Cylindrical storage tanks for general service: which roof shape is most commonly used?

Introduction / Context:
Fixed-roof cylindrical tanks store water, chemicals, and many non-volatile liquids. Roof geometry influences structural efficiency, drainage, and fabrication complexity. Among roof types, the conical (cone) roof is widely used for ambient-pressure tanks due to its simplicity and effectiveness.

Given Data / Assumptions:

• Atmospheric or low-pressure fixed-roof service.
• Typical field-erected steel tanks per industry standards.

Concept / Approach:
Conical roofs are easy to fabricate from plate segments, shed rain and snow effectively, and can be self-supporting or supported by rafters and columns. Dome roofs (spherical segments) are common for low-pressure or vapor-tight service but are more complex. Flat roofs are rare for outdoor storage due to drainage issues. “Umbrella” is a descriptive variant, not the standard default choice across industries.

Step-by-Step Solution:

Verification / Alternative check:
Vendor literature and tank construction standards consistently present conical roofs as the default for many ambient-pressure tanks.

Why Other Options Are Wrong:

• Dome: used, but not the most common across general services.
• Flat: drainage and ponding problems limit use.
• Umbrella: not a standard mainstream selection term.

Common Pitfalls:
Confusing floating roofs (for volatile hydrocarbons) with fixed roof types; floating roofs are a separate category.

Final Answer:
Cone (conical) roof