Plastic flanges comply with which code?

The correct answer is ANSI (American National Standards Institute) because ANSI provides the standards for various materials and components used within piping systems. Plastic flanges, which are used in various applications, must meet specific performance and safety requirements to ensure reliability and compatibility with different piping systems. ANSI standards are often referenced to assure that products, including flanges, meet industry-recognized benchmarks for quality and performance.

The other options represent different types of standards and organizations. ISO (International Organization for Standardization) develops international standards but may not specifically address plastic flanges in the same way ANSI does. ASTM (American Society for Testing and Materials) focuses more on materials and testing standards but might not specifically cover the application of flanges. UL (Underwriters Laboratories) is mainly concerned with safety and certification of products but is not focused on piping standards like ANSI. Understanding these distinctions is crucial for anyone working with piping systems and materials safety.