Under ASME Section V, Article 9, direct visual examination may normally be used when the eye can be placed within what distance of the surface, and at what minimum angle to it?
- 12 in. and 45 degrees
- 36 in. and 30 degrees
- 24 in. and 60 degrees
- 24 in. and 30 degrees
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D. 24 in. and 30 degrees
Article 9 treats access as adequate for direct viewing when the eye can be brought within 24 in. (600 mm) of the surface at an angle of not less than 30 degrees to it. Beyond that, or at flatter angles, remote aids are needed.
Reference: ASME BPVC Section V, Article 9, direct visual examination
What minimum light intensity at the examination surface does ASME Section V, Article 9 call for in direct visual examination?
- 20 footcandles (200 lux)
- 50 footcandles (500 lux)
- 100 footcandles (1000 lux)
- 200 footcandles (2000 lux)
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C. 100 footcandles (1000 lux)
Article 9 sets a minimum of 100 fc (1000 lux) at the surface for visual examination. Values such as 20 lux are limits on ambient white light during fluorescent penetrant or magnetic particle work, which is a different requirement.
Reference: ASME BPVC Section V, Article 9, lighting
What is the main advantage of a fiberscope over a rigid borescope?
- It can bend around corners
- It gives a much sharper image
- It needs no light source
- It reads depth directly
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A. It can bend around corners
A fiberscope carries the image through a flexible fibre bundle, so it can follow a curved path into piping or castings. A rigid borescope uses a lens train and usually gives the sharper image, which is the trade-off.
Reference: ASNT Level II VT study topic: remote visual equipment