Understanding Safety Goggles: How to Choose the Right DIN Shade for Your Needs

Understanding the Selection of Safety Goggles

Can anyone please help me clarify the concept of selecting safety goggles? Normally, the description comes with the product stating 4DIN, in a few 6DIN, and up to 11DIN shades. What exactly does the DIN shade convey? Which shade is suitable for specific purposes like welding, gas cutting, grinding operations, etc.? Are there any other factors we should consider when selecting safety goggles?

Regards,
Dipil Kumar V

Dear Dipil,

Understanding DIN in Safety Goggles

The DIN refers to the amount of light that can pass through the lens of the goggles. If it is 4, then the visibility range will be more transparent. As the value increases, its visibility level decreases and allows only the welding lights to be visible in its lens (not transparent).

For welding operations, 11 DIN would be best. For other operations, we need the proper visibility too. I don't know how to give you the correct value. 4 being the lowest (it is between 3 DIN to 14 DIN) and 11 being the highest of the shades commonly used.

Regards.

Dear Dipil,

I always appreciate the inquisitive nature of safety personnel. I consider it a privilege to impart whatever I have to help aspiring youngsters. What Mr. KVS has answered is correct. However, as safety professionals, we should be thorough, as I always say. Let us try with a little more information.

Understanding Lens Shade Numbers

It is not correct to think that the lens shade number corresponds to the amount of protection provided to the eyes. Because of this, many assume that by using a shield of a higher shade number, they get a higher level of protection. The fact is, all quality welding lenses filter out all the harmful ultraviolet (UV) and infrared (IR) wavelengths and provide perfect protection to the wearer. The shade number just denotes the amount of darkness provided by that particular shade lens. The shade number should be used by the welder only as a guide to select the one that most suits him, that he is comfortable with, and, of course, that provides him with good visibility for the work at hand. Shade numbers also correspond with the amperage being set for the welding.

If you are uncertain about what shade number to select for your work, there are some suggested lens shade numbers that you can use as a guide.

Protection Against UV, IR, and Visible Light

Remember there are Ultraviolet (UV), Infrared (IR), and high-intensity visible light to seek protection against. I will pose the question on hazards and protection against UV, IR, and high-intensity light in concluding this issue.

We will wait for more contributions, please.

Regards,

Kesava Pillai

Thanks for the great replies. I am looking forward to learning about the hazards and protection against UV, IR, and high-intensity light. I am still unclear about which activities require eye protection and which shade number to select for the respective eyewear. I hope that through more participation, we will come to the best conclusion.

Regards,
Dipil Kumar V

Dear All,

I have discussed the selection of Safety Goggles with one of the safety eyewear suppliers and received the following information:

Their product is made of Polycarbonate lens and has an exclusive scratch-resistant lens coating. It is available in clear and grey tints.

1. Clear Lens - Meant for applications requiring a clear view, such as for machine operators and applications where no optical filtering is necessary.

2. Grey Lens - Offers filtering of Visible Light up to 30% and 99% UV filtering.

3. Welding Lens DIN 5 - Intended for gas welding applications (gas output less than 40 lts/hr).

Regarding welding shade DIN 5, it can be used for gas and spot welding. Shade 11 is recommended for other welding processes.

I have also received the attached test certificate for the product.

Questions on Safety Goggles Selection

Can I recommend purchasing this product? Is a polycarbonate lens the right type for safety goggles? How can we utilize this test certificate for the selection of safety goggles? Are there any parameters missing in the test certificate that should be included for safety goggles?

The test certificate does not mention anything related to DIN. Should the DIN value be included in the test certificate?

I look forward to receiving solutions to my queries.

Regards,
Dipil Kumar V

Dear Dipil,

Understanding DIN Standards for Light Management Equipment

DIN is a European agency (German, I think) that sets standards for light sensing and light management equipment such as film, filters, photocells, etc. Their ratings are different from the standards set by the American Society of Testing and Materials (ASTM), which you would see referenced in OSHA and ANSI.

Generally, in terms of filter media, the number represents a ratio of the amount of light that is allowed to pass through the media - the higher the number, the darker the shade.

American Standards for Optical Grades

American standards follow a measure of optical grade - from 1.25 to 32. Some common optical grades:

- **Grade 3**: Used for very bright areas such as beaches, roofs, etc.
- **Grade 5**: Used for extremely bright areas such as snow, high altitudes. This grade is also the lowest grade used for oxyacetylene cutting and low-grade welding, such as a spot welder.
- **Grade 7**: Commonly used for oxyacetylene cutting, furnace inspections, boiler flame inspection.
- **Grades 10 - 14**: Specified for use for electrical arc welding, depending on factors like the size of the rod, arc voltage, length of exposure in an eight-hour workday, etc.
- **Grade 20**: Minimum recommended for momentary viewing directly at the Sun or at arc flash/plasma phenomena.

I do not have an ASTM/DIN conversion chart. The OSHA and EM385 regulations specify certain grades (American standard) for certain types of work or exposures.

Hope this helps...

Thanks & Besafe,

Raghu

Dear Dipil,

I had already made it clear that the shade numbers simply denote the amount of darkness provided by a particular lens. Thus, DIN 2-14 only indicates the darkness level of the lens and has no relevance to UV or IR protection. Depending on the user's eyesight, one may choose any shade—5, 14, or any other preference. There are no strict rules regarding this.

Polycarbonate is known for being hard and impact-resistant, nothing more. To achieve the same strength, glass lenses would need to be ten times thicker. You can test the durability of polycarbonate by using a 5 kg hammer and striking it on a flat surface—it will not break. You can even drive a sharp nail through the polycarbonate lens without it shattering. However, polycarbonate is not scratch-resistant; the coating provided is not very effective. Continuous rubbing with a cloth containing abrasive materials will cause scratches to develop.

The test certificate you possess holds no value as it lacks ownership. Certificates from reputable testing bodies like the National Physical Laboratory are the only acceptable ones. Some items are also tested by CLI.

Please specify your requirements. Where will the safety goggles be used, and what are the hazards you need protection against? Do you need safety glasses or safety goggles?

In most scenarios, safety glasses offer primary protection. In certain tasks like grinding or cutting, a face shield might also be necessary for secondary protection.

For impact protection, polycarbonate is the best choice.

The field of eye protection is vast, and detailing every aspect would require volumes.

For now, let's focus on meeting the current needs adequately.

Regards,
Kesava Pillai

Dear Sir, Thank you for your explanations. We require Safety Goggles for the following purposes:

- Gas Cutting
- Grinding
- Chipping
- General Purpose - For use in dusty atmospheres

Sir, could you please tell me what's the difference between safety glasses and safety goggles?

The test certificate attached by me was edited and does not reveal the identity. However, I believe there will be no issue in posting the original one which I received. Therefore, I am attaching the original one. It has been tested by CLI. Please let me know your comments on how we can effectively use such a test certificate in selecting goggles.

I have polycarbonate lenses and will conduct the experiment you mentioned. I will inform you of the results. Thank you for explaining in detail about the properties of polycarbonate. The supplier is promoting the product by saying it's scratch-resistant.

@ Raghu Thank you for your inputs on the thread. It will surely help.

Regards,
Dipil Kumar V

Dear Dipil, you need eye protection for gas cutting, grinding, chipping, and general purposes, whereas you obtained a test certificate from the supplier/manufacturer for chemical splash goggles.

Difference Between Safety Glasses and Safety Goggles

Regarding the difference between safety glasses and safety goggles, chemical splash goggles will not meet the requirements of eye protection for gas cutting, grinding, chipping, and general purposes. The certificate you obtained is specific to chemical splash goggles and does not apply to the aforementioned uses.

Safety glasses provide primary protection and should be used in conjunction with a face shield for activities such as grinding and chipping.

Contrary to common belief in the industry, safety glasses and safety goggles are not interchangeable. There are distinct differences between the two. While goggles are considered a type of safety glasses, safety glasses cannot replace safety goggles.

Safety goggles, similar to oversized safety glasses, have an extended protector that surrounds the glasses and connects to the cheek and brow. The lenses of both safety glasses and safety goggles are typically made from shatter-proof, heat-resistant plastic, glass, or polycarbonate. However, the method of securing them to your head differs significantly. Safety goggles are secured with an adjustable strap, ensuring a tighter fit compared to safety glasses.

Safety goggles offer complete protection from all angles, similar to ski goggles, making them ideal for situations where eyes could be exposed to sparks, liquid, or fragments from various directions. On the other hand, safety glasses rely on earpieces for support and are prone to falling off at inconvenient times. They may not provide adequate protection from shards or liquids hitting the eyes from underneath or the sides.

In scenarios where there is a risk of eye damage from various angles, safety goggles are essential as they offer comprehensive protection from the front, sides, and above and below the eye area.

Regards, Kesava Pillai

Dear Sir, Thank you very much for your excellent explanations. Could you please provide me with more information about safety glasses and safety goggles?

Key Properties of Safety Lenses

One other essential point that I gathered from your response is that regardless of the construction material of the lens, we should consider its following properties:
1. Shatter-proof
2. Heat-resistant.

I believe I understood this correctly, but if not, please do correct me.

@ Raghu, Thank you for your valuable contribution. Please continue to share your expertise with us through your posts. Unfortunately, I have not had the time to read everything thoroughly yet. I will print it out today for further review.

Regards,
Dipil Kumar V