What are the two categories of portable ladders?

The correct identification of the two categories of portable ladders as self-supporting and non-self-supporting is fundamental in understanding ladder safety and application.

Self-supporting ladders, such as step ladders, have a built-in support system that allows them to stand independently without any external support. They are typically designed for use in situations where a flat, stable surface is available. This type of ladder is particularly useful for indoor tasks or on stable ground, as users do not need to lean them against a wall or another structure.

Non-self-supporting ladders, like extension ladders, require support from a wall or another stable surface. These ladders are meant to reach greater heights and are extended and positioned against structures to provide the needed elevation. Understanding the distinctions between these two types ensures safe usage and helps workers choose the appropriate ladder for specific tasks, mitigating risks associated with improper ladder use.

The other options, while mentioning different characteristics of ladders, do not align with the primary functional categories recognized in occupational safety guidelines. Focusing on the functional categories aids in the safe and effective selection and use of ladders in construction and other environments.