autoclaved reinforced cellular concrete wall slabs

IS 6072: Scope - Key Specifications & Form Tolerances for Wall Slabs

1. Scope (Clause 2.0)

• Defines terms related to wall slabs.
• Applies to manufacture, dimensions, tolerances, and technical data.

2. Form Tolerances (Clause 5.3 & Table 1)

• Refer Fig. 2 for measurement directions (warp, torsion, edge straightness, squareness).

3. Manufacturer's Technical Literature (Clause 10.2)

Must include:

• Design & ultimate loads, deflections
• Residual water content (≥10% by weight at testing)
• Hole provisions
• Storage & handling guidelines (to prevent warping/torsion)
• Thermal conductivity data

Summary Diagram of Tolerances

graph LR
A[Wall Slab] --> B[Flatness (Warp)]
A --> C[Flatness (Torsion)]
A --> D[Edge Straightness]
A --> E[Squareness]
B --> F{Tolerance mm}
F --> F1[±2 to ±6 depending on length]
C --> G[Max 0.1% torsion]
D --> H[±1 to ±3 mm]
E --> I[±5 mm]

This ensures quality and dimensional accuracy of precast wall slabs per IS 6072.

IS 6072: Key Definitions, Form Tolerances & Specifications

Definitions (Clause 2.0)

• Standardizes terminology related to wall slabs for uniform understanding.

Form Tolerances for Wall Slabs (Clause 5.3, Table 1)

• Warp: Deviation from flatness.
• Torsion: Twist along slab length.
• Edge Straightness: Deviation of edges from straight line.
• Squareness: Angle between adjacent faces.

Manufacturer's Technical Literature (Clause 10.2)

Must include:

• Design load & deflection,
• Ultimate load,
• Residual water content (≥10% by weight at testing),
• Hole provisions,
• Storage & handling instructions (to prevent permanent deformation),
• Thermal conductivity data.

Visual Aid: Form Tolerances Concept

graph LR
A[Wall Slab] --> B[Flatness (Warp & Torsion)]
A --> C[Edge Straightness]
A --> D[Squareness of Angles]
B --> E{Tolerance Limits}
C --> E
D --> E

This summarizes essential definitions and tolerances for wall slabs per IS 6072.

IS 6072 Key Material Specifications & Formulas

1. Material Properties (Clause 7.1, Table 2)

• Drying Shrinkage: ≤ 0.09%
• Residual Water Content on Delivery: ≤ 6% by weight
• Fire Resistance: ≥ 2 hours

2. Form Tolerances for Wall Slabs (Clause 5.3, Table 1)

3. Additional Notes (Clause 10.2)

• Manufacturer must provide:
  • Design & ultimate load data
  • Deflection under design load
  • Residual water content
  • Hole-making provisions
  • Storage and handling instructions (to prevent warp/torsion)
  • Thermal conductivity values

flowchart TD
    A[Material Properties] --> B[Compressive Strength & Thermal Conductivity]
    A --> C[Drying Shrinkage & Water Content]
    A --> D[Fire Resistance]
   

IS 6072: Classification and Designation of Autoclaved Reinforced Cellular Concrete Wall Slabs

1. Classification (Clause 4.1)

Based on oven-dry density (without reinforcement):

2. Designation (Clause 4.2)

Wall slabs are designated by indicating:

• Compressive strength (kgf/cm²)
• Horizontal load bearing capacity (design load, kgf/cm²)
• Length (m)
• Breadth (mm)
• Thickness (mm)

Example: 50-15-3-600-100
(Means 50 kgf/cm² compressive strength, 15 kgf/cm² design load, 3 m length, 600 mm breadth, 100 mm thickness)

3. Physical Properties (Clause 7.1 & Table 2)

• Drying Shrinkage: ≤ 0.09%
• Residual Water Content: ≤ 6%
• Fire Resistance: ≥ 2 hours

4. Additional Notes

• Compressive strength is average of 3 samples; no individual value < 85% of average.
• Spot welding may be used to keep reinforcement in position (Clause 3.8.1).

flowchart TD
    A[Classification] -->|Density Range| B{Class A to E}
    B --> A1[Class

IS 6072: Dimensions and Tolerances for Wall Slabs

1. Dimensional Tolerances (Clause 5.2)

• Up to 500 mm: ± 2 mm
• Above 500 mm: ± 5 mm

2. Form Tolerances (Clause 5.3, Table 1)

3. Quality Control (Clause 12.5.1 & 12.4.1)

• Among 10 slabs inspected, max 1 slab can be outside tolerance or have visual defects.
• If >1 slab fails, entire lot must be tested and defective slabs rejected.

Visual Summary (Form Tolerances)

graph TD
    A[Wall Slab] --> B[Flatness]
    B --> B1[Warp ±2 to ±6 mm]
    B --> B2[Torsion max 0.1%]
    A --> C[Edge Straightness]
    C --> C1[Perpendicular ±1 to ±3 mm]
    C --> C2[In-plane ±3 mm]
    A --> D[Squareness ±5 mm]

Use these tolerances to ensure slab quality and dimensional accuracy per IS 6072.

IS 6072: Manufacture and Finish - Key Points

1. Form Tolerances (Clause 5.3 & Table 1)

Refer Fig. 2 for measurement methods.

2. Manufacturer's Technical Literature (Clause 10.2)

Must include:

• Design load & deflection under design load
• Ultimate load (≥ values in Clause 8.3)
• Residual water content on delivery
• Provisions for making holes
• Storage & handling instructions (to prevent permanent deformations)
• Thermal conductivity for product classes

3. Storage and Handling (Clause 3.8.1 & Note)

• Spot welding allowed for reinforcement positioning.
• Improper storage causes warp/torsion deformations.

Summary Diagram - Form Tolerances

graph TD
A[Wall Slab] --> B[Warp Tolerance ±2 to ±6 mm]
A --> C[Torsion Max 0.1%]
A --> D[Edge Straightness ±1 to ±3 mm]
A --> E[Squareness ±5 mm]

Use these tolerances and specifications to ensure quality and compliance in wall slab manufacture and finishing.

IS 6072: Key Formulas, Tables & Specs for Physical Properties (Clause 7.1)

• Density: As per Clause 4.1 (excluding reinforcement).
• Drying Shrinkage: ≤ 0.09%.
• Residual Water Content at Delivery: ≤ 6% by weight.
• Fire Resistance: ≥ 2 hours (IS: 3809-1966).
• Compressive Strength & Thermal Conductivity: See Table 2 below.

Notes:

• Compressive strength is the average of 3 cubes; no individual value < 85% of average.
• Thermal conductivity values relate to air-dry condition.

Additional Specifications:

• Wall slabs have tongue & groove or groove-to-groove edges for force transfer.
• Chamfered longitudinal edges.
• Manufacturer must provide design load, deflection, ultimate load, residual water content, hole provisions, storage, handling, and thermal conductivity data.

flowchart LR
    A[Wall Slab] --> B[Physical Properties]
    B --> C[Density (Clause 4.1)]
    B --> D[Drying Shrinkage ≤ 0.09%]
    B --> E[Residual Water ≤ 6%]
    B --> F[Fire Resistance ≥ 2 hrs]
    B --> G[Compressive Strength & Thermal Conductivity (Table 2)]

This summary helps ensure compliance with IS 6072 for autoclaved reinforced cellular concrete wall slabs.

IS 6072: Structural Requirements for Autoclaved Reinforced Cellular Concrete Wall Slabs

Key Physical Properties (Clause 7.1)

Compressive Strength & Thermal Conductivity (Table 2)

Note: Compressive strength is average of 3 samples; lowest individual ≥ 85% of average.

Form Tolerances for Wall Slabs (Clause 5.3, Table 1)

Deflection Limit (Clause 8.2)

• Max deflection under horizontal design load ≤ L/300 (L = effective span)

flowchart TD
    A[Wall Slab] --> B[Physical Properties]
    B --> C[Density, Shrinkage, Water Content, Fire Resistance]
    A --> D[Mechanical Properties]
    D --> E[Compressive Strength & Thermal Conductivity]
    A --> F[Dimensional Tolerances]
    F -->

IS 6072: Storage and Handling - Key Points

Ultimate Load (Clause 8.3.1)

• Ultimate load tested per Appendix A must not be less than:
  • The value in Clause 8.3, or
  • Manufacturer's specified value.

Manufacturer's Technical Literature (Clause 10.2)

Must include:

• Design load & deflection at design load
• Ultimate load capacity
• Residual water content at delivery
• Provisions for hole-making
• Detailed storage & handling instructions
• Thermal conductivity of product classes

Note: Improper storage/handling can cause permanent slab deformation (torsion, warp).

Form Tolerances for Wall Slabs (Clause 5.3, Table 1)

Markings on Slabs (Clause 11.1.1)

• Mark slabs for:
  • Correct handling & assembly positions
  • Special support/lifting points
  • Allowed hole-making locations

Summary Diagram: Storage & Handling Flow

flowchart TD
    A[Delivery] --> B[Check Technical Literature]
    B --> C{Storage Conditions}
    C -->|Proper| D[Store Horizontally on Firm Base]
    C -->|Improper| E[Risk of Warp/Torsion]
    D --> F[Markings for Handling]
    F --> G[Safe Handling & Assembly]

Ensure:

• Follow manufacturer's instructions strictly.
• Avoid uneven support to prevent permanent deformation.
• Use markings to guide lifting and hole-making.

IS 6072 - Marking Specifications & Form Tolerances

Marking Requirements (Clause 10 & 11)

Each wall slab shall be clearly and permanently marked with:

• Manufacturer's name/trade-mark
• Year of manufacture
• Designation
• The words "Do not cut"

Additional marking:

• ISI Certification Mark (optional, per ISI rules)
• Mark slabs for load-carrying capacity, handling points, and special hole locations (Clause 11.1.1)

Form Tolerances for Wall Slabs (Clause 5.3, Table 1)

Notes:

• Markings ensure correct handling, assembly, and usage.
• Form tolerances control dimensional accuracy for slab fitment.
• Refer to Fig. 2 in IS 6072 for dimensional illustrations.

flowchart LR
    A[Wall Slab] --> B[Marking]
    B --> C[Manufacturer Info]
    B --> D[Year of Manufacture]
    B --> E[Designation]
    B --> F["Do not cut" Warning]
    B --> G[Load & Handling Marks]
    A --> H[Form Tolerances]
    H --> I[Flatness: Warp & Torsion]
    H --> J[Edge Straightness]
    H --> K[Squareness]

This ensures slabs are traceable, handled safely, and fit accurately in construction.

IS 6072: Cost of Tests & Manufacturer's Certificate

Key Points from Clauses:

• Cost of Tests (Clause 11.4):

  • If slabs do not conform to the specification → Manufacturer bears the cost.
  • If slabs conform → Purchaser bears the cost.
  • Unless otherwise specified in enquiry/order.

• Manufacturer's Responsibility (Clause 11.3):

  • Manufacturer must supply slabs for testing free of charge.

• Certification Mark (Clause 10.2.1):

  • Slabs may carry the ISI Certification Mark indicating compliance.
  • ISI mark ensures continuous quality control and inspection.

Summary Table:

Additional Notes:

• Manufacturer’s certificate usually accompanies slabs confirming compliance.
• Sampling and conformity criteria are detailed in Clause 12 (e.g., number of tests).

flowchart TD
    A[Slabs Submitted for Testing] --> B{Do slabs conform?}
    B -- Yes --> C[Purchaser bears test cost]
    B -- No --> D[Manufacturer bears test cost]
    C & D --> E[Slabs marked with ISI Certification Mark (if applicable)]

This ensures clarity on cost responsibility and certification for quality assurance.

IS 6072: Sampling and Criteria for Conformity

Key Points from Clauses 12 & 11:

• Sampling Method (Clause 12.1):
  Representative samples of slabs shall be drawn as per Clauses 12.2 to 12.5.2 unless otherwise agreed.

• Criteria for Conformity (Clause 12.5):
  A lot is accepted if it meets conditions in 12.5.1 and 12.5.2 (typically related to test results falling within specified limits).

• Cost of Testing (Clause 11.4):

  • Manufacturer bears cost if slabs fail specification.
  • Purchaser bears cost if slabs conform to specification.

Typical Sampling Procedure (per IS 6072):

Criteria for Conformity (Generalized):

• All samples must meet minimum strength and dimensional tolerances.
• If any sample fails, the lot may be rejected or subjected to retesting.

Summary Table for Acceptance:

Mermaid Diagram: Sampling & Conformity Flow

flowchart TD
    A[Start: Lot Received] --> B[Draw Representative Samples]
    B --> C[Test Samples as per IS 6072]
    C --> D{Do all samples meet specs?}
    D -- Yes --> E[Accept Lot]
    D -- No --> F[Reject Lot or Retest]
    E --> G[Purchaser bears test cost]
    F --> H[Manufacturer bears test cost]

For exact sample sizes and detailed acceptance numbers, refer to Clauses 12.2 to 12.5.2 in IS 6072 or mutually agreed terms.

IS 6072: Test Methods for Load and Deflection – Key Points

1. Sample Preparation

• Residual water content at testing: ≥ 10% by weight (Clause 1.2).

2. Deflection Criteria (Clause 2.5 & 8.2)

• Maximum allowable deflection under design load = Span/300.
• If deflection > Span/300 or sample cracks, test is failed.

3. Load and Deflection Test (Appendix A)

• Manufacturer specifies horizontal design load.
• Under this load, deflection must not exceed Span/300.
• Ultimate load test determines max load before failure.

Summary Table: Deflection Limits

Deflection Formula

[ \delta_{max} \leq \frac{L_{eff}}{300} ]

• ( \delta_{max} ) = Maximum deflection
• ( L_{eff} ) = Effective span of slab

flowchart LR
    A[Start Test] --> B[Check Residual Water ≥ 10%]
    B --> C{Apply Horizontal Design Load}
    C --> D[Measure Deflection]
    D --> E{Deflection ≤ Span/300?}
    E -- Yes --> F[Pass Test]
    E -- No --> G[Fail Test]
    D --> H{Any Cracks?}
    H -- Yes --> G
    H -- No --> E

This ensures compliance with IS 6072 for load and deflection testing of autoclaved reinforced cellular concrete wall slabs.