Precast Ferro cement water tanks up to 10000 litres capacity

IS 13356: Scope - Key Formulas, Tables, and Specifications

1. Scope

• Covers precast ferrocement water tanks with capacities 270 to 10,000 litres.
• Tanks are made with wire mesh, steel bars, and rich cement-sand mortar.
• Suitable for domestic, industrial, and community use.

2. Capacity Recommendations

3. Tolerances on Dimensions (Clause 3.3)

4. Sampling and Permissible Defectives (Clause 8.1.3)

5. Definitions

• Net Capacity: Usable volume between overflow and outlet centers.
• Gross Capacity: Total volume including dead storage and freeboard.

Summary Diagram of Dimensions & Tolerances

flowchart TD
    A[Dimensions] --> B{Length, Breadth, Height, Diameter}
    B -->|≤ 1 m| C[± 5 mm]
    B -->|> 1 m| D[± 10 mm]
    A --> E[Thickness]
    E --> F[± 2 mm]

This concise summary aids in understanding the scope, dimensional tolerances, capacities, and quality control sampling of precast ferro

IS 13356: Precast Ferrocement Water Tanks (270 to 10,000 litres)

Key Specifications & Formulas

• Capacity Definitions:

  • Net Capacity: Usable water volume between overflow and outlet centers.
  • Gross Capacity: Total including dead storage and freeboard.

• Recommended Net Capacities:

• Shape & Dimensions:

  • Cylindrical tanks: Height = Diameter (H/D = 1)
  • Rectangular tanks: Length to Breadth = 1.5; Height to Length ratio varies

• Wall Thickness:

  • Mechanized casting (≤ 2,000 L): ≥ 12 mm
  • Hand casting (≤ 1,000 L): ≥ 15 mm
  • Larger tanks (up to 10,000 L): 20–40 mm depending on capacity

Notes:

• Water quality must comply with IS 456:1978.
• Dimensions are calculated based on capacity and shape ratios.
• Ferrocement offers high impermeability and durability.

Dimension Calculation Example for Cylindrical Tank:

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

For H = D,

[ V = \pi \times \left(\frac{D}{2}\right)^2 \times D = \frac{\pi D^3}{4} ]

Solve for D given volume (V).

flowchart LR
    A[Capacity (V)] --> B[Select Shape: Cylindrical or Rectangular]
    B --> C{Cylindrical?}
    C -- Yes --> D[Set H = D]
    D --> E[Calculate Diameter D from V]
    C -- No --> F[Set L/B = 1.5]
    F --> G[Calculate L, B, H from V]
    E & G --> H[Determine wall thickness based on capacity]
    H --> I[Construct tank]

This framework

IS 13356: Shape and Dimensions - Key Specifications

Tolerances on Dimensions (Clause 3.3)

Sampling and Permissible Defectives (Clause 8.3.1.1 & 8.1.3)

Recommended Net Capacities for Ferrocement Tanks (Litres)

• Domestic: 270, 540, 750, 1250
• Industrial/Community: 1250, 2500, 5000, 7500, 10000

Notes:

• Net capacity = usable volume between overflow and outlet centers.
• Dimensions must comply with tolerances to ensure quality and serviceability.
• Sampling ensures lot acceptance based on permissible defectives.

flowchart TB
    A[Specified Dimension] --> B{Dimension ≤ 1 m?}
    B -- Yes --> C[Tolerance ± 5 mm]
    B -- No --> D[Tolerance ± 10 mm]
    A --> E[Thickness]
    E --> F[Tolerance ± 2 mm]

This concise summary aids in design, quality control, and acceptance of ferrocement water tanks per IS 13356.

Key Specifications & Tables for Materials (IS 13356 - Precast Ferrocement Water Tanks)

Materials:

• Ferrocement: Made of wire mesh, mild steel bars, and rich cement-sand mortar.
• Cement, Sand, Wire Mesh, Steel Bars: Easily available and form the composite.
• Properties: Thin, light, durable, impermeable, moldable into any shape.

Tank Capacities (Net Usable Volume)

Dimensional Tolerances (Clause 3.3)

Quality Control - Lot Sampling (Clause 8.1.3)

Notes:

• Net capacity excludes dead storage and freeboard.
• Final test values rounded per IS 2:1960.
• Ferrocement tanks exhibit high impermeability, suitable for rapid erection and low skilled labor.

flowchart LR
    Cement --> Ferrocement
    Sand --> Ferrocement
    WireMesh --> Ferrocement
    SteelBars --> Ferrocement
    Ferrocement --> WaterTank
    WaterTank --> Capacity[Capacity: 270 to 10,000 L]
    WaterTank --> Tolerance[Dimensional Tolerances]
    WaterTank --> QC[Quality Control Sampling]

This summary highlights essential material

Key Design & Reinforcement Specifications from IS 13356

• Minimum Main Reinforcement Area (Clause 5.4):
  [ A_s \geq 1.0% \times A_g ]
  where ( A_s ) = area of main reinforcement,
  ( A_g ) = gross cross-sectional area of the element.

• Maximum Tensile Stress in Reinforcement (Clause 5.2):
  [ f_{st} \leq 200 , \text{N/mm}^2 ]

• Minimum Clear Cover to Reinforcement (Clause 5.10):
  [ \text{Clear cover} \geq 4 , \text{mm} ]

Typical Reinforcement Design Steps:

1. Calculate gross cross-section area ( A_g ).
2. Determine minimum steel area ( A_s = 0.01 \times A_g ).
3. Check reinforcement stress under service load ( f_{st} \leq 200 , \text{N/mm}^2 ).
4. Provide minimum clear cover of 4 mm for durability and corrosion protection.

Ferrocement Water Tanks Capacity Table (Clause 3):

flowchart TD
    A[Calculate Gross Area \(A_g\)] --> B[Minimum Steel Area \(A_s = 0.01 A_g\)]
    B --> C[Check \(f_{st} \leq 200 N/mm^2\)]
    C --> D[Provide Clear Cover ≥ 4mm]
    D --> E[Detail Reinforcement & Construct]

This ensures safe, durable ferrocement structures per IS 13356.

IS 13356 - Manufacturing & Casting Key Points

1. Hand Casting (Clause 6.1)

• Skeletal steel spacing: max 300 mm c/c in both directions (Clause 5.6).
• Lap length: minimum 150 mm where laps are provided.
• Fittings: G.I. sockets/nipples (15-40 mm dia) fixed before casting (Clause 6.1.2).
• Anchor bars: Two 6 mm dia bars, 100-150 mm long welded to each insert.
• Placement: Inserts positioned by displacing mesh wires so anchor bars contact innermost mesh layer.

2. Mechanized/Semi-Mechanized Casting (Clause 6.2)

• Used for full or segmented ferrocement tanks.
• Vertical segments joined onsite by overlapping reinforcement and plastering joints.
• Tempformer system and masonry moulds are acceptable casting methods.

Summary Table: Skeletal Steel & Fittings

flowchart LR
    A[Prepare skeletal steel mesh] --> B[Fix fittings with anchor bars]
    B --> C[Position inserts by displacing mesh wires]
    C --> D[Hand casting with mortar]
    D --> E[Mechanized casting (optional)]
    E --> F[Assemble vertical segments onsite]
    F --> G[Plaster joints to complete tank]

This ensures structural integrity and proper embedment of fittings during casting.

IS 13356 - Testing: Key Formulas, Tables & Specifications

1. Number of Units to Test (Clause 8.1.3 & Table 1)

2. Acceptance Criteria (Clause 8.3.1.1)

• The number of defective units (units not meeting dimensions and finish) in the sample must not exceed the permissible number of defectives from Table 1.

3. Procedure Summary (Clause 8.2)

• Select sample size n based on lot size N.
• Inspect all units in the sample for dimensions and finish.
• Accept the lot if defective units ≤ permissible number; otherwise, reject.

This sampling plan ensures quality control by statistically verifying dimensional and finish compliance based on lot size.

IS 13356: Quality Control and Conformity Key Points

Sampling Procedure (Clause 8.1.3.1)

• Arrange all units in the lot orderly.
• Select every rᵗʰ unit, where
  [ r = \frac{N}{n} ]
  • N = total units in the lot
  • n = sample size
• Start from any random unit.

Sampling & Acceptance Criteria (Table 1)

Conformity (Clauses 8.3.1 & 8.3.1.1)

• Lot conforms if:
  • Defectives ≤ permissible number (Table 1)
  • Both dimensions and finish requirements are met.

flowchart TD
    A[Lot of N units] --> B[Arrange units orderly]
    B --> C[Select every rth unit (r = N/n)]
    C --> D[Sample of size n]
    D --> E{Count defectives}
    E -- ≤ permissible --> F[Lot conforms]
    E -- > permissible --> G[Lot rejected]

This ensures statistically valid sampling and clear acceptance criteria for quality control.

IS 13356: Marking - Key Specifications & Tables

Clause 9.1.1: Marking

• Each water tank may be marked with the Standard Mark for identification and quality assurance.

Quality Control: Dimensions & Finish (Clause 8.3.1.1 & Table 8.1.1)

• No. of defective units in a lot must not exceed permissible limits.

Dimensional Tolerances (Clause 3.3)

Summary

• Marking ensures traceability & compliance.
• Sampling and permissible defectives control quality.
• Dimensional tolerances ensure uniformity.

flowchart TD
    A[Water Tank Production] --> B[Sampling as per Lot Size]
    B --> C{Defectives ≤ Permissible?}
    C -- Yes --> D[Mark with Standard Mark]
    C -- No --> E[Reject Lot / Rework]

This ensures tanks meet IS 13356 quality and marking standards.

IS 13356: List of Referenced Indian Standards

This standard for precast ferrocement water tanks references key IS codes essential for materials and construction:

Key Notes:

• These standards govern materials like cement types, steel reinforcement, aggregates, and admixtures.
• Refer to IS 456:1978 for concrete design and IS 383:1970 for aggregate grading.
• Cement strength and composition are per IS 269, 1489, and 455.
• Steel reinforcement follows IS 432 and IS 1566.

This ensures ferrocement tanks have durable, standardized materials for strength and impermeability.

Composition of Technical Committee (IS 13356 - Annex B)

The Technical Committee for Cement and Concrete Sectional Committee, CED 2 includes:

• Chairman: Dr. H. C. Visvesvaraya
• Members: Experts from various organizations such as:
  • Orissa Cement Ltd.
  • The Associated Cement Companies Ltd.
  • Central Public Works Department
  • Sardar Sarovar Narmada Nigam Ltd.
  • Irrigation and Power Research Institute
  • Structural Engineering Research Centre (CSIR)
  • Central Building Research Institute (CSIR)
  • Research, Designs and Standards Organization (Ministry of Railways)
  • Indian Hume Pipes Co Ltd.
  • National Test House
  • Larsen and Toubro Ltd.
  • Geological Survey of India
  • Central Board of Irrigation and Power
  • Roads Wing, Ministry of Transport
  • National Council for Cement and Building Materials
  • Development Commissioner for Cement Industry (Ministry of Industry)
  • Army Headquarters, Hindustan Prefab Ltd, Central Road Research Institute, Indian Roads Congress, Builders Association of India, Cement Corporation of India, National Buildings Organization, Gammon India Ltd, Public Works Department (Tamil Nadu), Central Soil and Materials Research Station, The Institution of Engineers (India), BIS (Ex-officio member)

Key points:

• The committee represents a wide spectrum of government, research, industry, and academic institutions.
• It includes alternate members to ensure continuity.
• The committee oversees formulation and revision of standards related to cement, concrete, and ferrocement water tanks.

Summary Table

This composition ensures broad expertise and stakeholder representation for standard development and review.

graph LR
A[Chairman: Dr. H.C. Visvesvaraya] --> B[Members]
B --> C[Cement Industry]
B --> D[Research Institutes]
B --> E[Government Departments]
B --> F[Construction Industry]
B --> G[BIS & Standards]

For detailed names and affiliations, refer to Annex B of IS 13356.