2018 International Building Code, Chapter 1 Scope and Administration, Section 104 Duties and Powers of Building Official
[A] 104.11 Alternative materials, design and methods of construction and equipment.
The provisions of this code are not intended to prevent the installation of any material or to prohibit any design or method of construction not specifically prescribed by this code, provided that any such alternative has been approved. An alternative material, design or method of construction shall be approved where the building official finds that the proposed design is satisfactory and complies with the intent of the provisions of this code, and that the material, method or work offered is, for the purpose intended, not less than the equivalent of that prescribed in this code in quality, strength, effectiveness, fire resistance, durability and safety. Where the alternative material, design or method of construction is not approved, the building official shall respond in writing, stating the reasons why the alternative was not approved.
2018 International Building Code, Chapter 2 Definitions, Section 201 General
[A] APPROVED SOURCE. An independent person, firm or corporation, approved by the building official, who is competent and experienced in the application of engineering principles to materials, methods or systems analyses.
DrJ Commentary: The "alternative to the code" approval process is generally created performed by "an independent person, firm or corporation who is competent and experienced in the application of engineering principles to materials, methods or systems analyses. The code definition of an "approved source" is identical to the definition of a registered design professional or professional engineer. These individuals are subject to professional licensing laws of the jurisdiction. Denial of a report or a design certified by registered design professional's seal, without providing the specific reasons for denial with details in writing, is superseding a registered design professional's commerce, which restrains trade. If the registered design professional is not competent to do the work, the competency issues need to be brought before the board of professional regulation. Please check with your jurisdiction's attorney for further information.