Final answer:
Personnel exposed to noise levels over 104 dba are required to wear both earplugs and muffs for optimal hearing protection, considering the recommendations not to exceed 85 dB for prolonged periods and the risk of immediate hearing damage in extremely loud environments.
Step-by-step explanation:
Personnel who work in areas where noises are greater than 104 dba are required to wear both earplugs and muffs for hearing protection. According to various government agencies and health-related professional associations, it is recommended that 85 dB not be exceeded for 8-hour daily exposures in the absence of hearing protection. Sound intensities of 80 dB and above can damage hearing over time, and utilizing a combination of hearing protection devices such as earplugs and earmuffs provides a greater degree of protection than either alone.
This is especially critical in extremely loud environments, such as those exceeding 104 dBA, where immediate damage to hearing can occur without proper protection. In such situations, it is essential to limit exposure time and increase the distance from the noise source, along with wearing the dual protection of earplugs and earmuffs to best preserve hearing health.