Basic Math for Plumbing - Free Printable

The image illustrates the relationship between water column height and pressure in pounds per square inch (PSI). It shows how pressure increases with the height of a water column, based on the principle that hydrostatic pressure depends on the height of the fluid.

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🔍 Key Concept:

1 PSI = 2.31 feet of water column
Or equivalently:
> 1 foot (12 inches) of water exerts 0.433 PSI

This is because:
- Water weighs approximately 62.4 pounds per cubic foot
- So, a column of water 1 foot high and 1 square inch in cross-section weighs 0.433 pounds, which creates 0.433 PSI of pressure at the base.

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📊 Breakdown of the Diagram:

#### 1. First Column (12" height):
- Height: 12 inches (1 foot)
- Pressure: 0.433 PSI
- This matches the known fact:
> 12" of water → 0.433 PSI

✔ Correct.

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#### 2. Second Column (24" height):
- Height: 24 inches = 2 feet
- Since pressure is directly proportional to height:
- 12" → 0.433 PSI
- 24" → 2 × 0.433 = 0.866 PSI

✔️ The gauge shows 0.866 PSI — this is correct.

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#### 3. Third Column (36" height):
- Height: 36 inches = 3 feet
- Pressure = 3 × 0.433 = 1.299 PSI ≈ 1.30 PSI

✔️ The gauge shows 1.30 PSI — this is also correct.

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✔ Final Answer:

The diagram correctly demonstrates that:
> Pressure (PSI) = (Height in inches) × (0.433 PSI per 12 inches)

So:
- 12" → 0.433 PSI
- 24" → 0.866 PSI
- 36" → 1.30 PSI

All values are accurate.

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💡 Summary:

This visual teaches that:
- Each additional 12 inches of water adds 0.433 PSI
- Pressure increases linearly with depth
- This is critical in plumbing, hydraulics, and HVAC systems for calculating static pressure

✔ The solution is correct.