What is the minimum length that the protective coating on vertical sections of underground steel gas pipe must extend above the finished grade?

The minimum length that the protective coating on vertical sections of underground steel gas pipe must extend above the finished grade is 2 inches. This requirement is crucial because it helps ensure that the protective coating serves its purpose effectively by preventing corrosion and damage to the steel pipe. The coating acts as a barrier against environmental factors such as moisture, salt, and chemicals found in the soil, which can accelerate corrosion. By specifying a minimum of 2 inches above grade, it ensures that the most vulnerable part of the pipe, where it exits the ground, is adequately protected and minimizes the risk of degradation over time.

This standard reflects best practices in the industry for maintaining the integrity and longevity of gas piping systems, aligning with safety regulations and ensuring reliable operation. The choice to set the height at 2 inches is likely based on practical experience and testing regarding the effectiveness of coatings and the likelihood of soil contact or degradation around that height. Understanding this requirement is essential for anyone involved in plumbing, especially when working with gas piping systems, as it emphasizes the importance of protective measures in hazardous environments.