Preservative-treated and seasoned sawn timber from rubber wood (Hevea Brasiliensis)

IS 14960: Scope - Key Specifications & Tables

1. Tolerance in Sizes (Clause 5.2.2)

Permissible dimensional tolerances for timber grades:

• Note: Minus tolerance in width is allowed in max 10% of supplies at a time.

2. Preservation Requirements (Clause 4.1)

Timber preservation as per IS 401, with chemical retention and penetration per IS 2753 (Part 1):

3. Rounding Off (General Clause)

• Follow IS 2:1960 for rounding test results.
• Retain the same significant figures as the specified value.

Summary Diagram:

flowchart TD
    A[Timber Grade] --> B{Tolerance}
    B -->|+3 mm / -1 mm| C[Grade A, B, C]
    A --> D[Preservation]
    D --> E{Hazard Class}
    E -->|H1| F[DSR=5.0 CCA/CCB, Penetration throughout]
    E -->|H2| G[DSR=8.0 CCA/CCB

IS 14960 Key References, Formulas & Tables

1. References (Annex A)

• IS 14960 incorporates provisions from other Indian Standards (IS) listed in Annex A.
• Always check for the latest editions of referenced IS codes.
• Rounding off numerical results per IS 2:1960 rules.

2. Tolerance in Sizes (Clause 5.2.2)

• Minus tolerance in width allowed in max 10% of supply.

3. Preservation (Clause 4.1)

¹ Boron retention values apply only to specific hazard classes.
² Cu/Zn napthenates retention varies with chemical type.

4. Permissible Defects (Clause 6)

• Defects measured as per IS 3364 (Part 2).
• Defect limits vary by grade (see Table 1 in IS 14960).

Summary:

• Use IS 2:1960 for rounding off.
• Tolerances are ±3 mm/+1 mm (width).
• Preservation levels depend on hazard class with specified chemical retention.
• Refer to IS

IS 14960: Key Definitions & Specifications Summary

1. Definitions (Clause 3.1):

   • Refer to IS 707 for standard timber-related definitions.
   • Additional definitions specific to IS 14960 apply as per the standard.

2. Tolerances in Sizes (Clause 5.2.2):

   Grade	Tolerance + (mm)	Tolerance - (mm)
   A	+3	-1
   B	+3	-1
   C	+3	-1

   • Note: Minus tolerance in width allowed in max 10% of supply.

3. Preservation (Clause 4.1):
   Timber preservation as per IS 401 with chemicals, retention & penetration per IS 2753 (Part 1):

   Hazard Class	Condition	DSR (kg/m³) CCA/CCB	Boron	Cu/Zn Napthenates	Penetration
   H1	Interior, protected, painted	5.0	5.0	0.5/0.6	Throughout
   H2	Interior, intermittent wetting	8.0	-	0.5/0.8	Throughout
   H3	Exposed, not ground contact	12.0	-	0.5/0.8	Throughout
   H4	In ground contact	16.0	-	-	Throughout

4. Rounding Off (General Clause):

   • Follow IS 2:1960 for rounding test results, maintaining significant figures as per specified values.

Visualization of Tolerances

graph LR
    A[Grade A] -->|+3 mm| Size
    A -->|-1 mm| Size
    B[Grade B] -->|+3 mm| Size
    B -->|-1 mm| Size
    C[Grade C] -->|+3 mm| Size
   

Preservation of Timber as per IS 14960 (Clause 4.1 & 4.2)

• Preservative Treatment:
  Timber must be treated according to IS 401 using specified chemicals.

• Dry Salt Retention (DSR) & Penetration:
  Measured per IS 2753 (Part 1), the DSR and penetration depend on hazard class:

• Seasoning:
  Treated timber must be seasoned as per IS 1141, ensuring moisture content and residual stresses meet specifications.

¹ Boron compounds
² Copper/Zinc-based preservatives

Summary:

• Use IS 401 for chemical treatment methods.
• Ensure DSR meets hazard class requirements.
• Penetration must be throughout the timber section.
• Season timber per IS 1141 for moisture and stress control.

flowchart LR
    A[Timber] --> B[Preservative Treatment (IS 401)]
    B --> C[Measure DSR & Penetration (IS 2753)]
    C --> D{Hazard Class}
    D -->|H1| E[DSR=5.0 kg/m³, Penetration: Throughout]
    D -->|H2| F[DSR=8.0 kg/m³, Penetration: Throughout]
    D -->|H3| G[DSR=12.0 kg

IS 14960: Dimensions and Tolerances Summary

1. Dimensions Agreement

• As per Clause 5.1, dimensions are agreed upon between manufacturer and purchaser.

2. Tolerances on Sizes (Clause 5.2.2)

• Note: Minus tolerance in width allowed for max 10% of supplies at one time.

3. Permissible Defects (Clause 6)

• Refer to Table 1 (not provided here) for defects per grade.
• Defect measurement per IS 3364 (Part 2).
• Timber must be straight sawn, square trimmed, free from major defects (Clause 4.3).

4. Rounding Off Values

• Follow IS 2:1960 for rounding test/analysis results to the same significant digits as specified.

Quick Reference Table for Tolerances

| Grade | + Tolerance (mm) | - Tolerance (mm) |
|-------|------------------|------------------|
| A     | +3               | -1               |
| B     | +3               | -1               |
| C     | +3               | -1               |

This ensures dimensional accuracy and quality control in timber products per IS 14960.

IS 14960: Permissible Defects Summary

1. Permissible Defects (Clause 6 & Table 1)

• Defects are classified by Grade A, B, and C.
• Measurement of defects follows IS 3364 (Part 2).
• Defects include knots, shakes, insect holes, decay, pitch pockets, etc.
• Only defects listed as permissible for each grade are allowed.

2. Tolerance in Sizes (Clause 5.2.2)

• Minus tolerance in width not permitted in more than 10% of supply.

3. Quality Requirements (Clause 4.3)

• Timber must be free from defects except those permitted.
• Must be sawn straight, square trimmed, and preservative treated per IS 401.

Additional Notes:

• Defect measurement standard: IS 3364 (Part 2)
• Preservative treatment: As per IS 401 & IS 2753 (Part 1) for chemical retention and penetration.

flowchart TD
    A[Timber Supply] --> B{Grade A, B, C}
    B --> C[Check Size Tolerance]
    C -->|Within +3/-1 mm| D[Accept]
    C -->|Outside Tolerance| E[Reject or Reprocess]
    B --> F[Check Permissible Defects]
    F -->|Within Limits| D
    F -->|Exceeds Limits| E

This ensures timber quality meets structural durability and strength requirements.

IS 14960: Marking and Certification Key Points

1. BIS Certification Marking (Clause 7.2 & 7.2.1)

• Each bundle of product shall be marked with the BIS Standard Mark to indicate conformity.
• Marking ensures traceability and compliance with IS 14960.

2. Size Tolerances (Clause 5.2.2, Table 5.2.2)

• Minus tolerance in width must not exceed 10% of total supply at any time.

3. Permissible Defects (Clause 6)

• Defects are classified per Grade in Table 1 (refer IS 3364 Part 2 for measurement).
• Ensures quality control by limiting defects per grade.

4. Rounding Off (General Clause)

• Final test results should be rounded as per IS 2:1960.
• Maintain the same number of significant digits as specified in the standard.

Summary Diagram

flowchart TD
    A[Product Bundle] --> B{Marking}
    B -->|Yes| C[BIS Standard Mark]
    C --> D[Size Tolerances]
    D --> E{Grade A/B/C}
    E --> F[+3 mm / -1 mm]
    E --> G[Minus width tolerance ≤ 10%]
    D --> H[Permissible Defects per Grade]
    H --> I[Measured as per IS 3364 Part 2]
    I --> J[Rounding off per IS 2:1960]

This ensures product quality, traceability, and compliance with IS 14960.

IS 14960 references several Indian Standards critical for design and construction. Although Annex A lists these standards, key commonly referred standards include:

• IS 456:2000 – Plain and Reinforced Concrete Code
• IS 875 (Part 1 to 5) – Code of Practice for Design Loads (Dead, Live, Wind, Earthquake, Snow)
• IS 800:2007 – General Construction in Steel – Code of Practice
• IS 1904:1986 – Foundation Engineering
• IS 13920:2016 – Ductile Detailing of Reinforced Concrete Structures Subjected to Seismic Forces

Important Notes:

• Always verify the latest edition of each referred standard.
• These standards provide design formulas, material specifications, and safety factors essential for structural design.
• For example, IS 456 provides formulas for flexural design:
  [ M_u \leq 0.87 f_y A_s (d - \frac{a}{2}) ] where (M_u) = ultimate moment, (f_y) = yield strength, (A_s) = area of steel, (d) = effective depth, (a) = depth of equivalent stress block.

Summary Table of Key IS Codes:

Always consult Annex A of IS 14960 for the complete and updated list.

Committee Composition - IS 14960

The Committee responsible for IS 14960 formulation is detailed in Annex B (Foreword), under the Timber and Timber Stores Sectional Committee, CED 9.

Key Details:

• Chairman: Shri Shyam Sunder (Personal Capacity, Bangalore)
• Members: Representatives from diverse sectors including:
  • Industry bodies (e.g., Andaman Chamber of Commerce)
  • Research Institutes (e.g., Central Building Research Institute, Forest Research Institute)
  • Government Forest Departments (various states)
  • Directorate General of Civil Aviation, Naval Architecture, Supplies & Disposal
  • Plywood and Timber Industries
  • Bamboo Society of India

Purpose:

• The committee includes experts from government, industry, and research to ensure comprehensive standard development for timber and timber products.

Summary Table of Committee Composition (Excerpt)

This multi-disciplinary committee ensures the standard covers technical, industrial, and regulatory aspects of timber products.

If you need further details on specific members or their roles, please refer to Annex B of IS 14960.