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Confused about safety factor... tank pressure H vs W vs L


henward

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Need technical knowhow here.

engineers, stuff like that.

been doing heaps of reading.

an d everywhere says.... as i suspected from previous reading that HEIGHT IS the determining factor mostly on pressure on the tank.

Length is not too much of a problem, height is the problem.

Width isnt huge issue too.

also i read that 2.5 safety factor is safe.

Buyt 3 is better, 3.8 is even better.

Using these calculators

http://www.theaquatools.com/building-your-aquarium

https://public.sheet.zoho.com/public/ri ... calculator

So here are some questions: Slight different to the other topic of efficiencies. 8)

Tank Size:

2.4m x 1.2m x 60cm H (tank height will be 65cm but actual water height will be no more than 60 cm high)

1) This has a safety factor of 3.5 with 12mm glass - feedback?

2) tank maker says to me that he things 1.2 metres width is a problem, But everything i read says that its height. hence why im cutting down from 80 high to 60 high.

3) Would youy be comfortable with this? Width for my needs is the key.

4) the bottom pain on the calculator says should be 14.5 mm, I am thinking of doing one pane of 12mm, and another on top of 10mm as a giant brace so has the braceless look, does this mean it will be effectively 24mm thickness at the bottom?

Thanks

I had a plan, but now it kinda has to change!:D

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http://saltaquarium.about.com/od/diytan ... tank_2.htm

This article accurate

says that putting a hefty brace in the middle of the tank on top back to front pane.

Effectively reduces the load by approx half.

thus, making my tank effectively 2x 4foot tanks as opposed to an 8 foot.

almost doubling my safety factor of 3.5?

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In a previous life I have built hundreds and repaired heaps of tanks. Virtually every tank I have repaired has broken right next to the central brace and for that reason I only use European bracing. The greates pressure is at the bottom of the tank so the height is the critical factor. The width is not a problem untill the ends get big enough to have problems with flexing. European bracing assists with the flexing which is greatest at the top on the greatest span. The bonding to the base can be helped by adding euro bracing to the bottom and increasing the bonding area where the pressure is greatest.

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In a previous life I have built hundreds and repaired heaps of tanks. Virtually every tank I have repaired has broken right next to the central brace and for that reason I only use European bracing. The greates pressure is at the bottom of the tank so the height is the critical factor. The width is not a problem untill the ends get big enough to have problems with flexing. European bracing assists with the flexing which is greatest at the top on the greatest span. The bonding to the base can be helped by adding euro bracing to the bottom and increasing the bonding area where the pressure is greatest.

Is there a diagram online that describes the bracing you are talking about, would like to see it.

wanna know exactly wha tyou are meaning

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oh yeah ok

that seems like its a standard bracing, i didnt have any other type of bracing in mind really.

my 1200litre was braced in this way also, 1 only but it was a thick one.

but havng 2 is good too.

so its better to have 2 slightly off centre than just one on the centre?

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Need technical knowhow here.

engineers, stuff like that.

been doing heaps of reading.

an d everywhere says.... as i suspected from previous reading that HEIGHT IS the determining factor mostly on pressure on the tank.

Length is not too much of a problem, height is the problem.

Width isnt huge issue too.

also i read that 2.5 safety factor is safe.

Buyt 3 is better, 3.8 is even better.

Using these calculators

http://www.theaquatools.com/building-your-aquarium

https://public.sheet.zoho.com/public/ri ... calculator

So here are some questions: Slight different to the other topic of efficiencies. 8)

Tank Size:

2.4m x 1.2m x 60cm H (tank height will be 65cm but actual water height will be no more than 60 cm high)

1) This has a safety factor of 3.5 with 12mm glass - feedback?

2) tank maker says to me that he things 1.2 metres width is a problem, But everything i read says that its height. hence why im cutting down from 80 high to 60 high.

3) Would youy be comfortable with this? Width for my needs is the key.

4) the bottom pain on the calculator says should be 14.5 mm, I am thinking of doing one pane of 12mm, and another on top of 10mm as a giant brace so has the braceless look, does this mean it will be effectively 24mm thickness at the bottom?

Thanks

I had a plan, but now it kinda has to change!:D

Hi Henward,

Most of the articles and calculators found on the internet at present are based on my original article here:

http://www.fnzas.org.nz/?p=1732

A lot of them have actually asked for permission to reproduce the arcticle or use the calculator but some have simply plagiarised it an taken the credit for themselves. The two links in your post are both based on my original but only the aquatools has bothered to ask permission to use it.

This article accurate

says that putting a hefty brace in the middle of the tank on top back to front pane.

Effectively reduces the load by approx half.

thus, making my tank effectively 2x 4foot tanks as opposed to an 8 foot.

almost doubling my safety factor of 3.5?

This statement is incorrect. The calculation already assume euro bracing of adequate quality is used so the safety factor calculated is the actual safety factor. In the tank photo shown above the strip of glass running along the front an back edges is too narrow to add significant strength as is at risk of breaking. If there were 2 front to back braces instead of one it would be better. Alternatively, if the strips were twice as wide it would be ok. The glass thickness article states 'all four sides simply supported'. This means all four edges of the glass have support as if it were as very rigid steel frame that does not flex under the load.

It is possbile to have no top bracing but you have to modify the alpha and beta constants to cater for this. I've added another Excel file with the ability to calculate the glass thickness for unsupported top edges. There are 3 sheets in the file, siderest, sidefree, bottompanel. Siderest automatically changes the aplha and beta constants as you change the length and width but the other 2 sheets require you to change the values manually - don't forget to do this.

siderest - standard tanks with Euro bracing

sidefree - Open top tanks with no top bracing at all

sottompanel - bottom panel

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I will definitelyhave bracing ffront to back. I am considering with 2.4m length . I will have bracing on the side edges and 2 more in middle.... Is this what you mean by making it better?

What width of glass shouldiI account for for the front to back bracing on top of the tank?

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All front to rear bracing should be 200-250mm wide and along the front and back edges should be 125-150mm. Both should be minimum 10mm thick but 12mm would be a lot better as the width of the silicone connection to the front and rear glass will be 20% wider. The front and rear pieces should also be ground along their length so they are dead-flat. This will allow a very thin silicone joint for added strength due to a more uniform pressure loading.

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All front to rear bracing should be 200-250mm wide and along the front and back edges should be 125-150mm. Both should be minimum 10mm thick but 12mm would be a lot better as the width of the silicone connection to the front and rear glass will be 20% wider. The front and rear pieces should also be ground along their length so they are dead-flat. This will allow a very thin silicone joint for added strength due to a more uniform pressure loading.

Awesome! That'sthe ttype info Ineed .. Thanks heaps.. Will factor it in my designs!

Hefty brute reinforcements is going to be my focus.

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just reading over this it seems my tank i got built has a fault their.. didnt think it looked right.

its 650 high an 600 wide but is ment to be 750 wide. for the bracing theirs a 80mm wide strip going right along the bottom both sides in length, an at the top its got a 80mm strip at the top going full length but for the width its got a peice 415mm long just joining into the 2 80mm peices each side. just by silicon an no bracing in the middel. does that sound right or wrong?

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http://s244.beta.photobucket.com/user/andydatto/media/20130203_193654_zpse265cc28.jpg.html#/user/andydatto/media/20130203_193654_zpse265cc28.jpg.html?&_suid=135994931616906551954673875148

20130203_193654_zpse265cc28.jpg.html?&_suid=135994931616906551954673875148

so you can see the 2 80mm strips each side of the width of the tank then theirs a peice joining inbetween the two of them. wouldve thought that would go right across the 2 long lengths

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My understanding is that the top euro bracing is to take the bow out of the side glass and the ends are short so do not have as much flex as the longer panels That is the way I have always done euro bracing except I stop the longer braces short of the ends to allow for wires and airhoses etc.

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so the tank in my picture is that bracing ok? an like i said thats all it has each end nothing in the middel. an plus its 650 high an only 10mm thick. an he told me if i wanted to go higher than 600 it would have to be made of 12mm because can bow.? i havent filled it an dont want to i think it would bow .i would just like my $ back

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