The 1963 edition of IS 399 offers an extensive categorization of commercial timber species available across India, organized by their practical applications and geographic zones. It specifies timber characteristics including availability, density, durability, preservative treatability, seasoning response, and relative strength values, supporting professionals in choosing suitable wood types for construction, furniture, packaging, tools, veneers, and plywood. This standard is vital for experts involved in timber sourcing and usage across diverse Indian environmental conditions.
Overview
The 1963 edition of IS 399 offers an extensive categorization of commercial timber species available across India, organized by their practical applications and geographic zones. It specifies timber characteristics including availability, density, durability, preservative treatability, seasoning response, and relative strength values, supporting professionals in choosing suitable wood types for construction, furniture, packaging, tools, veneers, and plywood. This standard is vital for experts involved in timber sourcing and usage across diverse Indian environmental conditions.
Audience
Contents
Structure
Overview of IS 399 including its purpose to provide strength indices and physical properties of Indian timbers for engineering applications. Data originates from the Forest Research Institute, Dehra Dun, based on timber assessments conducted in the 1950s. The document uses metric units primarily, supplemented by imperial units for ease of transition. Tables I through V present timber species arranged by zones and usage, detailing availability, average and range of weights, durability classes, preservative treatability, resistance to air seasoning, and strength coefficients essential for design.
This section outlines IS 399’s coverage of classification, properties, and applications of Indian commercial timbers. It details tables listing timber species by geographic zone, their intended uses, and comprehensive physical and mechanical properties. Key parameters include zone-wise availability, average weight at 12% moisture content, durability classification, preservative treatability, seasoning refractoriness, and strength coefficients derived from standard evaluation methods.
Timbers are categorized based on intended applications such as structural construction (posts, beams, sleepers), furniture making, light and heavy packing cases, agricultural tools and handles, turnery items and toys, and veneers and plywood production. The tables provide detailed data on species availability per zone, average weight, durability, preservative treatability, air seasoning resistance, and strength coefficients to assist in selecting appropriate wood for each use.
India, including Sikkim and Bhutan, is divided into five timber zones reflecting timber availability and major consumption centers: North, East, Centre, West, and South Zones. Each zone covers specific states and regions, influencing timber species distribution and supply. The zoning aids in timber selection based on regional availability and properties, with detailed species data provided in corresponding tables.
This section explains the classification of timbers by durability, availability, weight, treatability, refractoriness to air seasoning, and comparative strength. Durability classes are defined by average lifespans under exposure and ground contact. Availability is categorized by annual supply volumes. Treatability assesses heartwood penetration by preservatives under pressure. Refractoriness indicates susceptibility to cracking during air seasoning. Comparative strength coefficients provide relative mechanical suitability compared to teak.
Describes the classification of timber availability into classes based on annual volume: most common, common, and less common. It includes details on sources from forests and non-forest areas and notes practical limitations due to extraction challenges. The classification supports decisions considering supply constraints.
Provides average density and weight ranges for timber species at 12% moisture content, based on comprehensive sampling. Variations due to environmental and tree-specific factors are noted. The data supports weight estimation for design and handling purposes.
Details the classification of timbers into high, moderate, and low durability categories, reflecting expected service life under atmospheric exposure or ground contact. The classification guides selection for applications requiring varied longevity, supported by associated strength and treatability data.
Explains the grading of timber heartwood treatability based on penetration ease of preservatives under a pressure of 10.5 kg/cm². Grades range from easily treatable to highly refractory, with implications for preservation methods and expected effectiveness. Treatment conditions for different preservatives are also summarized.
Classifies timbers according to their tendency to crack or split during air seasoning into high, moderate, and low refractoriness categories. This property affects seasoning protocols and quality outcomes. Zone-wise data on species behavior during seasoning is provided.
Defines the relative strength index for timber species expressed as a percentage of teak’s strength (set at 100). This index aggregates key mechanical properties relevant to different uses, guiding species selection but not serving as a design parameter. Data is derived from authoritative research and presented in zone-specific tables.
Presents detailed classification tables (I to V) organizing commercial timber species by their respective zones. Each table lists botanical and trade names, availability, average weight, durability, treatability, refractoriness, and comparative strength coefficients to assist users in selecting appropriate species for their regional context.
Details standardized trade names, abbreviated symbols, and local vernacular names for timber species as per IS 399. Includes botanical names and key timber properties, facilitating uniform identification and communication among industry and professionals.
Highlights timber species suitable for veneers and plywood production, with data on availability, weight, durability, treatability, air seasoning behavior, and strength coefficients. This information supports material selection for veneer and plywood manufacturing consistent with quality and performance requirements.
Focuses on timber species used in light and heavy packing cases and tool handles. Presents classification by use, with relevant timber properties including availability, weight, durability, treatability, refractoriness, and comparative strength coefficients. Strength coefficients guide species selection according to mechanical suitability, although structural design must follow engineering standards.
Frequently Asked
IS 399 segments India into five timber zones formed around key timber consumption and supply areas: North Zone (including western Himalayan states), South Zone (covering Kerala, Mysore, Coastal Madras, Andhra Pradesh), East Zone (including Calcutta and Andaman timber regions), West Zone (covering Bombay and west Mysore), and Central Zone (central Indian regions). These zones support the categorization of timber species by regional availability, though timber may be commercially traded across zones.
Timber durability in IS 399 is classified into three categories based on average life under exposure: High durability (10 years or more), Moderate durability (5 to under 10 years), and Low durability (less than 5 years). Durability ratings reflect relative resistance to decay in atmospheric or ground contact conditions and are influenced by local environmental factors. Additionally, treatability grades assess how easily timber heartwood can be impregnated with preservatives under pressure, facilitating appropriate preservation choices.
Treatability is established by the ability of preservatives to penetrate timber heartwood during pressure treatment at 10.5 kg/cm². Two main preservative types are used: heated creosote-crude oil mixtures and cold water-soluble preservatives to avoid precipitation. Timber is graded from 'a' (heartwood easily treatable) through 'e' (heartwood very refractory with negligible penetration). This classification informs expected preservation efficacy and method selection.
Comparative Strength Coefficients (CSCs) represent a composite measure of timber mechanical suitability for specific applications relative to teak, which is assigned a value of 100. These coefficients combine weighted mechanical properties such as strength and stiffness, accounting for conditions in both green and dried states. CSCs guide the selection of timber species by indicating relative performance but are not intended for direct design or sizing. The coefficients are derived from research conducted by the Forest Research Institute and timber mechanics literature.
For construction purposes, timbers chosen typically possess high durability and strength, such as Teak, Sal, Sissoo, and Silver Oak, suitable for structural components like beams and posts. Furniture making favors species with fine grain, good workability, and appealing finish, including Walnut, Maple, Indian Oak, Mango, and Toon. Availability varies regionally, and factors like extraction difficulty and cost influence species selection for both uses.
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