When choosing a liquid or dry bulk storage system you take into consideration several key issues such as quality of the tank material, suitability of the tank material for the product to be stored, price of the tank and construction type.
The most common tank designs are bolted steel (carbon steel, stainless steel and glass-lined steel), field welded, factory welded, fiberglass and concrete.
Bolted Carbon Steel Tanks are excellent choices for larger jobs due to their quick installation and corrosion resistant epoxy coating. They also have the benefit of being able to be disassembled and moved to another location. They also may be installed without skilled labor, with only a supervisor to guide the installation.
Glass Lined Steel Tanks are a cost effective, low maintenance alternative to welded steel tanks. They offer fast construction and are easily expandable. Glass lined steel tanks are often the choice for use in potable water storage.
Field Welded Steel Tanks are notable for their ability to hold product in very large capacities. UIG offers welded tanks up to 25 million gallons in size.
Shop Welded Tanks are generally smaller in volume. They are coated in the factory and are shipped and ready to connect when they arrive at the site.
Concrete Tanks have been popular for many years because they can accommodate almost unlimited sizes of storage volume. Concrete, being porous, is highly susceptible to cracks and corrosion and is very difficult to repair.
Fiberglass Tanks are often chosen for their ability to resist corrosion. Common applications include alkyds, alkali, bleaches, brines, chlorides, solvents, oxidizers and other corrosive chemicals. Sizes range up to 14 feet for shop fabricated fiberglass tanks to 50 feet for field installed fiberglass tanks.
Many storage tank providers offer only the tank and immediate accessories, leaving the end-user the task of contacting several other suppliers to purchase all the other items needed to enable the tank to become part of the bigger picture. It is prudent to take into consideration companies that offer a complete package, thus ensuring that everything fits together and is a complete answer to their specific bulk storage and handling solution. Additionally, many tank suppliers sell only one type of tank and will attempt to make it fit into your project.
While ostensibly welded and bolted tanks are designed and fabricated to specific nationally and internationally recognized standards, for example in the case of welded tanks to API 650- field welded construction for Dry Bulk Storage, not all manufacturers follow all the rules all the time. Although metal thickness, welding procedures, coatings, etc. are specified, these are not always adhered to. These are some of the factors that will determine the longevity and suitability of the tank for a specific bulk storage application and cutting corners can produce disastrous results.
It is not unknown for tank manufacturers to have their tank design written into the specifications provided to end-users by ‘independent’ Consultants and Designers, in an attempt to disqualify any competition. Whether a specific and ‘unique’ type of coating, use of ‘special’ gaskets or other intangibles, it will prove beneficial to check on these matters to be certain that you receive competitive quotations from as many accredited sources as possible. Some guidelines to follow when choosing a tank are:
Make sure that the tank system is specifically fabricated to your projects application and that you obtain as many quotations as possible from reputable companies.
If you are looking for more than just a tank, it is better to deal with companies that are able to offer an integration option, ensuring that all the parts of the jigsaw fit together. That the conveying system or other material handling equipment being supplied will integrate into your existing system or satisfy your new requirements.
Consider who wrote the specifications that you are following and if they are providing you with all the technical options and pricing.
Always make sure that the offers you receive provide you with individual elements of the tank design, including plate thicknesses, coatings, welding methods and the certainty that the tank offered will fit into your overall design and is suited to your specific needs
If you are acquiring a field welded or field installed bolted tank ensure that the tank provider has a valid construction license, adequate insurance cover and safety certifications
Obtain a written guarantee of the life-span of the tank and other accessories and integrated components for your overall system.
If you receive competitive bids, be sure to compare like with like and as time is usually of the essence – investigate the installation methods that are to be employed. For example the tank jacking system allows the tank to be installed without the use of cranes and scaffolding. This is a faster and safer system and enables tanks and silos to be installed in areas where space is critical
When looking at price, don’t be tempted to opt for the cheaper product without first investigating if the lower price is due to the use of cheaper materials and inferior construction methods.
Whether you are looking for a traditional welded tank or silo or looking at the fast growing RTP-Rolled, tapered panel bolted tank or silo, follow the above guide lines and the correctly selected tank fabricator will be able to provide you with a product that should have a lifespan of more than 40+ years and that will be an integral and reliable part of your bulk storage and storage system.
Some information to provide your tank manufacturer to help design your storage tank system.
How much material is to be stored in the tank? What capacity will be needed to contain the material?
Are there any characteristics to the material to be stored that would be a concern in the design of the tank (e.g.: large particles, dissimilar ingredients, abrasive, non-free flowing, products that liquefy, products that clump or stick together).
What is the best and most economical material of construction? What type of discharge is needed? (funnel flow, mass flow, expanded flow, etc.)
Is an aid device needed for reliable discharge? (hopper, reclaimer, etc.) l Is a system interface needed? What is the tank configuration type? (flat bottom, sloped bottom, elevated, floating roof, domed roof, etc.)
Are there any corrosion allowance or cathodic protection requirements? What type of foundation is planned? Are there any specific design codes requirements.
Is a PE stamp required?
It is also prudent to plan for accessories needed as well.
Level control nozzles
Maintenance access platforms
Other custom requirements for system integration
Once you and your storage tank system manufacturer have discussed all of your challenges and options, the most economical and reliable tank choice will be made.