Hm I'm not sure, I haven't used it for that so I don't know. It's mostly designed so that you don't have to take them off for a quick interaction, so it's definitely not optimized for your use case. For example, the fan noise in our server room is at least partly in the frequency spectrum it lets through, so it's useless there.
Does it also work when the source of noise is a crowd? I'm near-deaf on one side, which has the side-effect of not being able to isolate voices.