What is the minimum rating for tees, elbows, and unions used in underground steel piping?

The minimum rating for tees, elbows, and unions used in underground steel piping in Pennsylvania is 150/Pn 20 ASTM. This designation refers to the pressure rating of the fittings and their ability to withstand certain pressures.

This rating is crucial because underground piping systems are subject to various pressures from factors such as soil weight, water tables, and internal pressures from the liquid or vapor being contained. A rating of 150/Pn 20 signifies that these components can safely handle pressures up to a certain limit, ensuring that the infrastructure remains resilient and leak-free under typical operating conditions.

Selecting components with an appropriate pressure rating is essential for compliance with safety regulations and for maintaining the integrity of the underground storage tank system. It ensures that all fittings can robustly handle the stresses they will encounter, which is vital for preventing leaks and environmental contamination.