I am a Safety Manager on a jobsite for a 7 story building that directly abuts three existing buildings. As we erect steel and decking, my concern is hospital employees being exposed to staring at the arc flash while our iron works work. I am working on providing documentation to the client that given the distance (closest distance is approx. 30 ft) and the fact that they are looking through a window that has some some low level of UV protection, we do not need to provide anything more than our standard welding screens around our larger "moment" welds.

But I don't know if the UV protection in the windows is enough. In all reality, no one is dumb enough to stare at an arc flash long enough to do damage to their retinas but unfortunately we are exposing ourselves to a lawsuit as long as the possibility is there. The AWS has a study on the distances at which the UVR becomes damaging to the eyes. The study helps but I need more. According to that study, if you expose your eyes to an Arc from a shielded metal stick weld for more than 10 minutes at a distance of 33ft, you will do damage. That study of course didn't include the factor of someone looking through a window. There's more info but that's my biggest exposure (30 feet) to worry about so I'm starting there.

The client is going a bit crazy with ideas from draping tarp over the whole side of the building to finding a welding screen-like film for all the windows. If that's actually whats necessary, i'll do it, but I don't think it.

So I'm not looking for ideas, I'm looking to see if anyone has any good documentation, study, experience, contacts (anything!) on the affect of looking at a flash through a standard double pane window (with some UV protection in the glass). Is the UV in the glass enough? Should they also be tinted to absorb more light?

Here is that document from the AWS: http://www.aws.org/technical/facts/FACT-26.pdf

By the way I called them but they didn't have much to offer aside from this.

Thanks in advance!!