ACGIH Threshold Limit Value for Upper Limb Localized Fatigue

Developed by: Dr. Thomas J. Armstrong, adapted from ACGIH (American Conference of Government Industrial Hygienists)

Description: An interactive webpage with background information and a way to control tasks to prevent upper arm fatigue. The assessment tool itself is on page 7 (ACGIH TLV button on the left); the rest of the links provide supporting information and examples. Users input either the duty cycle of a task or the expected effort (as a percentage of maximum effort) and the tool estimates the other. The tool defines a duty cycle as the percentage of total time applying a force or a work-rest ratio.

The recommended duty cycle (for a given effort) or maximum effort (for a given duty cycle) is a Threshold Limit Value (TLV), that represents the upper limit of what a person can safely expect to be able to. Tasks above the Threshold Limit Value are expected to cause an MSD or other injury. 

Keywords: fatigue, shoulder, elbow, wrist, upper arm, forearm, hand, muscle, duty cycle, effort, work-rest, tool, limit, TLV