Copper Alloy Gate, Globe and Check Valves for Waterworks Purposes

Scope of IS 778 (Valve Standard) – Key Points & Tables

• Clause 8.2: Specifies minimum flat-to-flat sizes for valves (both Class 1 & 2).

  Nominal Size (mm)	8	10	15	20	25	32	40	50	65	80	100
  Flat to Flat Size (mm)	18	22	26	32	39	49	55	68	85	98	127

• Material Tests (Clause 9.2):
  Material tests must comply with corresponding material specs in Table 1 and be certified by suppliers. Tests should be conducted at the manufacturer’s works if facilities exist.

• Valve Seat Types (Tables 9 & 10):

  • Gate valves:
    i) Screwed-in/on bonnet integral seat
    ii) Screwed-in/on bonnet renewable seat
  • Globe & lift check valves: same seat types as above.

• Material Specifications:
  Refer to IS codes for materials like compressed asbestos fibre (IS 2712), gland packing (IS 5414, IS 4687), phosphor bronze wire (IS 7608), brass (IS 5192), and others as per clause 4.6 references.

Summary Diagram - Valve Seat Types

graph TD
    A[Valve Types] --> B[Gate Valves]
    A --> C[Globe & Lift Check Valves]
    B --> B1[Screwed-in/on bonnet integral seat]
    B --> B2[Screwed-in/on bonnet renewable seat]
    C --> C1[Screwed-in/on bonnet integral seat]
    C --> C2[Screwed-in/on bonnet renewable seat]

This covers the scope and minimum dimensional & material requirements per IS 778 for valves. For detailed design and manufacture, refer to clauses 7 and 9.

IS 778: Terminology, Definitions & Key Specifications Summary

1. Terminology & Definitions (Clause 2.0)

• Defines terms used in valve standards for clarity and uniformity.
• Applies to valve types, seats, bonnets, and dimensions.

2. Minimum Flat-to-Flat Size (Clause 8.2, Table 5)

• Applies to both Class 1 and Class 2 valves.

3. Valve Seat Types (Table 9, Clause 8.6)

• Gate Valves:
  • Screwed-in bonnet integral seat
  • Screwed-in bonnet renewable seat
• Globe & Lift Check Valves:
  • Screwed-in bonnet integral seat
  • Screwed-in bonnet renewable seat

4. End-to-End Dimensions (Table 9, Clause 8.6)

• Dimensions vary by valve type, seat type, and nominal size.
• Example for Gate Valves (Screwed-in integral seats, Class 1 & 2):

5. Material Tests (Clause 9.2)

• Must comply with corresponding material specs (Table 1).
• Certified by suppliers; tests preferably at manufacturer’s works.

Summary Diagram: Valve Dimension Relationships

flowchart LR
   

Key Materials Specifications & Tables from IS 778 for Valves

1. Material Tests (Clause 9.2)

• Material tests as per referenced IS specifications (Table 1).
• Supplier certification mandatory.
• Tests at manufacturer's works if facilities exist.

2. Materials for Valve Components (Clause 6.1, Table 1)

3. Minimum Flat-to-Flat Sizes for Valve Nuts (Clause 8.2, Table 5)

| Nominal Valve Size (mm) | 8 | 10 | 15

IS 778 - Classification and Types of Valves: Key Points

1. Valve Classes (Clause 4.1)

• Class 1 and Class 2 valves as per IS 778.
• Classification affects design, material, and testing requirements.

2. Valve Types & Seats (Table 9, 10)

• Gate Valves:
  • Screwed-in or screwed-on bonnet integral seat
  • Screwed-in or screwed-on bonnet renewable seat
• Globe & Lift Check Valves (Straight):
  • Screwed-in or screwed-on bonnet integral seat
  • Screwed-in or screwed-on bonnet renewable seat
• Swing Check Valves:
  • Screwed-in integral or renewable seat bonnet
  • Bolted bonnet integral or renewable seat

3. Minimum Flat-to-Flat Size (Table 5)

4. Face-to-Face Dimensions of Flanged Valves (Table 11)

• Dimensions vary by valve type, seat type, and class.
• Example for Gate Valves (Screwed-in integral seat bonnet, Class 1 & 2):

Summary Diagram: Valve Classification & Types

graph TD
  A[Valve Classes] --> B[Class 1]
  A --> C[Class 2]
  B --> D[Gate Valves]
  B --> E[Globe & Lift Check Val

IS 778: Design and Manufacture Key Points

1. Flange Dimensions (Clause 7.1.4.1, Table 3)

• Flanges for Class 1 & 2 valves must follow these dimensions (all in mm):

• Tolerance: ±1.5 mm allowed on flange dimensions (Note 2, Clause 1.5).

2. Material Tests (Clause 9.2)

• Materials must comply with relevant IS specifications (see Table 1 references).
• Supplier certification mandatory.
• Manufacturer testing required if facilities exist.

3. Referenced Material Specifications

• Compressed asbestos fibre: IS

IS 778: Dimensions and Tolerances Summary

Key Tolerance:

• ± 1.5 mm permissible on all specified dimensions (Clause 1.5).

Notes:

• Dimensions not listed are generally not manufactured for those designs.
• Applies to both screwed end and flanged end angle valves.

1. Centre-to-End Dimensions of Screwed End Angle Valves (Clause 8.6, Table 10)

2. Centre-to-Face Dimensions of Flanged End Angle Valves (Clause 8.6, Table 12)

IS 778 Key Specifications for Valve Components & Construction

1. Valve Dimensions (Clause 8.6)

• Face-to-Face Dimensions of Flanged Valves (Table 11)
  Dimensions vary by valve type, design, class, and nominal size (in mm).
  Example for Gate Valves (Class 1,2, Screwed-in integral seat bonnet):

  Nominal Size (mm)	15	20	25	32	40	50	65	80	100
  Face-to-Face (mm)	72	76	90	100	110	120	140	150	190

• End-to-End Dimensions of Screwed End Valves (Table 9)
  Example for Gate Valves, Screwed-in integral seats bonnet (Class 1,2):

  Nominal Size (mm)	8	10	15	20	25	32	40	50	65	80	100
  End-to-End (mm)	50	50	60	60	70	80	90	100	105	125	160

• Centre-to-End Dimensions of Screwed End Angle Valves (Table 10)
  Example for Angle and type globe lift check valves, Screwed-in bonnet integral seat (Class 1,2):

  Nominal Size (mm)	8	10	15	20	25	32	40	50	65	80	100
  Centre-to-End (mm)	24	25	30	35	44	48	54	60	80	90	108

• Tolerance: ±1.5 mm permissible on all dimensions.

Stuffing Box and Stem Details as per IS 778

1. Stuffing Box Dimensions (Clause 8.5 & Table 8)

• Minimum stuffing box diameter = Stem diameter + 2 × Packing space
• Packing space for intermediate stem diameters uses next higher size in Table 8.
• Table 8: Stuffing Box Dimensions (mm)

2. Minimum Stem Diameter (Clause 8.4.1 & Table 7)

• Stem diameter measured at core of actuating thread (outside screw) or gland (inside screw).
• For non-rising stem gate valves, major diameter ≥ Table 7 values.

3. Additional Specifications:

• Stuffing box may be integral or separate from bonnet (Clause 7.3).
• Non-rising stem requires integral thrust collar for pressure-tight seal (Clause 7.6.7).

flowchart TD
    A[Stem Diameter] --> B[Determine Packing Space from Table 8]
    B --> C[Calculate Stuffing Box Diameter = Stem Diameter + 2 × Packing Space

IS 778: Testing and Inspection Key Points

1. Material Tests (Clause 9.2)

• Tests as per material specs in Table 1.
• Supplier certification mandatory.
• Tests preferably at manufacturer's works if facilities exist.

2. Sampling & Conformity (Clause 10.1 & Appendix B)

• Sampling follows Appendix B procedure.
• Lot accepted if no valves fail in sub-sample (Clause 2.2.1).

3. Valve Test Pressure & Duration (Clause 9.3, Table 13)

4. Inspection & Repairs (Clause 11)

• Follow general inspection rules for valves and cocks.
• Repairs must restore compliance to specs.

Summary Diagram of Testing Process

flowchart TD
    A[Material Receipt] --> B{Supplier Certification?}
    B -- Yes --> C[Material Tests @ Manufacturer's Works]
    B -- No --> D[Reject Material]
    C --> E{Tests Passed?}
    E -- Yes --> F[Sampling as per Appendix B]
    E -- No --> D
    F --> G{Lot Conforms?}
    G -- Yes --> H[Valve Body & Seat Tests (Table 13)]
    G -- No --> D
    H --> I{Tests Passed?}
    I -- Yes --> J[Inspection & Repairs if needed]
    I -- No --> D
    J --> K[Final Acceptance]

For detailed sampling, refer Appendix B; for material tests, see Table 1 of IS 778.

IS 778: Sampling and Conformity Criteria

Key Table: Scale of Sampling and Criteria for Conformity (Table A-1)

Conformity Criteria (Clause A-2.2.1)

• The lot is accepted if none of the valves in the sub-sample fail the specified tests.
• Sampling is random and per lot basis (Clause 1.2).

Sampling Procedure (Clause 10.1)

• Follow Appendix B for detailed sampling and conformity procedures.

Summary:

• Sample size and acceptance numbers depend on lot size.
• Sub-sample undergoes detailed tests.
• Zero or limited failures allowed depending on lot size.
• Ensures quality control by statistically valid sampling.

flowchart LR
    LotSize[Lot Size]
    SampleSize[Sample Size]
    SubSample[Sub-Sample]
    Test[Tests on Sub-Sample]
    Decision{Failures?}
    Accept[Accept Lot]
    Reject[Reject Lot]

    LotSize --> SampleSize
    SampleSize --> SubSample
    SubSample --> Test
    Test --> Decision
    Decision -- No --> Accept
    Decision -- Yes --> Reject

This concise framework ensures quality conformity per IS 778.

IS 778: Inspection and Repairs Key Points

Inspection (Clause 10.1 & 9.2)

• Sampling & conformity criteria: Follow Appendix B for sampling procedure.
• Material tests: Refer to material specs in Table 1; supplier certification mandatory.
• Tests done at manufacturer’s works if possible.

Repairs (Clause 11)

• Refer to related IS standards for materials used in repairs:
  • Gland packing: IS 5414 (hemp/jute), IS 4687 (asbestos)
  • Compressed asbestos fibre: IS 2712
  • Seating rings: IS 5192
  • Phosphor bronze wire: IS 7608
  • Brass & bronze specifications: IS 210, IS 5192, IS 1367, etc.

Design & Manufacture (Clause 8.2)

• Minimum flat-to-flat size for valves (mm):

Summary:

• Use certified materials per IS specs.
• Follow Appendix B for inspection sampling.
• Repair materials must conform to referenced IS standards.
• Valve sizes must meet minimum flat-to-flat dimensions in Table 5.

flowchart TD
    A[Inspection Sampling] --> B[Appendix B Procedure]
    B --> C{Material Tests}
    C -->|Certified| D[Supplier Certification]
    C -->|At Manufacturer| E[Material Testing]
    F[Repairs] --> G[Gland Packing (IS 5414, IS 4687)]
    F --> H[Seating Rings (IS 5192)]
    F --> I[Compressed Asbestos (IS 2712)]
    J[Valve Design] --> K[Min Flat-to-Flat Size Table 5]

This ensures compliance with IS 778 for inspection and repair of valves.

IS 778: Packing and Dispatch Key Points

Stuffing Box Dimensions (Clause 8.5 & Table 8)

• Minimum stuffing box diameter = Stem diameter + 2 × Packing space
• Packing space and stuffing box depth depend on stem diameter as per:

• For intermediate sizes, use packing space of next higher size.

Packing Materials (Clause 4.6 references)

• Use materials as per IS standards:
  • Compressed asbestos fibre: IS 2712
  • Gland packing (hemp, jute): IS 5414
  • Asbestos packing: IS 4687
  • Phosphor bronze wire: IS 7608
  • Seating rings: IS 5192

Dispatch Preparation (Clause 12.2)

• Valves must be packed to prevent damage.
• All openings must be closed to prevent dirt ingress.
• Material tests per corresponding IS specs (Clause 9.2).

flowchart LR
    A[Stem Diameter] --> B[Determine Packing Space]
    B --> C[Calculate Stuffing Box Diameter = Stem + 2 × Packing Space]
    C --> D[Select Stuffing Box Depth from Table 8]
    D --> E[Prepare Valve for Dispatch]
    E --> F[Close Openings & Protect Internals]
    F --> G[Material Certification & Testing]

This ensures compliance with IS 778 for stuffing box design and safe dispatch.

IS 778: Marking and Certification Key Points

1. BIS Certification Marking (Clause 13.3 & 13.3.1)

   • Products may be marked with the Standard Mark under BIS Act 1986.
   • License for use of Standard Mark is governed by BIS rules.
   • Manufacturers must comply with conditions set by BIS for marking.

2. Material Tests and Certification (Clause 9.2)

   • Material tests as per relevant IS specifications (see Table 1 in IS 778).
   • Supplier must certify material compliance.
   • Tests preferably done at manufacturer's works if facilities exist.

3. Information to be Supplied with Enquiry/Order (Appendix A)

   • Details on valves, gland packing, seating rings, etc.
   • Refer to associated IS codes for materials, e.g.:
     • IS 1367 for fasteners
     • IS 210 for FG 200 castings
     • IS 2712 for compressed asbestos fibre
     • IS 5414, IS 4687 for gland packing
     • IS 5192 for seating rings

Summary Table: Material Certification & Marking

flowchart TD
    A[Material Procurement] --> B[Supplier Certification]
    B --> C[Material Tests per IS Specs]
    C --> D[Manufacturer's Works Testing (if available)]
    D --> E[Product Manufacturing]
    E --> F{Apply BIS Standard Mark?}
    F -->|Yes| G[License from BIS]
    F -->|No| H[No Marking]

Note: Always refer to the latest BIS guidelines for licensing and marking conditions.

IS 778: Information to be Supplied with Enquiry or Order

Per Clause 1.1 and related clauses, the purchaser should specify the following when ordering valves:

• Type of valve: Gate, globe, angle, check (horizontal, vertical, angle, swing), integral or renewable seat, inside or outside screw, rising or non-rising stem.
• Class of valve: Pressure/temperature rating class.
• End connections: Screwed or flanged.
• Flanged valves: Whether drilled or undrilled.
• Additional tests: Specify if tests beyond Clause 9 are required.
• Inspection: Whether purchaser or representative will inspect valves.

Key Table: Minimum Flat to Flat Size (Clause 8.2, Table 5)

Sampling & Conformity (Appendix B)

• Lot definition: Valves of same material, size, type, class, batch.
• Acceptance: Lot passes if no valve in sub-sample fails tests.
• Random sampling methods apply.

This ensures clarity and conformity in valve orders per IS 778.

IS 778: Sampling Procedure & Criteria for Conformity

Sampling Scale & Acceptance Criteria (Table A-1)

• Acceptance Number (c): Maximum number of defective valves allowed in the sample for lot acceptance.
• Sub-sample Size: Number of valves tested for specific tests.

Criteria for Conformity (Clause 2.2.1)

• The lot is accepted if no valve in the sub-sample fails any test.
• Sampling must be random to ensure representativeness.

Procedure Summary

1. Identify lot size.
2. Select sample size (n) per Table A-1.
3. Test sub-sample for specific tests.
4. Accept lot if defective valves ≤ acceptance number and no failure in sub-sample.

Reference

• Sampling and conformity criteria are detailed in Appendix B of IS 778.
• Tests are performed on samples from each lot separately (Clause 1.2).

flowchart TD
    A[Start: Identify Lot Size] --> B{Lot Size?}
    B -->|Up to 150| C[Sample Size=8, Acceptance=0, Sub-sample=3]
    B -->|151-300| D[Sample Size=13, Acceptance=0, Sub-sample=5]
    B -->|301-500| E[Sample Size=20, Acceptance=1, Sub-sample=8]
    B -->|501-1000| F[Sample Size=32, Acceptance=2, Sub-sample=13]
    B -->|1001-3000|