Block Boards -Specification

IS 1659: Scope Overview

• Scope: IS 1659 covers specifications for steel tubes for structural purposes, including dimensions, tolerances, and mechanical properties.

• General Requirements (Clause 10.1):
  Specifies the need for compliance with test values rounded as per IS 2:1960 to maintain consistency in numerical precision.

• Definitions:
  Uses definitions from IS 707 (General Steel Tubes) plus additional specific terms relevant to structural tubes.

• Rounding Off Values:
  Final test or analysis values must be rounded off according to IS 2:1960 rules, retaining the same number of significant digits as specified.

Key Points Summary:

If you need dimensions, tolerances, or mechanical properties, please specify, and I can provide detailed tables or formulas accordingly.

IS 1659 - Definitions Summary

• Reference to IS 707:
  The definitions in IS 1659 rely primarily on those in IS 707 (Code for Structural Steel Sections).

• Rounding Off (IS 2:1960):
  Numerical results (test or analysis) must be rounded off per IS 2:1960 rules, retaining the same number of significant digits as specified.

• Key Dimensional Terms (Clause 8.1.4):

  • Length: The longitudinal dimension of the steel section.
  • Width: The transverse dimension, typically flange width for sections.

Important Notes:

Rounding Off Rule (IS 2:1960):

• If the digit to be dropped is <5, round down.
• If the digit is >5, round up.
• If the digit is exactly 5, round to make the last retained digit even.

flowchart LR
    A[Measured/Calculated Value] --> B{Check digit after last significant figure}
    B -->|<5| C[Round down]
    B -->|>5| D[Round up]
    B -->|=5| E[Round to even last digit]

This ensures consistency and accuracy in compliance checks per IS 1659.

IS 1659: Types and Grades of Block Boards

1. Grades and Types (Clause 4.3 & 4.2)

• Decorative Type: Veneers on one/both sides, used for aesthetics.
• Commercial Type: Commercial timber veneers, for painted or utility use.

2. Mechanical Properties (Clause 9.2.5)

3. Face Veneers for Decorative Type (Annex C)

Selected species include:

Species marked with * require treatment.

Summary Diagram of Types and Grades

graph TD
    A[Block Boards] --> B[BWP Grade]
    A --> C[MR Grade]
    B --> B1[Decorative (BWP-DEC)]
    B --> B2[Commercial (BWP-COM)]
    C --> C1[Decorative (MR-

IS 1659: Key Material Properties & Specifications

1. Modulus of Rupture (MOR) & Modulus of Elasticity (MOE) (Clause 9.2.5)

• Testing per Annex J (conditioning & test methods).

2. Test Conditioning (Clause 8.2 & Annex E-1.2)

• Specimens conditioned at 90 ± 5% RH and 40 ± 5% RH at 27 ± 2°C until constant mass.
• Use moist salts to create atmospheres if no humidity chamber:
  • 90% RH: Sodium carbonate
  • 65% RH: Ammonium nitrate
  • 40% RH: Magnesium chloride or zinc nitrate hexahydrate

3. Timber Species for Face Veneers (Annex C)

(*Species marked with * require treatment as per Clause 6

IS 1659: Face Veneers for Decorative Block Boards

Key Specifications

• Face Veneer Thickness (Clause 6.3.1):
  • Decorative block boards: 0.5 mm to 1.2 mm
  • Commercial block boards: 0.5 mm to 1.5 mm
• Cross Band Thickness: 1.0 mm to 3.0 mm

Timber Species for Decorative Face Veneers (Annex C)

IS 1659 - Preservative Treatment Key Points

1. Preservative Treatment (Clause 6.1)

• Timber species marked (*) in Annex B & C, sapwood of all species, and non-durable species must be treated as per IS 401.
• Trimmed/cut ends of block boards should receive protective treatment.

2. Spot Test for Penetration (Clause 9.2.6 & Annex K)

• Through and through penetration of preservative must be confirmed by spot test (Annex K).
• Method:
  • Spray/brush solution on bore dust or cross-section.
  • Chromium presence → purple color, untreated areas remain unchanged.
• Common preservatives: boric acid, borax (water-soluble), copper-chrome-arsenic, acid-cupric-chromate, ammoniacal-copper-arsenite.

3. Test Conditions for Eco-Mark (Clause 10)

• Maintain specimens at 27 ± 2ºC for 3 weeks.
• After incubation, wash and check compliance per Clause 9.2.4.

4. Modulus of Rupture & Elasticity (Annex J)

• Span = 20 × depth.
• Load applied centrally at 5 mm/min.
• Formulas:

flowchart LR
    A[Timber Species] -->|Marked * or Sapwood| B[Preservative Treatment IS 401]
    B --> C[Spot Test (Annex K)]
    C --> D{Chromium Detected?}
    D -->|Yes| E[Purple Color → Penetration Confirmed]
    D -->|No| F[No Penetration]

Summary: Use IS 401 for treatment, confirm penetration by spot test showing purple color for chromium preservatives

IS 1659: Dimensions and Tolerances for Plywood Boards

Key Tolerances (Clause 7.3)

Additional Notes:

• Thickness tolerances and permissible defects must comply with IS 303 (commercial veneers) and IS 1328 (decorative veneers).
• Edge straightness and squareness testing details are given in Annex D of IS 1659.
• Sampling and inspection procedures are outlined in Clause 8.

Visual Summary:

flowchart LR
    A[Finished Board] --> B[Length: +6/-0 mm]
    A --> C[Width: +3/-0 mm]
    A --> D[Thickness: ±5%]
    A --> E[Thickness Variation ≤ 0.5 mm]
    A --> F[Edge Straightness ≤ 2 mm/1000 mm]
    A --> G[Squareness ≤ 2 mm/1000 mm]

Use these tolerances to ensure plywood quality and dimensional accuracy per IS 1659.

IS 1659: Sampling and Inspection Key Points

1. Sampling Method (Clause 8.1.2)

• Representative samples must be drawn as per IS 7638.
• Visual inspection for surface defects (Clause 6.3.3) is mandatory.
• If any block board is unsatisfactory, the entire lot is rejected.

2. Tolerance Limits (Clause 7.3, Table 7.3)

3. Rounding Off (IS 2:1960)

• Final test values must be rounded off following IS 2:1960.
• Retain the same number of significant digits as specified.

4. Test Specimens & Number of Tests (Clause 8.2)

• Number and type of tests depend on the lot size and sampling plan (refer IS 7638).

flowchart TD
    A[Start: Lot of Block Boards] --> B[Draw Samples per IS 7638]
    B --> C[Visual Inspection for Surface Defects]
    C -->|Pass| D[Conduct Dimensional & Other Tests]
    C -->|Fail| E[Reject Entire Lot]
    D --> F[Compare Results with Tolerances (Table 7.3)]
    F -->|Within Limits| G[Accept Lot]
    F -->|Out of Limits| E

This ensures quality compliance and uniformity in block boards per IS 1659.

IS 1659 – Quality and Performance Requirements for Block Boards

Key Points from Clause 10.1 & Related Clauses:

• General Quality Compliance (10.1 & 10.1.1):
  Block boards must meet all quality and performance criteria specified in IS 1659.

• Lot Conformance (9.2.1 to 9.2.6):
  A batch (lot) is accepted only if all tests for quality, moisture content, bonding, strength, and other parameters meet the standard.

• Rounding Off Results:
  Test results must be rounded as per IS 2:1960 rules, keeping the same number of significant digits as the specified values in IS 1659.

Typical Quality & Performance Parameters (from IS 1659 context and general practice):

Rounding Off Rule (IS 2:1960)

• If the digit to be dropped is <5, round down.
• If >5, round up.
• If exactly 5, round to nearest even number.

flowchart LR
    A[Production Lot] --> B{Tests 9.2.1 to 9.2.6}
    B -->|All Passed| C[Lot Accepted]
    B -->|Any Failed| D[Lot Rejected]
    C --> E[Rounding off test results per IS 2:1960]

Summary: Ensure block boards meet all specified physical and mechanical properties, verify through tests, and apply IS 2 rounding rules for reporting results.

IS 1659: Additional Requirements for ECO-Mark on Block Boards

Key Specifications for ECO-Mark (Clause 10.2 & related)

• Marking Requirements: Each block board must be indelibly marked on any face with:

  • Source of manufacture
  • Grade and type of block board
  • Size: Length, Width, Thickness
  • Batch number and year of manufacture
  • Criteria for ECO-Mark labeling

• Environmental Compliance (Clause 10.1.2):

  • Manufacturers must submit environmental consent clearance from the State Pollution Control Board under:
    • Water (Prevention and Control of Pollution) Act, 1974 & 1977
    • Air (Prevention and Control of Pollution) Act, 1981
    • Authorization under Environment (Protection) Act, 1986 if required
  • Compliance with Forest Department regulations is mandatory.

• Certification:

  • Documentary evidence (certificate/declaration) must be provided to BIS for ECO-Mark application.
  • Product must carry BIS Standard Mark along with ECO-Mark.

Spot Test for Preservative Penetration (Clause 9.2.6)

• Preservative must penetrate through and through across the entire cross-section width.
• Tested as per Annex K method.

Summary Table: ECO-Mark Requirements

flowchart TD
    A[Manufacture Block Board] --> B[Ensure Environmental Clearance]
    B --> C[Apply for BIS ECO-Mark]
    C --> D[Submit Documentary Evidence]
    D --> E[Mark Block Board with Required Info]
    E --> F[Conduct Spot Test for Preservative Penetration]
    F --> G[Block Board Certified with ECO-Mark]

This ensures eco-friendly production and traceability as per IS 1659.

IS 1659: Marking and Labelling Key Points

BIS Certification Mark (Clause 11.1)

• Use governed by Bureau of Indian Standards Act, 1986.
• Licence conditions available from BIS.
• Product may carry the Standard Mark indicating conformity.

Marking Requirements on Block Boards (Clause 10.2)

Each block board shall be legibly and indelibly marked on any face with:

• Source of manufacture
• Grade and type of block board
• Size: length, width, and thickness (in mm)
• Batch number and year of manufacture
• ECO-Mark labelling criteria (if applicable)

Timber for Face Veneers (Annex C, Clause 5.1.2)

Use standard trade names and botanical names for veneers, e.g.:

* Species marked with * require treatment.

Summary Table for Marking:

flowchart LR
    A[Block Board] --> B{Marking on Face}
    B --> C[Manufacturer Info]
    B --> D[Grade & Type]
    B --> E[Size (L×W×T)]
    B --> F[Batch No. & Year]
    B --> G[ECO-Mark Criteria]

This ensures traceability, quality, and eco-compliance per IS 1659.

IS 1659: Method of Test for Edge Straightness and Squareness of Plywood

Edge Straightness (Annex D - D-1.1)

• Use a straight edge at least the full length of the plywood.
• For convex edges, hold the plywood so gaps at both ends are approximately equal.
• Measure the largest gap between plywood edge and straight edge to the nearest mm.

Squareness (Annex D - D-2.1)

• Use a square with 500 mm arms.
• Place one arm along the plywood edge.
• Measure the maximum gap between the other arm and plywood edge.

Setup (Annex G - G-1.2)

• Conduct test on a stout table.
• Fix a wooden batten on the table as a reference edge.
• Place plywood edge against the batten (see Fig. 2 in IS 1659).

Summary Table

flowchart LR
    A[Plywood Edge] -->|Place against| B[Wooden Batten on Table]
    B --> C{Test Type}
    C -->|Straightness| D[Straight Edge (Full Length)]
    C -->|Squareness| E[Square (500 mm arms)]
    D --> F[Measure Max Gap]
    E --> F

IS 1659: Test for Adhesion of Plies (Clause 9.2.3 & Annex G)

Key Specifications & Procedure:

• Test Method (G-4.1.1):
  • Insert a chisel into the glue line between core strips and adjoining veneers.
  • Forcefully separate the plies in the direction of the core strips.
  • Assess the bond by the amount of wood fibres left on the fractured surface.

Grading Criteria:

Tool:

• Knife approx. 250 mm x 25 mm made from a file (see Fig.1 in IS 1659).

Visual Aids:

• Figures 2 to 5 illustrate the test method and adhesion quality examples.

flowchart LR
    A[Insert Chisel at Glue Line] --> B[Force Separation Along Core Strips]
    B --> C{Assess Fractured Surface}
    C -->|Torn Fibres Present| D[Excellent or Pass Adhesion]
    C -->|No Fibres, Easy Separation| E[Poor Adhesion]

This qualitative test ensures plywood's structural integrity by confirming strong glue bonds between plies.

IS 1659: Mycological Test (Clause 9.2.4 & Annex H)

Key Specifications:

• Test Purpose: Check MR grade block board specimens for fungal resistance.
• Requirement: No visible edge separation after test.
• Test Setup (Annex H):
  • Sawdust inoculated with Indian fungi spores is loosely compacted.
  • Test specimens pressed so their upper surface is flush with sawdust.
  • Incubate at 27 ± 2ºC for 3 weeks.
  • After incubation, specimens washed in cold water and checked for edge separation.

Reporting:

• Results are reported as conforming or non-conforming to the standard.

Additional Relevant Tests:

Where:

• ( P_{\max} ) = max load (N)
• ( P ) = load at proportional limit (N)
• ( L ) = span (mm)
• ( b ) = breadth (mm)
• ( d ) = depth (mm)
• ( A ) = deflection at proportional limit (mm)

Summary Diagram (Mycological Test Setup):

flowchart TD
    A[Sawdust + Indian fungi spores] --> B[Loosely compacted in dish]
    B --> C[Test specimen pressed flush with sawdust]
    C --> D[Incubate at 

IS 1659: Spot Test for Preservative Penetration (Clause 9.2.6 & Annex K)

Key Specifications:

• Through-and-through penetration of preservative must be visible after cutting entire cross-section of block board (Clause 9.2.6).
• Test specimens maintained at 27 ± 2ºC for 3 weeks before testing (Eco-mark Clause 1.4).
• Test results reported as conforming/non-conforming (Clause H-2).

Spot Test Method (Annex K):

Preservatives Tested:

• Copper-chrome-arsenic (CCA)
• Acid-cupric-chromate (ACC)
• Borated-copper-chrome
• Ammoniacal-copper-arsenite

Summary Diagram of Spot Test Procedure:

flowchart TD
    A[Cut cross-section of block board] --> B[Apply Solution 1]
    B --> C[Wait 2 min, shake off excess, dry 1 min]
    C --> D[Apply Solution 2]
    D --> E[Wait 2 min, shake off excess, dry 1 min]
    E --> F[Apply Solution 3 (pour over surface)]
    F --> G{Color Change?}
    G -->|Bluish| H[Preservative Penetration Confirmed]
    G -->|No Color| I[No Penetration Detected]

This test ensures complete preservative penetration by colorimetric indication, critical for durability of block boards per IS 1659.