Glazed Stoneware Pipe and Fittings

IS 651 Scope Summary & Key Specifications

• Scope (Clause 1.2):

  • Covers dimensions of glazed stoneware pipes and fittings in two sections:
    • Section A: Straight pipes & fittings forming normal pipeline; strict dimensional accuracy.
    • Section B: Common fittings not part of normal pipeline; hand-moulded, less strict dimensional control.

• Dimensional Standards:

  • Pipes and fittings dimensions follow Tables 1 to 12 (internal diameters, bends, junctions).
  • Internal diameters for taper pipes, channels, junctions per Table 1 (Clause 13.1).
  • Bends dimensions (quarter, eighth, sixteenth bends) per Tables 2-6.
  • Section B fittings dimensions per Tables 7-12.

• Grooving (Clause 2.5 & 18):

  • Socket interiors and spigot exteriors grooved circumferentially.
  • Groove depth: 1 mm to 2.5 mm; length on spigot = 1.5 × socket depth.
  • Grooving optional if rubber ring joints agreed.

• Test for Acid Resistance (Annex A):

  • Specimen immersed in acid solution; resistance measured as % acid soluble matter (sulphate).

Key Dimensional Tables Excerpts (All dimensions in mm)

Reference Standards Incorporated

• IS 808: Hot rolled steel sections dimensions
• IS 2730: Magnesium sulphate specifications
• IS

IS 651: Dimensions and Tolerances Summary

1. Dimensions (Clause 13.1)

• Internal diameters of taper pipes, half-section straight/taper channels, and junctions must be selected from Column 2 of Table 1.
• Dimensions of bends must follow Tables 2 to 6.
• Refer to respective figures (Fig. 2 to Fig. 6) for dimensional references (d, D).

2. Permissible Tolerances

a. Internal Diameter Tolerances (Clause 10.1 & Table 10.2)

b. Length Tolerance (Clause 12.3)

• Length tolerance is specified but exact values depend on pipe type and length (refer IS 651 Clause 12.3 for details).

c. Thickness Tolerance (Clause 11)

• Thickness tolerances for barrels, sockets, and bends are specified (refer Clause 11 for exact values).

Key Notes:

• Always select pipe internal diameters from Table 1, Column 2.
• Use Tables 2-6 for bends and junction dimensions.
• Tolerances ensure manufacturing precision and proper fitment.

flowchart TD
    A[Select Internal Diameter] --> B[From Table 1, Col 2]
    B --> C[Check Tolerances]
    C --> D{Diameter Range}
    D -->|100-350 mm| E[±3% Tolerance]
    D -->|400-800 mm| F[±2.5% Tolerance]
    C --> G[Check Length & Thickness Tolerances]
    G --> H[Refer Clauses 12.3 & 11]

For exact dimensions and detailed tolerance values, consult IS 651 Tables 1-6 and Clauses 10-13.

IS 651 - Classification and Specifications of Pipes

1. Classification of Pipes (Clause 3.1)

• Pipes are classified based on crushing strength into:
  • SP 1 (Lowest strength)
  • SP 2 (Medium strength)
  • SP 3 (Highest strength)

2. Key Dimensions (Table 1 - Clause 10.1, 11.1, 13.1)

(Refer Table 1 for full details)

3. Permissible Variation in Thickness (Clause 11.1)

4. Notes

• Internal diameters of taper pipes, channels, and junctions must conform to Table 1.
• Grooving length may be omitted for pipes joined by rubber rings/flexible seals if agreed.
• Right-hand and left-hand fittings

IS 651: Right-Hand and Left-Hand Fittings - Key Specifications & Tables

1. Definitions (Clause 4)

• Right-Hand Fitting: Viewed from spigot to socket, junction arm or bend socket projects right.
• Left-Hand Fitting: Projects left under same view.

2. Grooving (Clause 2.5 & 18)

• Sockets interior & spigots exterior must be circumferentially grooved.
• Groove length on spigot = 1.5 × socket depth.
• Groove depth = 1 mm to 2.5 mm.
• Optional if rubber ring joints agreed.

3. Dimensions (Clause 13.1 & Tables)

4. Junctions (Branch Angles)

• Branch ≤ 200 mm: ~45° angle to barrel.
• Branch > 300 mm: ~55° to 60° angle.
• Branch diameter (d) ≤ barrel diameter (D).

5. Socket Taper & Depth (Clause 13.1)

• Socket taper: 1 mm diameter increase per 15 mm length (1:30 taper).
• E.g., 50 mm deep socket diameter increases by ≥ 3 mm.
• Socket depth per Table 1 (not provided here).
• Socket shoulder width > mean barrel thickness by values in Table 1.

6. Permissible Tolerances on Bend Dimensions (Clause 13.3.2)

IS 651: General Quality Requirements - Key Points

Sampling & Inspection (Clause D-4.2 & Table 13)

• Lot size determines sample size for inspection of general quality & dimensions.
• Inspect first sample; if defectives ≤ acceptance number (a), accept lot.
• If defectives ≥ rejection number (r), reject lot.
• If defectives between a and r, inspect second sample; combined defectives ≥ r → reject.

Tests & Specimens (Clause 3.3 & 4.6)

• Number of pipes tested for:
  • Water absorption, acid resistance, alkali resistance, crushing strength.
• Crushing strength test specimens must satisfy requirements in Clause 7.6.

Acid Resistance Test (Annex A)

• Specimen immersed in acid solution.
• Resistance measured by % acid soluble matter (as sulphate).

Summary Flowchart for Sampling Inspection

flowchart TD
    A[Select Lot Size] --> B[Select First Sample]
    B --> C{Defectives ≤ a

IS 651: Marking and Certification Key Points

1. BIS Certification Marking (Clause 9.2)

• Pipes and fittings may be marked with the BIS Standard Mark.
• Use of the Standard Mark follows the Bureau of Indian Standards Act, 1986.
• Manufacturers must obtain a license from BIS to use the Standard Mark.

2. Sample Size and Criteria for Conformity (Table 13)

• Sampling is done in two stages (first and second samples).
• Criteria ensure quality and dimensional conformity.

3. Grooving Dimensions (Clause 9.2.5, Table 19 excerpt)

4. Acid Resistance Test (Annex A, Clause 7.4)

• Specimen immersed fully in acid solution.
• Resistance measured as

IS 651 Testing Requirements Summary

1. Number of Tests (Clause 3.3, Table D-3)

2. Acid Resistance Test (Annex A, Clause 7.4)

• Reagent: Sulphuric Acid, 4.90% (specific gravity 1.84)
• Specimen: ~5 cm², ≤ 200 g, clean, crack-free
• Procedure:
  • Dry specimen to constant mass ( M ) at ≥150°C.
  • Immerse in acid solution for 48 hours at ambient temperature.
  • Wash, filter solution, add 5 ml concentrated H₂SO₄.
  • Evaporate, ignite to constant mass ( M_2 ).
• Calculation:

[ \text{Acid soluble matter %} = \frac{M - M_2}{M} \times 100 ]

3. Alkali Resistance Test (Annex B, Clause 7.5)

• Test Medium: Magnesium sulphate solution
• Sample Size: 75–130 cm², sound and defect-free
• Purpose: To assess resistance of stoneware/vitrified clay pipes to alkali attack.

4. General Testing Facilities (Clause 7.1)

• Manufacturer must provide all necessary equipment, labor, and apparatus at their premises for testing.

This concise guide covers key testing protocols, specimen preparation, and acceptance criteria per IS 651.

IS 651: Sampling and Criteria for Conformity

1. Sampling Procedure (Clause D-2 & Table 13)

• Pipes/fittings of same type, size, and production conditions form a lot.
• Sample size depends on lot size (see Table 13):

• Inspect first sample for general quality & dimensions.
• If defectives ≤ a → lot accepted.
• If defectives ≥ r → lot rejected.
• If defectives between a and r → test second sample; combined defectives ≥ r → reject.

2. Number of Pipes for Specific Tests (Clause D-3.3)

3. Crushing Strength (Clause 4.1 & D-4.6)

• Ultimate crushing strength (kN/m) = Load at fracture (kN) / Inside length of barrel (m)
• All specimens must satisfy crushing strength requirements.

Summary Flowchart of Sampling & Acceptance

flowchart TD
    A[Select Lot] --> B[Select First Sample]
    B --> C{Defectives ≤ a?}
    C -- Yes --> D[Accept Lot]
    C -- No --> E{Defectives ≥ r?}
    E -- Yes --> F[Reject Lot]
    E -- No --> G[

IS 651: Hydraulic Test Key Points

Hydraulic Test Pressure (Clause 7.2)

• Straight pipes (Section A): 0.15 MPa
• Fittings (Section B): 0.075 MPa
• Pressure application rate: ≤ 0.075 MPa per 5 seconds
• Maintain full pressure for ≥ 5 seconds
• Ensure all air is expelled before testing

Sampling (Clauses 3.2, D-3.2)

• Test 5% of the lot selected randomly
• Lot: Pipes/fittings of same type, size, and production conditions

Ultimate Crushing Strength (Clause 4.1)

• Calculated as:
  [ \text{Ultimate Crushing Strength (kN/m)} = \frac{\text{Load at fracture (kN)}}{\text{Inside length of barrel (m)}} ]

Summary Table for Hydraulic Test

flowchart TD
    A[Start] --> B[Expel all air from pipe/fitting]
    B --> C[Apply pressure gradually (≤0.075 MPa / 5 s)]
    C --> D[Reach full test pressure (0.15 or 0.075 MPa)]
    D --> E[Maintain pressure for ≥ 5 seconds]
    E --> F{Check for leaks or damage}
    F -- No --> G[Pass test]
    F -- Yes --> H[Fail test]

Note: Follow IS 4905 for sampling details and Table 13 for lot size vs. sample size.

IS 651: Internal Diameter Specifications for Pipes

Key Clauses:

• Clause 13.1:
  Internal diameters for taper pipes, half-section channels, and junctions must be selected from Column 2 of Table 1. Bends dimensions follow Tables 2 to 6.

• Clause 10.1:
  Internal diameter of barrels (straight pipes, junctions, bends) sized 100 mm to 800 mm as per Column 2 of Table 1.

• Clause 10.2 (Tolerance):

Summary:

• Select internal diameters strictly from Table 1 (Col 2) for all pipe components.
• Maintain tolerances as above to ensure proper fit and function.
• Thickness and other dimensions are governed by related clauses (e.g., Clause 11 for thickness).

Typical Formula for Diameter Tolerance Check:

[ D_{actual} = D_{nominal} \pm \left( \frac{Tolerance%}{100} \times D_{nominal} \right) ]

Where:

• (D_{nominal}) = specified internal diameter from Table 1
• (D_{actual}) = acceptable internal diameter range

flowchart LR
    A[Select Pipe Type] --> B{Check Table 1}
    B --> C[Get Internal Diameter (Col 2)]
    C --> D[Apply Tolerance]
    D --> E[Use in Design & Manufacturing]

For exact diameters, refer to Table 1 of IS 651.

IS 651: Thickness & Dimensions of Barrels, Sockets, and Bends

1. Mean Thickness Calculation (Clause 11.1)

• Measure minimum 4 thickness points (excluding grooves).
• Mean thickness = (Minimum thickness + Maximum thickness) / 2
• Calculate separately for barrel and socket.
• Mean thickness ≥ values in Table 1, Col 4.

2. Permissible Variation in Thickness (Clause 11.1, Table 11.2)

3. Key Dimensions (Table 1 Extract)

4. Socket Taper (Clause 11)

• Minimum taper: 1 mm diameter increase per 15 mm length (1:30).
• Example: 50 mm socket depth → diameter difference ≥ 3 mm.

5. Permissible Tolerance on Bends (Clause 13.3.2)

IS 651 Key Specifications on Length and Straightness of Pipes

1. Permissible Deviation from Straightness (Clause 12.4)

• Maximum deviation = 1% of pipe length
• Measured on inside of curve using a straight edge.

2. Length and Dimensions (Clause 12)

• Internal diameters, thickness, and socket dimensions are per Table 1.
• Lengths and grooving dimensions vary by pipe size and class (SP1, SP2, SP3).

3. Table 1 Summary (Key Dimensions for Pipes up to 800 mm ID)

4. Permissible Thickness Variation (Clause 11.1)

• Thickness variation limits depend on pipe diameter:

Summary Formula for Straightness Deviation:

[ \text{Max deviation} = 0.01 \times L ] where (L) = length of pipe.

flowchart LR
    A[Pipe Length, L] --> B[Measure inside curve with straight edge]
    B --> C{Deviation ≤ 1% of L?}
    C -->|Yes| D[Pipe accepted]
    C

IS 651: Key Specifications for Tapers, Bends & Junctions

1. Internal Diameters (Clause 13.1)

• Select from Column 2 of Table 1 for:
  • Taper pipes (d, D in Fig. 2)
  • Half-section straight channels (D in Fig. 3)
  • Half-section taper channels (d, D in Fig. 4)
  • Junctions (Fig. 5 & 6)
• Barrel lengths: 600 mm, 750 mm, or 900 mm

2. Permissible Deviation from Straightness (Clause 12.4)

• Max deviation = 1% of pipe length (measured inside curve with straight edge)

3. Bend Tolerances (Clause 13.3.2)

4. Junctions (Clauses 13.1.1 & 13.3.2)

• Branch diameter d ≤ barrel diameter D
• Branch angle:
  • ≤ 200 mm: approx. 45°

  • 300 mm: approx. 55° to 60°

• Socket taper: minimum 1 mm diameter increase per 15 mm length (1:30 taper)
• Socket depth & shoulder width as per Table 1
• Junction angles: 45° ± 3° or 90° ± 3°

5. Socket Shoulder Width

• Must exceed mean barrel thickness by values in Column 5 of Table 1

flowchart LR
    A[Taper Pipes] -->|Select diameter| B[Table 1, Col 2]
    C[Half-Section Channels] -->|Select diameter| B
    D[Junctions] -->|Branch dia ≤ Barrel dia| B
    B --> E[Socket: 1:30 taper]
    E --> F[Socket depth & shoulder width per

IS 651: Grooving and Jointing Key Specifications

• Grooving (Clause 2.5 & 18):

  • Interior of sockets and exterior of spigots shall be circumferentially grooved.
  • Groove length on spigot = 1.5 × socket depth.
  • Groove depth: 1 mm to 2.5 mm.
  • Rubber ring joints may omit grooving if agreed.

• Spigot & Socket Dimensions:

  • Spigots and sockets conform to pipe dimensions in Table 1 (not fully shown here).
  • Fittings’ spigots/sockets match corresponding pipe sizes.

• Fittings Dimensions:

  • Bends (quarter, eighth, sixteenth) and taper bends dimensions are provided in Tables 2 to 6.
  • Junctions have branch diameters ≤ barrel diameter (Clause 13.1.1).
  • Junction angles: 45° ± 3° or 90° ± 3° (Fig. 7).

Example Table Extract: Grooving Dimensions (Clause 2.5)

Grooving & Jointing Diagram (simplified):

graph LR
A[Spigot] -- Groove length = 1.5× socket depth --> B[Socket]
B -- Groove depth 1-2.5 mm --> C[Groove Detail]

Summary: IS 651 mandates circumferential grooves on spigots and sockets (except rubber ring joints), with specific groove depth and length to ensure secure joints. Dimensions of bends, junctions, and fittings are standardized in Tables 2-12 for uniformity and compatibility.

IS 651: Annexes on Test Procedures & Sampling Plans

Annex A: Test for Resistance to Acids (Clause 7.4)

• Test Solution: 4.90% Sulphuric Acid (specific gravity 1.84)
• Specimen: ~5 cm square, max 200 g, cleaned & dried at ≥150°C to constant mass (M)
• Procedure: Immerse specimen in acid for 48 hours at ambient temperature, wash, filter solution, add 5 ml conc. H2SO4, evaporate & ignite to constant mass (M2)
• Calculation:

[ \text{Acid Soluble Matter (%)} = \frac{M - M_2}{M} \times 100 ]

Annex B: Test for Alkali Resistance (Clause 7.5)

• Test Solution: Magnesium sulphate solution
• Specimen: Sample size 75–130 cm², free from cracks
• Procedure: React specimen with solution as per standard method (details in IS 651)

Sampling Plan (Clause D-3.3 & Table 13)

• Samples selected randomly from lot for tests: water absorption, acid & alkali resistance, crushing strength.

Key Dimensions for Grooving (Clause 92.5, Table 19 excerpt)

This summary