Specification for Couplings, Double Male And Double Female, Instantaneous Pattern For Fire Fighting
1988 Edition

Overview of IS 901: Scope and Specifications

Scope: IS 901 specifies the requirements for copper alloy-based couplings, including material grades, dimensions, and hydraulic testing criteria.

1. Material Specifications (Clause 2.1):

*Covers leaded tin bronze, high tensile brass, leaded brass, naval brass, aluminium alloys, phosphor bronze, and stainless steel wires.

2. Hydraulic Test (Clause 4.1):

• Couplings must endure a hydraulic pressure of 2.1 MN/m² (21 kgf/cm²) for 2 minutes without any leakage or seepage.

3. Dimensional Details:

• Refer to Figures 1 and 2 for typical shapes and critical dimensions.

4. Conformance Requirements (Clause 7.1):

• Each coupling shall fully comply with the standard’s stipulated requirements.

Process Flow:

flowchart TD
    A[Select Material] --> B[Manufacture (Casting/Forging)]
    B --> C[Dimension Verification (Fig.1 & 2)]
    C --> D[Conduct Hydraulic Pressure Test]
    D --> E{Leakage Detected?}
    E -->|No| F[Conformance Approved]
    E -->|Yes| G[Reject or Reprocess]

Note: Always consult the latest edition of IS 901 and relevant IS codes for comprehensive dimension and testing instructions.

IS 901: Material Specifications Summary

1. Copper Alloy Materials (Clause 2.1)

• *Lead tin bronze ingots and castings
• +High tensile brass ingots and castings

2. Aluminium Alloys (Clause 2.2)

• Aluminium castings shall comply with IS:617-1975 designations 4450, 4225, or 4600.

3. Hydraulic Testing (Clause 4.1)

• The couplings must withstand 2.1 MN/m² (21 kgf/cm²) hydraulic pressure for 2 minutes with no leakage.

Copper Alloy Summary Table

For detailed chemical and mechanical properties, refer to the cited IS standards.

IS 901: Couplings’ Form and Dimensions

• The standard defines the typical shapes and exact dimensions in Figures 1 (Double Male Coupling) and 2 (Double Female Coupling).
• All measurements are expressed in millimetres (Clauses 3.1, 11.3).
• Example dimensions from Fig. 1:
  • Diameter: 35 ± 1 mm
  • Thickness: 6.0 ± 0.5 mm

Material Grades (Clause 2.1)

Summary:

• Use Figures 1 and 2 for accurate shape and size details.
• Strict adherence to dimensions is essential for proper fit and sealing.
• Material specifications ensure robustness and corrosion protection.

flowchart LR
    A[Choose Coupling Type] --> B{Male or Female}
    B -->|Male| C[Consult Fig.1 - Double Male Coupling]
    B -->|Female| D[Consult Fig.2 - Double Female Coupling]
    C --> E[Verify Dimensions (e.g., 35±1 mm diameter)]
    D --> E
    E --> F[Select Material Grade as per Clause 2.1]
    F --> G[Manufacture and Inspect Following IS 901]

Hydraulic Pressure Test Requirements as per IS 901

Clause 4.1 outlines the test procedure:

• Pressure to be applied: 2.1 MN/m² (equivalent to 21 kgf/cm²)
• Test duration: 2 minutes
• Acceptance: No visible leakage or seepage permitted

Test Parameters Summary

Additional Details

• Materials must comply with relevant copper alloy IS standards (e.g., IS 318, 304, 291, 1264).
• Coupling dimensions conform to Figures 1 and 2 of IS 901.
• The test confirms structural integrity and manufacturing quality.

flowchart LR
  A[Coupling Sample] --> B[Apply Hydraulic Pressure 2.1 MN/m²]
  B --> C[Maintain for 2 Minutes]
  C --> D[Inspect for Leakage]
  D -- No Leakage --> E[Test Passed]
  D -- Leakage Detected --> F[Test Failed]

Note: Testing should be conducted under controlled conditions with appropriate safety measures.

IS 901: Standards for Craftsmanship and Finish

1. Craftsmanship (Clause 5.1)

• Components must be free from burrs, sharp edges, porosity, blow-holes, cracks, and scale.
• Castings and forgings should be sound with no concealed repairs.
• Internal water passages require a smooth surface finish.
• Aluminium surfaces exposed externally must have an anodized coating.
• Threaded aluminium alloy parts are to be coated with molybdenum-based lubricant.

2. Material Grades (Clause 2.1, Table 2)

3. Testing Requirements (Clause 4.1)

• Couplings must endure 2.1 MN/m² hydraulic pressure for 2 minutes with no leakage.

Workmanship Process Flow

flowchart LR
    A[Raw Casting/Forging] --> B[Defect Inspection]
    B -->|No Defects| C[Machining and Finishing]
    B -->|Defects Found| D[Reject or Remanufacture]
    C --> E[Surface Treatment]
    E --> F[Final Inspection]
    F -->|Pass| G[Apply Coating & Grease if Aluminium]
    G --> H[Ready for Deployment]

Note: Refer to the respective IS standards for comprehensive mechanical and chemical property details.

IS 901: Marking Guidelines for Couplings

Marking Requirements (Clause 6.1)

Each coupling must be legibly and permanently marked with:

• Manufacturer’s name and trademark
• Year of manufacture
• Material type

BIS Standard Mark (Clause 6.1.1)

• Couplings may carry the BIS Standard Mark indicating compliance with IS 901.
• Use of the Standard Mark is regulated under the Bureau of Indian Standards Act, 1986.
• This mark assures quality under BIS surveillance and inspection.

Material Grades Reference (Clause 2.1)

Additional Points

• Couplings must pass the hydraulic pressure test of 2.1 MN/m² for 2 minutes without leakage (Clause 4.1).

Marking Flow Diagram

graph LR
A[Coupling] --> B[Manufacturer Name & Trademark]
A --> C[Year Manufactured]
A --> D[Material Type]
A --> E[BIS Standard Mark (Optional)]

This marking system ensures traceability, material verification, and quality assurance.

IS 901: Conformance Requirements (Clause 7.1)

• Every coupling must fully comply with all provisions of IS 901.
• Compliance includes adherence to material specifications, dimensional accuracy, and performance standards.
• Typical materials include copper alloys as specified:
  • Sand castings: Grade LTB 2 (IS 318:1981) or Grade HTB 1 (IS 304:1981)
  • Die castings: Grade 3 (IS 292:1983)
  • Hot forgings: Grade 1 (IS 291:1977)
  • Gravity die castings: IS 1264:1981

Important Details:

• Couplings should bear the BIS Standard Mark to confirm conformity.
• BIS conducts ongoing inspections and monitoring.
• Unauthorized reproduction of the standard is prohibited.

Material Grade Table

This ensures couplings deliver the required strength, longevity, and safety for firefighting equipment.