Which of the following is a building code?

The International Building Code (IBC) is a comprehensive set of regulations that governs the design and construction of buildings. It establishes minimum standards for safety, health, accessibility, and energy efficiency, ensuring that structures are safe for occupants and the general public. The IBC is widely adopted across many jurisdictions, providing uniformity in building practices and facilitating compliance with safety regulations.

In contrast, the other options—UL (Underwriters Laboratories), ANSI (American National Standards Institute), and ISO (International Organization for Standardization)—serve different purposes in the realm of standards and safety but do not function specifically as building codes. UL focuses on safety testing and certification for products, ANSI oversees the development of consensus standards for various industries, and ISO establishes international quality and safety standards across different sectors. Therefore, the IBC stands out as the specific document that addresses and regulates building safety and construction practices, making it the correct answer in this context.