#### Trevor

##### Well-known member

- Joined
- Jul 17, 2009

- Messages
- 4,513

- Points
- 113

As a few of you know, I made a site (in the midst of the Arctic fiasco), safelasers.org, that hosts my warning label generator, some other laser-related tools, and safety information. It gets a lot of hits off of Google from people looking for laser safety information.

The calculator pages receive a lot of Google hits too. I have a recommended OD calculator (using information from Sperian's numbers they gave me when I consulted them about goggles), a divergence calculator, and an eye-hazard distance calculator.

The hazard calculator uses Sperian's numbers to arrive at the distance (in meters) necessary for a laser to have traveled (and thus diverged) such that taking a direct hit from that distance with a fully dilated pupil would be the same as taking a direct hit through a pair of Sperian's laser safety goggles at the OD they recommend. I forget the residual power, but I believe it's on the order of 0.3-0.4mW entering the eye. This is by no means a perfect number, but it illustrates the danger of lasers - even far away from them.

I made an interesting discovery the other day - WL used my calculator to calculate their "NOHD" (I quote because I think this is only posted to make WL look good, not to keep their customers safe). They put their specs into my calculator, clicked submit, rounded the number, then published it on their website on the specifications page for each of the lasers below (all of the ones on their site).

The "WL" column is the number posted on their site, and the "SL" column is the number yielded by using my website. Unfortunately they rounded all of them down.

How can I be positive? The number used to calculate a "safe" exposure is unique - changing it at all will result in a much different distance.

So... on the one hand, at least they indirectly used the recommendation of a legitimate safety goggles company - Sperian.

On the other hand, they used a calculator they found online, never inquired the owner (me!) as to how the calculator actually computes the number, and proceeded to post the number as a specification.

oke:

-Trevor

The calculator pages receive a lot of Google hits too. I have a recommended OD calculator (using information from Sperian's numbers they gave me when I consulted them about goggles), a divergence calculator, and an eye-hazard distance calculator.

The hazard calculator uses Sperian's numbers to arrive at the distance (in meters) necessary for a laser to have traveled (and thus diverged) such that taking a direct hit from that distance with a fully dilated pupil would be the same as taking a direct hit through a pair of Sperian's laser safety goggles at the OD they recommend. I forget the residual power, but I believe it's on the order of 0.3-0.4mW entering the eye. This is by no means a perfect number, but it illustrates the danger of lasers - even far away from them.

I made an interesting discovery the other day - WL used my calculator to calculate their "NOHD" (I quote because I think this is only posted to make WL look good, not to keep their customers safe). They put their specs into my calculator, clicked submit, rounded the number, then published it on their website on the specifications page for each of the lasers below (all of the ones on their site).

The "WL" column is the number posted on their site, and the "SL" column is the number yielded by using my website. Unfortunately they rounded all of them down.

Code:

```
| Laser | Div | Dia | Pwr | WL | SL |
| -------|-----|-----|------------|------- |
| E2 405 | 1.0 | 1.0 | 100 | 70 | 71.5 |
| E2 532 | 1.5 | 1.5 | 100 | 47 | 47.33 |
| E2 650 | 1.0 | 2.0 | 100 | 70 | 70.5 |
| -------|-----|-----|------------|------- |
| E3 405 | 1.0 | 1.0 | 200 | 100 | 101.53 |
| E3 532 | 1.5 | 1.5 | 200 | 67 | 67.35 |
| E3 650 | 1.0 | 2.0 | 200 | 100 | 100.53 |
| -------|-----|-----|------------|------- |
| Arctic | 1.5 | 5.0 | 1000 | 149 | 149.5 |
```

So... on the one hand, at least they indirectly used the recommendation of a legitimate safety goggles company - Sperian.

On the other hand, they used a calculator they found online, never inquired the owner (me!) as to how the calculator actually computes the number, and proceeded to post the number as a specification.

oke:

-Trevor

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