 | ||||||||||||||||||||||||||||||||||||||||||||
|
||||||||||||||||||||||||||||||||||||||||||||
|
A Look at Auto-Darkening Welding Helmets, Eye ProtectionPosted 1/8/2002By Jim Harris
Welding helmets are one of the most common accessories in welding. Let's face it, you can't weld without one - or without at least some type of protective eye shield. But what types of questions should you be asking as you are looking for your next helmet? Below are some of the most common.
 To make the right choice in selecting a helmet, it is important to understand the meaning of arc flash and what types of emissions radiate from the welding arc. Arc flash is simply the unexpected exposure of the eyes to the welding arc. The welding arc emits several forms of light including ultraviolet (UV), infrared (IR) radiation and high-intensity visible light. Both IR and UV radiation can cause permanent damage - such as retinal burns - to the eyes. While high-intensity visible light may not cause permanent eye damage, it may leave the operator with temporary discomfort, similar to being exposed to the flash of a camera bulb. All helmets that comply with the current ANSI Z87.1 standard (when in the proper down position) always protect operators from the harmful UV and IR damaging elements of the arc.
Therefore, when selecting a helmet, the first thing to look for is that the helmet is certified by the manufacturer to comply with ANSI standard Z87.1. Look for labeling on the auto-darkening cartridge to confirm that the helmet does indeed comply with this standard.
 Many people mistakenly think the lens shade number corresponds to the amount of protection provided to the eyes and hence the higher the number, the better the protection. But in reality, since all helmets that comply with ANSI standards filter out a vast majority of the harmful UV and IR emissions to protect the eyes, the choice is simply a matter of comfort. The shade number just denotes the level of shading provided by that particular lens and should be used by operators as a guide to select the one that is most comfortable and yet provides good visibility for the particular application.
Of course, there are some suggested lens shade numbers you can use as a guide if you are unsure what to select for your application. These correspond with the amperage being welded (see shade chart, Figure 1). Always select a shade that allows you to see the weld puddle clearly and that most aids your welding ability.
No. Again, all helmets that comply with the current ANSI Z87.1 standard (when in the proper down position) always protect operators from the harmful UV and IR emissions from the arc. This protection occurs whether the lens is darkened or not. However, the faster the helmet darkens, the more likely it is to prevent discomfort from the high-intensity visible light. Less than a millisecond in response time is not perceivable by the human eye and will provide the most comfort. Look for a helmet that has a response darkening time of a millisecond or less.
Remember: All auto-darkening helmets that comply with the ANSI standard for helmets, whether battery- or solar-powered, protect the operator from damaging UV and IR radiation even when they are not darkened.
However, solar-powered helmets offer the following advantages:
If you are always using the same arc welding process on the same material, a fixed shade is sufficient. But if - like most welders - you are welding using a variety of processes, amperages or materials, your best bet is a variable shade helmet, which can be adjusted to the correct shade level for your particular need. For instance, when you are GTAW (TIG) welding at lower amperages, you may need to lighten up the lens to see what you are doing. A variable shade will permit this while a fixed shade will not.
Besides looking for something lightweight, you may want to find a helmet that has a sensor bar. With this feature, it will limit the peripheral field of response so the helmet won't be triggered by the person welding next to you. A helmet that has a curved, rather than a flat, clear spatter shield over the optics will provide the best optical clarity so you can see what you are welding. In addition, a helmet that is fully adjustable to your head and body type is important.
Consider tilt of the helmet to the chest and the location or closeness of the helmet to the face, especially for those who wear glasses. Lastly, look for a reputable manufacturer and consider its warranty and availability of replacement parts. So, in summary, auto-darkening helmets can be a benefit for novices first learning to weld - as well as experienced professionals. Many models are currently on the market from a variety of manufacturers. However, armed with the guidelines discussed above, you should be able to make an informed decision when purchasing. Look for the ANSI label. Then, make your selection - based on optical clarity; comfort or adjustability; convenience and features; and the presence of a reliable, reputable helmet supplier.
|
|||||||||||||||||||||||||||||||||||||||||||
Copyright (c) 1996-2008. Automotive Service Association. All rights reserved.
| ||||||||||||||||||||||||||||||||||||||||||||
