What type of pipe is not acceptable for a standpipe?

Ductile iron pipe is not acceptable for use in standpipe systems primarily due to its susceptibility to corrosion and the specific standards that guide fire protection systems. Unlike other materials that can handle the stresses and environment typically present in a standpipe application, ductile iron's corrosion issues can compromise the integrity of the piping over time, leading to system failures.

In contrast, galvanized steel pipe is often approved for use in standpipe systems because it has a coating that helps resist corrosion. CPVC pipe is also used in certain applications for fire protection due to its lightweight nature and resistance to corrosion. Concrete pipe, while not commonly used in standard standpipe applications, can be acceptable in specific instances, particularly in larger infrastructure projects where its durability is a key factor.

Understanding the materials and their properties is crucial for ensuring the safety and effectiveness of fire protection systems.