Section 8-403 Interior Finish Materials
New non-historical interior wall and ceiling finishes shall conform to the provisions of the regular code. Existing non-conforming materials used in interior walls and finishes may be surfaced with an approved fire-retardant to increase the rating of the natural finish to within reasonable proximity of the required rating. For wood lath and plaster walls, see Section 8-404.
Exception: When an automatic sprinkler system is provided throughout the building, existing finishes shall be approved.