Most datacenters should have racks with soundproofing and soundproofed offices away from the datacenter floor. When working within noisy rooms, the general rule of thumb is to always wear hearing protection to limit exposure to noise.
The Health and Safety manager should have a meter to test the ambient volume. In cases with an average of 75 dB, and a peak of 79 guidance suggests that protection is not needed unless the individual is spending long periods of time (30 plus minutes) in the main area of maximum noise. Past 82 dB protection is mandatory.
Ear plug dispensers should be kept around the entrances and the company should provide an annual checkup. Hearing tests as well as tests for colour-blindness must be made mandatory for all data center staff prior to employment.