MCC-NH Gas Fitters Practice Exam

When installing gas pipe inside a larger pipe, what must be prevented?

1. Gas leaks

2. Water accumulation

3. Trapping gas

4. Corrosion

The correct answer is: Trapping gas

When installing gas pipe inside a larger pipe, it is crucial to prevent the trapping of gas. Trapped gas within the annular space can create dangerous situations, such as increased pressure that could lead to a rupture or a leak. Ensuring that gas can escape freely is essential for safety and functionality. This is particularly important because gas can accumulate and create an explosive atmosphere if it is not allowed to vent or if it gets trapped in an enclosure where it has no escape route. While preventing gas leaks is certainly important in any gas installation, the specific concern with gas pipes installed within larger pipes highlights the risks associated with gas trapping. Similarly, while water accumulation and corrosion are valid considerations in the context of gas installations, they do not directly relate to the concerns surrounding trapping gas in the context of this question. Proper ventilation and installation practices are critical to ensuring gas pipelines operate safely without the risk of entrapment or buildup within the outer pipe.