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IS 5246 : 2000Coniferous logs

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EN 1927-2 · GOST 9463 · ISO 4480
CurrentSpecializedSpecificationMaterials Science · Timber and Timber Stores
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Link points to Internet Archive / others. Not hosted by InfraLens. Details
OverviewValues6InternationalTablesFAQ4Related

IS 5246:2000 is the Indian Standard (BIS) for coniferous logs. This standard lays down the specifications for coniferous logs intended for conversion into sawn timber, veneers, and other wood products. It covers species, grading based on defects, dimensional requirements, and the method for measuring volume.

Coniferous logs

Overview

Status
Current
Usage level
Specialized
Domain
Materials Science — Timber and Timber Stores
Type
Specification
International equivalents
EN 1927-2:2008 · CEN (European Committee for Standardization), EuropeGOST 9463-2016 · Rosstandart, Russian FederationISO 4480:2020 · ISO (International Organization for Standardization), InternationalEN 1310:2020 · CEN (European Committee for Standardization), Europe
Typically used with
IS 707IS 3364
Also on InfraLens for IS 5246
6Key values2Tables4FAQs
Practical Notes
! The Quarter-girth formula (Hoppus's formula) is the standard method for volume calculation, using the girth measured at the mid-point of the log's length.
! Grading is critical for valuation. Class I logs have the fewest defects and yield the highest quality timber, while Class III logs are suitable for less demanding applications.
! Always measure girth under bark for accurate volume calculations, unless specified otherwise.
Frequently referenced clauses
Cl. 3TerminologyCl. 4SpeciesCl. 5GradingCl. 6DefectsCl. 7Method of Measurement
Pulled from IS 5246:2000. Browse the full clause & table index below in Tables & Referenced Sections.
timberconiferous woodlogspinefirdeodarspruce

International Equivalents

Similar International Standards
EN 1927-2:2008CEN (European Committee for Standardization), Europe
HighCurrent
Classification of round coniferous timber - Part 2: Qualitative classification for logs
Directly addresses the qualitative grading of coniferous logs, similar to the core purpose of IS 5246.
GOST 9463-2016Rosstandart, Russian Federation
HighCurrent
Round coniferous timber. Specifications.
Covers classification, dimensions, defects, and quality grades for coniferous logs, mirroring the scope of the IS code.
ISO 4480:2020ISO (International Organization for Standardization), International
MediumCurrent
Round timber — Measurement and rules for volume calculation
Matches the measurement and volume calculation aspects of IS 5246, but does not cover qualitative grading.
EN 1310:2020CEN (European Committee for Standardization), Europe
MediumCurrent
Round and sawn timber - Method of measurement of features
Provides standardized methods for measuring defects (features) which are then used for grading, a supporting but not equivalent role.
Key Differences
≠IS 5246 uses three quality grades (Grade I, II, III). European standard EN 1927-2 uses a four-class system (A, B, C, D) which is more directly tied to specific end-uses like veneer, sawing, or pulp.
≠IS 5246 often defines defect limits relative to log dimensions (e.g., knot diameter as a fraction of girth). EN standards, supported by EN 1310, tend to use more absolute measurements (e.g., maximum knot diameter in millimeters) for a given quality class, leading to less ambiguity.
≠The Indian standard is based on Himalayan coniferous species (Deodar, Kail, Chir, Fir/Spruce), whereas international standards like EN and GOST are based on European and Russian species (Pine, Spruce, Larch, Fir) with different growth characteristics.
≠IS 5246 specifies a single method for volume calculation using mid-girth (Quarter Girth formula). ISO 4480 provides multiple methods (Huber's, Smalian's) and defines Huber's (mid-diameter) as the reference method, offering more precision and flexibility.
Key Similarities
≈All standards share the fundamental purpose of classifying logs based on dimensions (length, diameter) and quality (defects) to determine their value and suitability for processing.
≈The types of defects considered for grading are universally recognized across all standards, including knots (sound, unsound), checks/splits, decay, sweep (curvature), taper, and insect damage.
≈The basic measurement principles are similar, involving the capture of log length and a cross-sectional dimension (diameter or girth) to calculate volume.
≈Both IS 5246 and international standards mandate the marking of logs with their grade and dimensions, ensuring traceability and clear communication in trade and processing.
Parameter Comparison
ParameterIS ValueInternationalSource
Grading CategoriesGrade I, Grade II, Grade IIIClass A, Class B, Class C, Class DEN 1927-2:2008
Diameter MeasurementMeasurement of girth at the mid-point of the log.Measurement of diameter (two perpendicular readings) at the mid-point of the log (Huber's method).ISO 4480:2020
Sweep (Curvature) Limit for Top GradeMax 1/24 of the length for Grade I.Max 1 cm per meter of length for Class A (equivalent to 1/100 of length).EN 1927-2:2008
Sound Knot Limit for Top GradeDiameter not exceeding 1/8 of the girth at the point of occurrence for Grade I.Sum of knot diameters on worst whorl is max 30% of perimeter for Class B (sawlogs).EN 1927-2:2008
End Splits/Checks in Top GradeNot permitted for Grade I.Not permitted to extend further than 10 cm from the log end for Class A.EN 1927-2:2008
Volume Calculation FormulaV = (G/4)^2 * L (Quarter Girth Formula).V = (π * d_mid^2 / 4) * L (Huber's Formula - Reference Method).ISO 4480:2020
⚠ Verify details from original standards before use

Key Values6

Quick Reference Values
Minimum log length3.0 m
Minimum girth for Class I & II logs90 cm
Minimum girth for Class III logs60 cm
Free trimming allowance over nominal length10 cm
Maximum permissible individual sound knot diameter (Class I)1/6th of log diameter at the point of occurrence
Maximum permissible heartwood rot or hollow (Class I)Not permitted
Key Formulas
V = L × (G/4)² — Formula for calculating log volume (Quarter-girth or Hoppus's formula)

Tables & Referenced Sections

Key Tables
Table 1 - Classification of Coniferous Logs on the Basis of Out-turn
Table 2 - Permissible Defects for Coniferous Logs
Key Clauses
Clause 3 - Terminology
Clause 4 - Species
Clause 5 - Grading
Clause 6 - Defects
Clause 7 - Method of Measurement

Related Resources on InfraLens

Cross-Referenced Codes
IS 707:2011Timber Technology And Utilization of Wood, Ba...
→
IS 3364:2000Methods of measurement and evaluation of defe...
→

Frequently Asked Questions4

How is the volume of a coniferous log calculated according to this standard?+
Volume (V) is calculated using the quarter-girth formula: V = L × (G/4)², where L is length and G is the mid-girth under bark (Clause 7.3).
What are the main grades for coniferous logs?+
Logs are graded into Class I, Class II, and Class III based on the extent of permissible defects like knots, splits, and decay (Clause 5 and Table 2).
What is the minimum length of a log covered by this standard?+
The minimum length specified for logs is 3.0 meters (Clause 7.1.1).
Which common Indian timber species are covered?+
The standard includes species like Deodar (Cedrus deodara), Kail/Blue Pine (Pinus wallichiana), Chir Pine (Pinus roxburghii), and Fir (Abies pindrow/spectabilis) (Clause 4).

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