When conducting a close interval survey, the reference cell should be __________.

Placing the reference cell directly above the pipeline being surveyed ensures that accurate measurements of the pipeline’s potential can be obtained during a close interval survey. This positioning enables effective detection of localized corrosion potentials and ensures that the readings reflect the actual conditions of the pipeline at that specific point.

By having the reference cell directly in line with the pipeline, the influences of external factors on the readings are minimized, leading to more reliable data. This helps in identifying areas that may require attention in terms of corrosion control or monitoring, which is crucial in maintaining the integrity of pipeline systems.

Other options may involve disconnecting important components or positioning things incorrectly, which could distort the readings and result in less effective assessment of the pipeline’s condition. Proper placement of the reference cell is fundamental for achieving the technical objectives of a close interval survey.