The 2009 and 2015 irc verbiage is similar and still applicable.
Attic access irc.
This is applicable to finished and unfinished spaces.
See section m1305 1 3 for access requirements where mechanical equipment is located in attics.
30 x 22 however irc m1305 1 3 regarding the attic passageway access not attic access is not as clear because it uses two different dimensions in relation to the term opening used twice in the same paragraph.
Bajnai chesterfield county va icc building code action committee revise as follows.
When the access is located in a ceiling minimum unobstructed headroom in the attic space shall be 30 inches 762 mm at some point above the access measured vertically from the bottom of ceiling framing members.
Buildings with combustible ceiling or roof construction shall have an attic access opening to attic areas that have a vertical height of 30 inches 762 mm or greater over an area of not less than 30 square feet 2 8 m 2 the vertical height shall be measured from the top of the ceiling framing members to the underside of the roof framing members.
Section r807 attic access r807 1 attic access.
Buildings with combustible ceiling or roof construction shall have an attic access.
Attics that meet the size and ceiling height criteria of the habitable attic definition in chapter 2 are considered habitable.
Irc 807 1 is clear to me with its dimensions for attic access.