If the planks in sawn or glued-laminated plank floors in Type IV construction are a minimum of 3" in thickness, they must be covered with a flooring of:

In Type IV construction, which is commonly known as heavy timber construction, there are specific fire-resistance and structural integrity requirements that must be met. When the planks in sawn or glued-laminated floors are a minimum of 3 inches thick, the code provisions allow for the use of certain types of flooring materials to be applied over them as part of the system.

Both options of a 15/32" wood structural panel and 1/2" particleboard serve as acceptable coverings for this type of flooring. The wood structural panel is approved due to its strength and structural integrity, which helps maintain the load-bearing capacity of the assembly and contributes to fire-resistance. On the other hand, particleboard also fulfills the necessary criteria as a flooring material suitable for use in this context.

Thus, since both materials meet the requirements established by the building codes for Type IV construction when the underlying planks are of sufficient thickness, it is accurate to state that either can be used as a covering for the planks. Therefore, verifying the options points to the fact that either type fulfills the requirement, justifying why the answer encompasses both selections.