What characteristic is true about commercial pipe in terms of its sizing?

The correct characteristic of commercial pipe sizing is that it is made in standard sizes but with several different weights and thicknesses. This standardization is essential for ensuring compatibility and ease of installation in various applications. The range of weights and thicknesses allows for flexibility in choosing pipes that can withstand different pressure ratings and environmental conditions, while still fitting the same nominal sizes.

Standard pipe sizes make it simpler for engineers and contractors to work with materials that are readily available and widely understood in the industry. This also aids in ensuring that fittings and connections remain consistent across different installations, which is critical for maintaining system integrity and performance.

In contrast, the other options do not accurately reflect the characteristics of commercial pipes. For instance, having only large diameters limits utility in many applications, while custom fabrication, although available, generally pertains to specialized projects rather than standard commercial use. Additionally, the notion that pipes are only available in one thickness would restrict their versatility and practical applicability in various engineering scenarios.