Re: [asa] Ban on computers reportedly wanted.

After re-reading my post, I did notice I have my units wrong... they are in usage per second for the factory to produce the entire production of wafers. Still seems like a lot, but maybe?? You would have to figure in all the other things the factory did combined with their total waste output to really check this, unfortunately I don't know how to come by such figures...
-Paul
  ----- Original Message -----
  From: Paul Greaves

  Is there a way to check these figures? I have checked other things Janice has posted and found them to be not true or unsubstantiated so I have learned to be cautious. I did some quick calculations (below), and so I am doubtful, ...but also open to learning more if I am missing something.

  For the water use figure... 3,787 gallons of waste water
  I looked up on google and found a Taiwanese company recently was able to produce 70,000 8 inch wafers per month. (http://www.us.design-reuse.com/news/news8044.html).
  So let's say for the sake of argument that they are in production 24 hours a day 30 days per month. That works out to (3,787 x 70,000) / 30 / 24 = 368,180.5 gallons per day per wafer. That's about 102 gallons per second! I find that a little hard to believe...

  Similarly, I get these figures translated to usage per second per wafer:

  115.2 cubic feet of bulk gases
  102.3 gallons of waste water
  0.73 pounds of chemicals
  0.78 cubic feet of hazardous gases
  0.24 pounds of hazardous waste
  81.6 gallons of de-ionized water

  Am I missing anything here? This does not seem possible. Even if the average company was less efficient, I doubt they would differ by an order of magnitude, and even that seems excessive.

  (As an aside, it should be pointed out that a single 8-inch wafer yields a great many computer chips, so the figures would have to be translated to something like "usage per computer produced" to have any real meaning...)
  -Paul Greaves

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Received on Thu Apr 5 20:48:44 2007