How to Identify Cast Iron and Ductile Iron Pipe

When ductile iron pipe was introduced into the marketplace in the late 1950s, it was destined to supplant cast iron pipe as the pipe of preference for many utilities. However, there was a time when both pipes were available, which has resulted in some difficulty in identifying which pipe was which, today. While cast iron and ductile iron pipe are similar, there are significant differences in physical properties and failure modes that differentiate the two. For proper asset management, it is important that the iron pipe in a system be correctly identified. If performance data are incorrectly attributed to the wrong pipe material, it will result in inaccurate analyses leading to potentially flawed planning decisions. This paper provides information that will be useful in the effort to correctly identify cast and ductile iron pipes in service.