(a) The load-bearing capacity of elements or assemblies shall be established by calculations in accordance with generally established principles of engineering design. However, when the composition or configuration of elements, assemblies, or details of structural members is such that calculations of their safe load-carrying capacity and basic structural integrity cannot be accurately determined in accordance with generally established principles of engineering design, structural properties of such members or assemblies may be established by the results of tests acceptable to the department.

If a manufacturer chooses to substantiate a design or method of construction by tests, the manufacturer shall contact the department prior to performing the tests to obtain information on testing criteria. If a department representative is required to witness the tests, the manufacturer shall be so notified.

(b) When any structural design or method of construction is substantiated by calculations and supporting data, such calculations and supporting data shall be signed by an architect or engineer and shall be submitted to the department.

(c) When the design of an earthquake resistant bracing system is substantiated by calculation or tests, all structural plans shall be signed by an architect or engineer in charge of the total design.

(d) When any design or method of construction is substantiated by tests, all test procedures and results shall be reviewed, evaluated, and signed by an architect or engineer.