Above-ground pressurized storage tanks are divided into what two categories?

• A. Medium-pressure and high-pressure
• B. Low-pressure and high-pressure
• C. Very high-pressure and atmospheric
• D. Vacuum and pressure

Answer: (B)

The key idea is that above-ground pressurized storage tanks are grouped by the pressure they’re built to hold: low-pressure versus high-pressure. Low-pressure vessels are designed for modest internal pressures and tend to use simpler safety devices, while high-pressure vessels withstand much greater pressures and require tougher construction and more robust relief systems. This classification matters because it shapes how a release behaves and what safety steps are needed; high-pressure releases can push gas out rapidly and require larger exclusion zones and more urgent response, whereas low-pressure releases tend to vent more gradually and may be managed with quicker isolation.

Other paired options don’t fit because they describe conditions or categories not used for classifying these tanks in typical hazmat practice—vacuum or atmospheric, for example, aren’t about pressurized storage in the same sense, and “very high” or a mix like “medium and high” aren’t standard distinctions for these vessels.