This Guide describes a complete process for conducting field hardness testing to estimate the yield strength of pipeline steels. The process is non-destructive so it is suitable for in-situ testing on operating pipelines, at pipe storage facilities, or various other locations. It also allows for process variations that are suitable for application in different situations and conditions that may be encountered on a pipeline right-of-way and elsewhere. Field hardness testing is not a "one size fits all" methodology where a single hardness testing methodology is suitable for application in all situations that can be encountered.