Unplasticized PVC Pipes for Potable Water Supplies

IS 4985: Scope & Key Specifications

Scope (Clause 3.0 & related notations)

• Applies to PVC pipes for potable water supply.
• Covers dimensions, classification, testing, and quality requirements.

Important Notations (Symbols)

Classification of Pipes (Clause 5.0 & Table C-4.1.3)

• Pipes classified by Nominal Outside Diameter (d)
• Impact test parameters (mass of falling weight & fall height):

Testing Notes

• Convex (outer) surface of pipe specimen faces light source during inspection.
• Updated nomenclature and dimensional values in tables for accuracy.

flowchart LR
    A[PVC Pipes Scope] --> B[Dimensions & Tolerances]
    A --> C[Classification by Diameter]
    C --> D[Impact Test Parameters]
    A --> E[Material & Mechanical

IS 4985 - Definitions & Key Specifications

Key Definitions (Clause 3.0 & 3.22)

• Own Rework Material: Material from rejected unused pipes or trimmings, reprocessed with known formulation.
• Symbols:

Pipe Classification - Falling Weight Test (Clause 4.1.2)

Sampling

IS 4985 - Classification of PVC Pipes

1. Classification by Working Pressure (Clause 5.1)

2. Key Dimensions (Excerpt from Table 7.2)

• Pipes are specified by Nominal Outside Diameter (DN).
• For each DN and class, minimum and maximum wall thickness values are defined.
• Wall thickness increases with pressure class for the same DN.

3. Important Symbols (Clause 3.22 & Notations)

Summary:

• Pipes are classified by **

IS 4985: Dimensions and Tolerances for uPVC Pipes

1. Outside Diameter & Tolerances (Clause 7.1.1, Table 1)

• Mean Outside Diameter (D_mean) and Outside Diameter at any point (D_point) have specified min and max limits.
• Measured as per IS 12235 (Part 1).
• Example for DN 50:
  • Mean Outside Diameter: 50.0 mm (min), 50.3 mm (max)
  • Outside Diameter at any point: 49.4 mm (min), 50.6 mm (max)

2. Socket Dimensions for Solvent Cement Jointing (Clause 7.2.1.1, Table 3)

• L = Socket length (minimum depth of engagement)
• d = Internal diameter at mid-point of socket length

3. Wall Thickness Classes (from Table 1)

• Classes 1 to 6 correspond to working pressures 0.25 MPa to 1.25 MPa.
• Wall thickness varies with nominal size and class.
• Example for DN 50:
  • Class 1: 1.5 mm (min), 1.1 mm (max)
  • Class 6: 4.0 mm (min), 3.4 mm (max)

Summary:

IS 4985: Material Requirements - Key Points

1. Material Definition (Clause 3.22)

• Own Rework Material: Reprocessed from rejected/unused pipes or production trimmings.
• Must be processed at the manufacturer's plant with known formulation.
• Only manufacturer's own rework material is allowed (Clause 6.2).

2. Notations (Key Symbols)

3. Sampling & Testing (Quality Control)

• Sampling scales for Visual, Dimensional, Vicat Softening, Density, Sulphated Ash Tests are tabulated for different lot sizes.
• Example: For lots up to 1,000 pipes, first sample size for visual/dimensional test is 13 pipes with acceptance 0 rejects, rejection at 2 rejects.
• Refer to Tables 13, 14, 15 for detailed sampling sizes and acceptance criteria.

4. Pressure Calculation (Reference Fig. 1)

• Maximum continuous working pressure depends on temperature (up to 45°C).
• Use derating factors f and fₜ to adjust nominal pressure Pₙ.

Summary Formula for Design Stress:

[ \sigma_d = \frac{P_n \times d_m}{

IS 4985: Physical and Chemical Characteristics — Key Points

1. Chamfering for Elastomeric Sealing Rings (Clause 9.2)

• Pipes with plain ends must be chamfered at ~15° to the pipe axis.
• Chamfer depth: ~2/3 of the wall thickness.
• Ensures proper seating of elastomeric sealing rings.

2. Sampling for Physical Tests (Tables 14 & 15)

• Sampling is based on lot size and pipe diameter (d).
• Tests include: Reversion, Vicat Softening Temperature, Density, Sulphated Ash Content.

For pipes with diameter >110 mm, sample sizes are reduced.

3. Toxic Substance Limits (Clause 1.0)

• Lead: 0.001 mg/l (ppm)
• Mercury: 0.001 mg/l
• Other toxic organotin compounds: 0.01 mg/l

4. Minimum Depths of Engagement (Table 5)

• For joints involving sulphuric acid (density 1840 kg/m³), specific engagement depths are prescribed (refer to Table 5 in IS 4985).

Summary Diagram: Chamfering Detail

graph LR
A[Pipe End] --> B[Chamfer at 15°]
B --> C[Depth = 2/3 Wall Thickness]
C --> D[Proper Seal with Elastomeric Ring]

**Use IS 4985 Tables for sampling and chemical

IS 4985: Sockets and Jointing Key Specifications

1. Sockets for Solvent Cement Jointing (Clause 7.2.1.1)

• Socket Length (L) and Mean Internal Diameter (d) at midpoint per Nominal Size DN:

• Minimum Socket Length Formula:

[ L_s = 0.5 \times d_n + 6 \text{ mm} ]

where (d_n) = nominal outside diameter.

• Total taper angle ≤ 0°30'.

2. Sockets for Elastomeric Sealing Ring Joints (Clause 7.2.1.2)

• Must conform to Table 4 and Fig. 4 (not provided here).

• Minimum Depth of Engagement (m):

[ m = \begin{cases}

50 \text{ mm} + 0.22 d_a, & d < 280 \text{ mm} \ 70 \text{ mm} + 0.15 d_a, & d \geq 280 \text{ mm} \end{cases} ]

• (d_a) = outer diameter at any point.

• Wall thickness at socket (including groove) ≥ minimum pipe wall thickness.

• Joint pressure rating per Table 6 (not provided).

3. Sealing Rings (Clause 8)

• Types 1 to 6 as per IS 5382.

• Manufacturer specifies ring type.

• Test certificate recommended every 3 months.

4. Additional Notes

• Wall thickness for pipes based on safe working stress 8.6 MPa at 27°C.

• Effective length and insertion length differ for plain-ended, solvent cement, and rubber jointed pipes (see Fig. 3).

IS 4985 - Marking of Pipes (Clause 13)

Key Specifications for Marking:

• Marking Interval:
  Every pipe must be marked at intervals ≤ 3 meters.

• Marking Method:
  Ink/paint or hot embossing on a white base; alternatively, inkjet printing in contrasting color.

• Information to Mark:

  • Manufacturer's name or trade-mark
  • Outside diameter (OD)
  • Class of pipe and pressure rating
  • Batch or lot number
  • The word "plumbing" (for plumbing pipes)

• Colour Coding by Pipe Class (Clause 13.1.1):

• Additional Marking:
  Pipes may also carry the Standard Mark as per Clause 13.2.1.

Summary:

Markings ensure easy identification of pipe specifications and quality control. Colour coding aids quick visual classification on site.

flowchart LR
    A[Pipe] --> B{Marking Interval ≤ 3m}
    B --> C[Manufacturer's Name/Trade-mark]
    B --> D[Outside Diameter]
    B --> E[Class & Pressure Rating]
    B --> F[Batch/Lot Number]
    B --> G["Plumbing" (if applicable)]
    B --> H[Colour Code by Class]
    B --> I[Standard Mark (optional)]

IS 4985: Sampling and Testing Key Points

Sampling Scales for Different Tests

IS 4985: Type Tests Summary

Type tests validate new pipe compositions or sizes, ensuring performance per IS 4985 requirements.

Key Points from Clauses:

• When to conduct:

  • Change in polymer composition
  • Introduction of new pipe size or series

• Samples:

  • 3 samples of different diameters & classes from regular production
  • Tested for compliance with Tables 6 & 7 (mechanical & physical properties)

• Relevant Clauses:

  • Clause 2.1.3.1: Selection & testing of 3 samples
  • Clause 3.20.1: Type tests for suitability & performance
  • Clause 2.1.3: Internal Hydrostatic Pressure Test as a mandatory type test

Essential Type Tests (per IS 4985):

Internal Hydrostatic Pressure Test Formula:

[ P = \frac{2 \times \sigma_t \times t}{D} ]

Where:

• (P) = Design pressure
• (\sigma_t) = Allowable tensile stress of pipe material
• (t) = Wall thickness
• (D) = Outside diameter

Summary Diagram

flowchart TD
    A[Change in Polymer or Size] --> B[Select 3 Samples]
    B --> C[Perform Type Tests]
    C --> D[Internal Hydrostatic Pressure Test]
    C --> E[Tensile Strength Test]
    C --> F[Impact Resistance Test]
    C --> G[Dimensional Checks]
    D & E & F & G --> H[Compliance Verification]

Note: Refer IS 4985 Tables 6 & 7 for detailed test parameters and acceptance criteria.

IS 4985 Acceptance Tests for Steel Tubes

Key Acceptance Test Parameters:

• Internal Hydrostatic Pressure Test (Clause 1.10):

  • Test pressure = 1.5 × PN (Nominal Pressure)
  • Duration: Minimum 5 seconds
  • Purpose: Check tube integrity under pressure without leakage or permanent deformation.

• Tensile Strength Test (Clauses 2.20 & 1.16):

  • Tensile strength acceptance limit = ≥ 2.20 × PN (MPa) or ≥ 1.16 × PN (MPa) depending on test type (verify specific clause for exact application).

• Acceptance Tests (Clause 3.20.2):

  • Samples taken from each lot for testing
  • Tests include dimensional checks, mechanical properties, and hydrostatic pressure tests
  • Lot acceptance based on compliance with all specified criteria.

Summary Table:

flowchart TD
    A[Lot of Tubes] --> B[Sample Selection]
    B --> C{Acceptance Tests}
    C --> D[Dimensional Checks]
    C --> E[Mechanical Tests (Tensile)]
    C --> F[Hydrostatic Pressure Test]
    D --> G{Pass?}
    E --> G
    F --> G
    G -->|Yes| H[Accept Lot]
    G -->|No| I[Reject Lot]

Note: Always refer to the specific clauses for detailed test procedures and acceptance criteria.

IS 4985 - Inspection & Quality Control Key Points

1. Sampling for Visual & Dimensional Requirements (Clause 1.4.1, Table 13)

2. Sampling for Reversion, Vicat Softening Temp., Density (Clause 1.6, Table 14)

• Sample sizes vary by lot size and pipe diameter.
• For example, for up to 1,000 pipes, first sample size is 5; for 10,001+, first sample size is 20.
• Acceptance and rejection numbers are similar to Table 13 but adjusted per test.

3. Sampling for Sulphated Ash Content Test (Clause 1.8, Table 15)

IS 4985: Packaging and Storage - Key Specifications & Tables

1. Conditioning Period (Table 12, Clause C-7 A):

• Conditioning ensures pipe material attains required properties before testing or use.

2. Acceptance Sampling for Quality Tests (Tables 14 & 15):

• Sampling size depends on lot size and pipe diameter.
• Example from Table 14 (Reversion, Vicat Softening Temp, Density):

• Table 15 is similar for Sulphated Ash Content test but with smaller sample sizes.

3. Test Evaluation - Number of Blows & Failures (Table 11, Clause C-6.5):

• Minimum 25 blows initially.
• Accept if failures = 0; Reject if failures ≥4.
• Continue testing for intermediate failures (1-3) until decision region is reached.

Notations for Pipes (Clause 3.22):

• d = Nominal outside diameter
• d_max, d_min = Max/Min mean outside diameter
• e = Mean wall thickness
• e_max, e_min = Max/Min wall thickness
• L = Overall length
• P = Nominal pressure (working pressure)
• σ = Design stress

This ensures proper handling, conditioning, and quality acceptance during packaging and storage of IS 4985 pipes.

IS 4985 - List of Referenced Indian Standards (Annex A, Clause 2):

This standard references key IS codes related to PVC pipes and materials testing:

Key Notes:

• Sulphated Ash Content Test (Clause 10.7):
  Calcination with sulfuric acid followed by heating at 850°C until constant mass.

• Rounding Off (IS 2:1960):
  Test results must be rounded to the same decimal places as specified values.

• BIS Certification Mark (Clause 13.2.2):
  Use governed by BIS Act 1986; license details available from BIS.

Summary Diagram of Reference Standards Relation

graph TD
  A[IS 4985] --> B[PVC Resin Testing - IS 4669]
  A --> C[PVC Pipe Testing - IS 12235]
  A --> D[Rubber Sealing Rings - IS 5382]
  A --> E[UPVC Pipes for Agriculture - IS 12231]
  A --> F[Safety for Food Contact - IS 10148/10151]
  A --> G

IS 4985: Key Test Methods - Formulas, Tables & Specifications

1. Sampling for Tests (Clauses 1.6, D-1.5 to D-1.8)

Table 14: Sampling for Reversion, Vicat Softening Temp., and Density Tests

For pipes diameter (d) > 110 mm, reduced sample sizes apply.

2. Sampling for Sulphated Ash Content (Clause D-1.8)

Table 15: