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2330 views
00:23 Apr-30-2009

David Harvey

Engineering
ATI - Wah Chang,
USA,
Joined Nov 2002
42
Visual inspection and tinted lenses

Hoping for some quick help here...

Our company's policy for years has been that visual inspectors are not allowed to wear tinted lenses, whether photosensitive or permanently tinted. Having just been challenged on this, I am trying to determine if this is an appropriate requirement, or just an antique "legacy" requirement that we could do without. Again, we are talking about visual inspection, of metals in flat or tubular shapes, often with a mirror finish, often with an as belt sanded or ground finish.

I appreciate your answers!

 
13:57 Apr-30-2009

Dent

Consultant, NDE Manager NDELevel III/3
NDT Consultant,
Canada,
Joined Nov 1998
247
Re: Visual inspection and tinted lenses In Reply to David Harvey at 00:23 Apr-30-2009 (Opening).

I can make a strong case that in bright sunlight conditions that polarized tinted lenses may be a mandatory requirement.

It really is case by case specific.

 
19:36 Apr-30-2009

Michel Couture

NDT Inspector,
consultant,
Canada,
Joined Sep 2006
818
Re: Visual inspection and tinted lenses In Reply to Dent at 13:57 Apr-30-2009 .

This would bring some relief if polarized lenses were accepted. Mind you I do believe seeing in a Boeing or Airbus spec that they allowed "yellow tinted" glasses for PT and MT inspection, but that was about 10 years ago. Don't quote me on that, I've been out of the aircraft industry for quite some time. I never used them myself, but I used to have a pair of those yellow glasses that I used to wear to drive at night and in the fog. What a difference!!!

The problem sometimes when allowing tinted glasses is that for some people they're never tinted enough. A little like what is being experienced with tinting of car windows. In Canada, the code says that a police officer still be able to see in the car, but I find often that is not the case. Yet no one has taught about coming with a measurement using a light meter where the distance would remain the same and a difference in light radiation would be the limit for the degree of tinting.

Maybe the same could be apply for safety glasses. After all, nothing means headache better than a chiny piece of steel in a nice July sunny afternoon.

Cheerio's

 
19:49 Apr-30-2009

Dent

Consultant, NDE Manager NDELevel III/3
NDT Consultant,
Canada,
Joined Nov 1998
247
Re: Visual inspection and tinted lenses In Reply to Michel Couture at 19:36 Apr-30-2009 .

Imagine working at a fabrication yard in Egypt. Bright sun reflecting off light sand and you are looking at welds. I'd want my polaroids for sure. Above deck on a ship mid day!
Lots of scenarios for this.

When you are in a mineshaft another story.

Case by case.

 
20:08 Apr-30-2009

Ed Ginzel

R & D, -
Materials Research Institute,
Canada,
Joined Nov 1998
1208
Re: Visual inspection and tinted lenses In Reply to David Harvey at 00:23 Apr-30-2009 (Opening).

David: I am not sure if it applies to your particular application with visual inspection but I am aware that there are some people that wear "isochrome" glasses (red tint) to allow them to have a colour vision. An associate of mine requires them to pass the colour vision requirements (Ishihara)

 
02:25 May-01-2009

Nick Welland

Other, Quality and NDT
Aben Technical Services,
Australia,
Joined Oct 1999
42
Re: Visual inspection and tinted lenses In Reply to Dent at 19:49 Apr-30-2009 .

Quite agree for visual it is case specific. AS3978 requires that visual acuity be J1 or equivalent, annual. No specific prohibition on tinted lenses, but there is a stipulation that lighting conditions must avoid glare, also to using diffusers on artificial light sources.
The main objection to darkened and automatic tinting lenses is when using UV; this is also where some standards recommend the yellow tint to help cut down the violet cast and glare, also to prevent eyeball fluorescence.
I agree that in harsh outdoor lighting conditions, every effort to reduce eye fatigue is desirable.

I have never encountered anyone testing for visual acuity when wearing tinted lenses. Since the wearing of these lenses alters the amount of light entering the eye, I would be interested to know the effect, since it might reduce visual acuity below that required. Does it? Any optometrists on NDTNet?

 
15:24 May-01-2009

Roger Duwe

NDT Inspector, API-510, 570, 653
MISTRAS,
USA,
Joined Jan 2009
148
Re: Visual inspection and tinted lenses In Reply to Nick Welland at 02:25 May-01-2009 .

An excellent, easy Field test for VT lighting has always been: Can you read the 1/32" or 1/64" graduations on your 6-inch ruler? Those graduations are printed/engraved approximately 0.005" wide. If those cannot be read, you certainly do not have the 100 Foot-Candles / 1000 Lux required for a Code VT exam. I would presume it you can read the scale wearing dark glasses, you would meet Code. You will have absolutely exhibited a visual acuity equal to or greater than J1.

 
15:58 May-06-2009

David Harvey

Engineering
ATI - Wah Chang,
USA,
Joined Nov 2002
42
Re: Visual inspection and tinted lenses In Reply to Nick Welland at 02:25 May-01-2009 .

I think the approach I will take will be to evaluate the tinted safety glasses using a light meter, thereby determining just how much light is transmitted. Using clear lenses as a control, we'll measure the amount of reduction in intensity caused by the lens, and place our restrictions based on that and our requirements for lighting versus what our inspection areas actually are.
Should be interesting, always seem to learn something unexpected in such experiments.

 


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