What are the dimensions of mineral wool block available?

The dimensions of mineral wool block commonly available in the industry are indeed 12"-24" in width and 3' in length. Mineral wool, also known as rock wool, is a versatile insulation material used in a variety of applications due to its excellent thermal and acoustic properties. The specified dimensions make it suitable for fitting into standard wall cavities and for various industrial applications.

This choice aligns with typical manufacturing standards, providing a product that is manageable and effective for insulation purposes, while also balancing considerations of material performance with ease of handling and installation. The other dimensions presented in the other choices do not correspond with the common industry standards often used in various building projects.