Even i had the same problem at our data centre.. i feel 80db as suggested by many of them should be good... i used it for sometimes. thanks. will wait for any other solution too
I sometimes use earplugs. Not all DC's that I work in offer them though I always have them with me. But some dc's just make less noise than others I use them 2/3 of the time.
Our HES Manager requested that we install a box of disposable ear plugs and suggested that we wear them if we are in there for prolonged periods. Our new data centre is much smaller and rarely exceeds 75db; however if we experience an AC issue and the server fans kick into high gear i am sure that it is closer to 90db.