Rectangular Tank Wall Thickness Calculator
Here’s a comprehensive table covering everything you need to know about Rectangular Tank Wall Thickness, including factors affecting thickness, typical formulas used, materials, and other considerations for designing a safe and effective rectangular tank.
Rectangular Tank Wall Thickness Guide
| Category | Details |
|---|---|
| Formula for Wall Thickness | Thickness equals Pressure times Longest Side divided by Allowable Stress. Where: - Pressure is calculated as water height times density of water times gravity - Longest Side is the longer dimension of the tank wall (length or width) - Allowable Stress depends on the material's strength limit |
| Pressure Calculation | Pressure at the tank base is calculated as height times density of water times gravity. - Height is the water height (inches or feet) - Density of Water is typically 62.4 pounds per cubic foot or 0.0361 psi per inch - Gravity is 32.2 feet per second squared |
| Factors Affecting Thickness | - Water Depth: Higher water levels create more pressure, requiring thicker walls - Longest Side: Thicker walls are needed if the tank has a larger width or length dimension to withstand bending - Material Strength: Stronger materials handle higher pressures with less thickness |
| Common Materials | - Steel: Used in large industrial tanks for strength - Concrete: Suitable for very large tanks due to durability and affordability - Polyethylene: Common in smaller, residential, or transportable tanks - Fiberglass: Resistant to corrosion, ideal for chemical or saltwater storage |
| Allowable Stress of Materials | - Steel: 12,000 to 20,000 psi, depending on grade and temperature - Concrete: Around 3,000 to 6,000 psi, generally lower than steel - Polyethylene: Typically around 2,500 to 4,000 psi - Fiberglass: Ranges from 4,000 to 10,000 psi, depending on specific formulation |
| Corrosion Allowance | Additional thickness is often added to account for corrosion over time, especially for steel tanks. This allowance usually ranges from one-sixteenth to one-fourth inch |
| Safety Factor | A safety factor is applied to ensure the tank can handle unexpected loads or environmental factors. Commonly ranges from 1.5 to 4, based on industry requirements |
| Temperature Effects | Higher temperatures can reduce material strength, especially in plastics and metals, and may require additional wall thickness for safety |
| Bracing Requirements | Large rectangular tanks may require internal bracing to reduce wall bowing under pressure. Bracing helps support the walls and distribute load evenly |
| Industry Standards and Codes | - ASME Boiler and Pressure Vessel Code (for large industrial tanks) - API Standards for oil, gas, and chemical storage - EN 13445 for European pressure vessel design |
| Testing Requirements | - Hydrostatic Testing: Filling the tank with water to test structural integrity under pressure - Nondestructive Testing: Using ultrasonic, radiographic, or magnetic particle inspection to detect wall defects |
| Maintenance and Inspection | Routine inspections help identify early signs of corrosion, fatigue, or structural weakness. Common methods include visual inspection, ultrasonic wall thickness measurements, and hydrostatic testing |
| Applications of Rectangular Tanks | - Water Storage: Used in residential, commercial, and industrial facilities - Chemical Storage: Especially when paired with materials like fiberglass or polyethylene to resist corrosion - Process Tanks: Common in wastewater treatment and other industrial processes |
Example Calculation for Wall Thickness
For a rectangular tank with:
- Water height of 72 inches
- Longest side of 48 inches
- Material allowable stress of 10,000 psi for polyethylene
Using the wall thickness formula:
- Calculate pressure as water height times density of water times gravity, resulting in approximately 2.6 psi.
- Required wall thickness will then be approximately 0.012 inches.