Under what condition must feasible engineering or administrative controls be considered mandatory?

The requirement for implementing feasible engineering or administrative controls becomes mandatory when the 8-hour Time Weighted Average (TWA) noise level reaches 90 dB(A) or above. This threshold is significant because exposure to noise levels at or above this level can lead to permanent hearing loss and other hearing-related issues.

When the TWA is at or over 90 dB(A), it indicates that the noise levels in the work environment pose a substantial risk to employees' auditory health. Therefore, to enhance workplace safety and protect hearing, engineering controls, such as sound insulation or barriers, and administrative controls, like job rotation or limiting exposure time, must be adopted actively.

This practice aligns with guidelines and regulations designed to minimize the impacts of occupational noise exposure, reflecting a proactive approach to safeguarding workers' health. Thus, it is crucial to implement these controls when noise levels are at or exceed the 90 dB(A) threshold to ensure compliance with health and safety standards.