Flushing Cistern for Water Closets and Urinals (Other Than Plastic Cisterns)

IS 774 - Scope Summary

Scope (Clause 1.2):

• Covers specifications for flushing cisterns except plastic flushing cisterns (not covered).
• Applies to materials, construction, finish, operational, and performance requirements of cisterns.

Referenced Standards:

Sampling & Conformity Criteria (Clause 2.3):

Rounding Off (IS 2:1960):

• Final test values should be rounded off as per IS 2 rules, retaining significant figures as specified.

This scope ensures quality and conformity of flushing cisterns (excluding plastic types) through material standards, testing, and sampling procedures.

IS 774 References Summary

IS 774 references several related Indian Standards essential for materials and components used in flushing cisterns:

Additional Notes:

• Rounding off test results per IS 2:1960.
• Sampling and conformity criteria detailed in Table 2 for lot sizes (e.g., up to 50 cisterns: sample size 8, acceptance 0).
• Endurance tests required after design/material changes.

This ensures materials and components meet quality and performance standards referenced by IS 774.

flowchart LR
    A[IS 774 Standard] --> B[Material Specs]
    B --> IS210[Grey Iron Casting IS 210]
    B --> IS404[Lead Pipes IS 404]
    B --> IS407[Brass Tubes IS 407]
    B --> IS513[Steel Sheets IS 513]
    B --> IS1239[Mild Steel Tubes IS 1239]
    A --> C[Painting Code IS 1477]
    A --> D[Float Valves IS 1703]
    A --> E[Sampling & Testing per IS 2, Table 2]

For detailed design or testing, refer to the specific IS codes listed.

IS 774: Definitions & Key Specifications Summary

Clause 3.0 - Definitions:
This clause sets the basis for terms used in the standard for flushing cisterns (excluding plastic flushing cisterns per Clause 1.2). Definitions ensure uniform understanding of components, materials, and testing methods.

Important Notes on Values and Rounding (IS 2:1960)

• Final test or analysis values must be rounded off per IS 2:1960 rules.
• Number of significant digits in rounded values = number in the specified standard value.

Sampling & Conformity Criteria (Clause 2.3 & Table A-2)

Referenced IS Standards (for materials, components, and testing)

IS 774 - Materials for Flushing Cisterns: Key Specifications

Notes:

• Materials must conform to the specified IS standards for quality and corrosion resistance.
• Cast iron components require **Grade

IS 774: Construction - Key Specifications and Sampling Criteria

Sampling & Conformity (Clauses 2.1, 2.1.1, 2.2.1, 2.3)

• Lot conformity is checked by randomly selecting sample cisterns as per Table 2.
• Material, Construction & Finish: Lot passes if non-conforming samples ≤ acceptance number (Col 3, Table 2).
• Operational & Performance: Lot passes if non-conforming samples ≤ acceptance number (Col 5, Table 2).
• Endurance Test: Conducted after design/material/manufacture changes; 1 sample tested and if passed, all subsequent lots under same conditions are accepted.

Table 2: Sampling & Acceptance Numbers

Summary:

• Select samples based on lot size.
• Check material, construction, and finish first.
• Then check operational and performance on sub-samples.
• Acceptance numbers are zero or low, indicating strict quality control.
• Endurance test needed after any design or process change.

flowchart TD
    A[Start: Lot of Cisterns] --> B[Select Samples as per Table 2]
    B --> C{Material, Construction, Finish Tests}
    C -->|Pass| D[Select Sub-samples for Operational Tests]
    C -->|Fail > Acceptance No| E

IS 774 - Finish: Key Specifications & Tables

1. Finish Requirements

• Finish quality is assessed alongside material and construction.
• Lot conformity is checked by sampling (Clause 2.1, 2.1.1 & Table 2).
• Covers must fit closely and be secured against displacement (Clause 5.2).
• Covers with operating mechanisms may be two-sectioned, securely bolted/screwed.

2. Material & Finish Table (Excerpt from Table 1)

3. Rounding Off Values

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

Summary Diagram: Finish Compliance Check

flowchart TD
    A[Select Sample Cisterns] --> B{Check Material, Construction, Finish}
    B -->|Meets Requirements| C[Accept Lot]
    B -->|Fails ≤ Allowed No.| C
    B -->|Fails > Allowed No.| D[Reject Lot

IS 774: Operational and Performance Requirements — Key Points

Sampling & Conformity (Clauses 2.2, 2.2.1, 9)

• Lot conformity is based on the number of cisterns failing operational/performance tests.
• Use Table 2 for:
  • Col 4: Number of cisterns to test (sub-sample size).
  • Col 5: Maximum allowable failures for lot acceptance.
• Sampling follows Annex A procedure.

Endurance Test (Clause 8.3)

• Random sample passing material, construction, and performance checks.
• Operate 3,000 cycles continuously.
• Post-test: No damage, defects, or leakage (valve or siphon).
• Test done by recognized lab; repeated after design/material changes.

Summary Table (from Table 2, example format):

Flowchart: Sampling & Testing Process

flowchart TD
    A[Start: Lot Production] --> B[Random Sample Selection]
    B --> C[Check Material & Construction]
    C -->|Pass| D[Operational & Performance Tests]
    D --> E[Endurance Test (3000 cycles)]
    E --> F{Any Failures?}
    F -->|No| G[Lot Accepted]
    F -->|Yes| H[Check Failures ≤ Max Allowed?]
    H -->|Yes| G
    H -->|No| I[Lot Rejected]

For exact sample sizes and acceptance numbers, refer to Table 2 and Annex A of IS 774.

IS 774: Testing Procedures – Key Points & Formulas

1. Rounding Off (IS 2:1960)

• Final test values must be rounded to the same number of significant digits as specified in IS 774.

2. Endurance Test (Clause 8.3)

• Random sample cistern must meet material, construction, and performance criteria first.
• Operate the cistern 3,000 times continuously.
• After 3,000 cycles:
  • No damage or defects allowed.
  • Valve (if used) must show no leakage at rated capacity.
• This is a type test done by recognized labs, repeated if design/material changes occur.

3. Sampling & Conformity (Clause 9 & Annex A)

• Lot: Group of cisterns with same type, design, material, and manufacturing conditions.
• Sampling follows Annex A procedures for lot acceptance.
• Sub-sample size for operational tests is per Table 2 (Annex A) — number depends on lot size.

Summary Table: Endurance Test

flowchart TD
    A[Start: Sample Selection] --> B[Check Material & Construction]
    B -->|Complies| C[Perform 3,000 Flush Cycles]
    C --> D{Any Damage or Leakage?}
    D -->|No| E[Pass Endurance Test]
    D -->|Yes| F[Fail - Reject Sample]

For detailed sampling sizes and acceptance criteria, refer to Annex A of IS 774.

IS 774: Sampling and Criteria for Conformity

Key Points from Annex A (Clause 9):

• Sampling for Material, Construction, and Finish (A-2.1):
  Select sample cisterns randomly from the lot as per Column 2 of Table 2.

• Sampling for Operational and Performance Tests (A-2.2):
  From the satisfactory samples in A-2.1, take a sub-sample randomly as per Column 4 of Table 2.

• Endurance Test (Clause 8.3):

  • Sample cistern must pass material, construction, and performance tests first.
  • Operate cistern 3,000 times continuously.
  • No damage, defects, or leakage (especially valve leakage) allowed after test.
  • This is a type test done by recognized labs, repeated on design/material changes.

Table 2 (Sampling Sizes) - Summary

(Note: Exact values to be confirmed from IS 774 Table 2)

Summary:

• Random sampling ensures lot conformity on materials, construction, finish, and performance.
• Endurance test validates durability (3,000 flush cycles).
• Standard Mark usage governed by BIS Act 1986.

flowchart TD
    A[Lot of Cisterns] --> B[Random Sampling (Table 2 Col 2)]
    B --> C{Pass Material, Construction, Finish?}
    C -- Yes --> D[Sub-sample for Performance (Table 2 Col 4)]
    D --> E{Pass Performance?}
    E -- Yes --> F[Endurance Test: 3000 flushes]
    F --> G{No Damage/Leakage?}
    G -- Yes --> H[Lot Conforms]
    C -- No -->

IS 774 — Supply Conditions Summary

Clause 10: Supply Conditions

• Lot conformity is judged based on sampling per Annex A.
• As per Clause 2.2.1, a lot passes if the number of defective samples ≤ acceptance number in Table 2 (col 5).

Clause 7.6: Discharge Rate

• Specifies the required discharge rate for flushing cisterns (details depend on cistern capacity/type).
• Ensures operational performance under rated capacity.

Endurance Test (Clause 8.3)

• Sample cistern must operate 3,000 cycles without damage or leakage.
• Valve leakage not allowed during test.

Key Table (Excerpt from Table 2 - Sampling & Acceptance)

(Exact values depend on lot size and are detailed in Annex A)

References for Materials & Components

• Grey iron castings (IS 210)
• Lead pipes (IS 404 Pt 1)
• Brass tubes (IS 407)
• Mild steel tubes (IS 1239 Pt 1)
• Copper alloy float valves (IS 1703)
• Painting codes (IS 1477)

flowchart LR
    A[Lot of Cisterns] --> B[Sampling per Annex A]
    B --> C{Number of Defective Samples ≤ Acceptance Number?}
    C -- Yes --> D[Lot Accepted]
    C -- No --> E[Lot Rejected]

Summary: Supply conditions rely on sampling inspection (Annex A), endurance testing (3,000 cycles), and compliance with discharge rates to ensure performance and durability.

IS 774: Operating Instructions & Specifications for Dual-Flush Cisterns

Key Points from Clause 11 (Dual-Flush Cisterns):

• Definition (3.4): Dual-flush cistern allows user to select:

  • Full flush (for solids)
  • Partial flush (for urine)

• Operating Instructions (11.1):

  • Must be legibly marked on cistern.
  • Instructions must be permanent and visible.
  • Optional self-adhesive label for concealed cisterns.
  • Use 6/3 litres capacity cisterns with matching sanitary appliances.

• Discharge Capacities (11.1.3.1):

• Material requirements: Refer Table 1 for component materials conforming to IS standards.

Typical Illustrations:

• Fig 1: Siphonic dual-flush cistern (curved siphonic type, lever-operated)
• Fig 2: Non-siphonic dual-flush cistern

Summary Table: Dual-Flush Discharge Volumes

flowchart LR
    A[User] -->|Press Full Flush| B[Full Flush Valve]
    A -->|Press Partial Flush| C[Partial Flush Valve]
    B --> D[Discharge 6 or 10 L]
    C --> E[Discharge 3 or 5 L]
    D --> F[To Toilet Bowl]
    E --> F

Note: Ensure flush pipes comply with IS 774 Clause 5.3 and Table 1 for dimensions and materials.

IS 774: Marking and Certification Key Points

1. BIS Certification Marking (Clause 12.3)

• Each cistern may be marked with the BIS Standard Mark.
• Usage governed by the Bureau of Indian Standards Act, 1986.
• License conditions for use of the Standard Mark are provided by BIS.

2. Sampling and Criteria for Conformity (Annex A, Clause 9)

• Rounding off test results per IS 2:1960.
• Endurance test required after any design/material/manufacture change.
• One cistern sampled from compliant lots for endurance testing.
• Passing sample means entire lot conforms until change occurs.

3. Sampling Table for Conformity (Table A-2.3)

Summary:

• Marking: BIS Standard Mark mandatory for certified cisterns.
• Sampling: Defined sample sizes and acceptance criteria ensure quality.
• Endurance Testing: Triggered by design/material changes; one sample tested to validate entire lot.

For detailed licensing and marking rules, contact BIS offices listed in the standard.

flowchart TD
    A[Manufacture Cisterns] --> B{Design/Material Change?}
    B -- No --> C[Sample from Lot per Table A-2.3]
    B -- Yes --> D[Endurance Test on 1 Sample]
    D --> E{Pass?}
    E --

IS 774: Sampling and Criteria for Conformity (Summary)

Sampling Procedure (Annex A, Clause 2.1 & 2.2)

• Step 1: Randomly select sample cisterns from the lot as per Column 2, Table 2 for checking:
  • Material requirements (Clause 4)
  • Construction requirements (Clause 5)
  • Finish requirements (Clause 6)
• Step 2: If Step 1 is satisfactory, select sub-sample cisterns from these for operational and performance tests (Clause 7) as per Column 4, Table 2.

Endurance Test (Clause 8.3)

• Sample cistern must:
  • Meet material, construction, and performance requirements.
  • Operate 3,000 flushing cycles without damage or leakage.
  • Valve (if used) must show no leakage during test.
• This is a type test done by recognized labs, repeated after design/material changes.

Table 2 (Sampling Numbers Example)

(Exact numbers to be confirmed from IS 774 Table 2)

Key Points

• Sampling is random.
• Conformity is sequential: material → construction → performance.
• Endurance test ensures durability and leak-proof operation.
• Type test required on design changes.

flowchart TD
    A[Select Sample Cisterns] --> B{Material, Construction, Finish?}
    B -- Pass --> C[Select Sub-Sample]
    C --> D{Performance Test}
    D -- Pass --> E[Endurance Test: 3000 Cycles]
    E -- Pass --> F[Lot Accepted]
    B -- Fail --> G[Lot Rejected]
    D -- Fail --> G
    E -- Fail --> G

For exact sample sizes and acceptance criteria, refer directly to Table 2 of IS 774 Annex A.

IS 774 - Endurance Test Guidelines (Clause 8.3)

• Purpose: Verify flushing cistern durability by operating it 3,000 times.
• Sample Selection: Randomly pick one cistern from production that meets material, construction, and performance requirements.
• Test Details:
  • Operate cistern 3,000 cycles.
  • No damage or defects allowed post-test.
  • If valve replaces siphon, valve must show no leakage at rated capacity.
• When to Test: After any change in design, materials, manufacture, or construction.
• Testing Agency: Recognized testing laboratory.

Sampling & Conformity Criteria (Annex A, Table A-2.3)

Summary Flow for Endurance Test

flowchart TD
    A[Select Random Sample] --> B{Check Material & Construction}
    B -- Pass --> C{Check Operational & Performance}
    C -- Pass --> D[Operate 3000 times Endurance Test]
    D --> E{Check for Damage or Leakage}
    E -- No Defect --> F[Lot Approved for Endurance]
    E -- Defect Found --> G[Lot Rejected]
    B -- Fail --> G
    C -- Fail --> G

Note: Rounding of test results must follow IS 2:1960 rules.

This ensures flushing cisterns meet durability and leakage standards before mass production approval