What is the primary requirement for aerial line markers?

The primary requirement for aerial line markers is that they must be visible from the air. This is essential because aerial patrols often monitor pipelines from aircraft, and the markers need to be identifiable from these heights to ensure that pilots can easily spot them. Their visibility aids in the quick identification of pipeline routes, facilitating effective monitoring and maintenance.

While durability and weather-resistance are important qualities for the markers to maintain their functionality over time, and brightness or reflectiveness can enhance visibility under certain conditions, none of these factors surpass the fundamental necessity for the markers to be distinctly noticeable from the air. The ultimate goal is to allow for efficient and safe aerial inspections, making visibility the top priority.