The only Delta 60mm fan I could find with 30.05 cfm is the AFB0612VH model 60 x 60 x 25. thats the 12 volt model and it's rated at 39.5 dba. It spins at 5500 rpm. The famous Delta 38 is the same size but spins at 6800 rpm and flows 37.61 cfm at 46.5 dba. The Delta 38 is famous for being a screamer and I have one and it is!
It not that load compare to oh, say, a 747. Seriosely though, I forget about the noise myself and there are two running in a small room that I live in (dorm) and it doesn't bother me. There are some people who it does bother though, it comes to down to personal preference. If your talking for a heatsink I'd say try them, and if you don't like it then you can mount a 80mm fan in its place.