A tank's specific gravity (SG) rating indicates its capacity to safely contain materials denser than water. It's a measure of the maximum density a tank can handle.
Here's a breakdown:
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Definition: Specific gravity is the ratio of a substance's density to the density of water (which is 1 g/cm³ or 62.4 lb/ft³ at standard conditions). A tank's specific gravity rating represents the highest density of liquid the tank is designed to hold safely.
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Why it Matters: A tank rated for a specific gravity of 1.0 can hold liquids with the same density as water. A tank rated for 1.5 can hold liquids 50% denser than water. Exceeding a tank's SG rating can lead to tank failure, leaks, and potential environmental hazards.
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How it Works: Tank manufacturers design tanks with varying wall thicknesses and structural support to withstand the hydrostatic pressure exerted by the liquid inside. Higher specific gravity liquids exert more pressure. Therefore, tanks designed for higher specific gravities are built stronger.
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Common Ratings: Tanks are commonly manufactured with specific gravity ratings ranging from 1.0 to 1.9 or higher. The required SG rating depends on the specific liquid intended for storage.
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Example:
- A tank with a specific gravity rating of 1.2 can safely hold a chemical solution that is 20% denser than water.
- If you have a liquid with a specific gravity of 1.6 and a tank rated at 1.4, you cannot safely store the liquid in that tank. You need a tank with a rating of 1.6 or higher.
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Considerations: Besides specific gravity, other factors like temperature, chemical compatibility, and external forces must also be considered when selecting a tank. Always consult with a qualified engineer or the tank manufacturer to ensure safe and appropriate tank selection for your application.
In short, tank specific gravity is a critical specification reflecting the maximum density of liquid a tank is designed to safely contain, directly impacting its structural integrity and suitability for storing various substances.
