Avoiding freezing in water tanks 2

[DerekLJ]

What are the most common systems to avoid freezing in water storage tanks i.e fire water storage tank...?

thanks

 

[CarlB]

Well no one's mentioned so I will - what's wrong with a little freezing in a water tank? I have passing knowledge of water tanks in southeast Alaska. I don't believe any of the large ones are insulated. With proper design they can function OK with a floating layer of ice and accumulation along the walls. It does take away from your storage volume though.

 

[DerekLJ]

CarlB, I agree with you that in some cases, who cares. The problem is that in this case it is a fire water tank, And it would kinda suck if the turbine is on fire or a 200,000 bbl. crude storage tank is on fire, and shoot theres no water.

I want to thank all of you for your help. I really appreaciate all the ideas that arrived. When i really started searching, we found that in our case, NFPA only accepts one answer, insulation and a heater.

Once again, tanks (chessy joke) for all the expertise of our faithful eng-tips friends

 

[Cockroach]

Man....don't know where you are writing from, but in Canada this is almost a trivial problem.

You can add common anti freeze also known as ethylene glycol in a concentration approximately 1:4 with water. This makes the system good to -40C. If you are talking about a tank with potable drinking water, then you need to bury the tank below the freezing line. Typically this is six (6) feet or so.

The other way of doing it is head to your local corner grocery and buy a bottle off the shelf. Works every time!

Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada

 

[IRstuff]

Common antifreeze is considered a hazardous material.

It's probably illegal to allow it to flow down city sewer systems.

TTFN

FAQ731-376

 

[eromlignod]

...not to mention putting out fires with it.

Don
Kansas City

 

[Cockroach]

If it such a hazardous material, then why is it commercially available at gas stations: PetroCanada, Shell, Esso (Exxon Mobile), not to mention hardware outlets such as Canadian Tire, WalMart, Home Hardware, etc? Would the federal government allow such wholesale hazardous material "known" to be problematic?

Interesting! What would you boys recommend as an automobile anti freeze for your radiators, rated -45C?

Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada

 

[eromlignod]

Just because it's sold in a store doesn't somehow magically render it "non-hazardous". You can buy herbicide, rat poison, brake fluid, paint stripper, engine degreaser, and dozens of other nasty potions over the counter. That doesn't mean that you can merrily flush them down a toilet.

It had already been reported by the OP that a heater and insulation is the only acceptable answer for the NFPA anyway.

Don
Kansas City

 

[mshimko]

For cockroach:

The question isn't to to protect a few gallons in a closed loop system from freezing, it's for a large storage tank (433,000 gal) that supplies water for fire fighting!

Not sure the "owner" would want to purchase 100,000 gallons of antifreeze to provide a 1:4 mixture, also not sure any wildlife (or people) in the area would appreciate having tens of thousands of gallons of antifreeze being sprayed in the open air.

Ethelyne glocol is hazardous, and that's why it should be properly handeled and disposed of, even in small quantities (in my state, it's illegal to dump ANY quantity of antifreeze, including from a treated radiator, in the environment or sewer).

 

[Cockroach]

If money is an issue, and I appreciate the scale of economy argument, then your problem has now become increasingly complex. Probably the best thing to do is to have designed the system correctly in the first place, acknowledging thermal variations in water temperature is an issue due to seasonal influences.

One response was to increase the salinity concentration of the water volume. Probably price will be an issue here also. Another has suggested water heater and mixers for stirring the volume. Probably you need worry about the electrical bill on a monthly basis.

Short of throwing ice cubes at the fire, I guess you have a real problem. Sorry nothing matched your particular specifications for a viable solution set. Good luck with it, none-the-less.

Kenneth J Hueston, PEng
Principal
Sturni-Hueston Engineering Inc
Edmonton, Alberta Canada