Which of the following is not a standard confined space class?

• A. Class A
• B. Class B
• C. Class C
• D. Class D

Answer: (D)

The idea being tested is how confined-space safety is organized through standard classifications. In this framework, there are three recognized classes used to signal the level of hazard and the controls required for entry, such as atmospheric testing, ventilation, PPE, and rescue planning. A label beyond those three isn’t part of the standard system, so it doesn’t correspond to an established set of safety requirements. When a space is described using a nonstandard label, you should treat it as needing a thorough hazard assessment and apply the permit-required confined-space procedures, using site-specific safety rules until a formal classification is determined. If you’re ever unsure, always refer to your employer’s safety manual or relevant regulations for the exact classifications used locally.