Water Tank Wall Thickness Calculator
Here’s a comprehensive table covering everything you need to know about Water Tank Wall Thickness, including factors affecting thickness, typical formulas used, materials, and other considerations for designing a safe and effective water tank.
Water Tank Wall Thickness Guide
| Category | Details |
|---|---|
| Formula for Wall Thickness | Thickness equals Pressure times Radius divided by Allowable Stress of the Material. Where: - Pressure is the force at the base of the tank, calculated as height times density of water times gravity - Radius is the tank's inside radius - Allowable Stress depends on the material used for construction |
| Pressure Calculation | Pressure at the bottom of the tank is calculated as height times density of water times gravity. where: - height is the water height, typically in feet or inches - density of water is often set to 62.4 pounds per cubic foot or approximately 0.0361 psi per inch - gravity is set to 32.2 feet per second squared |
| Factors Affecting Thickness | - Water Depth: Increased depth raises the pressure and required wall thickness - Tank Radius: Larger tanks require thicker walls to resist internal pressure - Material Strength: Stronger materials can handle more pressure with less thickness |
| Common Materials | - Steel: High strength, often used in large industrial tanks - Concrete: Suitable for very large tanks due to its durability - Polyethylene: Common for smaller or portable tanks, especially for residential use - Fiberglass: Corrosion-resistant, widely used in environments with chemicals or saltwater |
| Allowable Stress of Materials | - Steel: Ranges from 12,000 to 20,000 psi depending on the grade and temperature - Concrete: Between 3,000 to 6,000 psi, typically lower than steel - Polyethylene: Typically around 2,500 to 4,000 psi - Fiberglass: Around 4,000 to 10,000 psi, depending on the manufacturing process |
| Safety Factor | Safety factor is typically added to the calculation to ensure the tank can withstand unexpected loads or environmental factors. Ranges from 1.5 to 4, depending on industry standards |
| Corrosion Allowance | Extra wall thickness is often added to account for corrosion over the tank’s lifespan, especially for steel tanks. Commonly between one-sixteenth to one-fourth inch |
| Temperature Considerations | Temperature can affect material strength, especially for metals and plastics. Higher temperatures may lower allowable stress, requiring thicker walls |
| Industry Standards and Codes | - ASME Boiler and Pressure Vessel Code (BPVC) is commonly used for large tanks in the USA - API standards apply for petroleum and chemical industry tanks - EN 13445 applies in Europe for unfired pressure vessels |
| Inspection and Testing | - Hydrostatic Testing: Involves filling the tank with water to test its strength under maximum pressure - Nondestructive Testing: Methods such as ultrasonic or radiographic tests ensure there are no flaws or weaknesses in the walls |
| Maintenance and Inspection | Regular inspections are essential, especially in corrosive environments. Visual checks, ultrasonic thickness measurement, and hydrostatic testing are commonly used methods |
Example Calculation for Water Tank Wall Thickness
For a cylindrical water tank with:
- Water height of 120 inches
- Tank radius of 36 inches
- Material allowable stress of 16,000 psi for steel
Using the wall thickness formula:
- Calculate pressure as height times density of water times gravity, resulting in approximately 4.332 psi
- Required wall thickness will then be approximately 0.0097 inches