Non-coniferous sawn timber (Baulks and scantlings)
1992 Edition

Scope Overview (Clause 2.1)

• Defines specifications for non-coniferous sawn timber referencing related IS codes:
  • IS 401:1982 – Timber preparation guidelines
  • IS 707:1976 – Timber terminology glossary
  • IS 1141:1973 – Timber seasoning practices
  • IS 1150:1976 – Trade names and symbols for timber species
• Timber species included are detailed in Annexes A & B.
• Species nomenclature conforms to IS 1150:1976.

Dimensional Specifications (Clauses 5.2 & 6.2)

• Volume calculation formula: Volume (m³) = Length × Width × Thickness
• Volume precision to three decimal places.
• Measurements based on standardized sizes.

Measurement Summary Table

flowchart TD
    Timber --> LengthMeasurement[Measure Length (m)]
    Timber --> WidthMeasurement[Measure Width (m)]
    Timber --> ThicknessMeasurement[Measure Thickness (m)]
    LengthMeasurement & WidthMeasurement & ThicknessMeasurement --> ComputeVolume[Calculate Volume = L × W × T]
    ComputeVolume --> FinalVolume[Volume in m³ (3 decimals)]

This section ensures standardized measurement and grading procedures as per IS 1326.

Key Referenced Standards

• IS 401:1982 – Timber preparation (3rd revision)
• IS 707:1976 – Timber terminology glossary (2nd revision)
• IS 1141:1973 – Timber seasoning code (1st revision)
• IS 1150:1976 – Trade names and abbreviations for timber species (2nd revision)
• IS 1326:1992 – Timber dimensions and measurement code

Timber Species and Nomenclature

• Species listed in Annexes A & B of IS 1326.
• Naming and abbreviations per IS 1150:1976.

Typical Timber Sizes (Example from IS 1326)

Note: Actual dimensions are reduced due to seasoning and planing.

flowchart TD
    IS1326 --> IS707[Definitions (IS 707)]
    IS1326 --> IS1150[Nomenclature (IS 1150)]
    IS1326 --> IS401[Preparation (IS 401)]
    IS1326 --> IS1141[Seasoning (IS 1141)]

This clarifies the interrelation of IS 1326 with other Indian standards for timber.

Definitions

• Timber-related terms follow IS 707:1976 glossary.
• Species names and abbreviations are as per IS 1150:1976.

Volume Computation (Clause 5.2.3)

• Formula: Volume (m³) = Length (m) × Width (m) × Thickness (m)
• Accuracy: Rounded to three decimal places.
• Based on accepted standard sizes.

Related Standards Overview

flowchart TD
    Definitions --> IS707[IS 707 Terms]
    Definitions --> SpeciesList[Annex A & B]
    SpeciesList --> IS1150[IS 1150 Nomenclature]
    Definitions --> VolumeCalc[Volume = L × W × T]

This section standardizes terminology and measurement for structural timber.

Covered Species

• Indian non-coniferous timber species as per Annexes A & B.
• Species abbreviations conform to IS 1150:1976.

Sample Species List from Annex A

Marking Requirements (Clause 10.1)

• Mark each piece with:
  • Species abbreviation
  • Dimensions
  • Supplier identifier
  • Year of supply

Additional References

• IS 190:1991 for coniferous timber specifications.
• IS 401, IS 707, IS 1141, and IS 1150 for preparation, seasoning, terminology, and species symbols.

flowchart TD
    Inspection --> Marking[Mark Timber]
    Marking --> SpeciesAbbr
    Marking --> Dimensions
    Marking --> SupplierInfo
    Marking --> YearOfSupply

This ensures traceability and uniform identification of timber.

Measurement Guidelines (Clause 5.2)

• Width and thickness are measured at the narrowest section, rounded to the nearest 10 mm.
• Volume is calculated as: Volume (m³) = Length × Width × Thickness
• Volume rounded to three decimal places.

Reference Standards

• IS 707:1976 – Definitions
• IS 1150:1976 – Species nomenclature
• IS 401, IS 1141, IS 1150 – Preparation, seasoning, and defect evaluation

Measurement Summary

This section standardizes sizing and volume calculations for uniformity.

Volume Formula (Clause 5.2.3)

• Volume (m³) = Length × Width × Thickness
• Accuracy to three decimal places with standard sizes.

Grading and Defect Limitations (Clauses 6.2, 7.1, 7.2)

Other Notes

• End splits length limited (80 mm/m for Special Grade, 100 mm/m for Grade 1).
• Defect measurement per IS 3364.

This grading framework ensures timber quality meets structural and durability requirements.

Prohibited Defects (Clause 7.1)

• For all grades: No spiral or twisted grain, warping, decay, or active insect damage.
• Special Grade additionally excludes center heart, wane, cup shakes, borer holes (dead infestation), sapstain, and knots.
• Grade 1 excludes cup shakes.

Permitted Defects (Summary from Table 1)

Additional Notes

• Knot counts and sizes are restricted per metre length.
• End split lengths have prescribed limits.
• Defects measured according to IS 3364 (Part 2).

This clarifies the quality limits for each timber grade.

Prophylactic Treatment Procedures (Clause 8)

• Based on IS 401:1982 (Timber preparation).
• Objective: Minimize defects such as end cracking and splitting.

End Coating Specifications

• Apply protective coatings on ends of baulks and scantlings up to:
  • Minimum 150 mm, or
  • At least 25 mm beyond the longest end split, whichever is greater.
• Coating materials to comply with IS 1141:1973 (Seasoning code).
• Coating must be applied immediately after timber inspection.

Summary Table

flowchart TD
    Inspection --> MeasureSplit[Measure Longest Split]
    MeasureSplit --> Decision{150 mm > (Split + 25 mm)?}
    Decision -->|Yes| Apply150[Apply coating 150 mm]
    Decision -->|No| ApplySplit[Apply coating Split + 25 mm]
    Apply150 & ApplySplit --> UseMaterial[Use IS 1141 specified materials]
    UseMaterial --> Result[Prevents cracking and splitting]

This treatment enhances timber durability by controlling moisture loss and mechanical damage.

Marking Instructions (Clauses 10.1 & 10.1.1)

• Mark each timber piece clearly and permanently approximately 300 mm from one end immediately after inspection.

Required Markings

• Species name abbreviation (per Annex A).
• Dimensions (length × width × thickness).
• Supplier’s name, initials, or registered trademark.
• Year of supply.

Optional Marking

• Use of the Standard Mark as per Clause 10.1.1.

Sample Species Abbreviations (Annex A)

Volume Calculation (Clause 5.2.3)

[\text{Volume (m}^3) = \frac{\text{Length (mm)} \times \text{Width (mm)} \times \text{Thickness (mm)}}{1,000,000,000}]

flowchart LR
    Timber --> Inspection[Inspection]
    Inspection --> Marking[Mark at 300 mm from end]
    Marking --> SpeciesAbbr
    Marking --> Dimensions
    Marking --> SupplierInfo
    Marking --> YearSupply
    Marking --> OptionalMark[Optional: Standard Mark]

This ensures traceability and standardization for timber identification.

Defect Allowances (Clause 7.2)

• Defects permitted as per Table 1 for different grades.
• Measured according to IS 3364 (Part 2):1976.
• Includes splits, shakes, knots, etc., with grade-specific limits.

Prophylactic Treatment (Clause 8)

• Conducted following IS 401:1982.
• End coating applied to at least 150 mm or 25 mm beyond longest split as per IS 1141:1973.
• Coating applied immediately post-inspection to prevent end cracking.

Volume Measurement (Clause 5.2.3)

• Volume (m³) = Length × Width × Thickness.
• Rounded to three decimal places.

Related Standards

• IS 401:1982 (Preparation)
• IS 3364 (Part 2):1976 (Defect measurement)
• IS 1141:1973 (Seasoning and end coating)
• IS 707:1976 (Glossary)
• IS 1150:1976 (Species nomenclature)

Summary Table

flowchart TD
    Inspection --> DefectCheck[Check Defects per IS 3364]
    Inspection --> ApplyTreatment[Apply Prophylactic Treatment]
    Inspection --> MeasureVolume[Measure Dimensions & Calculate Volume]
    Inspection --> IdentifySpecies[Confirm Species & Terminology]

This ensures consistent inspection, sampling, and quality control.

List of Non-Coniferous Species (Excerpt from Annex A)

Complete species list available in IS 1326 Annex A.

Related Standards

• IS 1150:1976 – Trade names and abbreviated symbols
• IS 707:1976 – Glossary of timber terms
• IS 401:1982 – Timber preparation
• IS 1141:1973 – Seasoning procedures
• IS 190:1991 – Coniferous timber specifications

Notes

• Non-coniferous timber is sold mainly as baulks and scantlings.
• Identification uses standardized trade names and abbreviations.
• Marking with the Standard Mark is encouraged.
• Dimensioning and measurement adhere to IS 401 and IS 1141.

flowchart TD
    Sample --> IdentifySpecies{Identify Species}
    IdentifySpecies --> VisualMatch[Match Trade Name]
    VisualMatch --> AssignAbbreviation[Assign Abbreviated Symbol (IS 1150)]
    AssignAbbreviation --> MarkStandardMark[Apply Standard Mark]

This annex ensures accurate timber species classification and marking.