Safety Trained Supervisor (STS) Practice Exam 2025 – Comprehensive Prep Guide

A personal fall arrest system (PFAS) is designed to safely stop a person from falling when working at heights. A fully body harness is an essential component because it distributes the impact forces across the body in the event of a fall, preventing injury.

The lifeline plays a critical role as it is a connecting element that attaches the harness to a secure anchorage point. This means it must be anchored to a reliable structure that can carry the expected load, ensuring that in the event of a fall, the fall arrest system functions properly to catch the worker before they reach the ground.

While the other options involve components related to fall safety, they do not adequately define a personal fall arrest system. For example, a harness and cable attached to the ground might not provide adequate protection if a fall occurs, as it lacks the necessary anchorage points and could lead to more dangerous situations. Safety nets serve a purpose but are not classified under personal fall arrest systems; they are more of a passive fall protection measure. Ropes tied to surrounding structures may not have the required strength or stability, and this setup can introduce fall hazards due to improper securing or insufficient load-bearing capabilities.

Hence, the combination of a full body harness and lifeline connected to secure anchorage