Visual examination- Any reference

[s. pratheep]

Dear expert, 

please review the screenshot above. Is it correct? If so, could someone please provide a reference? Article 9 of ASME Section V does not mention this. Can anyone confirm?

With regards

Pradeep 

[sridhar cn]

Dear Mr. Pradeep,

The statement is essentially correct. It is not a present Section V requirement but, it was in the earlier editions and is still preserved through 

cross-references in other ASME sections. The controlling clause is: ASME Section V– Article 9 (T-952  or T-953, depending on the edition).

Typical wording is edition-dependent and wording shift slightly between editions, which is why you may not see the exact sentence you

quoted in your copy.

·   Viewing distance: The VT shall be conducted at a distance not greater than 24 in. (600 mm)

·   Lighting: Illumination shall be sufficient to provide a minimum of 15 foot-candles (≈160 lux) for general examination and 50 foot-candles 

    (≈540 lux) for the detection of small discontinuities.

Later editions of Section V streamlined Article 9, removing some descriptive text. The same technical requirements are now referenced 

rather than repeated. Many construction codes restate the VT requirements directly. As a result, clients often quote VT requirements from:

·  Older Section V editions

·  Construction codes (Section VIII, IX, B31, etc.)

·  Employer/Owner VT procedures derived from Article 9.

For example, ISO 17637 explicitly states:

·  Viewing distance ≤ 600 mm

·  Minimum illumination:

160   lux (~15 fc) general

500 lux (~50 fc) for fine indications

This is why many VT procedures include exactly your quoted values. 

Best way to cite it in a procedure is:

Visual examination shall be performed in accordance with ASME Section V, Article 9. Illumination and viewing conditions shall comply with 

the requirements referenced therein (minimum 15 fc for general examination; 50 fc for detection of small discontinuities, and viewing distance

not exceeding 600 mm).

Trust it is clear.

rgds,

C Sridhar.

Virus-free.www.avg.com

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