Which of the following is NOT a type of construction commonly recognized in fire protection?

In fire protection, construction types are categorized based on their materials and fire resistance properties. Types I, II, and V have recognized definitions within fire protection and building codes.

Type I construction refers to fire-resistive materials, typically involving reinforced concrete or steel, designed to offer extensive fire protection. Type II involves non-combustible materials but is less fire-resistant than Type I. Type V, on the other hand, includes wood frame construction, which is more susceptible to fire but is widespread in residential buildings.

Type IX does not exist within the standard classifications of construction types recognized by fire protection codes and standards. This absence indicates that it is not a valid classification, making it the correct choice as the answer to the question.