I asked one of my county's building inspector: what is the reference when people say "the code specifies......"? He told me this was a reference to IRC 2000 edition.

I got on the web and apparently IRC is an acronym for International Residential Construction. I found 2000, 2003 & (soon to be released) 2006 editions.

I am puzzled why he recommended an "old" version.....maybe he knew that there was no updates after 2000, i.e., the publisher was low on inventory and produced books in 2003 &2006; but, the information is the same as the 2000 edition?