BOCA Not Impressed To the Editor: I'd like to address the letter of Mr. Marcus S. Barnes ("Steep Stair Blues," 4/93) regarding BOCA's consideration of the 7-11 stair rule. First, any change to the BOCA National Codes is approved by a vote of the BOCA membership of practicing code officials, after public debate, and not by the directors of BOCA. Second, stair safety is the subject of ongoing investigation and consideration by BOCA, including a special committee established for precisely that purpose. Any information, including statistical reports, that Mr. Barnes or anyone else wishes to offer is welcome. The welcome includes participation in the discussion before the committee and the BOCA membership. Third, BOCA is not enamored with any particular symbol, nor are we impressed by