Glass safety Q...R my readings correct

Discussion in 'General Discussions and Advice' started by shiks, 20 Nov 2008.

  1. shiks

    shiks

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    Hi hennie....i was wondering what am i doing wrong....or are my inputs right??
    have planned a new tank 1.5 x 700 x 700 and was told 10mm glass is fine.....but i seem to be getting dangerous red blocks appearing when i type in the figures ...could u take a look ....thanks
    Aquarium glass calculator​



    Tank Water Height (H) (mm):​
    650​
    Tank Length (L) (mm):​
    1500​
    Tank Width (W) (mm):​
    700​
    Recommended Safety factor (Sf) :​
    3.8​


    Recommended Side Glass Thickness at Sf :​
    13.2​
    Maximum Deflection of Glass (mm):​
    0.41​


    Recommended Bottom Glass Thickness at Sf :​
    17.6​
    Maximum Deflection of Glass (mm):​
    0.31​


    If side glass thickness is changed to (mm):​
    10​
    then actual safety factor =​
    2.2​


    If bottom glass thickness is changed to (mm):​
    10​
    then actual safety factor =​
    1.2​
     
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  3. leslie hempel

    leslie hempel Moderator MASA Contributor

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    i have a 1.5 x .700 x .700 constrycted with double bottom bracing allround and single top bracing allround with a strap 8cm wide over the middle out of 10mm.. solid as a rock..

    used 15 tubes of glue to make sure bubbles between bracing was minimal.
     
  4. shiks

    shiks Thread Starter

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    ok the tank is going to be double braced at the bottom with center brace on top like u say...i was under the impression though that this would have been sufficient safety accord to the calc..but actually if my inputs r right then its not enough....
     
  5. leslie hempel

    leslie hempel Moderator MASA Contributor

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    in practice mine was fine.. no bowing etc.. will be building another but lower and wider due to problems acessing the bottom..
     
  6. Mtroboer

    Mtroboer

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    Just brace it you'll be fine, the calculator doesn't take bracing of any kind into account.
     
  7. Reef Maniac

    Reef Maniac MASA Contributor

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    Unfortunately, the figures are correct.

    There are, however, a few things to consider:

    • The calculator does not make any allowance for bracing, and although I don't have actual data, one could possibly get away with thinner glass on a well-braced tank... it all depends on how lucky you feel :whistling: Having personally experienced a disastrous tank failure (bursting of the front glass) with about 500 liters of salt water dumped into my sitting room, I can only recommend that you consider the bracing as just that - bolts and braces - and that you design the tank to work even without the bracing.
    • The calculator has different design parameters for side panes and for the bottom glass. The reason for this is that many (most?) tanks are only supported around the outside edge of the tank. If the tank is supported over the total area of the bottom pane, and if this support is strong enough to have a deflection of less than the predicted glass deflection, then one can safely use the same thickness glass as that of the side panes. This support will have to remain ridged for the life of the tank - in other words, there must not be any possibility of the support sagging agter a few years, as can easily happen with wood. To summarise, if you place the tank on a strong enough concrete slab you only need to use the same glass thickness as that recommended for the side panes.
    • One needs to consider the risk profile of the tank's location. A tank located in a busy passageway, or e.g. kitchen area in a house with small children, should be designed with the full recommended safety factor (3.8), but one could relax this to (say) 2.5 if the tank is in a "safe" location where there is no risk of someone accidentally bumping into it. One should also consider factors such as possible earth tremors caused by rock bursts in mining areas, etc.
    Hennie
     
    Last edited: 21 Nov 2008
  8. leslie hempel

    leslie hempel Moderator MASA Contributor

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    let me tell you as an experienced tank builder go 10mm.. you cannot govern what little kid will do or what they will pick up an hit against the tank.. my boy headbutted the tabk a fierce shot 2 days ago 9has a bruse on his head) and although i was upset he got hurt i was confident the tank would withstand the blow and not inflict any serious harm.. a tank over the height of .600 should be out of 10mm and well braced for better adhesion on the base..

    dont take a chance its expensive and could be potentioally dangerous..
     
  9. shiks

    shiks Thread Starter

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    thanks guys..hennie and les......will make sure the bracing is done right and ask for an 'extras' that will make it more secure....
     
  10. Tobes

    Tobes Retired Moderator

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    Howzit Shicks, why not rather make it 600H and 800W? You'll work easier in the tank and have a bit better light penetration. Or are your sizes like that because of space issues?
     
  11. lindsay pollard

    lindsay pollard pipefish

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    howzit shicks,my tank is 1500 x 550 x 550 with urobracing on the bottom and around the top of the tank,heres the shock its only 8mm glass. im sure it would be better to use 10mm glass.My 2c worth:thumbup:
     
  12. SIMS

    SIMS

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    mine is 1500x850x700....12mm with euro bracing...why put a centre brace on your tank?

    Also agree go wider...
     
  13. shiks

    shiks Thread Starter

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    shew...ok tobes my size constraints are a factor and seeing as i am upgrading i figured go wide as possible which is 700...also tank is 700 high but realistically only gonna fill up to 650 with water to allow for hood and so that light penetration isnt compromised with the corals using t5s.....i watched the tank being built yest and have the utmost confidence in its construction....bracing was done all along the bottom and top with off center supports....the dude even had to climb in ...all looks secure...
    thanks for all the advice guys.....
     
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