What is the required outside diameter of grab bars with circular cross sections?

The required outside diameter of grab bars with circular cross sections being between 1-1/4 inches to 2 inches is based on safety and usability standards that ensure the bars are both comfortable to grip and effective in providing support. This diameter range allows for a secure grip for most individuals, including those who may have limited hand strength or dexterity. If the diameter is too small, such as 1 inch, it might not provide sufficient grip for users, potentially leading to slips or falls. Conversely, a diameter that is too large, like 2-1/2 inches or 3 inches, can also make it challenging for users to grasp the bar securely. Therefore, the specified range strikes an optimal balance between safety and functionality, thereby making it the correct answer.