Red Seal Boilermaker Practice Exam

What defines a pressure vessel?

1. A container that holds liquids only at atmospheric pressure

2. A container designed to hold gases or liquids at high pressures

3. A device that only allows steam to escape

4. A structure that receives thermal energy from heating elements

The correct answer is: A container designed to hold gases or liquids at high pressures

A pressure vessel is defined as a container specifically designed to hold liquids or gases at pressures significantly different from the ambient atmospheric pressure. The critical factor here is the vessel's capability to safely contain fluids under high pressure, which can involve both liquids and gases. This definition encompasses various applications, such as in industrial processes, where the containment of pressurized fluids is essential for safety and efficiency. While containers that hold liquids at atmospheric pressure are not classified as pressure vessels, and devices that allow steam to escape or structures merely receiving thermal energy do not inherently indicate pressure containment, the defining characteristic of a pressure vessel is its structural integrity and engineering features that enable it to endure the stress and potential hazards associated with high-pressure operation. Therefore, the option that states a container designed to hold gases or liquids at high pressures is the most accurate interpretation of what constitutes a pressure vessel.