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Recommended Light Levels

Discussion in 'The Tool Shed' started by timgr, Mar 18, 2021.

  1. Mar 18, 2021
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    This came up in Chris's shop panic discussion over on off-topic. I think a general discussion is something that could persist.

    Ok, from the astronomy guys at the National Observatory, supported by the National Science Foundation.

    https://www.noao.edu/education/QLTkit/ACTIVITY_Documents/Safety/LightLevels_outdoor+indoor.pdf

    upload_2021-3-18_10-14-7.png

    Compare to natural sources - upload_2021-3-18_10-18-1.png

    Looking at the first chart, I think the ideal target is somewhere at the bottom of the chart.

    I estimated the illumination in my garage, using the specs from the bulb suppliers.

    I have 4 banks of 4 shop lights and 2 extra shop lights over the bench. That's 36 bulbs at 18 watts each and 131 lumens per watt. 18 * 131 * 36 = 84,888 lumens. My floor is 21' x 17', 357 sq ft or 33 sq meters.

    Now lux are defined as the lumens per square meter; that's 2572 lux. Pretty bright, but way below full daylight (which I expect you could call "bright shade.") Maybe 2.5 times as bright as an overcast day.

    Comparing to the illumination standards that the astronomers suggest, it's well above the requirement for detailed mechanical workshops. Looks like I'm set for light, for now.
     
  2. Mar 18, 2021
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Tantallon, Nova...
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    Nov 22, 2003
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    Interesting, but have you taken into account how well the ceiling/walls/floor are reflecting the light around? I went from grimy dark walls & ceiling to lighter walls (fresh OSB) & reflective foam ceilings- the difference with the same light fixtures is astounding but even with all that new bounce the light is still not even, there's still comparatively still areas.
     
  3. Mar 18, 2021
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    Nope not at all. Just a WAG. Might be useful for planning how many fixtures you need in your work area, however.
     
  4. Mar 18, 2021
    CHUGALUG

    CHUGALUG Member

    Silverton, OR
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    May 11, 2019
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    I used to be a Custom Knifemaker. In the back of my shop I have a room that is 12 x 12 that has my two 2x72" belt grinders a cut off wheel machine a 4x6" Horizontal/Vertical bandsaw a flap sander and a small wood lathe. For 30 years this room had 4) 40wat dual bulb florescents on the ceiling which is only about 7' high. A couple years ago I went nuts and swapped the Florescents out with the cheap Harbor Freight Braun 42" LED fixtures and the first time I walked into the room I felt like I needed sun glasses. The improvement in visual acuity was amazing. The room is painted White (though its now more of a light gray) With a Gray floor. I have since been changing over the rest of the shop to these cheap LED units. Its amazing how much better my old eyes work with a lot of light.
     
    dozerjim likes this.
  5. Mar 18, 2021
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Hills of NH
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    Interesting but it is not just numbers.

    To me the spectrum (color/warmth) makes a huge difference, not just the lumens. And for instance in filing timber saws, the reflected angle of the light is a critical factor.

    And there is NOTHING as good as natural daylight.
     
    tcfeet and dozerjim like this.
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