VERIFY THE QUALITY OF AUTO DARKENING FILTER LENSES

In our last post we talked about the need to separate welding helmets with ADF's from the leading helmet manufacturers from those being imported by welding machine manufacturers, welding supply distributors and Internet Marketers. In this post we will talk about what to look for in an ADF to verify that it is a top quality filter lens with certification from the leading certification bureaus in the world.

The first place to look to determine and confirm the quality of an ADF is the markings on the lens. The first marking, moving left to right, confirms the selectable shade range. The next marking is the most important. It confirms the optical quality ratings according to the EN 379 Standard. The third marking is the DIN Plus designation confirming that the ADF has been tested by a third party testing agency. These verifications of quality are a must if you only want to invest in a ADF that will increase welder safety and comfort, improve productivity and increase profitability.

The Standards situation is more complex with ADF's than it is with any other PPE product. A detailed explanation is beyond the scope of a blog post. But in summary, there are ANSI and CSA Standards for ADF's but they are not as rigorous and complete as the European Standards. EN 379 is the recognized standard worldwide for ADF quality. Understanding that optical quality must be maximized, EN 379 sets high performance requirements in the four primary factors that determine ADF optical quality.

Those factors are:

• Spherical, astigmatic and prismatic refractive powers (optical quality)
• Diffusion of light (scattering)
• Variations in luminous transmittance (homogeneity)
• Angle dependence of luminous transmittance (angular dependence).

The first statements are the official, scientific terms of the standard. The comments in parentheses are the more common terms for them. In layman's language, they measure the optical clarity (absence of hazing and other visual defects) of the ADF in both the light and dark stages, the quality of visual definition (lack of distortion), how clearly the arc can be seen in low light conditions, angular dependency (the ability to retain shading when viewing at an angle), and the over all optical quality of the lens.

Each property can be marked from 1 to 3, with 1 exceeding the highest requirement and 3 the minimum still acceptable. ADF's with results over 3 do not pass the tests and cannot acquire the CE and other European certificates and therefore should not be considered.

While all of the measures of optical quality are important when selecting an ADF lens, perhaps the most important is angular dependency. It was an option in the EN 379 Standard until 2009 when it was made mandatory. The truth of the matter is most of the major welding helmets with ADF's do well in the first 3 measures of optical quality. But most of them struggle with angular dependency.

Angular dependency measures the shade level not only perpendicularly through the ADF, but also at slant angles. Most ADF's show a significant decrease in shade level at angles larger than 10 degrees. The welder’s viewing angle through a helmet equipped with an ADF is about +/- 30 degrees, so within this angle range it is necessary to provide as little shade level variation as possible. Most brands available on the market vary up to 3-4 shade levels within +/- 30 degrees. That is quite annoying for a welder and although it does not directly affect eye safety, it adversely affects welders working comfort, causing eye fatigue because of constant adjustment of the eye’s iris to the shade level variations. If a welder tries to compensate by assuming uncomfortable working positions, neck and back pain can result.

New Angular Dependence Compensation (ADC) technology being marketed by Fibre-Metal by Honeywell in their High Performance ADC brand ADF's provides a solution with only up to one shade level variation within +/- 30 degrees of perpendicular viewing. It was achieved by new technology and a new design of the internal structure of the lens. It is the only ADFin the world to achieve a 1/1/1/1 EN 379 Standard rating for optical quality. The Fibre-Metal by Honeywell ADC series consists of the ADC model with an EN 379 optical quality rating of 1/1/1/2 and the ADC Plus model with a 1/1/1/1 optical quality rating.

The DIN mark is important on an ADF lens because it confirms the performance to standards ratings. DIN Certo functions much like SEI (Safety Equipment Institute) does in the United States. An ADF manufacturer can submit a sample to CE to have it tested and can use the CE mark if it passes. But DIN Certo goes way beyond like SEI. They require an audit of the manufacturer’s production premises. They randomly select from production the required number of units of the model being tested and tests them in their test laboratories. All selected samples are tested and all samples have to pass all the tests. A single failure to comply with the standard results in not issuing the DIN certificate.

Once the ADF passes the tests, a retest will follow after one year and when the second test is successfully finished, another retest follows after 4 years. Such permanent monitoring of the manufacturer by the certifying body assures a much higher level of quality to the end user.

DIN Plus certification goes beyond DIN certification by requiring 2 times better results for all protective parameters and 3 times better results for switching speed. The ratings for optical quality, diffusion of light and homogeneity have to be 1/1/1 or at least 1/2/1 or 1/1//2. In addition, the manufacturer has to prove that it has all necessary testing equipment available on site. The correct functioning of the test equipment and production are checked on yearly basis by regular audits by DIN Certco

If you only want to invest in a top quality welding helmet with ADF lens,that you want to contribute to the success of your operation, consider only the major welding helmet manufactuers to begin with. Then take a close look at the ADF. Look for the EN 379 optical quality certification and optical quality ratings and the DIN and DIN Plus independent third party quality assurance markings. Look for the latestest ADF technology like ADC (Angular Dependency Compensation). Then and only then will you select an ADF that will return your investment many times over. Compare. Place various brands side by side and using the information presented here as a guide, see what brand offers what and accept nothing but the best.