Fresh air pipe in mechanical room – GreenBuildingAdvisor

I have recently purchased an older home, and there is a 10″ hard pipe running into my mech room from the exterior of the home. It is not connected to anything. I have been told that this fresh air pipe is for the combustion air of tank water heaters. I want to use the pipe to install an AprilAire ventilator as I work to tighten the envelope of my home.

My question is if this fresh air pipe is required, or if it was an old code requirement from the 90’s that I can remove? My water heaters are gas tank with b-vents.