Corrugated and semi-Corrugated Asbestos Cement Sheets

IS 459: Scope – Key Specifications for Corrugated & Semi-Corrugated Sheets

Dimensions & Tolerances (Table 1 Summary)

• Pitch tolerance is measured over 6 pitches (corrugated) and 3 pitches (semi-corrugated).
• Optional sheet width: 1086 mm overall, 1016 mm effective (by mutual agreement).

Additional Notes:

• Dimensions must conform to Table 1 and Figures 1 & 2 (corrugated and semi-corrugated profiles).
• Rounding off test results follows IS 2:1960 rules.

flowchart LR
    A[Start: Sheet Type] --> B{Corrugated or Semi-Corrugated?}
    B -->|Corrugated| C[Depth=48 mm, Pitch=146 mm]
    B -->|Semi-Corrugated| D[Depth=45 mm, Pitch=338 mm]
    C --> E[Width & Thickness per Table 1]
    D --> E
    E --> F[Check Tolerances & Lengths]
    F --> G[Conforms to IS 459?]

This scope ensures standardized dimensions and quality for roofing sheets under IS 459.

IS 459: Key Specifications & Tables for Corrugated and Semi-Corrugated Sheets

Table 1: Dimensions and Tolerances (All in mm)

• Pitch tolerance is measured over six pitches for corrugated and three for semi-corrugated sheets.
• Lengths available: 1500, 1750, 2000, 2250, 2500, 2750, 3000 mm.
• Corrugated sheets of overall width 1086 mm and effective width 1016 mm can be made by mutual agreement.

Notes:

• Depth and pitch define the corrugation profile.
• Effective width is the cover width after overlapping sheets.
• Thickness tolerance allows slight variation for manufacturing.

flowchart LR
    A[Corrugated Sheet] -->|Depth D=48 mm| B[Pitch P=146 mm]
    A -->|Overall Width B=1050 mm| C[Effective Width C=1010 mm]
    A -->|Thickness T=6 mm| D[Length A=1500-3000 mm]
    
    E[Semi-Corrugated Sheet] -->|Depth D=45 mm| F[Pitch P=338 mm]
    E -->|Overall Width B=1100 mm| G[Effective Width C=1014 mm]
    E -->|Thickness T=6 mm| H[Length A=1500-3000 mm]

This table and specifications form the core reference for manufacturing and

IS 459 - Definitions & Key Specifications for Corrugated and Semi-Corrugated Sheets

Key Dimensions & Tolerances (Table 1, Clause 5.1.2)

• Pitch tolerance is measured over six pitches (corrugated) and three pitches (semi-corrugated).
• Optional size: Corrugated sheets with overall width 1086 mm and effective width 1016 mm can be made by mutual agreement.

Definitions:

• Depth of Corrugation (D): Vertical height of the corrugation wave.
• Pitch of Corrugation (P): Distance between two adjacent corrugation peaks.
• Overall Width (B): Total width of the sheet.
• Effective Width (C): Usable width after overlapping.
• Nominal Thickness (T): Thickness of the sheet.
• Length of Sheet (A): Length along the corrugation.

flowchart LR
    A[Depth of Corrugation (D)]
    B[Pitch of Corrugation (P)]
    C[Overall Width (B)]
    D[Effective Width (C)]
    E[Nominal Thickness (T)]
    F[Length of Sheet (A)]

   

IS 459 - Key Specifications for Materials (Corrugated & Semi-Corrugated Sheets)

1. Dimensions & Tolerances (Table 1 - Clause 5.1.2)

• Note: Pitch tolerance is measured over 6 pitches for corrugated and 3 pitches for semi-corrugated sheets.
• Corrugated sheets of overall width 1086 mm and effective width 1016 mm can be made by mutual agreement.

2. Quality Requirements (Clause 9.2)

• Sheets must meet dimensional tolerances (Clause 5 & 7).
• Must pass tests for:
  • Impermeability
  • Frost cracking resistance
  • Density (as per Clause 6)

Visual Summary

graph LR
A[Corrugated Sheets] -->|Depth 48 mm| B[Dimensional Tolerances]
A -->|Pitch 146 mm| B
A -->|Width 1050 mm| B
C[Semi-Corrugated Sheets] -->|Depth 45 mm| B
C -->|Pitch 338 mm| B
C -->|Width 1100 mm| B
B --> D[Quality Tests: Impermeability, Frost Cracking, Density]

This

IS 459: Dimensions and Tolerances for Corrugated & Semi-Corrugated Sheets

• Length options: 1500, 1750, 2000, 2250, 2500, 2750, 3000 mm.
• Tolerances for pitch are measured over multiple pitches as noted.
• Sheets may be natural or coated (Clause 4.2).

Note: Sheets of overall width 1086 mm and effective width 1016 mm can be made by agreement (Fig 1A).

flowchart LR
    A[Depth of Corrugation (D)] --> B[Pitch of Corrugation (P)]
    B --> C[Overall Width (B)]
    C --> D[Effective Width (C)]
    D --> E[Nominal Thickness (T)]
    E --> F[Length of Sheet (A)]

This table and tolerances ensure dimensional consistency critical for structural and roofing applications.

IS 459: Physical & Mechanical Characteristics Summary

Key Dimensions & Tolerances (Table 1)

• Pitch Measurement:
  • Corrugated: Length over 6 pitches measured; tolerance applies to 6×pitch.
  • Semi-corrugated: Length over 3 pitches measured; tolerance applies to 3×pitch.

Mechanical & Physical Requirements

• Tests: Impermeability, frost cracking, density as per Clause 9.2.
• Load Bearing Capacity (Clause 9.3):
  Calculate average (X) and range (R) of test results.
  Acceptance criterion:
  [ P - 0.2R \geq \text{specified limit} ]

Visual Summary:

flowchart LR
    A[Corrugated Sheets] -->|Depth 48mm| B[Pitch 146mm]
    A -->|Width 1050mm| C[Length 1500-3000mm]
    D[Semi-Corrugated Sheets] -->|Depth 45mm| E[Pitch 338mm]
    D -->|Width 1100mm| F[Length 1500-3000mm]

Note: Refer to IS 459 Table 1 for exact tolerances and measurement

IS 459 Sampling Key Points

1. Scale of Sampling (Clause 8.1.2, Table 2)

• Randomly select sheets from the lot as per above to ensure representative quality testing.

2. Dimensions and Tolerances (Clause 5.1.2, Table 1)

• Pitch tolerance applies over 6 pitches (corrugated) or 3 pitches (semi-corrugated).

3. Rounding Off (Clause 8)

• Test results shall be rounded as per IS 2:1960 rules.
• Maintain same decimal places as specified values.

flowchart TD
    A[Lot Size] --> B{Select Sample Size}
    B --> |<=500| C[3 Sheets]
    B --> |501-1000| D[5 Sheets]
    B --> |1001-1500| E[7 Sheets]
    B --> |>1500| F[10 Sheets]

Summary: Use Table

IS 459: Testing Key Points

1. Sampling & Number of Tests (Clause 8.2)

• Tests are performed on selected sheets as per Clause 6.
• Number of tests depends on batch size and sampling plan (refer Clause 8.2).

2. Dimensions & Tolerances (Clause 5.1.2, Table 1)

3. Criteria for Conformity (Clause 9.3)

• Calculate average (X) and range (R) of test results.
• Characteristic satisfies if:
  [ X - 0.2R \geq \text{specified limit} ]

4. Inspection & Test Certificates (Clause 10)

• Manufacturer must provide test certificates confirming compliance.

Summary Diagram: Testing Flow

flowchart TD
    A[Select Sheet Sample] --> B[Perform Tests as per Clause 6]
    B --> C[Calculate Average (X) and Range (R)]
    C --> D{Is X - 0.2R ≥ Limit?}
    D -->|Yes| E[Accept Batch]
    D -->|No| F[Reject Batch]
    E --> G[Issue Test Certificate]

This ensures

IS 459: Criteria for Conformity - Key Points

1. Conformity Clause (9.1)

• A lot is conforming if conditions under Clauses 9.2 and 9.3 are met.
• Tests must be performed on selected sheets as per Clause 8.2.2 and 6.

2. Sampling & Testing (Clause 8.1.1.1)

• Conformity is based on tests from sheets randomly selected from the lot.

3. Dimensions & Tolerances (Table 1, Clause 5.1.2)

Note: Pitch tolerance is measured over 6 pitches (corrugated) and 3 pitches (semi-corrugated).

Summary for Conformity Check:

• Verify dimensional tolerances per Table 1.
• Perform tests as per Clause 6 on selected sheets.
• Confirm all test results meet specification limits under Clauses 9.2 & 9.3.

flowchart TD
    A[Lot of Sheets] --> B[Select Sample Sheets]
    B --> C[Perform Tests (Clause 6)]
    C --> D{Test Results within Limits?}
   

IS 459: Inspection & Manufacturer's Test Certificate Key Points

1. Load Bearing Capacity (Clause 9.3)

• Calculate average (X) and range (R) of test results.
• Acceptance criterion:
  [ P - 0.2R \geq \text{Characteristic Limit} ] where (P) = average test result, (R) = range (max-min).

2. Inspection and Test Certificate (Clause 10.2)

• Manufacturer must provide a certificate confirming compliance with IS 459.
• Certificate should affirm that finished products meet all specifications.

3. Marking on Sheets (Clause 11)

Each sheet must be indelibly marked with:

• Source of manufacture
• Year and date of manufacture
• Pictorial warning signs per IS 12 (Part 2):1987

4. Dimensions & Tolerances (Table 1, Clause 5.1.2)

Pitch tolerance measured over 6 pitches (corrugated) or 3 pitches (semi-corrugated).

Summary Diagram: Inspection & Certification Flow

flowchart TD
    A[Manufacturing] --> B[Testing at Manufacturer's Premises]
    B --> C{Test Results}
    C -->|Pass| D[Issue Test Certificate]
    C -->|Fail| E[Rework or Reject]
    D --> F[Mark Sheets with Info]
    F --> G[Dispatch with

IS 459 Testing Facilities - Key Formulas, Tables & Specs

1. Dimensions & Tolerances (Clause 5.1.2, Table 1)

Note: Pitch tolerance is measured over 6 pitches (corrugated) or 3 pitches (semi-corrugated).

2. Sampling & Testing (Clause 8.2.2)

• Tests per Clause 6 performed on each selected sheet.
• Test results averaged (X) and range (R) calculated.
• Load Bearing Capacity Criterion (Clause 9.3):
  [ P - 0.2R \geq \text{Specified Limit} ] Where P = average test result, R = range (max-min).

3. Inspection & Certification (Clause 10)

• Manufacturer must provide test certificates.
• Compliance confirmed by IS 2:1960 rounding rules.

flowchart LR
    A[Select Sheets] --> B[Perform Tests (Clause 6)]
    B --> C[Calculate Average (X) & Range (R)]
    C --> D{Is P - 0.2R ≥ Limit?}
    D -->|Yes| E[Accept Batch]
    D -->|No| F[Reject Batch]

Summary: Use Table 1 for sheet dimensions

IS 459 - Marking: Key Dimensions & Tolerances for Corrugated & Semi-Corrugated Sheets

• Pitch tolerance is measured over 6 pitches (corrugated) and 3 pitches (semi-corrugated).
• Optional sheet width: 1086 mm overall, 1016 mm effective (by mutual agreement).
• Final test values should be rounded per IS 2:1960 rules.

This ensures dimensional accuracy and interchangeability in roofing sheets.

flowchart LR
    A[Marking of Sheets] --> B[Depth of Corrugation (D)]
    A --> C[Pitch of Corrugation (P)]
    A --> D[Overall Width (B)]
    A --> E[Effective Width (C)]
    A --> F[Nominal Thickness (T)]
    A --> G[Length of Sheet (A)]

IS 459 - Safety Rules Sheet: Key Specifications & Tables

1. Dimensions & Tolerances (Table 1, Clause 5.1.2)

• Pitch tolerance applies over 6 pitches (corrugated) or 3 pitches (semi-corrugated).
• Sheets must conform to these dimensions and tolerances as per Clause 5.1.

2. Testing (Clause 8.2.2)

• Tests are performed on selected sheets as per Clause 6 (mechanical, chemical, etc.).

3. Additional Notes

• Sheets of 1086 mm overall width and 1016 mm effective width may be manufactured by mutual agreement.

Visual Summary (Corrugated Sheet Profile)

graph LR
A[Depth of Corrugation (D) = 48 mm] --> B[Pitch of Corrugation (P) = 146 mm]
B --> C[Overall Width (B) = 1050 mm]
C --> D[Effective Width (C) = 1010 mm]
D --> E[Thickness (T) = 6 mm]
E --> F[Length (A) = 1500 to 3000 mm]

This table and specifications ensure dimensional accuracy and **