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IS 12120:1987 is the Indian Standard (BIS) for preservation of plywood and other panel products. This standard provides a code of practice for the preservative treatment of plywood and other lignocellulosic panel products like particle boards and fibreboards. It details the types of chemical preservatives, methods of application (such as pressure treatment and dipping), and the required retention levels of preservatives needed to protect the products against bio-deterioration under different environmental hazard conditions.
Code of practice for preservation of plywood and other panel products
Overview
Status
Current
Usage level
Specialized
Domain
Materials Science — Wood and Other Lignocellulosic Products
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
Practical Notes
! The effectiveness of treatment heavily depends on achieving the specified preservative penetration and retention, which varies significantly with the product type and density.
! Always select the preservative and treatment level based on the end-use hazard classification (e.g., H1 for interior, H3 for exterior above-ground).
! Glue lines in plywood can act as a barrier to preservative penetration, making full impregnation challenging compared to solid timber.
AWPA U1-21American Wood Protection Association (AWPA), USA
HighCurrent
Use Category System: User Specification for Treated Wood
Defines service conditions and preservative requirements, analogous to IS 12120's hazard levels.
AS/NZS 1604.4:2012Standards Australia / Standards New Zealand, Australia/New Zealand
HighCurrent
Specification for preservative treatment - Part 4: Plywood
A direct equivalent specifically covering the preservative treatment of plywood.
BS EN 335:2013BSI - British Standards Institution, UK (European Standard)
MediumCurrent
Durability of wood and wood-based products. Use classes: definitions, application to solid wood and wood-based products
Provides the framework for classifying end-use biological hazards, which IS 12120 does in a more condensed manner.
ISO 21887:2020International Organization for Standardization (ISO), International
MediumCurrent
Durability of wood and wood-based products — Use classes
Establishes a global framework for use classes, similar in principle to the hazard levels in IS 12120.
Key Differences
≠IS 12120 is a single, self-contained 'Code of Practice', whereas international systems (like EN) are a modular series of standards for use classes (EN 335), treatment processes (EN 351), and preservative efficacy (EN 599).
≠The terminology for service conditions differs: IS 12120 uses 'Hazard Levels' (Low, Moderate, High, Very High), while EN standards use 'Use Classes' (1-5) and AWPA uses 'Use Categories' (UC1-UC6).
≠IS 12120:1987 lists older preservative formulations like CCA without the same level of restrictions now common internationally. Modern standards (e.g., AWPA) have phased out CCA for most residential uses and specify newer formulations like ACQ and Copper Azole.
≠International standards like AS/NZS 1604.4 and AWPA T1 place a much stronger, quantifiable emphasis on preservative penetration depth into veneers, whereas IS 12120 describes it more qualitatively ('complete penetration is desirable').
Key Similarities
≈All standards are fundamentally based on matching the preservative treatment level (preservative type, retention, penetration) to the anticipated biological hazard of the end-use environment.
≈The classification of hazards, despite different naming conventions, follows a similar progression from dry interior use (lowest risk) to marine immersion (highest risk).
≈The primary methods of treatment are consistent across standards, recognizing surface application (dipping, brushing) for low-hazard situations and vacuum-pressure impregnation for high-hazard applications.
≈There is an overlap in the fundamental chemical types used for preservation, with water-borne copper-based salts and boron compounds forming the basis of many treatments in all standards.
What preservative is recommended for plywood used in exterior locations like cladding?+
For Hazard Class H3 (Exterior, above ground), Copper-Chrome-Arsenic (CCA) or Borated Copper-Chrome-Arsenic (BCCA) preservatives are recommended as per Table 1.
Can I use this code for treating solid wood doors?+
No, this code is specifically for panel products like plywood and particle board. For solid timber, refer to IS 401.
What is the minimum required retention of CCA for interior plywood?+
For interior use (Hazard Class H1), the minimum retention of CCA preservative is 4.0 kg/m³ according to Table 1.
Is pressure treatment mandatory for all plywood?+
No, for lower hazard levels like H1 (interior), processes like dipping may be sufficient. However, for higher hazard levels (H3 and above), pressure treatment is generally required to achieve adequate protection (Clause 5.2).