The IS 5247 Part 1 (1982) standard outlines the specifications for processed coniferous timber used in the production of light furniture in India. It details grading rules, acceptable defects, dimensional limits, moisture content thresholds, and identification marks for species including Chir, Deodar, Fir, and Spruce, promoting uniform quality and consistency for manufacturers, suppliers, and inspectors.
Overview
The IS 5247 Part 1 (1982) standard outlines the specifications for processed coniferous timber used in the production of light furniture in India. It details grading rules, acceptable defects, dimensional limits, moisture content thresholds, and identification marks for species including Chir, Deodar, Fir, and Spruce, promoting uniform quality and consistency for manufacturers, suppliers, and inspectors.
Audience
Contents
Structure
This section defines the scope of IS 5247 Part 1, which pertains to sawn coniferous timber suitable for light furniture manufacturing. It enumerates the permissible species with their trade names, botanical names, and standard abbreviations such as Chir (Pinus roxburghii), Deodar (Cedrus deodara), Fir (Abies spp.), and others. The section also clarifies rounding rules based on IS 2-1960 and references definitions from IS 707-1976.
Key terms and definitions follow IS 707-1976, supplemented by additional terminology specific to IS 5247. The timber species are identified with standardized trade and botanical names along with abbreviated symbols, facilitating uniformity in communication and documentation.
This part lists the coniferous species addressed, including Chir, Cypress, Deodar, Fir, Kail, Khasi Pine, and Spruce, along with their botanical classifications and abbreviated codes. It also outlines limits on defects such as permissible knot sizes, sap stain presence, grain deviation, surface cracking, twisting, and center heartwood allowance, ensuring suitability for light furniture applications.
Describes the nominal sizes for timber pieces and the permissible tolerances, including ±2 mm width variation and a positive thickness tolerance of +8 mm only. Limits on warping types such as bow, crook, and cup are specified, ensuring that timber dimensions remain within acceptable ranges for quality furniture making.
Details the classification of timber into two grades based on the types and extents of defects allowed. It emphasizes restrictions on width tolerances, prohibiting negative deviations beyond 25% of the supplied quantity and disallowing width variations outside specified ranges. The section guides adherence to defect limits for maintaining consistent quality.
Explains the procedures for measuring length, width, and thickness, including rounding down length to the nearest 0.01 m, width to the nearest 1 cm, and thickness to the nearest 0.5 cm. The volume calculation uses these accepted sizes, computed to three decimal places, without adding tolerances, ensuring precision in quantifying timber volume.
Defines acceptable defects such as knots, shakes, wane, decay, and sapwood, with specific size and frequency limits derived from Table 1 of the standard. Defect measurement follows IS 3364 (Part II) - 1976, and defects are evaluated collectively. The section also highlights prophylactic treatment recommendations per IS 401-1982.
Specifies that each timber piece must be permanently marked with supplier identification, year of supply, species abbreviation, and timber grade. Timber may carry the ISI Certification Mark, which assures compliance and quality, backed by rigorous inspection and testing under ISI supervision, governed by the Indian Standards Institution (Certification Marks) Act.
Requires application of protective coatings on timber ends extending at least 25 mm beyond the longest detected split, using materials conforming to IS:1141-1973. This coating must be applied immediately after inspection to minimize moisture loss and prevent cracking, thus enhancing durability.
Encourages the use of prophylactic treatments as per IS:401-1982 to protect timber against biological deterioration. The application of these treatments, along with end coating as specified, is subject to purchaser-supplier agreement, ensuring enhanced preservation and longevity of timber products.
Frequently Asked
IS 5247 Part 1 pertains to converted coniferous timbers used for light furniture, commonly covering species such as Pine (Pinus spp.), Deodar (Cedrus deodara), Fir (Abies spp.), and Spruce (Picea spp.). These species are favored for their ease of workability, strength, and finishing characteristics suitable for furniture production. For detailed species listings and grading specifics, refer to the full IS 5247 Part 1 document.
The standard permits certain natural timber defects within specified limits outlined in Clause 7 and Table 1. Allowed defects include knots (with size and frequency constraints), shakes (limited crack length and width), wane (restricted surface area affected), and sapwood (within defined thickness limits). Measurements follow specified rounding rules for length, width, and thickness to ensure timber quality aligns with light furniture manufacturing requirements. Precise defect limits should be verified against the detailed tables in IS 5247 Part 1.
According to IS 5247 Part 1 (1982), the moisture content for coniferous timber intended for light furniture must not exceed 15% for pieces up to 50 mm thick. For timber thicker than 50 mm, the maximum moisture content allowed is 16%, measured within 20 mm from the surface. These limits are determined as per IS 287:1973 and help maintain dimensional stability and durability.
Dimensions are taken as per the nominal sizes ordered. Measurements for length, width, and thickness must use accepted sizes, rounding length down to the nearest 0.01 m, width down to the nearest 1 cm, and thickness down to the nearest 0.5 cm. Width tolerance is ±2 mm, while thickness tolerance allows only a positive variation of +8 mm. Plus tolerances are excluded from volume calculations to prevent overestimation, ensuring consistent and accurate sizing.
Each timber piece must be clearly and permanently marked with the supplier's name or trademark, the year of supply, the species abbreviation, and the timber grade. Timber may also bear the ISI Certification Mark, indicating conformity with the standard, verified through ISI supervised inspection, testing, and quality control processes. Rounding of test results follows IS 2-1960 to maintain precision and consistency.
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