What criteria must a material meet to be recognized as insulation?

To be recognized as insulation, a material must meet specific performance and safety-related criteria as stipulated by building codes. The correct answer highlights that the insulation material must be made from materials recognized by the relevant code, ensuring that it meets safety standards and effectiveness in thermal resistance. Additionally, proper thickness is vital as it directly influences the material's insulating capability, ensuring it can effectively reduce heat transfer and improve energy efficiency in buildings.

This emphasis on recognized materials ensures that the insulation will perform as intended, providing adequate thermal protection. Proper thickness is equally crucial because insulation that is too thin may fail to provide the necessary thermal barrier, while excessively thick insulation can lead to unnecessary costs and weight. Therefore, adherence to these criteria ensures that the insulation used is both safe and effective in its application.