MCC-NH Gas Fitters Practice Exam

What type of piping can be used for gas service underground instead of black steel pipe?

1. Glass pipes

2. Copper only

3. Plastic, Polyethylene (PE), or Polyamide pipe

4. Concrete pipes

The correct answer is: Plastic, Polyethylene (PE), or Polyamide pipe

The correct answer is the use of plastic, specifically Polyethylene (PE) or Polyamide pipe, for gas service underground as an alternative to black steel pipe. These materials are specifically designed to handle the needs of gas distribution while also providing resistance to corrosion, which is a significant concern in underground applications. Polyethylene pipes are lightweight, flexible, and have a long service life, making them ideal for various underground installations. Moreover, the use of plastic piping aligns with regulations and standards set forth for safe and efficient gas delivery systems. These materials also allow for easier installation and can be joined using heat fusion techniques, which enhances the integrity of the joints in the piping system. In contrast, glass pipes do not possess the necessary durability and pressure ratings for gas distribution. Copper is typically restricted due to its higher cost and potential concerns with corrosion in certain environments. Concrete pipes are generally used for drainage applications rather than for gas service, as they are heavy and not designed to withstand the pressure and conditions associated with gas transport. Thus, the use of Polyethylene (PE) or Polyamide pipe underground is the preferred, safe, and effective choice for gas service installations.