Fibre hardboards -Specification

IS 1658 - Scope: Key Formulas, Tables & Specifications

1. Scope Summary (Clause 1.3)

• Values relate to product properties, not for design calculations.
• Covers dimensions, tolerances, physical & mechanical requirements of hardboards.

2. Dimensions & Tolerances (Table 7.1)

3. Physical & Mechanical Requirements (Table 10.1)

IS 1658 Key References: Dimensions, Tolerances & Mechanical Properties

1. Dimensions & Tolerances (Table 7.1)

2. Physical & Mechanical Properties (Table 10.1)

IS 1658 Key Definitions, Dimensions & Specifications

1. Definitions

• IS 1658 refers to IS 707 for standard definitions related to hardboards.
• Swelling in thickness (%) = Arithmetic mean of all test specimens, expressed to 1 decimal place (Clause 2.2).

2. Dimensions & Tolerances (Clause 7.1, Table I)

3. Physical & Mechanical Properties (Clause 10.4.5, Table 2)

IS 1658: Types of Fibre Hardboards - Key Specifications & Formulas

Classification (Clause 4)

Manufacturing Process (Summary)

• Wood chips → Defibrated at 170-200°C → Wet lap (68-72% moisture) → Hydraulic press → Trimmed panels.

Physical & Mechanical Requirements (Table 2 Highlights)

Dimensional Tolerances (mm/m)

Notes:

• Tempered Hardboard is chemically or heat treated to improve durability.
• ECO-Mark boards require wood from plantations or residues, not natural forests.
• Thickness ≥ 1.5 mm is mandatory for all types.

flowchart LR
    A[Wood Chips] --> B[Preheater (170-200°C)]
    B

IS 1658: General Requirements Summary

1. Dimensions & Tolerances (Clause 7.1, Table 7.1)

• Squareness max: 3 mm/m (Standard Hardboard)
• Edge straightness max: 2 mm/m (Standard Hardboard)

2. Physical & Mechanical Properties (Clause 10.4.5, Table 10.1)

IS 1658: Surface Quality - Key Specifications & Tolerances

1. Dimensional Tolerances (Table 7.1)

2. Surface Quality Testing

• Thickness Measurement: After soaking for 24h, specimens are wiped, rested 1h at room temp on glass, then thickness is measured at marked points.
• Density Test: Cut 100 ± 1 mm square specimens; smooth edges; average density must meet Table 2 requirements.

Summary:

• Length & width tolerances are ±3 to ±5 mm/m depending on board type.
• Thickness tolerance varies from ±0.4 mm to ±0.9 mm depending on thickness & type.
• Squareness and edge straightness max deviations are 3 mm/m and 2 mm/m respectively for standard hardboard.
• Specimens must be conditioned before

IS 1658: Dimensions and Tolerances for Fibre Hardboards (Clause 7.1 & Table 1)

Notes:

• Dimensions are measured per Annex A of IS 1658.
• Surface quality must be free from stains, cracks, blisters, and deformations (Clause 6.2).
• Tolerances are linear, e.g., ±3 mm per meter length.

Summary Diagram of Tolerance Application

flowchart LR
    A[Nominal Dimension] --> B{Type of Hardboard}
    B --> C[Medium Hardboard]
    B --> D[Standard Hardboard]
    B --> E[

IS 1658: Physical & Mechanical Requirements for Hardboards (Table 2 Summary)

Key Formulas:

• Tensile Strength Perpendicular to Board (Internal Bond Strength):

[ F_1 = \frac{F_{\text{max}}}{a \times b} ]

Where:

• (F_{\text{max}}) = breaking load (N)

• (a, b) = length and width of test specimen (mm)

• Thickness Measurement:
  Average of 8 points (4 corners + midpoints of edges), accuracy ±0.05 mm.

Sampling & Test Specimen Size:

• Test specimens: 900 mm × 450 mm panels, cut avoiding 150 mm edges.
• Density test specimens: 100 ± 1 mm squares.
• Length & Width measurement accuracy: ±1 mm.

flowchart TD
    A[Cut Test Specimens] --> B

IS 1658: Sampling and Criteria for Conformity

1. Scale of Sampling (Clause 9.1)

• Sampling is done from a lot of hardboards.
• The lot is accepted if it meets criteria under Clauses 6.1, 6.2, 7.1, 7.2, and 8.
• Sampling size and acceptance criteria depend on lot size and product type (medium, standard, tempered hardboard).

2. Criteria for Conformity (Clause 9.2)

• A lot conforms if all sampled boards meet the physical and mechanical requirements (Clause 8).
• Parameters include:
  • Thickness (mm)
  • Density (kg/m³)
  • Squareness (max mm/m)
  • Edge straightness (max mm/m)
  • Mechanical strength properties

3. Key Physical & Mechanical Requirements (Table 2 Summary)

4. Acceptance Formula (General)

• Let n = sample size, c = acceptance number (max allowable defects).
• If defects ≤ c, lot is accepted.
• Typical sampling follows ISO 2859-1 or similar acceptance sampling plans.

flowchart TD
    A[Lot of Hardboards] --> B[Sampling as per Clause 9.1]
    B --> C{All samples meet Clause 8?}
    C -- Yes --> D[Lot Accepted]
    C -- No --> E[Lot Rejected]

Summary:
Sampling ensures product quality by

IS 1658: Key Test Methods & Formulas Summary

1. Density Test (Clause 10.4.1)

• Cut 3 square specimens of size 100 ± 1 mm.
• Smooth edges with sandpaper.
• Calculate average density (kg/m³).
• Must meet values in Table 2:
  • Medium Hardboard: 350–800
  • Standard & Tempered Hardboard: 800–1025

2. Moisture Content Test (Clause 10.4.2)

• Use 3 specimens (100 ± 1 mm).
• Determine moisture %; must be 5–15%.

3. Tensile Strength Perpendicular to Board (Clause G)

• Specimen size: 50 mm × 50 mm bonded to loading blocks.
• Load applied perpendicular to the plane.
• Tensile strength, ( F_1 ) (N/mm²):

[ F_1 = \frac{F_{\text{max}}}{a \times b} ]

Where:

• ( F_{\text{max}} ) = breaking load (N)

• ( a, b ) = length & width (mm) of specimen

• Average of 3 specimens used.

• Minimum values (N/mm²):

  • Medium: 0.25
  • Standard: 1.0
  • Tempered: 1.5

4. Modulus of Rupture & Modulus of Elasticity (Annex H)

• Measure length, width (±1 mm), thickness (mean of 8 points, ±0.05 mm).
• Minimum individual MOR (N/mm²):
  • Medium: 5.5
  • Standard: 27
  • Tempered: 45
• Average MOR (N/mm²):
  • Medium: 6
  • Standard: 30
  • Tempered: 50
• Minimum individual MOE (N/mm²):
  • Medium: 550
  • Standard & Tempered: 2700
• Average MOE (N/mm²):
  • Medium: 600
  • Standard & Tempered: 3000

5. Water Absorption & Swelling (Clauses E & F)

• 24

IS 1658: Additional Requirements for ECO-Mark (Clause 11)

Key Specifications for ECO-Mark:

• Environmental Compliance:

  • Manufacturer must submit environmental consent clearance from the State Pollution Control Board as per:
    • Water (Prevention and Control of Pollution) Act, 1974
    • Air (Prevention and Control of Pollution) Act, 1981
    • Water (Prevention and Control of Pollution) Cess Act, 1977
    • Authorization under Environment (Protection) Act, 1986 if applicable
  • Compliance with Forest Department rules is mandatory.

• Marking Requirements (Clause 11.2): Each hardboard must be legibly and indelibly marked with:

  • Manufacturer's name/trade-mark
  • Type of hardboard
  • Nominal dimensions (length, width, thickness in mm)
  • Date of manufacture
  • ECO-Mark criteria label

• Documentation:

  • Manufacturer must provide documentary evidence (certificate/declaration) to BIS when applying for ECO-Mark.

Mechanical Properties (Clause 10.4.6):

• Modulus of Elasticity & Rupture:
  • Tested on 2 specimens each direction.
  • Minimum individual and average values must meet Table 2.

Summary Diagram of ECO-Mark Process:

flowchart LR
    A[Manufacturer] --> B[Environmental Clearance]
    B --> C[Produce Hardboard]
    C --> D[Mark Hardboard with ECO-Mark Details]
    D --> E[Submit Certificate & Samples to BIS]
    E --> F{BIS Approval?}
    F -- Yes --> G[Grant ECO-Mark]
    F -- No --> H[Rework &

IS 1658: Marking & Dimensional Specifications Summary

1. Marking Requirements (Clause 11.2 & 13)

Each hardboard must be legibly and indelibly marked with:

• Manufacturer's name/trade-mark/ID
• Type of hardboard (Medium, Standard, Tempered)
• Nominal dimensions (Length, Width, Thickness in mm)
• Date of manufacture
• ECO-Mark criteria (if applicable)
• Optional: BIS Standard Mark under license

2. Dimensions & Tolerances (Table 1, Clause 7.1)

3. Measurement Procedures (Annex A & B)

• Length & Width: Measure ±1 mm accuracy, 100 mm from edges, average recorded.
• Thickness: Use micrometer with 16 ±1 mm diameter anvils, force 4 ±1 N, 8 readings around edges, accuracy 0.05 mm.
• Straightness: Use straightedge, max gap recorded in mm/m.
• Squareness: Mechanical square 1000 ±1 mm arms, measure max gap at corners.

4. Density & Moisture Content Formulas (Annex C & D)

• **Density (

BIS Certification Marking (IS 1658) - Key Points & Formulas

1. Marking Requirements (Clause 11.2 & 13)

Each fibre hardboard must be indelibly marked with:

• Manufacturer's name/trade-mark
• Type of hardboard (see Clause 4)
• Nominal dimensions (length, width, thickness in mm)
• Date of manufacture
• ECO-Mark labelling criteria

Standard Mark usage governed by BIS Act, 1986 (Clause 13.1).

2. Measurement Specifications

3. Key Formulas

• Density (kg/m³) (Annex C-4):

[ \text{Density} = \frac{\text{Mass (g)} \times 10^6}{\text{Length (mm)} \times \text{Width (mm)} \times \text{Thickness (mm)}} ]

• Moisture Content (%) (Annex D-2):

[ \text{Moisture Content} = \frac{M_1 - M_0}{M_0} \times 100 ]

where (M_1) = initial mass, (M_0) = oven dry mass.

• Water Absorption (%) (Annex E-2):

[ A = \frac{M_2 - M_1}{M_1} \times 100 ]

where (M_1) = mass before immersion, (M_2) = mass after immersion.

• Tensile Strength Perpendicular to Board (N/mm²) (Annex G-3):

[ F_1 = \frac{F_{max}}{a \times

IS 1658 - Measurement of Dimensions: Key Points

1. Dimensional Tolerances (Table 1, Clause 7.1)

2. Measurement Procedures (Annex A & B)

• Length & Width: Measure parallel to edges, 100 mm inside, accuracy ±1 mm.
• Thickness: Use micrometer with 16±1 mm flat faces, force 4±1 N; take 8 readings near edges and center; accuracy 0.05 mm.
• Straightness: Use straight edge; measure max gap; express as mm/m.
• Squareness: Use 1000±1 mm mechanical square; measure gaps at corners; max gap per Table 1.

3. Density Calculation (Annex C)

[ \text{Density (kg/m}^3) = \frac{\text{Mass (g)} \times 10^6}{\text{Length (mm)} \times \text{Width (mm)} \times \text{Thickness (mm)}} ]

4. Moisture Content (Annex D)

[ \text{Moisture Content (%)} = \frac{M_1 - M_0}{M_0} \times 100 ]

• (M_1): Initial mass, (M_0): Oven

IS 1658: Measurement of Straightness and Squareness

Key Specifications (from Table 1, Clause 7.2):

(Values for Medium and Tempered Hardboards are not specified here)

Measurement Procedures (Annex B):

• Straightness:

  • Use a straight edge along the board edge.
  • Measure the largest gap (mm) between edge and straight edge.
  • Calculate deviation as:
    [ \text{Deviation (mm/m)} = \frac{\text{Largest gap (mm)}}{\text{Edge length (m)}} ]
  • Should not exceed values in Table 1.

• Squareness:

  • Use a mechanical square with arms 1000 ± 1 mm.
  • Place one arm along one side; measure gap at the other arm to the adjacent edge at all four corners.
  • Average the four measurements.
  • Maximum gap per corner must not exceed Table 1 values.

Summary Table for Tolerances:

Diagram: Measurement of Squareness

graph LR
A[Side 1 of Board] -- Place square arm --> B[Mechanical Square Arm 1]
B -- Measure gap --> C[Gap at Adjacent Edge]
D[Side 2 of Board] -- Along Square Arm 2 --> B

Note: Use precise instruments (mechanical square, straight edge) and record measurements to nearest 1 mm as per IS 1658 Annex B