flush valves and fittings for water closets and urinals

IS 9758 - Scope: Key Points, Materials & Sampling

Scope (Clause 2.0 & 3.1):
IS 9758 covers specifications for flush valves, flush pipes, and stop valves, including materials, manufacturing, and conformity criteria.

Key Specifications

Sampling & Conformity (Clause 10.1 & Appendix A)

• Sampling follows random sampling methods.
• A lot is accepted if defectives ≤ permissible number (Table 2, Col 3).
• Refer to Appendix A for detailed sampling criteria.

Units & Symbols (SI Units)

Summary Diagram

graph LR
A[Flush Valve System] --> B[Body: Brass]
A --> C[Flush Pipe: Steel/PVC/HDPE/Lead]
A --> D[Stop Valve: Brass]
A --> E[Washers: Rubber]
A --> F[Springs: Phosphor bronze/Stainless steel]
A --> G[Spindle: Extruded brass]

For detailed material grades and testing methods, refer to respective IS codes listed above.

IS 9758 - Definitions: Key Points & Units

1. Definitions (Clause 2.0)

• The standard defines terms specifically for clarity.
• Substitutions in related IS standards:
  • Grade LCB2 of IS:292-1983 replaces Grade 3 of IS:292-1961.
  • IS:1264-1981 replaces IS:1264-1965.

2. International System of Units (SI Units)

3. Derived Units

IS 9758: Key Materials Specifications for Flush Valve Components

Notes:

• Grade 3 of IS:292-1961 refers to specifications for brass ingots and castings.
• Materials must comply with the listed IS standards to ensure quality and durability.
• Sampling and conformity criteria are per Appendix A (Clause 10.1).

Units & Definitions (SI Units from IS 9758):

• Force: Newton (N) = 1 kg·m/s²
• Pressure/Stress: Pascal (Pa) = 1 N/m²
• Energy: Joule (J) = 1 N·m
• Power: Watt (W) = 1 J/s

flowchart TD
    A[Flush Valve Components] --> B[Body: Cast/Die Cast Brass]
    A --> C[Flush Pipe: Steel

IS 9758: Nominal Sizes & Specifications for Flush Valves

Nominal Sizes (Clause 4.1):

• Flush valves nominal sizes: 15 mm, 25 mm, 32 mm
• Nominal size = nominal bore of supply pipe connected to valve.

Outlet Dimensions (Clause 5.1):

Material Specifications (Table 1, Clause 3.1):

Summary:

• Nominal size = pipe bore size (15, 25, 32 mm).
• Outlet diameters increase with nominal size.
• Threads conform to IS 2643.
• Materials strictly per IS standards for durability and compatibility.

flowchart LR
    A[Nominal Size] -->|15 mm| B[Outlet 20 mm OD]
    A -->|25 mm| C[Outlet 32 mm OD]
    A -->|32 mm| D[Outlet 40 mm OD]
    B & C & D --> E[Threads per IS 264

IS 9758: Manufacture and Construction - Key Points

1. Materials Specification (Clause 3.1, Table 1)

2. Manufacturing & Quality Control

• Sampling and Criteria for Conformity (Clause 3.1, Table A-3):
  A lot is accepted if defectives ≤ permissible number in Table 2 (sampling plan).

• Service Instructions (Clause 9.1):
  Manufacturers must provide maintenance instructions.

3. Units and Definitions

• SI units are used as per IS standards (e.g., length in meters, force in newtons, pressure in pascals).

Summary Diagram: Material-Component Relation

graph TD
  A[Flush Valve Components] --> B[Body: Cast/Die Cast Brass]
  A --> C[Flush Pipe: Steel/Vitreous Enamel/PVC/HDPE/Lead]
  A --> D[Washers: Rubber]
  A --> E[Springs: Phosphor Bronze/Stainless Steel]
  A --> F

IS 9758: Discharge Capacity and Rate for Flush Valves

1. Discharge Capacity (Clause 6.1)

• Flush valves must have discharge capacities of 5 litres or 10 litres.
• Tolerance: ±0.5 litre.

2. Discharge Rate (Clause 6.2)

• When tested as per IS 774-1971:
  • Average discharge rate = 5 litres ± 0.5 litre in 3 seconds.
  • The force of flush should remain consistent during discharge.

3. Working Pressure (Clause 6.3)

• Flush valves must operate under pressure range: 0.15 MPa to 0.5 MPa.
• Must discharge full capacity in a single operation.

Summary Table

flowchart LR
    A[Working Pressure 0.15-0.5 MPa] --> B[Flush Valve]
    B --> C[Discharge Capacity: 5 or 10 litres ±0.5]
    C --> D[Discharge Rate: 5 ±0.5 litres in 3 sec]
    D --> E[Consistent Flush Force]

This ensures reliable, efficient flushing aligned with IS 9758 standards.

IS 9758: Testing Requirements - Key Formulas, Tables & Specifications

Sampling & Criteria for Conformity (Clause 10.1 & Table 2)

• Sample size and permissible defectives depend on lot size as per Table 2:

• A lot passes if the number of defectives ≤ permissible defectives.

Sampling Method

• Random sampling is to be used for selecting valves from the lot.

Service Instructions (Clause 9.1)

• Manufacturer must provide maintenance instructions with the product.

Summary:

• Use Table 2 for determining sample size and acceptance criteria.
• If defectives exceed permissible number, lot is rejected.
• Follow random sampling methods.
• Always provide service/maintenance instructions.

flowchart TD
    A[Start: Lot of Valves] --> B[Determine Lot Size]
    B --> C{Check Lot Size Range}
    C -->|Up to 100| D[Sample 5 valves, max 0 defectives]
    C -->|101-150| E[Sample 8 valves, max 0 defectives]
    C -->|151-300| F[Sample 13 valves, max 1 defective]
    C -->|301-500| G[Sample 20 valves, max 2 defectives]
    C -->|501-1000| H[Sample 32 valves, max 3 defectives]
    C -->|1001+| I[Sample 50 valves, max 5 defectives]
    D & E & F & G & H & I --> J[Count Defectives in Sample]
    J --> K{Defectives ≤ Permissible?}
    K -->|Yes| L[Lot Accepted]
    K -->|No

Surface Finish and Plating (IS 9758: Clause 8.1)

• Surface Finish:
  The outside of the valve body shall be polished bright.

• Plating:

  • Must be chromium plated of service grade 3 as per IS 4827-1968.
  • Plating should allow high polish and resist tarnishing or scaling.
  • Concealed parts need not be plated.

Key Specifications for Plating Quality (IS 4827-1968, Service Grade 3)

Materials for Components (Related to Surface Finish)

Summary Diagram: Surface Finish & Plating Process Flow

flowchart LR
    A[Flush Valve Body] --> B[Polished Bright]
    B --> C[Chromium Plating (IS 4827 Grade 3)]
    C --> D{Is Part Concealed?}
    D -- Yes --> E[No Plating Required]
    D -- No --> F[Plating Retained]
    F --> G[High Polish & Tarnish Resistance]

Note: For concealed parts, plating is optional. Always refer to IS 4827 for detailed plating procedures and quality control.

IS 9758: Supply Conditions - Key Specifications & Tables

Clause 9: Supply Conditions

• Products must conform to the standard with defectives not exceeding permissible limits (see Table 2, Col 3).
• Sampling is done by random methods ensuring lot quality.
• Surface finish:
  • Outside body: Bright polished and chromium plated (minimum service grade 3 as per IS 4827-1968).
  • Concealed parts need not be plated.
• Material grades updated:
  • Use Grade LCB2 of IS:292-1983 instead of older grades.
  • Use IS:1264-1981 for relevant specifications.

Important Tables & Values

Sampling & Conformity Formula (per IS 9758 Clause 3.1)

Let:

• n = sample size
• d = number of defectives found
• d_max = permissible number of defectives from Table 2

Conformity condition:

d \leq d_{max} \implies \text{Lot accepted}

Summary Diagram

flowchart TD
    A[Lot Received] --> B{Random Sampling}
    B --> C{Defectives ≤ d_max?}
    C -- Yes --> D[Lot Accepted]
    C -- No --> E[Lot Rejected]
    D --> F[Supply Conditions Met]

Note: Always refer to latest IS 9758 edition for updated tables and sampling plans.

IS 9758: Sampling and Criteria for Conformity

1. Sampling Procedure (Clause 10.1 & Table 2)

• Sample size depends on lot size.
• Random sampling method to be used.
• Sample sizes and permissible defectives:

2. Criteria for Conformity (Clause 3.1)

• A lot passes if the number of defectives ≤ permissible defectives in the sample.
• If defectives exceed permissible number, the lot is rejected.

3. Summary:

• Random sampling as per Appendix A.
• Use Table 2 for sample size and acceptance criteria.
• Maintain service instructions for maintenance (Clause 9.1).

flowchart LR
    A[Lot Received] --> B[Select Sample Size (Table 2)]
    B --> C[Inspect Sample]
    C --> D{Defectives ≤ Permissible?}
    D -- Yes --> E[Accept Lot]
    D -- No --> F[Reject Lot]

This ensures quality control by statistically verifying conformity with IS 9758.

IS 9758 - Marking: Key Specifications and References

The provided context from IS 9758 does not explicitly detail marking requirements. However, based on typical IS standards practice and related clauses:

Marking Requirements (General Guidance)

• Marking on Products usually includes:

  • Manufacturer’s name or trademark
  • Batch or lot number
  • Grade or specification reference (e.g., IS number)
  • Date of manufacture
  • Size or dimension

• Purpose: To ensure traceability and conformity to IS 9758 standards.

Relevant IS Code References:

• Clause 3.1: Sampling and conformity criteria (Table A-3) ensure lot acceptance based on defectives.
• Table 1 (Page 4): Specifies substitutions for material grades (e.g., Grade LCB2 of IS:292-1983 instead of Grade 3 of IS:292-1961).
• SI Units Table: Ensures all markings and documentation use standard SI units (e.g., length in meters, force in newtons).

Typical Marking Format Example:

Summary:

• Marking must be clear, durable, and legible.
• Use SI units as per IS 9758.
• Follow material grade substitutions as per Table 1.

flowchart TD
    A[Manufactured Product] --> B{Marking}
    B --> C[Manufacturer's Name/Logo]
    B --> D[IS Standard Number]
    B --> E[Material Grade]
    B --> F[Batch Number]
    B --> G[Date of Manufacture]
    B --> H[Dimensions in SI Units]

For exact marking details, consult the full IS 9758 text or related IS codes referenced therein.

IS 9758: Maintenance Instructions & Sampling Criteria

Maintenance Instructions (Clause 9.1)

• The manufacturer must provide detailed service instructions for maintenance.
• Instructions should cover routine checks, cleaning, lubrication, and part replacements to ensure product longevity and performance.

Sampling and Conformity Criteria (Clause 3.1 & Table 2)

• Sampling is based on lot size; conformity is accepted if defectives ≤ permissible number.

• Sampling should be random to fairly represent the lot quality.

Key Notes

• Maintenance instructions ensure safe and efficient operation.
• Sampling tables help in quality control and acceptance.
• Use SI units as per the standard (e.g., newton for force, pascal for pressure).

flowchart LR
    A[Manufacturer] --> B[Provide Maintenance Instructions]
    B --> C[Routine Checks]
    B --> D[Cleaning & Lubrication]
    B --> E[Part Replacement]
    F[Lot Size] --> G[Sample Size Selection]
    G --> H[Check Defectives ≤ Permissible]
    H --> I[Accept Lot]
    H --> J[Reject Lot]

This ensures compliance with IS 9758 for product quality and maintenance.