I'm back with another question this time about welding lens safety and z87.1 standard. I am curious as the information
doesn't seem to be talked about too much in my brief searching and the spec seems to be hidden from the user behind a pay wall. I doubt people read that stuff for fun but I was curious so I dove to section 10 which is the welding section. Note: I only could find the 2003 version which clearly replaced by the 2015 spec which cost $60 so no thanks.
Impact resistance is a large part of the spec which is great, I am glad to know I am protected. I am mainly interested in the UV/IR protection in the standard.
Page 43 in the pdf linked below specifies the near and far maximum UV/IR allowance. This is particularly interesting as this is what ruins our eyes.
First off does anyone know how they came up with these numbers? Is this just the side effect of what their best possible results from testing? Section 14 is how they test it, but it doesn't specify why the numbers are acceptable.
Second, it specifies as shade increases it blocks more UV radiation. Why is that the case? Does this have to do with the way they manufacturer filtering media in 2003? Is this true for modern lenses? Does this mean that safety glasses offer far less protection than shade 10 lenses for compliance to be met, even if a mfg does a better job.
For a shade 10 near UV avg allowance is 0.0023% where far max is UV is 0.001. That seems great right 99.9% on the box right?
Third: It also specifies ADF switching speeds. Have there been studies on what speeds allow more light that they should? Obviously faster is better to allow less light in, however even between the top manufacterers the numbers are greatly different. For example the Lincoln 4C ADF markets 1/25000s (0.00004) where speedglass 9100xxi 1/10000 (0.0001). That's a big difference, does it actually matter though? They are both way beyond what the z87.1 spec says in 2003.
Forth: In section 10.13: Cover lenses do not need to follow anything in the specification.
That's fine as long as your welding lens is z87.1+, however do many manufacturers comply anyways with z87+ for their cover lens. I'll have to check my replacements as I'm not in the shop, but doubling down on UV protection sounds ideal. Do mfgs use safety glasses material for outer lenses so they are blocking UV as well?
This is probably quite a rant at this point but I'm mostly just curious, and I sure that I am not alone. We all love our eyes (I hope) so it's probably a good thing to understand what all this stuff really means and to keep an eye out for it when purchasing PPE.
Documents for reference:
Z87.1 2003: http://buildingsaferinri.org/wp-content ... 1.2003.pdf
Speedglass Marketing: http://multimedia.3m.com/mws/media/8162 ... 01248e.pdf
Lincoln Marketing: https://m.lincolnelectric.com/assets/gl ... mc1828.pdf
