Texas Compressed Natural Gas (CNG) Category 3 Practice Exam

Vertical supports for guardrails must be made of Schedule 40 steel pipe due to its strength and durability. Schedule 40 steel pipe is designed to withstand significant loads and resist bending or breaking under pressure, making it an ideal choice for supporting guardrails which must ensure safety in potentially hazardous environments. Its resistance to corrosion and physical damage adds to its longevity and reliability as a material for vertical supports.

While aluminum and wood may have some structural integrity, they do not provide the same level of strength and durability required for guardrails as Schedule 40 steel pipe does. Aluminum, though lightweight and resistant to corrosion, may not bear heavy loads effectively. Wood, while readily available, can decay or deteriorate over time, compromising the structural integrity needed for guardrails. Fiber glass, while strong and corrosion-resistant, is generally not as widely used or specified in the construction of guardrail supports compared to steel piping options. Thus, Schedule 40 steel pipe stands out as the appropriate material of choice for vertical supports in guardrail systems.