Section 6-1405 - Conflicts(a) If conflict arises between the provisions of this chapter and the D.C. Supplement, the Model Codes, or their reference standards, the provisions of this chapter shall take precedence.(b) If conflict arises between the D.C. Supplement, the Model Codes, and their reference standards: (1) The provisions of the D.C. Supplement shall take precedence over the Model Codes and their reference standards, except as provided in paragraphs (2) and (3) of this subsection;(2) The provisions of the BOCA Basic/National Existing Structures Code/1984, 1st Edition, and the CABO One and Two Family Dwelling Code, 1983 Edition, shall take precedence over the D.C. Supplement, other Model Codes, and their reference standards with regard to existing structures and Use Group R-4 buildings;(3) The most stringent provisions of the BOCA Basic/National Existing Structures Code/1984, 1st Edition or the CABO One and Two Family Dwelling Code, 1983 Edition, shall take precedence when a building is both an existing structure and in Use Group R-4;(4) The provisions of the 1985 Supplement to the BOCA Basic/National Building Code, Basic/National Fire Prevention Code, Basic/National Mechanical Code, and Basic/National Plumbing Code shall take precedence over the provisions of the other Model Codes that they amend; and(5) The provisions of the Model Codes other than their reference standards shall take precedence over their reference standards.Mar. 21, 1987, D.C. Law 6-216, § 6, 34 DCR 1072.