Effects of Briny Water on Cast Iron Tanks
Effects of Briny Water on Cast Iron Tanks
(OP)
Hi guys - First post on this forum. I am in Aghanistan doing some project management and engineering for a clinic that is being built in a very small village in Helmand Province. The design calls for an above ground water tank made of 3/4 inch cast iron that will be charged by a local water well. Ground water here tends to be on the briny side with a salt content high enough that the locals can taste it and will generally avoid it if they can. Anyway, what I need to know is whether the brine will have a corrosive effect on the cast iron and any alternatives that you think appropriate. Thanks in advance guys.





RE: Effects of Briny Water on Cast Iron Tanks
Can't you use a plastic tank? PVC will work well.
Take care of yourself!
RE: Effects of Briny Water on Cast Iron Tanks
If you are using cast iron because it is locally available then you might consider using a liner in it.
Two coats of a good epoxy or other suitable resin will give good life.
However be warned that the surface preparation is critical. Without proper blasting and cleaning it will never stick.
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Plymouth Tube
RE: Effects of Briny Water on Cast Iron Tanks
RE: Effects of Briny Water on Cast Iron Tanks
Perhaps a good idea would be to pain it on the exterior also. Is it drinking water or some cleaning use? The internal paint might need to be suitable for potable water. The rust will leach into the water contaminating it. The paint must be checked carefully for holidays (pin holes), which could cause rapid localised corrosion.
Why dont you use the corrugated galvanised sheet metal storaage tanks, which can be delivered in flat packages, easy on the truck and can be errected on site with hand tools. If needed, it can be lined interior with prefabricated plastic or rubber liner, you only hang it inside the shell like your laundry washings on the fence and it will stay there for decades, no corrosion problems. Besides of the joke, a bullet will put a hole on the liner, which can be patched easily like a bicycle tube, for another 20 years. Look up on the web for AWWA bolted and lined tanks, fabricators everywhere in the world, very cheap and delivery no problem.
Cheers,
gr2vessels
RE: Effects of Briny Water on Cast Iron Tanks
RE: Effects of Briny Water on Cast Iron Tanks
Thanks for the replies guys. In general, I don't thiunk this is a very good design. But it's what I have to work with. Also, there is the issue of culture. I've attempted to add a pdf of the prfile elevation drawing. It's my first time at this so I hope I get it right. In it you'll notice a whole lot of design features that are unique to this part of the world - things that we probably would not do in the states. You'll need to zoom the pdf up to 200% to see the detail on the tank. With enough input from you guys, I'm hoping to convince the powers that be here through a Request For Information [RFI] to re-think the cast iron in favor of something more suitable, given the remoteness of the area. If at the end of it all, I have to go with cast iron, I still have a "make or buy" decision in front of me which brings on a host of other issues. Any input is appreciated guys.
RE: Effects of Briny Water on Cast Iron Tanks
RE: Effects of Briny Water on Cast Iron Tanks
If iron, perhaps push to have it concrete-lined. Huge amounts of ductile iron pipe is used world-wide for potable water mains, much/most of it concrete-lined.
RE: Effects of Briny Water on Cast Iron Tanks
RE: Effects of Briny Water on Cast Iron Tanks
Steve Jones
Materials & Corrosion Engineer
http://www.linkedin.com/pub/8/83b/b04
RE: Effects of Briny Water on Cast Iron Tanks
RE: Effects of Briny Water on Cast Iron Tanks
In this regard, ductile iron and steel water pipes (the latter at least in larger sizes) are standardly furnished with a cement mortar lining (and it appears based on a quick internet search many users of ferrous tanks have apparently now gravitated towards mortar linings, perhaps/I suspect based on history relative to thinner polymeric linings).
RE: Effects of Briny Water on Cast Iron Tanks
You said the lined light tank is the best way to go. Stick to it.
Anything else would be far more expensive, unreliable, potential of corrosion and other damages, perhaps irreparable. The rupture of the lined, bolted sheet metal tank is almost impossible, unles using heavy artilery, but even then, in two days is up again and stores water. No corrosion problems, lining with 20-30 years of life. No cement to crack, no rust to perforate the shell, assembly with normal hand tools, a little chain block for lifting panels, what could possibly be easier and less expensivethan this? However, if they want cast iron, give them cast iron. Just make sure to protect yourself from blame, if the iron turn the potable water into a red likor.
RE: Effects of Briny Water on Cast Iron Tanks
RE: Effects of Briny Water on Cast Iron Tanks
I witnessed a camper company that fitted glass wool behind beauty board panels adjacent to factory steel skin. Results were not at all good after a year or two. Skin showed rust bubbles on outsides at bottoms of sections(where interstitial condensation collected). No provisions were made to allow this moisture to dry, or drain so corrosion was a certainty.
Take care,
Brian,
RE: Effects of Briny Water on Cast Iron Tanks
Brian,
RE: Effects of Briny Water on Cast Iron Tanks