Which of the following is NOT a material change in elevator specifications?

Changing the color of the door does not affect the mechanical or operational capabilities of the elevator, nor does it influence safety or functionality. Material changes in elevator specifications typically involve alterations that could impact performance, structural integrity, or operational workflow.

Increasing the speed, relocating the machine room, or extending the travel are all changes that could significantly affect how the elevator operates, its installation requirements, and potentially its compliance with safety codes. These changes require careful consideration, planning, and often, regulatory approvals. In contrast, a simple aesthetic change, such as the color of the door, falls outside the scope of material changes, as it doesn't alter any of the elevator's essential functions or characteristics.