Specification for Unlined Flax Canvas Hose for Fire Fighting

IS 4927: Scope - Key Specifications & Tables

Scope:
IS 4927 covers Unlined Flax Canvas Hose for Fire Fighting, specifying dimensions, performance, and testing criteria.

Key Tables & Formulas

1. Percolation Requirements (Clause 8.1)

Percolation measured during 6th to 10th minute after reaching maximum pressure.

2. Maximum Mass per Metre Length (Clause 6.1)

3. Sampling & Conformity Criteria (Annex C)

Notes:

• Hydrostatic proof pressure and moisture content tests are detailed in clauses 10 and Annex A.
• The standard mark certifies compliance with BIS quality control.
• Always verify with latest amendments for updated values.

flowchart TD
    A[Fire Fighting Hose] --> B{Nominal Diameter}
    B --> C[38 mm]
    B --> D[50 mm]
    B --> E[63 mm]
    B --> F[70 mm]
    C --> G[Max Mass: 250 g/m]
    D --> H[Max Mass: 300

IS 4927: Key References, Tables & Specifications

1. Percolation Requirements (Clause 8.1)

Percolation during 6th to 10th minute after reaching max pressure:

2. Hydrostatic Proof Pressure

Refer Clause 10 for testing requirements (not detailed here).

3. Sampling Criteria (Clause 1.2, Table C-2)

Sample size based on lot length (in meters):

4. Mass per Metre Length (Clause 6.1)

5. Additional Notes

• Use of Standard Mark governed by BIS Act, 1986.
• Amendments update key values (e.g., percolation values, sample sizes).
• Always verify with latest amendments.

flowchart TD
    A[Nominal Diameter] --> B[Percolation Limits]
    A --> C[Mass per Metre]
    D[Lot Size] --> E[Sample Size & Acceptance]
    F[Hydrostatic Proof Pressure] --> G[Testing]

Summary: IS 4927 specifies hose per

IS 4927: Material Requirements Summary

1. Mass of Finished Hose (Clause 6.1)

2. Percolation Requirements (Clause 8.1)

Percolation is measured during the 6th to 10th minute after reaching maximum pressure.

3. Sampling & Conformity Criteria (Clause 12.1, Annex C)

Notes:

• Mass and percolation values ensure quality and performance of unlined flax canvas hoses.
• Sampling ensures lot conformity to standards.
• Refer to IS 4927 for detailed testing procedures and acceptance criteria.

flowchart TD
    A[Material Requirements] --> B[Mass per Metre Length]
    A --> C[Percolation Limits]
    A --> D[Sampling & Conformity]
    B -->|Diameter vs Mass| Table1[Mass Table]
    C -->|Diameter vs Percolation| Table2[Percolation Table]
    D -->|Lot Size vs Sample Size| Table3[Sampling Table]

This concise summary helps ensure compliance with IS 4927 material specs for fire fighting hoses.

IS 4927 - Sizes and Tolerances Summary

1. Internal Diameter Tolerance (Clause 4.2)

• Finished internal diameter (ID):
  • Minimum: Not less than nominal diameter.
  • Maximum: Nominal diameter + 2 mm.

2. Material Specification (Clause 3.1)

• Hose made from flax yarn with alkali solubility ≤ 10% (Annex A test).

3. Percolation Requirements (Clause 8.1, Table 9.2)

• Percolation measured during 6th to 10th minute after reaching max pressure.

4. Change in Diameter (Clause 9.2)

• Diameter change limits are specified post hydrostatic proof pressure testing (details in Clause 9.2).

Summary Diagram: Diameter Tolerance and Percolation

flowchart TD
    A[Nominal Diameter] --> B[Finished ID]
    B -->|Min: Nominal| C[≥ Nominal]
    B -->|Max: Nominal + 2 mm| D[≤ Nominal + 2 mm]
    A --> E[Percolation Test]
    E --> F[6th-10th min after max pressure]
    F --> G{Percolation Limits}
    G -->|Min| H[See Table]
    G -->|Max| I[See Table]

For detailed dimensional checks, always refer to the exact clauses and tables in IS 4927.

IS 4927 - Mass of Finished Product (Clause 6.1)

The mass of the finished hose per metre length is specified as follows:

Key Points:

• The mass limits ensure quality and consistency in hose manufacturing.
• Mass is measured per metre length.
• Refer to Clause 2.1 for weighing procedures using weighing bottles.
• Percolation limits (Clause 8.1) and alkali solubility (Clause 5.1) relate to material durability but do not affect mass directly.

Practical Use:

To check compliance, weigh a 1m hose segment and ensure it does not exceed the specified mass for its nominal diameter.

graph TD
A[Nominal Diameter] --> B[Mass per Metre]
B --> C{Check Mass}
C -->|≤ Max Mass| D[Pass]
C -->|> Max Mass| E[Fail]

This ensures hoses meet IS 4927 mass specifications for quality control.

IS 4927: Percolation Requirements (Clause 8.1, Annex B)

Key Specifications:

• Percolation Test: Measures leakage during 6th to 10th minute after reaching max pressure.
• Test Pressure: Hydrostatic proof pressure of 0.7 MPa (7 kgf/cm²).
• Preconditioning: Sample wetted for at least 15 minutes at 0.7 MPa before testing.

Percolation Limits (Table 1):

Summary:

• Percolation volume must be within these limits during the 6th to 10th minute.
• Ensures pipe integrity and leak tightness under hydrostatic pressure.

flowchart LR
    A[Sample Preparation]
    B[Wetting at 0.7 MPa for 15 min]
    C[Apply Hydrostatic Proof Pressure]
    D[Measure Percolation 6th-10th min]
    E[Check Limits from Table 1]
    F[Pass/Fail]

    A --> B --> C --> D --> E --> F

This test confirms pipe quality per IS 4927 standards.

IS 4927: Key Specifications for Change in Size

1. Change in Length (Clause 9.1)

• Maximum permissible increase: 6%
• Test procedure: As per Clause 9.1.1 (specific testing method for length change)

2. Change in Diameter (Clause 9.2)

• Maximum permissible change: 6%
• Test procedure: As per Clause 9.1.1 (same as length change test)

3. Percolation Limits (Clause 8.1 & Table 1)

• Percolation must comply with limits in Table 1 (Annex B test procedure)
• Ensures material integrity and performance

Summary Table

Formula for % Change in Dimension

[ \text{Change (%)} = \frac{\text{Final Dimension} - \text{Initial Dimension}}{\text{Initial Dimension}} \times 100 ]

flowchart TD
    A[Test Specimen] --> B[Measure Initial Length & Diameter]
    B --> C[Conduct Test (Clause 9.1.1)]
    C --> D[Measure Final Length & Diameter]
    D --> E[Calculate % Change]
    E --> F{Is Change ≤ 6%?}
    F -- Yes --> G[Pass]
    F -- No --> H[Fail]

This ensures dimensional stability within limits for structural reliability.

Hydrostatic Proof Pressure Test (IS 4927)

Key Specifications (Clause 10.1)

• Test Length: Full length of hose
• Test Pressure: 2.1 MPa (21 kgf/cm²)
• Pressure Increase Rate: ≤ 1 MPa/min (10.2 kgf/cm²/min)
• Duration at Test Pressure: 1 minute
• Acceptance: No leakage or yarn breakage

Hydrostatic Burst Pressure Test (Clause 11.1)

• Test Length: 1 m clear of fittings
• Pressure Increase Rate: ≤ 1 MPa/min
• Acceptance: Hose shall not burst

Percolation (Leakage) Test (Clause B-1.1)

• Test Length: 3.5 m isolated portion
• Test Pressure: 7 kg/cm² (0.7 MPa)
• Pressure Build-up: Steady over 2 minutes
• Leakage Measurement: Between 6th and 10th minute
• Percolation Limits (litres):

Summary Flow of Hydrostatic Proof Test

flowchart LR
    A[Start Test] --> B[Increase pressure ≤ 1 MPa/min]
    B --> C[Reach 2.1 MPa]
    C --> D[Maintain pressure for 1 minute]
    D --> E{Leakage or yarn breakage?}
    E -- No --> F[Pass Test]
    E -- Yes --> G[Fail Test]

References: IS 443:1975 for pressure application details.

Hydrostatic Burst Pressure Test (IS 4927)

Key Specifications:

• Test Length: Minimum 3.5 m portion of hose (Clause B-1.1)
• Pressure Application Rate: Increase pressure at ≤ 1 MPa/min (10.2 kgf/cm²/min) (Clause 10.1, 11.1)
• Test Pressure:
  • Proof Pressure: 2.1 MPa (21 kgf/cm²) for 1 minute (Clause 10.1)
  • Burst Pressure: Pressure increased steadily to failure, no bursting below specified limits (Clause 11.1)
  • For leakage measurement, maintain 7 kg/cm² (70 N/cm²) for 5 minutes (6th to 10th minute) (Clause B-1.1)

Acceptance Criteria:

• No leakage or yarn breakage during test.
• Percolation limits during 6th to 10th minute (litres leakage):

Procedure Summary:

1. Fill hose with water.
2. Increase pressure gradually to 2.1 MPa at ≤ 1 MPa/min.
3. Maintain pressure for 1 minute; check for leakage or yarn breakage.
4. For leakage test, maintain 7 kg/cm² for 5 minutes and measure leakage.
5. Hose must not burst below specified burst pressure.

flowchart LR
    A[Prepare 3.5 m hose length] --> B[Fill with water]
    B --> C[Increase pressure ≤ 1 MPa/min to 2.1 MPa]
    C --> D[Maintain pressure for 1 min]
    D --> E{Leakage or yarn breakage?}
    E -- No --> F[Pass test]
    E -- Yes --> G[Fail test]
    F --> H[Maintain 7 kg/cm² for 5 mins]
    H --> I[Measure leakage (litres)]
    I --> J{Leakage within limits?}
    J -- Yes

IS 4927 Key Specifications: Flexibility & Coil Diameter

1. Coil Diameter (Clause 7.1)

• For a 30 m dry hose (without coupling), the maximum coil diameter = 45 cm.
• This ensures ease of handling and storage without damaging the hose.

2. Internal Diameter Tolerances (Clause 4.2)

• Finished internal diameter (ID) must satisfy: [ \text{Nominal ID} \leq \text{Finished ID} \leq \text{Nominal ID} + 2 \text{ mm} ]

3. Change in Diameter (Clause 9.2)

• The hose must maintain dimensional stability under operating conditions. Specific limits on diameter change are detailed in Clause 9.2 (not fully provided here).

4. Material Specification (Clause 3.1)

• Hose made from flax yarn with alkali solubility ≤ 10% (Annex A test).

Summary Table: Coil Diameter Limits

Practical Notes:

• Smaller coil diameter improves flexibility but risks hose damage.
• Maintaining internal diameter tolerance ensures proper flow and coupling fit.

flowchart LR
A[Hose Length = 30m] --> B{Coil Diameter ≤ 45 cm?}
B -- Yes --> C[Acceptable Flexibility]
B -- No --> D[Risk of Hose Damage]

For detailed dimensional change limits, refer to Clause 9.2 in IS 4927.

IS 4927: Sampling and Criteria for Conformity (Annex C)

C-1 Scale of Sampling

• Lot size (N): Total number of hoses in the batch.
• Sample size (n): Number of hoses to be tested.
• Calculate r = integer part of N/n.
• Sampling method: Starting from any hose, select every r-th hose for testing.

C-2 Number of Tests and Criteria for Conformity

• Each selected hose undergoes inspection and testing.
• Pressure test must be done before 3.5 MPa (35.7 kgf/cm²).
• The lot is accepted if all sampled hoses meet the specified criteria.

Summary Table for Sampling

flowchart TD
    A[Lot of N hoses] --> B[Calculate r = N/n]
    B --> C[Select every r-th hose]
    C --> D[Test selected hoses]
    D --> E{All pass?}
    E -- Yes --> F[Accept lot]
    E -- No --> G[Reject lot]

This ensures statistically valid sampling and conformity verification per IS 4927.

IS 4927: Marking Specifications for Unlined Flax Canvas Hose

Marking Requirements (Clause 13.1)

• Marking shall be done every 15 m, starting 30 cm from each hose end.
• Marking must include:
  • Manufacturer's name or trademark.
  • The words: "UNLINED FLAX CANVAS HOSE" with nominal diameter (38 mm, 50 mm, 63 mm, or 70 mm).
  • Month and year of manufacture.
  • Length of hose in meters.

Sampling Table (Clause 1.2, Table C-2)

Percolation Limits (Clause 8.1, Table 1)

Summary

• Mark hoses clearly every 15 m with specified info.
• Sampling depends on lot length.
• Percolation limits ensure quality under pressure testing.

For detailed quality control, refer to Annex C (Clause 12.1) for sampling and conformity criteria.

IS 4927: Determination of Alkali Solubility of Flax

Key Concept:

• Alkali solubility measures the percentage of non-cellulosic substances in flax that dissolve in a sodium carbonate solution after commercial boiling.

Procedure Summary (Clause 3.1 & Annex A):

1. Boil flax sample in distilled water and record weight loss (%).
2. Boil another sample in sodium carbonate solution (alkaline boil) and record weight loss (%).
3. Calculate alkali solubility as:

[ \text{Alkali Solubility (%)} = \text{Weight loss in carbonate boil} - \text{Weight loss in water boil} ]

• Both losses are based on oven-dry weight of the flax.

Specification (Clause 3.1):

• Flax yarn used for hose manufacturing must have alkali solubility ≤ 10%.

Summary Table:

flowchart TD
    A[Flax Sample] --> B{Boil in Distilled Water}
    A --> C{Boil in Sodium Carbonate}
    B --> D[Weight loss % (Water Boil)]
    C --> E[Weight loss % (Carbonate Boil)]
    D --> F[Calculate Difference]
    E --> F
    F --> G[Alkali Solubility % = Carbonate Loss - Water Loss]

This test ensures flax quality by quantifying soluble impurities affecting durability and microbial resistance.

IS 4927 - Percolation Test Procedure Summary

Key Specifications (Clause 8.1, Annex B)

• Test: Percolation measured during 6th to 10th minute after reaching max hydrostatic pressure.
• Hydrostatic Proof Pressure: 0.7 MPa (7 kgf/cm²).
• Sample Preparation: Wet sample for ≥15 minutes at 0.7 MPa before testing (Clause 10.2).

Percolation Limits (Table 1)

Procedure Outline:

1. Wet sample at 0.7 MPa for 15 minutes.
2. Apply hydrostatic pressure.
3. Measure percolation volume between 6th and 10th minute.
4. Ensure percolation is within limits above.

flowchart LR
  A[Start: Wet sample at 0.7 MPa for 15 min] --> B[Apply hydrostatic proof pressure]
  B --> C[Reach maximum pressure]
  C --> D[Measure percolation volume (6th-10th min)]
  D --> E{Percolation within limits?}
  E -- Yes --> F[Sample passes test]
  E -- No --> G[Sample fails test]

This ensures pipe integrity and leak tightness per IS 4927 requirements.

IS 4927: Sampling and Conformity Criteria (Annex C, Clause 12.1)

Sampling Procedure (Clause C-1.3.1)

• Given:
  • N = Lot size
  • n = Sample size
• Calculate:
  [ r = \text{Integral part of } \frac{N}{n} ]
• Sampling:
  Starting from any hose, count sequentially (1, 2, 3, …). Select every r-th hose for inspection/testing.

Scale of Sampling

• The sample size n and lot size N define the scale of sampling.
• The method ensures uniform coverage of the lot.

Criteria for Conformity (Clause C-2)

• Tests are performed on the sampled hoses.
• Acceptance or rejection is based on the number of failures allowed in the sample (specific acceptance numbers depend on the test type and standard limits).

Pressure Criterion (Clause 3.5)

• Testing pressure must be below 3.5 MPa (35.7 kgf/cm²) before final acceptance.

Summary Table: Sampling Selection

This systematic sampling ensures statistically valid conformity assessment per IS 4927.