§ 191. Wainscoting. Wainscoting in any stair or public hall shall be removed unless such wainscoting is backed against a fire-retarded wall or the stair or hall is equipped with a sprinkler system conforming to the provisions of section one hundred eighty-seven. Where wainscoting is removed in order to fire-retard a public hall or stair, such wainscoting may be replaced or additional wainscoting may be applied to make the surfaces of any new partitions or walls conform to existing partitions or walls provided such additional wainscoting is similarly backed with fire-retarded materials.