and Class II for use in door and window shutters and frames. The classification is based on key properties like natural durability, treatability, and strength, guiding the selection of suitable wood for different quality and exposure requirements.
Indian timbers for door and window shutters and frames- Classification
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
Practical Notes
! Class I timbers (e.g., Teak, Sal) are recommended for exterior use or high-quality applications due to high natural durability. Class II timbers are suitable for interior use, often requiring preservative treatment.
! This code classifies the species, but for actual use, the timber must also be properly seasoned as per IS 1141 (for frames) or IS 2202 (for shutters).
! Always verify the regional availability of a specified timber species before finalizing the design.
Specifies requirements for milled softwood products, including for joinery, but is broader and less focused on species classification for doors/windows.
Key Differences
≠IS 12896 provides a prescriptive list of suitable Indian timber species, whereas BS EN 942 provides a performance-based grading system (e.g., J2, J10, J30) applicable to any timber species based on visual defects.
≠The classification in IS 12896 is a simple grouping (Group I/II/III for shutters, Group A/B for frames) based on a holistic assessment of suitability. European standards use a more granular, quantitative approach based on the size and frequency of specific features like knots, grain slope, and fissures.
≠IS 12896 is exclusively focused on timber species native to or commonly used in India. International equivalents like BS EN 942 are species-agnostic in their grading rules but often provide informative annexes with species common in the European market.
≠IS 12896 references other Indian Standards for properties like durability (IS 401) and seasoning (IS 1141). BS EN 942 is part of a larger, interconnected suite of European standards (ENs) for all aspects, such as durability (EN 350) and moisture content.
Key Similarities
≈Both IS 12896 and its international counterparts share the fundamental goal of ensuring that timber used for doors and windows possesses adequate quality and performance characteristics.
≈The evaluation criteria, though applied differently, are based on similar core timber properties: natural durability, dimensional stability, strength, workability, and freedom from defects that would impair performance or appearance.
≈All standards recognize the need for different quality tiers. IS 12896 uses 'Groups' (e.g., Group I being higher quality than Group III), while BS EN 942 uses 'Classes' (e.g., J2 being a higher appearance class than J10) to match timber quality to the application's requirements (e.g., transparent vs. opaque finish).
≈Moisture content is a critical parameter in all standards to ensure dimensional stability and prevent issues like warping or shrinkage after installation.
Parameter Comparison
Parameter
IS Value
International
Source
Primary Classification Method
Prescriptive list of suitable Indian timber species categorized into Groups (A/B for frames, I/II/III for shutters).
Performance-based grading system (e.g., J-classes) based on limits for visual characteristics like knots, grain, and fissures.
BS EN 942:2019
Durability Specification
Implicit in species grouping. Refers to durability classes from IS 401 (e.g., High, Moderate, Low durability).
Explicit requirement referencing durability classes from BS EN 350 (e.g., Class 3 'moderately durable' or treatment required for external use).
BS EN 942:2019
Species Focus
Restricted to a list of specified Indian timbers (e.g., Tectona grandis, Shorea robusta).
The grading rules are applicable to any timber species, though common European species are often referenced.
BS EN 942:2019
Moisture Content (for use)
Refers to IS 287, typically specifying a range like 10-14% depending on the climatic zone in India.
Specifies moisture content at time of delivery/fabrication, e.g., 15% ± 3% for external joinery.
BS EN 942:2019
Knot Limitation
Controlled indirectly by selecting species in higher groups which naturally have fewer defects. No specific knot size rules.
Explicit quantitative limits on the size, type, and number of knots for each grade (e.g., 'Class J10 allows sound knots up to 10mm').
BS EN 942:2019
Example of a Top-Tier Timber
Teak (Tectona grandis) is listed in Group I for shutters and Group A for frames.
Oak (Quercus robur) is a species often specified to meet high-grade classes like J2 for clear-finished joinery.
BS EN 942:2019
⚠ Verify details from original standards before use
Key Values6
Quick Reference Values
Natural durability for Class I timber (graveyard test)> 120 months
Natural durability for Class II timber (graveyard test)60 to 120 months
Strength requirement for Class I timberBelongs to Strength Group A, B or C as per IS 399
Treatability requirement for Class I timberHeartwood treatability class (a), (b) or (c) as per IS 401
Strength requirement for Class II timberBelongs to Strength Group A, B or C as per IS 399
Treatability requirement for Class II timberHeartwood treatability class (a), (b), (c) or (d) as per IS 401
Tables & Referenced Sections
Key Tables
Table 1 - List of Suitable Species of Timber for Door and Window Shutters and Frames
What is the main difference between Class I and Class II timber?+
Class I timber has a higher natural durability (average life > 120 months) and is more resistant to decay. Class II has moderate durability (60-120 months) and may require preservative treatment for longevity (Clause 4).
Is Mango wood suitable for window frames?+
Mango (Mangifera indica) is listed as a Class II timber, making it suitable, but it falls under treatability class 'd', meaning it requires preservative treatment (Table 1 and IS 401).
Which code should I refer to for the strength group of a timber?+
The strength group classification (A, B, or C) for various timber species is given in IS 399.
Does this standard apply to plywood doors?+
No, this standard is for solid timber. Plywood and other engineered wood products for doors are covered by different standards, such as IS 2202.