Access Door 2 : A fire door smaller than conventional doors which provides access to utility shafts, chases, manways, plumbing, and various other concealed spaces and equipment
Ralph W. Burklin & Robert G. Purington, Fire Terms: A Guide to Their Meaning and Use, National Protection Association, Boston, MA 1980 USA. (Guide: Meaning and Use, Nat Prot Association Fr Srvc - Amer) {457}