question in Building Construction Illustrated (3)

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lotus0418

February 10, 2021 22:57

Hi guys,

I have some questions about below image. I cannot quite understand the text passage and the relationship of it with the graph. In the graph, what's the meanings of the dotted, dashed and solid lines curves? I hope someone can kindly answer me. Many thanks in advance!

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  Joseph February 16, 2021 12:44

  beam spread differently as the angle of light beam change. (ex. short angle correspond to cont. line)

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  lotus0418 February 16, 2021 15:43

  Hi Hang,

  Thanks for your message. But my question still didn't get answer about the curve lines? Sorry!

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  Joseph February 16, 2021 16:12

  each curves indicate the area the light beam can reaches.

  see attached (page 19)

  https://www.ncarb.org/sites/default/files/BS_Exam_Guide.pdf

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  rebekkak February 21, 2021 19:31

  I dont have that book in front of me. But think of that as a section, with the light source being at the center.

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  Joseph February 22, 2021 00:23

  each line (dotted vs continuous) relate to light fixture spacing. (see attachment 1 & 2)

  attachment 1 - building construction illustrated

  attachment 2 - MEEB (ch. 16.6)

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  rebekkak February 22, 2021 22:37

  The dotted outline is typically the light distribution of the sides, so this fixture doesn't throw light symmetrically. And this fixture's light is mostly going down. (There's just 2 tiny shapes above the horizontal) The spacing ÷ mounting height ratio shows that the higher the fixture is, the less light you'll get from it.  Makes sense, right??

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  Joseph February 22, 2021 23:37

  Yes, you are right! (as this ratio shows.)

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