Jim,
Everyone who reads your blog should own and read Nuclear War Survival Skills, by Cresson H. Kearny. [It is available for free download in PDF, but be sure to also get an EMP-proof hard copy!] Chapter 6 deals with ventilation, lets the air out of assumptions about the subject (couldn’t help myself) and explains how to do it without electricity for when the Schumer really Hits The Fan. – R.J.W.
Sir:
For those planning to use the basement for a retreat, do not forget to test for Radon Gas, a carcinogenic found in many basements throughout the county. Here is a link about it. – Dr. A.W.