By-product gypsum for use in plaster, blocks and boards

IS 12679: Scope - Key Specifications & Tables

Scope:
IS 12679 covers By-Product Gypsum used in construction, specifying chemical requirements and testing methods to ensure quality.

Key Chemical Requirements (Clause 3.1, Table 1)

Sampling (Clause 4.2, Table 2)

IS 12679 Key References and Specifications

1. Rounding Off (Clause None)

• Follow IS 2:1960 for rounding numerical values.
• Retain the same number of significant digits as the specified value.

2. Chemical Requirements for By-Product Gypsum (Clause 3.1, Table 1)

Note: Impurities above limits require processing.

3. Sampling (Clause 4.2, Table 2)

IS 12679 - Chemical Requirements for By-Product Gypsum

Key Chemical Limits (Table 1, Clause 3.1)

Important Notes:

• If impurities exceed limits, gypsum must be processed to reduce them.
• Tests are performed on composite samples from randomly selected packages (IS 4905 : 1968).
• Sampling and testing procedures ensure representativeness and conformity.

Summary of Sampling (Clause 4):

• Group packages from the same batch as a lot.
• Select sample packages randomly per IS 4905.
• Prepare composite sample by mixing equal quantities from each package.

This ensures by-product gypsum quality for safe and effective use in construction

IS 12679 - Sampling: Key Formulas, Tables, and Specifications

Sampling Size (Clause 4.2 & Table 2)

• Sampling: Select packages at random from the lot.
• Randomness Procedure: Follow IS 4905:1968 for random selection methods.

Important Notes:

• Sampling ensures representativeness of the lot.
• Final test results should be rounded off per IS 2:1960, retaining the same significant figures as specified values.

flowchart LR
    A[Start: Lot Size Known] --> B{Lot Size?}
    B -->|Up to 100| C[Select 3 Packages]
    B -->|101-150| D[Select 4 Packages]
    B -->|151-300| E[Select 5 Packages]
    B -->|301-500| F[Select 7 Packages]
    B -->|501+| G[Select 10 Packages]
    C & D & E & F & G --> H[Select Randomly per IS 4905]
    H --> I[Conduct Tests]
    I --> J[Round Results per IS 2]

This ensures statistically valid sampling and consistent test reporting.

IS 12679: Packing and Marking - Key Points

Packing (Clause 5.1)

• By-product gypsum shall be packed in bags or containers suitable for protection.
• Each package must be legibly marked with:
  • Name of the material and manufacturer
  • Date of manufacture

Marking

• Use of the Standard Mark is governed by BIS rules.
• The Standard Mark assures compliance with BIS inspection, testing, and quality control.
• Continuous conformity checks by BIS ensure product reliability.

Sampling (Clause 4.2, Table 2)

Summary Diagram: Packing & Marking Process

flowchart TD
    A[By-product Gypsum] --> B[Pack in Bags/Containers]
    B --> C[Mark Package]
    C --> D[Name & Manufacturer]
    C --> E[Date of Manufacture]
    C --> F[Standard Mark (BIS)]
    F --> G[Quality Assurance & Inspection]

This ensures traceability, quality, and compliance with IS 12679.

IS 12679 - Criteria for Conformity (Clause 4.4)

• All test results of the composite sample must meet the specified requirements in the standard for the product to be accepted.
• Rounding off of test values must follow IS 2:1960 rules, retaining the same number of significant digits as the specified value.
• Sampling:
  • A lot consists of all packages from the same batch.
  • Samples are randomly selected from the lot as per IS 4905:1968.
  • Number of packages sampled depends on lot size (see Table 2 in IS 12679).

Summary Table: Sampling Size (Indicative)

Key Points:

• Composite sample test results must satisfy all chemical and physical requirements (see Table 1, Clause 3.1).
• Use IS 1288, IS 2411, IS 2720 (Part 22), IS 5741 for test methods.
• Random sampling ensures unbiased conformity assessment.

flowchart TD
    A[Lot of Packages] --> B[Random Sampling per IS 4905]
    B --> C[Composite Sample]
    C --> D{Test Results}
    D -->|Meets Requirements| E[Conformity Confirmed]
    D -->|Fails Any Test| F[Non-Conformity]

This ensures quality control by statistically verifying compliance through representative sampling and standardized testing.

IS 12679 - Methods of Test: Key Formulas, Tables & Specifications

Rounding Off:

• Final test values must be rounded per IS 2:1960 rules, maintaining the same significant figures as specified.

Sampling (Clause 4)

• Lot: All packages from the same batch form a lot.
• Sampling: Select samples randomly from the lot (see IS 4905:1968).
• Sample size: Depends on lot size, per Table 2 (not fully provided).

Chemical Requirements & Test Methods (Table 1, Clause 3.1)

Notes:

• If impurities exceed limits, gypsum must be processed to reduce them.
• Refer to respective IS codes for detailed test procedures.

flowchart

IS 12679: Key Notes, Annexures, and Tables

1. Rounding Off (IS 2:1960)

• Final test/analysis values must be rounded off per IS 2:1960.
• Retain same significant figures as specified values.

2. Sampling Table (Clause 4.2)

3. Chemical Requirements of By-Product Gypsum (Clause 3.1)