New Tanks
Advantages and Disadvantages of Panel Tanks
Steel panel tanks, also known as modular tanks, have a number of advantages and disadvantages over their counterparts. The goal of this article is to provide quality, concise, information for assisting consultants, engineers and project managers with making the best decisions regarding specifications and procurement best suited for application requirements.
Storage Capacity
The first and most important question to answer is how much water storage is needed?
Panel Round tanks are the most cost-effective method of storing most non-hazardous liquids from 80,000 to 10,000,000 Litres. For tanks smaller than 80KL it is usually cost and time-effective to install a couple of small poly tanks with a similar design life as lower-spec panel tanks (described in the following paragraph). There are very few tanks, panel or modular, built for more than 10 Mega liters (10 million liters). At this capacity, design life becomes a limiting factor. Many larger tanks are designed for council drinking water reservoirs or oil storage tanks and are specified to last between 50 to 100 years.
The Price
The unique quality in panel tanks is evident when comparing their cost to concrete and welded steel tanks. One can expect to spend from 100% to 500% more on a concrete or welded steel tank than on a panel tank. When an oil processing plant in Western Australia required a 250,000 litre fire tank they originally preferred welded steel due to its design life. However when the budget came back at just shy of $1,000,000.00 they explored alternatives and selected a high spec panel tank with all the upgrades for $220,000.00.
Design Life
The second important question is: What are the design life requirements of this tank?
Most tanks over 10 Mega litres are concrete or welded steel for one reason; they need to achieve a design life of 50 to 100 years. Panel tanks are extremely versatile, and by selecting ‘modifications’ and other options, the design life can be extended from 25 years to 50 years. It’s important to note that the price of the tank increases depending on its specifications. Like a car, and unlike all other tanks, a panel tank has the benefit of being like a Mecca-no set—meaning you have options to easily bolt on, add, remove, and modify all components in them including stairs, ladders, fittings, roofs, manholes and even change the waterproofing. What this means is that you could purchase a cost effective panel tank with a design life of 25 years, then at 20 years you could upgrade it to a 50 year design life by modifying the roof and waterproofing. A very useful feature for mines, councils and large construction firms is the fact that a panel tank company can pull down a 10 mega litre tank within a week and then rebuild it on the other side of Australia the following week often within a couple of weeks of notice.
Panel Tank Options
So what are the tank components which affect its design life?
In short everything in panel tanks is variable. Wall sheet thickness’s range from 0.48mm thick for some rural farm tanks up to 20mm thick for mega litre reservoir storage. Coatings include colour-bond for farm tanks to galvanised steel for fire tanks to glass resin and epoxy coatings. Similarly, panel tanks can be built without roofs, however, if a roof is required, you have the option of purchasing a cheaper durian purling roof structure with zinc-alum sheeting and a centre column support or a self-supported hot-dipped galvanised roof structure with colour-bond ultra-sheeting and a roof liner. Another option would be using a new membrane liner roof to avoid corrosion altogether.
Waterproofing
Waterproofing selection is critical as it is the main contributing factor to a panel tanks design life, a poor liner selection can cause significant costs in the short run as well as the long term. As a rough guide, if you need to store council water for fire protection—meaning that the tank will almost always be full—then you may want to select a 0.75mm PVC liner for price competitiveness. However, if the tank will be filling and emptying regularly with a variety of chemicals then you’ll need a reinforced liner with a scrim (a thread inside the liner) which will not shrink and can handle the fluctuations. There is no shortage of liner or waterproofing options and ATM is well experienced in installation all types. Spray on liquid rubber and polyurethane coatings are becoming popular, but these coatings are more costly and require significantly more attention to detail in preparation. Unfortunately this means that many companies doing these coatings get it wrong due to insufficient preparation which results in higher repair costs. Most panel tanks can be manufactured and installed within 8 weeks from order compared to the 6 months for concrete and welded tanks.
The Conclusion
Like most products, panel tanks have their time and place. They have limited application, capacity, and design life. When there is a storage need of 80,000L or more and a design life of 25-50 years, the round panel tank is an excellent choice. There is really no competition for the versatility and customisable nature of panel tanks.