Why is cast iron steel pipe commonly used in many commercial buildings?

Cast iron pipe is commonly used in commercial buildings primarily due to its compatibility with building codes that often regulate the materials used for plumbing and drainage systems. These codes are designed to ensure safety, reliability, and longevity of the piping systems in structures that accommodate many occupants and various types of waste. Cast iron offers robust properties such as strength, durability, and resistance to fire and corrosion, making it a preferred choice that meets or exceeds the stringent requirements set by these codes.

The other options, while they may seem beneficial, do not reflect the primary reason for the widespread use of cast iron in commercial settings. For instance, while cost might be a consideration, it is often not the lowest option available. Lightweight and ease of installation are also not strengths of cast iron relative to other materials, which tends to favor plastic or other modern alternatives. Thus, the emphasis on compliance with building codes greatly justifies the prevalent choice of cast iron pipe in many commercial construction projects.