# How to design a vertical cylindrical Water tank

## Main Question or Discussion Point

I Need to design a Vertical cylindrical water tank to be build by Fiberglass. I need to calculate the tank also for 7.5 m bar pressure and 2.5 m bar vacuum pressure. Tank Dimensions to be 4m Dia, 5 m High (60000 Liters). I have Fiberglass laminate of 6 mm Thk and Modules is 1470000 psi. I have 50mm Dia plastic pipe ribs (rings) in an every 500 mm intervals on tank outside wall. How do I calculate this tank? Please help me.

## Answers and Replies

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Mech_Engineer
Science Advisor
Gold Member
Is this a homework problem? It always helps to write down the problem statement in some sort of a methodical way, have you started with some basics like a free body diagram?

Thanks for the reply. This is for build the same tank for one of our factories. I need to clarify the design requirements satisfaction. I'm not in touch with this calculations for a long time. So please help me to go through this.

Is this a homework problem? It always helps to write down the problem statement in some sort of a methodical way, have you started with some basics like a free body diagram?
Thanks for the reply. This is for build the same tank for one of our factories. I need to clarify the design requirements satisfaction. I'm not in touch with this calculations for a long time. So please help me to go through this.

Not sure what you are using it for, but I have worked 29 years in project engineering and have bought and installed hundreds of tanks.

First things first. Unless you are a plant that builds its own equipment, do not design the tank. It does not pay off especially if used for chemicals or anything regulated.
Second, most tank manufacturers have in house people who can design their tanks in hours and know how they build it. use their expertise. that is why they are in business.
third, draft a design specification. Give them the service volume, the total volume (NEVER fill a tank 100%), operating pressure, design pressure, operating temperature, materials to be stored along with MSDS sheets, all fittings, manholes, instrumentation requirements, piping connections, flow rates, and a general description of how you use the tank. Also determine if the tank must meet government regulations and an industry spec. Is the tank a pressure vessel? Will the tank be inside or outside, heated, insulated or jacketed? What type of foundation will it sit on. Where is it and what is your access to install it? how do you rig the tank to set it and how close can the delivery vehicle get? What kind of rigging fixtures are needed. I always add a crude drawing showing the nozzles and fittings from each end and the side. Show them as degrees from 0 ref. and elevation from bottom of tank. Also remember you need to allow maintenance to service things. If insulated allow space.

Take the time to answer those issues, write up the spec, and send it out for comment in your organization. Then send it out to bid with at least 3 companies. Tell them to deliver at least 4 weeks prior to when you need it. It stinks to coordinate a delivery just in time during plant construction. Go to the supplier when they have basically assembled the tank in case there is an issue. Cheaper to alter the tank there.

Good luck.