plastic equilibrium float valve for cold water services
1988 Edition

Overview of Scope

• Applies to float valves with both horizontal and vertical inlet shank designs.
• Dimensions to comply with Figures 2A & 2B as specified in clause 6.4.

Sampling & Acceptance (Clause 8.1.3, Table 2):

Testing Procedure (Clause 2.1):

• One test cycle lasts minimum 6 seconds:
  • Valve must open fully in at least 1 second.
  • Remain open for 2 seconds.
  • Close fully in at least 1 second.
  • Remain closed for 2 seconds.

Dimensional Requirements (Clause 6.4):

• Valve body sizes to match Figures 2A (horizontal) and 2B (vertical).

Diagram: Test Cycle Flow

flowchart TD
    Start[Test Cycle Begins] --> OpenValve{Open Valve}
    OpenValve -->|≥1 sec| HoldOpen[Hold Open 2 sec]
    HoldOpen --> CloseValve{Close Valve}
    CloseValve -->|≥1 sec| HoldClosed[Hold Closed 2 sec]
    HoldClosed --> EndCycle[Test Cycle Ends]

Refer to figures for exact dimensions and ensure sampling complies with lot sizes.

Sampling and Acceptance Guidelines (Clauses 8.1.3 & 8.2.2):

• Sample size depends on batch size.
• Batch acceptance if defects ≤ allowed number.
• Exceeds allowed defects leads to rejection.

Purpose:

• To maintain quality control by statistically validating production lots.

flowchart TD
    Start[Identify Lot Size] --> CheckSize{Lot Size}
    CheckSize -->|≤100| Sample5[Sample 5, Accept if ≤0 defects]
    CheckSize -->|101-150| Sample8[Sample 8, Accept if ≤0 defects]
    CheckSize -->|151-500| Sample13[Sample 13, Accept if ≤1 defect]
    CheckSize -->|501-1000| Sample20[Sample 20, Accept if ≤1 defect]
    CheckSize -->|>1000| Sample32[Sample 32, Accept if ≤2 defects]
    Sample5 --> Decision[Make Decision]
    Sample8 --> Decision
    Sample13 --> Decision
    Sample20 --> Decision
    Sample32 --> Decision

This classification supports reliable acceptance testing.

Nominal Valve Size (Clause 3.1):

• Standard nominal size is 15 mm.

Dimensional Specifications (Clause 6.4):

• Valve bodies must conform to Figures 2A (Horizontal Inlet Shank) and 2B (Vertical Inlet Shank).
• Dimensions define length, diameter, inlet, and outlet fitting sizes to ensure compatibility.

Pressure Reducing Attachments (Clause 2.2):

• Permitted to fit High Pressure (HP) and Low Pressure (LP) reducers.
• Typical flow restrictor designs are shown in Figure 1.

Sampling for Quality Control (Clause 8.1.3):

Refer to figures 2A and 2B for precise sizing.

Materials and Restrictions (Clauses 4.1, 4.2 & Table 1):

• Recycled material usage is limited to 15%, excluding valve seats where recycled content is prohibited.

Materials for Components:

Quality Inspection (Clause 8.2.1):

• Valves are examined for material, manufacturing quality, and workmanship.
• Failure in any criterion marks the valve as defective.

Material Flowchart:

graph TD
    ValveComponents[Valve Components] --> BodyParts[Valve body, inlet, back nut, cap, float arm]
    ValveComponents --> Seat[Valve seat]
    ValveComponents --> Others[Float, flow restrictors, discharge horn]
    ValveComponents --> Pin[Diaphragm pin]

    BodyParts -->|Material| Steel[Stainless Steel or Non-Corrosive]
    Seat -->|Material| Polyacetal[Polyacetal (No Recycled Material)]
    Others -->|Material| Mixed[Polyacetal or Stainless Steel]
    Pin -->|Material| Steel

These materials ensure durability and corrosion resistance.

Guidelines for Manufacture and Workmanship:

• Recycled material use is capped at 15%, except valve seats which must be free of recycled content (Clause 4.2).
• Valves sampled per Table 2 must be inspected for material quality, workmanship, and construction integrity (Clauses 8.2.1 & 8.2.2).
• Any failure in inspection renders the valve defective.
• Lot acceptance depends on the number of defects not exceeding acceptance criteria (Table 2).

Summary of Sampling and Acceptance:

Manufacturing Workflow:

flowchart TD
    Manufacture[Manufacturing Process] --> ReworkCheck{Using Reworked Material ≤ 15%?}
    ReworkCheck -- Yes --> SeatCheck{Is Component Valve Seat?}
    SeatCheck -- Yes --> NoRework[Rework Not Permitted]
    SeatCheck -- No --> AllowedRework[Rework Permitted]
    AllowedRework --> Inspection[Inspection per Table 2]
    NoRework --> Inspection
    Inspection --> DefectCountCheck{Defects ≤ Acceptance Number?}
    DefectCountCheck -- Yes --> LotAccepted[Lot Accepted]
    DefectCountCheck -- No --> LotRejected[Lot Rejected]

Refer to Table 2 for exact sample sizes and acceptance numbers.

Material and Construction Standards:

• Materials contacting water must be non-toxic, not encourage microbial growth, and must not cause taste, odor, turbidity, or discoloration (Clause 5.2).
• Recycled materials up to 15% are allowed except for valve seats which prohibit recycled content (Clause 4.2).
• Sampling and lot acceptance follow criteria in Table 2 based on number of defects and sample sizes (Clause 8.2.2).

Sampling Acceptance Table Snapshot:

(Exact values detailed in IS 12234 Table 2)

Process Flow:

flowchart TD
    RawMaterials --> Manufacturing
    Manufacturing --> ReworkCheck{Rework Used?}
    ReworkCheck -- Yes & ≤15% --> Allowed
    ReworkCheck -- Yes & Valve Seat --> NotAllowed
    Allowed --> FinalInspection
    NotAllowed --> FinalInspection
    FinalInspection --> DefectCheck{Defects ≤ Acceptance Number?}
    DefectCheck -- Yes --> AcceptLot
    DefectCheck -- No --> RejectLot

This ensures safe, reliable construction.

Key Performance Tests:

• Endurance Test (Clause 7.4 & Appendix C):

  • Validates valve durability through repeated operation.
  • Test involves cycling valve for specified number of times (e.g., 5,000 cycles as typical).
  • Valve must show no leakage or mechanical failure post-test.

• Testing Frequency and Conformity (Clause 8.2):

  • Tests are conducted on samples from production batches.
  • Results must meet defined performance standards including leak tightness and pressure ratings.

• Back Nut Specifications (Clause 6.10):

  • Must have parallel internal threads as per IS 2643 (Part 3)-1975.
  • Size should match the float valve.

Typical Endurance Test Parameters:

Endurance Test Flowchart:

flowchart LR
    StartTest --> OperateCycles
    OperateCycles --> LeakCheck{Leakage Detected?}
    LeakCheck -- No --> IntegrityCheck
    IntegrityCheck --> PassCriteria{Meets Criteria?}
    PassCriteria -- Yes --> TestPassed
    PassCriteria -- No --> TestFailed
    LeakCheck -- Yes --> TestFailed

Refer to Appendix C and IS 2643 Part 3 for detailed procedures.

Sampling and Acceptance (Clause 8.2):

• Sample size depends on batch size (Clause 8.1.3).
• Lot acceptance requires defective items to be at or below acceptance limit (Clause 8.2.2).
• Exceeding defects results in lot rejection.
• Endurance tests per Appendix C may be applied for quality assurance.

Acceptance Formula: [ \text{Accept Lot if } D \leq A ] Where:

• (D) = Number of defective items in sample
• (A) = Acceptance number from Table 2

This statistical sampling ensures production quality control.

Marking (Clause 9.2):

• Valves can be affixed with the BIS Standard Mark indicating conformity.
• Use of the Standard Mark complies with the BIS Act, 1986 and is subject to licensing.

Sampling and Testing (Clauses 7.2.1, 8.2, 8.2.2):

• Random sampling is performed as per Appendix A (Clause 7.2.1).
• Acceptance depends on defective valve count within limits specified in Table 2.

Example Acceptance Numbers:

(Refer to IS 12234 Table 2 for precise values)

Marking and Sampling Flowchart:

flowchart TD
    ProductionStart --> MarkCheck{Apply BIS Mark?}
    MarkCheck -- Yes --> ApplyMark
    MarkCheck -- No --> NoMark
    ApplyMark --> Sampling
    NoMark --> Sampling
    Sampling --> Testing
    Testing --> Decision{Defects ≤ Acceptance Number?}
    Decision -- Yes --> LotAccepted
    Decision -- No --> LotRejected

Always consult IS 12234 Table 2 and Appendix A for detailed sampling plans.

Test Setup (Clause 1.5 & Figure 3):

• Apparatus includes:
  • Mild steel cylinder connected to vacuum pump or injector.
  • Vacuum gauges with range 0–0.1 MPa (0–762 mm Hg).
  • Valves for closing (g) and opening (j).
  • Catchpot for detecting back siphonage.
  • Cistern with water level maintained at 1.5 ± 0.1 m above valve inlet center.

Test Method (Clause 7.2.1 & Appendix A):

• Close valve at position (g), open valve at (j).
• Maintain vacuum while water level is kept steady.
• Test duration is 180 seconds.
• Absence of water in catchpot indicates no back siphonage.
• This is a type test for validating valve design.

Test Parameters:

Interpretation:

• No water detected = pass.
• Water presence = fail (risk of back siphonage).

Test Setup Flowchart:

flowchart LR
    WaterCistern -->|Water flow| ValveUnderTest
    ValveUnderTest --> Catchpot
    Catchpot --> CloseValve
    OpenValve --> Catchpot
    VacuumGauge --> WaterCistern
    WaterCistern --> VacuumPump

This test verifies the valve’s ability to prevent reverse flow as per standard.

Flow Test Setup (Clause 7.3.1 & Appendix B):

• Container A with water level at 1.5 ± 0.1 m above valve inlet.
• Cistern B meeting IS 7231-1984 standards.
• Connecting tube of 15 mm internal diameter.
• Test duration is 180 seconds.

Test Procedure (Clauses 1.5, B-2, B-3):

1. Maintain water level in container A.
2. Allow float valve to discharge into cistern B for 3 minutes.
3. Measure water volume collected in cistern B at test end.

Flow Calculation:

• Flow rate (Q) = Volume (V) / Time (t)
• Where t = 180 seconds, V in liters, Q in liters/second.

Test Parameters Table:

Flow Test Diagram:

flowchart LR
    ContainerA[Water level 1.5m] -->|Water flow| CisternB[IS 7231 Cistern]
    CisternB -->|Volume measured| Measurement

This test evaluates flow capacity and valve shut-off effectiveness.

Endurance Test Summary (Clause 7.4 & Appendix G):

• Objective: Confirm valve durability through extensive cycling.
• Requirement: Complete 200,000 full open-close cycles without failure.
• After cycling, valve must pass hydraulic and shut-off tests (Clause 7.1).

Details:

• Test type is a type test, performed on one valve per design.
• A cycle consists of one complete valve opening and closing.
• Acceptance requires no leakage and functional integrity post testing.

Endurance Test Procedure:

1. Mount valve in test rig simulating normal use.
2. Cycle valve continuously for 200,000 operations.
3. Inspect for wear, leakage, and functional performance.
4. Perform hydraulic and shut-off assessments.

Summary Table:

Endurance Test Flow:

flowchart LR
    StartTest --> CompleteCycles{200,000 cycles done?}
    CompleteCycles -- No --> StartTest
    CompleteCycles -- Yes --> PostTestChecks
    PostTestChecks --> PassFail{Tests Passed?}
    PassFail -- Yes --> Approved
    PassFail -- No --> Rejected

This test assures long-term reliability.