What is the most accurate dimension measured on pipe and tubing?

The most accurate dimension measured on pipe and tubing is the outside diameter. This is because the outside diameter is typically manufactured to precise specifications and is the dimension referenced in most industry standards and specifications. Manufacturers have stringent processes in place to ensure that the outside diameter is consistently accurate, as it plays a crucial role in determining the compatibility of pipes and fittings.

In many applications, the outside diameter allows for easier measurement compared to the other dimensions, especially in the context of fitting connections and the overall integrity of the piping system. While wall thickness and inside diameter are also important, they can be more subject to variability based on factors such as material and manufacturing methods, which can lead to variations in the measurements that are not as prevalent in the outside diameter.

Length is a critical measurement for installation purposes but is typically less critical than the outside diameter in the context of ensuring compatibility with other piping components.