rotational moulded polyethene water storage tanks

IS 12701 Scope - Key Specifications and Tables

• Scope: Covers cylindrical vertical tanks with specified dimensions, capacities, and weights.

Key Tables & Figures

Important Specifications from Table 1 (Summary)

• Note: Gross capacity ≥ 5% more than net capacity.
• Band: 25 mm wide painted band at inlet/overflow and outlet levels (center line ≥ 50 mm from top/bottom).

Routine Tests (Table 3 Highlights)

• Band width/location (Fig. 1)
• Outer dimensions & weight (Tables 1 & 2)
• Net & gross capacity (Tables 1 & 2)
• Thickness (Tables 1 & 2)
• Resistance to deformation, impact, top load (Clauses 7.1-7.3, Annex B & C)
• Tensile strength and flexural modulus (Clauses 7.4 & 7.5)

flowchart LR
    A[Tank Dimensions & Capacity] -->|Table 1| B[Net & Gross Capacity]
    A --> C[Thickness & Weight]
    D[Routine Tests] -->|Table 3

IS 12701 Key References: Routine Tests & Tank Specifications

Routine Tests (Clause 8.1 & Table 3)

Cylindrical Vertical Tank (Clause 5.1 & Table 1)

• Capacity Range: 200 to 20,000 liters
• Diameter Range: 650 mm to 3,150 mm
• Height Range: 490 mm to 5,000 mm
• Wall Thickness: 3.0 mm to 13.2 mm
• Minimum Weight: 7.8 kg to 566 kg
• Man-hole Diameter: 265 mm to 450 mm
• Note: Gross capacity ≥ 5% more than net capacity

Rectangular Loft Tank (Clause 5.2 & Table 2)

• Refer to Table 2 for dimensions and weights (not provided here).

Important Notes:

• Band width: 25 mm wide painted band at inlet/overflow and outlet levels, center line ≥ 50 mm from top/bottom.
• Sampling and conformity criteria per Annex D.

flowchart LR
    A[Routine Tests] --> B[Band width/location (Fig.1)]
    A --> C[Dimensions & Weight (Table 1 & 2)]
    A --> D[Resistance Tests (Clause 7 & Annexes)]
    A --> E[Strength Tests (Clause 7.3 - 7.5)]
    F[Cylindrical Tank Specs] --> G[Diameter, Height, Thickness (Table 1)]
    F --> H[Capacity & Weight (Table 1)]

For detailed dimensions and weights, always refer to Table 1 (cylindrical tanks) and Table 2 (rectangular tanks) in IS 12701.

IS 12701 Key Definitions & Specifications (Clause 3.0 & 5.1)

Definitions (Clause 3.0):

• Standardizes terminology for tank dimensions, capacities, and components.

Cylindrical Vertical Tank (Clause 5.1 & Table 1)

• Note: Gross capacity ≥ 5% more than net capacity.
• Marking: 25 mm wide painted band at inlet/overflow & outlet levels, 50 mm from tank top/bottom.

Routine Tests (Clause 8.1 & Table 3)

Typical Dimensions Illustration (Fig. 1)

flowchart TB
    A[Cylindrical Vertical Tank]
    A --> B[Overall Diameter]
    A --> C[Effective Height]
    A --> D[Wall & Bottom Thickness]
    A --> E[Man-Hole Diameter]
    A --> F[Painted Bands at Inlet/Outlet Levels]

This summary provides essential dimensional specs

IS 12701: Material Requirements Summary

1. Dimensions & Capacities

• Cylindrical Vertical Tanks (Table 1, Clause 5.1):

  • Wall thickness ranges from 3.0 mm to 13.2 mm depending on capacity (200 L to 20,000 L).
  • Minimum internal man-hole diameter: 265 mm to 450 mm.
  • Gross capacity ≥ 5% more than net capacity.
  • Weight varies from 7.8 kg to 566 kg (without lid).

• Rectangular Loft Tanks (Table 2, Clause 5.2):

  • Wall thickness fixed at 2.75 mm for capacities 150 L to 600 L.
  • Minimum internal hand-hole diameter: 300 mm.
  • Gross capacity ≥ 5% more than net capacity.
  • Weight ranges from 6.6 kg to 17.5 kg (without lid).

2. Wall Thickness Specification (Clause 5.4)

• Thickness at bottom/top edges ≥ values in Table 1 (cylindrical tanks).
• Thickness above effective height ≥ 75% of Table 1 values.
• Thickness measured at ≥ 20 points on sides, top, bottom; lid thickness at ≥ 4 points.

3. Routine Tests (Table 3, Clause 8.1)

4. Important Notes

• A 25 mm wide painted band is mandatory at inlet/overflow and outlet levels, minimum 50 mm from top/bottom inside.
• Connections:

IS 12701: Types and Features of Water Tanks

1. Permissible Material Use (Clause 4.3)

• Max 10% reworked material from tank manufacture allowed.
• No other recycled or filler materials permitted.

2. Cylindrical Vertical Tanks (Clause 5.1, Table 1)

• Gross capacity ≥ 5% more than net capacity.
• Man-hole size and wall thickness increase with tank size.
• 25 mm paint bands at inlet/overflow and outlet levels for visibility.

3. Rectangular Loft Tanks (Clause 5.2)

• Dimensions and specs given in Table 2 (not provided here).
• Used for loft water storage with specified net/gross capacities and weights.

4. Typical Features (Fig.1)

• Male threaded G.I./PVC connections.
• Optional float-type level indicator.
• RCC/PCC platform recommended.

Summary Diagram (Cylindrical Tank)

graph TD
A[Overall Diameter] --> B[Wall Thickness]
B --> C[Effective Height]
C --> D[Man-hole Diameter]
D --> E[Capacity & Weight]

Use Table 1 for quick selection of tank size

IS 12701 Key Specifications for Dimensions and Capacities

1. Cylindrical Vertical Tanks (Clause 5.1, Table 1)

2. Rectangular Loft Tanks (Clause 5.2, Table 2)

3. Wall Thickness (Clause 5.4)

• Thickness at bottom, top, and edges is greater due to rotational moulding.
• For cylindrical tanks:
  • Up to effective height: as per Table 1.
  • Above effective height: ≥ 75% of Table 1 thickness.
• Thickness measured at multiple points on sides, top, bottom; lid thickness at ≥ 4 locations.

Formula: Volume of Cylindrical Tank (for verification)

[ V = \pi \times \left(\frac{D}{2}\right)^2 \times H ]

Where:

• (V) = volume (liters)

IS 12701: Performance Requirements and Tests (Clause 8.1)

Routine Tests Overview (Table 3)

Sampling and Conformity Criteria

• Sampling scale and acceptance criteria are specified in Annex D.
• Visual, dimensional, and capacity requirements are detailed in Clause 2.1 (D-2.1).

Key Specifications Summary

Example: Tensile Strength Test (Clause 7.4)

• Tensile strength, (\sigma_t = \frac{P_{max}}{A

IS 12701 – Routine Tests Summary

Key Routine Tests (Table 3)

Sampling & Conformity (Annex D)

• Sampling: Tanks selected randomly (per IS 4905:1968).
• Scale: For tanks ≤1000 liters, samples undergo tests i) to iv).
• Acceptance: Lot is accepted if defectives ≤ acceptance number in Table 4 (Annex D).

Important Notes

• Dimensions & Weight: Refer to Tables 1 & 2 for standard values.
• Mechanical Tests: Follow detailed procedures in Clauses 7.1 to 7.5 and Annexes B & C.
• Random Sampling: Ensures unbiased quality check.

flowchart LR
    A[Lot of Tanks] --> B[Random Sampling per IS 4905]
    B --> C{Capacity ≤ 1000 L?}
    C -- Yes --> D[Perform Tests i) to iv)]
    C -- No --> E[Refer to extended sampling]
    D --> F{Defectives ≤ Acceptance Number?}
    F -- Yes --> G[Lot Accepted]
    F -- No --> H[Lot Rejected]

This encapsulates the routine test framework for compliance per IS 12701.

IS 12701: Fittings and Connections - Key Specifications & Tables

1. Threaded Connections (Clause 9.1 & Table 6)

• Full threaded G.I./brass connections recommended.
• Use rubber gaskets and hexagonal check nuts (Fig. 4).
• Avoid jointing compounds; use PTFE tape for sealing.
• Holes for connections must be clean and notch-free.

2. Overflow Pipe (Clause E-9.1.1)

• Must have a non-corrodible mosquito-proof device with max clearance ≤ 1.6 mm.

3. Thread & Fitting Standards (Clause 9.2)

• Threads conform to IS 554:1985.
• Dimensions (centre-to-face, face-to-face) conform to IS 1879:1987.
• Manufacturer instructions to be followed.

4. Installation Recommendations (Annex E)

• Support tank base fully on rigid, level platform.
• Avoid distortion by proper alignment of pipelines and fittings.
• Avoid proximity to heat sources.
• Use clamping and anchoring where required.

5. Sampling for Quality Tests (Clauses 2.2, Tables 4 & 5)

• Sampling size and acceptance criteria depend on lot size and tank capacity.
• Sub-samples tested for quality per Table 3 requirements.

flowchart TD
    A[Water Storage Tank] --> B[Threaded Connection]
    B --> C{Capacity of Tank}
    C -->|Up to 750L| D[12.5 mm Bore]
    C -->|750-2000L| E[25 mm Bore]
    C -->|2000-4000L| F[40 mm Bore]
    C -->|4000-10000L| G[50 mm Bore]
    C -->|Above 10000

IS 12701: Marking and Certification Key Points

1. Marking Requirements (Clause 10.1)

All water storage tanks must be marked with:

• Manufacturer's name, initials, or trademark
• Net capacity (litres)
• Lot or batch number and year of manufacture
• "For indoor use only" (if applicable)

2. Use of Standard Mark (Clause 10.3 & 10.3.1)

• Tanks may be marked with the BIS Standard Mark.
• Use governed by BIS Act, 1986 and related rules.
• License conditions for using the Standard Mark are available from BIS.

3. Routine Tests for Certification (Table 3, Clause 8.1)

4. Relevant IS References (Annex A)

• IS 554: Pipe threads dimensions
• IS 1879: Malleable cast iron pipe fittings
• IS 2530, 7328: Polyethylene materials
• IS 8543, 13360: Plastic mechanical properties testing

Summary Diagram

flowchart TD
    A[Water Tank] --> B[Marking]
    B --> B1[Manufacturer's Name/Trademark]
    B --> B2[Net Capacity (L)]
    B --> B3[Batch No. & Year

IS 12701: List of Indian Standards Referenced (Annex A)

This standard references key Indian Standards essential for materials, testing, and dimensions related to tanks and plastics:

Key Specifications for Cylindrical Vertical Tanks (Clause 5.1, Table 1)

• Gross capacity ≥ 5% more than net capacity.
• Man-hole size increases with tank size for access.
• Wall thickness and weight increase with capacity for

IS 12701: Method of Deformation Test - Key Points

1. Deformation Calculation (Clause 2.4, B-2.4)

• Deformation in longer side (DL):
  [ DL = \frac{W_2 - W_1}{W_1} \times 100 ]
• Deformation in shorter side (Dw):
  [ Dw = \frac{L_2 - L_1}{L_1} \times 100 ]

Where:

• (W_1), (W_2) = Width at start and end of test
• (L_1), (L_2) = Length at start and end of test

2. Method of Deformation Test (Clause 7.1, B-1)

• Method 1 applies specifically to cylindrical vertical tanks.
• Resistance to deformation is measured by comparing dimensional changes before and after applying load.

3. Routine Tests Including Deformation (Clause 8.1, Table 3)

Summary:

• Measure initial dimensions (length, width).
• Apply test load as per Clause 7.1.
• Measure final dimensions.
• Calculate deformation % using formulas above.
• Confirm conformity using sampling criteria in Annex D.

flowchart TD
    Start[Start: Measure Initial Dimensions] --> ApplyLoad[Apply Load per Clause 7.1]
    ApplyLoad --> MeasureFinal[Measure Final Dimensions]
    MeasureFinal --> CalculateDeform[Calculate Deformation %]
    CalculateDeform --> CheckConformity[Check Against Annex D Criteria]
    CheckConformity --> End[End: Pass/Fail]

This method ensures structural integrity by quantifying dimensional changes under load.

IS 12701: Impact Resistance Test for Polyethylene Water Tanks

Key Specifications (Clause 7.2 & Annex C)

• Test Objective: Ensure tank resists impact without cracking or puncture.
• Test Method: As per Annex C, simulate impact conditions on the tank.
• Acceptance Criteria: No visible cracking or puncture after impact.

Impact Resistance Test Method (Annex C Summary)

• Test Setup:
  • Tank filled to specified level (usually full or as per Annex C).
  • Impact applied using a standard weight dropped from a specified height.
• Impact Energy Calculation:
  [ E = m \times g \times h ] where:
  • (E) = Impact energy (Joules)
  • (m) = Mass of the impactor (kg)
  • (g) = Acceleration due to gravity (9.81 m/s²)
  • (h) = Height of drop (m)

Routine Test Reference (Table 3, Clause 8.1)

Summary Table for Impact Test Parameters (Typical)

flowchart TD
    A[Fill Tank to Specified Level] --> B[Drop Impactor of Mass m from Height h]
    B --> C[Observe Tank for Cracks or Puncture]
    C --> D{Any Damage?}
    D -- No --> E[Pass Impact Test]
    D -- Yes --> F[Fail Impact Test]

Note: Refer Annex C of IS 12701 for exact test setup, impactor dimensions, and acceptance criteria.

IS 12701: Sampling & Conformity Criteria for Routine Tests

1. Scale of Sampling (Clause 8.1 & Annex D)

• Sampling is done randomly as per IS 4905:1968 to ensure unbiased selection.
• Tanks are selected from each lot for testing.

2. Routine Tests & Reference (Table 3)

3. Number of Tests & Conformity (Clause D-1.2)

• Samples from each lot are tested separately.
• The lot is accepted if all samples meet the criteria specified in the relevant tables and clauses.

Summary of Sampling & Conformity Process:

flowchart TD
    A[Lot Received] --> B[Random Sampling (IS 4905:1968)]
    B --> C[Perform Routine Tests (Table 3)]
    C --> D{All Samples Conform?}
    D -- Yes --> E[Lot Accepted]
    D -- No --> F[Lot Rejected or Reprocessed]

For detailed dimensions, weight, and capacity limits, refer to Table 1 and Table 2 of IS 12701. For deformation, impact, tensile, and flexural tests, follow the respective clauses and annexes.

IS 12701 - Threaded Connection Details (Clause 9.1 & 9.2)

Key Specifications:

• Material: Full threaded G.I. brass or PVC connections, non-corrosive and safe for potable water.
• Thread Dimensions: As per IS 554:1985 (G.I./PVC/Brass threaded connections).
• Fittings Dimensions: Elbows, tees, bends, couplings, nipples conform to IS 1879:1987.
• Mosquito-proof Device: Overflow pipes must have non-corrosive mesh with max clearance 1.6 mm.

Threaded Connection Sizes (Table 6):

Design Notes:

• Provide flat surfaces on tanks for fixing outlet pipes.
• Threaded fittings include hexagonal check nuts and rubber gaskets (see Fig 4 in IS 12701).
• Manufacturers must supply fitting instructions.

Summary Diagram of Threaded Connection (Fig 4):

graph LR
A[Wall of Tank] --> B[Rubber Gasket]
B --> C[Male Threaded Connection]
C --> D[Hexagonal Check Nut]
D --> E[Outlet Pipe]

This ensures a leak-proof, corrosion-resistant connection suitable for potable water tanks.