Visual Testing Fundamentals Flashcards

What is the minimum illuminance level (in foot-candles) required for general visual inspection per ASME standards?

Answer: 50 fc

ASME standards require a minimum illuminance of 50 foot-candles (540 lux) for general visual inspection.

During remote visual inspection (RVI), which tool is best suited for inspecting internal bores of small-diameter tubing?

Answer: Rigid borescope

Rigid borescopes provide superior image quality and are ideal for straight, small-diameter bores where flexibility is not required.

What does the term 'depth of field' mean in the context of visual testing optics?

Answer: The range of distances over which objects appear acceptably sharp

Depth of field is the range of distances within which objects remain in acceptable focus without readjusting the optic.

Which discontinuity type is MOST likely to be missed during a direct visual inspection of a weld surface?

Answer: Subsurface lamination

Subsurface laminations are internal discontinuities not visible at the surface, making them undetectable by direct visual methods.

A pit gauge is used during visual testing primarily to measure:

Answer: The depth of a corrosion pit

A pit gauge (or depth gauge) is specifically designed to measure the depth of corrosion pits and similar surface depressions.

In visual testing, 'raking light' technique is most effective for detecting:

Answer: Surface roughness and shallow surface irregularities

Raking (oblique) light cast at a low angle creates shadows that highlight subtle surface irregularities and shallow discontinuities.

Which personal protective factor is MOST critical when performing visual inspection inside a confined space vessel?

Answer: Atmospheric testing and continuous air monitoring

Confined space entry requires atmospheric testing for toxic gases, oxygen deficiency, and flammable vapors before and during entry.