[mikeh]

I was told by a employer that an arc flash could travel farther in low light or dark conditions. After a power outage we had to wait for the lights to power up before welding because they worried about people getting flash burn(eyes). Do you think this is B.S. or not. If not could H.O. F. lights be used to disperse arc flash intensity.
Thanks

[weldin mike 27]

Hi there,

I havent heard about the arc rays traveling farther in low light, but i have heard that the have potential to cause more damage under these conditions. This, Im told, is because your pupils are open more in low light and therefore let in more harmful rays. Bs maybe?

Mick.

[delraydella]

It's not so much that the arc light will travel farther in the dark, it has more to do with the balance of light around the arc. The arc rays are going to travel the same distance in dark or light, but a brighter surrounding light will make the intensity of the arc seem less.

A high output light with a high Kelvin temperature lamp may help reduce arc light in the surrounding area, but never to a point where you wouldn't need some type of shielding.

[mikeh]

We aren't worried about the welders. We work in a high traffic area enclosed with weld curtains. Office, customers and other non-fabricators are in the regularly in the area or near the welders. We are adding lighting to the area and wanted to see if there would be a secondary safety benefit of minimizing arc flash to eyes of those passing by the area.
Thanks for any thoughts.

[jpence38]

The surrounding ambient lighting has nothing to do with the ultraviolet A and B rays emitted by a welding arc. Plain and simple, if you are in the area of a welding arc without eye protection you are asking for trouble. UV rays travel in straight lines and cannot go up and over welding curtains (they can be reflected), but if any of the actual arc (not the light emitted by the arc) is visible to the eye, you are burning the surface of the eye. Basically giving your eyeball a sun tan. Whether the room is lit up or completely dark makes no difference.
delraydella was right is saying a lighted room will reduce the intensity of the arc light, NOT the intensity of the UV rays emitted by the arc.