Preload – Your prestressed concrete tank solution

Preload offers you nearly a century of experience in prestressed storage tank design and construction. Many of the storage challenges our customers present to us today are challenges we’ve met throughout our many years in business.

From potable water to wastewater and thermal energy storage (TES) to industrial applications including the storage of liquids at cryogenic temperatures, you can rely on Preload engineering and construction expertise to develop the perfect solution for your challenge.


Preload’s wire-wound prestressed concrete tanks meet water storage needs for thousands of communities worldwide

Worldwide, communities have discovered unmatched advantages of owning Preload tanks, including no routine maintenance or scheduled downtime! Preload delivers the highest-quality and most cost-effective water storage solutions, leading the wire-wound prestressed concrete tank industry in:

  • High-efficiency baffle wall designs that meet mandated disinfection requirements
  • Flexible site options that accommodate virtually any site, no matter how challenging
  • Security features that safeguard and protect community water systems

Whatever your water storage requirements, Preload has the resources, experience, and specialty to help you meet them.


Preload’s baffle wall designs achieve optimal disinfection

Baffle Wall Specialists – At Preload, we have unmatched experience in building baffle wall tanks to help you meet the Safe Drinking Water Act (SDWA) regulations for disinfection. We know how to shape and position the baffles and direct the water flow to efficiently achieve the required chlorine contact time (CT).

Why Use Baffle Flow– To kill or inactivate such harmful organisms as Giardia cysts and bacteria, disinfectants are added to water systems. The effectiveness of the disinfectant depends on several factors, an important one being the amount of time the water stays in contact with the disinfectant: its “hydraulic residence time.” A water storage tank’s baffle wall design configuration can result in a higher, more-efficient “hydraulic residence time.”

Baffle Wall Designs – The most common baffle wall configurations are straight or a combination of C-shaped and straight. Baffle walls may be precast, cast-in-place, masonry block, or fabric.

At Preload, we are well versed in designing and constructing all varieties of baffle wall solutions. As a leading provider of effective water storage solutions since 1930, we are at the forefront of configuring water storage tanks to meet SDWA-mandated CT values. Communities nationwide are turning to Preload for today’s most advanced baffle wall tank designs.


No matter the weather, site, or soil conditions, Preload can build a tank at virtually any location

The Preload Team analyzes the topography, geology, and other local conditions when designing and constructing a tank. Our flexible designs can accommodate a wide range of adverse or unusual loading conditions.

We can vary the height-to-diameter ratio and tank elevation to meet your facility’s design, hydraulic gradient, and space requirements.

Preload tanks can be fully buried, and can even be designed to resist hydrostatic uplift in flood-prone areas. We frequently design and construct tanks in seismic zones and on sites with differential backfill elevations.


Protecting unauthorized access to water storage

Security of a community’s water system is essential to public safety. That’s why Preload offers many features to protect your tank from unauthorized access.

Security vents – Preload offers securely fastened, stainless steel security vents protected by heavy-duty cages. We can further protect these vents with two layers of stainless steel screening. For buried tanks, we can install gooseneck vents that utilize two layers of stainless steel screening.

Anti-climb ladder accessories – Preventing unauthorized climbing on tank ladders is an especially important security feature that Preload offers. We install anti-climb plates that securely lock the ladder to stop intruders.

Manway covers – Manways are protected with heavy-duty security covers equipped with padlocks.

Overflow exit screens – Preload offers stainless steel screening to guard tank overflow exits. Our screening is heavy-duty and securely fastened. In addition, we can install a duckbill-type check valve up-line of the exit.

Dome hatch alarms – We offer and install dome hatch intruder alarms that notify a central control station in the event of an attempted intrusion.

Tank security systems – Preload can install intruder detection systems that integrate video and motion detection features located on and around the tank, with wireless connection to a central control station.


Preload wastewater tanks are reliable, efficient, and cost-effective

Since 1930, Preload has provided municipalities and private industry with the highest quality, most dependable wastewater and process tanks. Not only is a Preload wire-wound prestressed concrete tank a superior containment structure, it’s a good value because it requires negligible maintenance throughout its long life.

With their proven reliability, efficiency, and long-term cost savings, Preload wire-wound prestressed concrete tanks deliver the ideal wastewater CSO/SSO/EQ storage, wastewater treatment, and wastewater reuse storage solutions.

You can choose from a wide range of styles and sizes. Our tanks can be built at grade or partially buried, incorporate a clear-span dome roof or designed as an open top. They can accommodate almost any site location and withstand severe loading conditions.


Preload sewer overflow storage tanks prevent erosion and environmental health hazards

Combined sewer overflows (CSO’s) and sanitary sewer overflows (SSO’s) occur during major storm events due to a wastewater system’s design or infiltration into piping. Sewage system overflows can create serious health hazards and can endanger habitats, leading to closure of streams and recreation waterways.

Preload tanks are the cost-effective solution to collect sewage system overflow and store the water until it can be reused or treated. Since Preload tanks can be built covered or open top, above and below grade, they can accommodate myriad CSO/SSO/EQ storage configuration needs faced by today’s engineers and municipalities.

Preload engineers have a broad range of experience in the successful design of CSO/SSO storage tanks and equalization basins, and can easily incorporate the required conical floors, odor control systems, wash-down systems, and mixing equipment for these storage applications.


Optimal storage solutions for a broad range of wastewater treatment tanks

Preload tanks are proven to provide effective solutions for wastewater treatment including aerobic and anaerobic digesters, primary and secondary clarifiers, and sludge storage. Our wastewater treatment tanks are designed to incorporate the necessary structural components for the treatment process.

  • Primary and secondary clarification tanks include effluent launders with connection points for weir plates, internal or external drop boxes, and center piers that support treatment equipment and incorporate process sumps.
  • Aerobic and anaerobic storage tanks include sloped floors designed to increase the efficiency of the treatment process. Gas-tight concrete domes are incorporated into the design of anaerobic storage tank structures, enabling the structure withstand internal pressures generated through the treatment process.

Regardless of the application, our engineering team can easily incorporate customized connection points for equipment, as well as incorporate multiple penetrations through the tank wall for process piping.

To contain highly aggressive materials, such as those with low pH, Preload tanks typically incorporate interior liners or coatings.


Water reuse: Recycling is not just for bottles, papers, and cans

Water reuse continues to be an important step in the treatment process, particularly in geographic regions where water is scarce and rainfall is inconsistent to meet the demands of industries and residential customers. Reuse water is stored after the treatment process and is made available to businesses , to homeowners, to the agriculture industry for irrigation water, and to other industries for process and cooling water.

Recycling water on site or nearby reduces the energy needed to move water longer distances or to pump water from deep within an aquifer. In addition, tailoring water quality to a specific water use, such as golf course irrigation, reduces the energy needed to treat potable water.

Preload tanks have proven to provide effective solutions for water reuse tanks.


Reducing energy costs, one Preload tank at Trenton_NJa time

In line with Preload’s tradition of designing and building sustainable and maintenance-free prestressed concrete tanks, Preload thermal energy storage (TES) tanks serve as vital components in highly efficient, long-lasting centralized cooling systems.

Preload TES tanks provide universities, hospitals, and government facilities the capability to realize hundreds of thousands of dollars in savings on energy costs while increasing sustainability and overall efficiency.

TES has a variety of other applications including turbine inlet cooling (TIC) at power generation facilities, emergency cooling for data centers and server farms, and dual purposing for fire protection water storage as a secondary use.


How thermal energy storage (TES) works

Thermal energy in the form of chilled water or heated water is produced during the off-peak times of less electrical demand. This chilled or heated water is collected in a thermal energy storage tank, and is then withdrawn and distributed to the facility during the peak heating or cooling periods. This technique is known as “load shifting.”


Load shifting is beneficial in two ways:

  • It allows the chilling facility to cut costs on energy use by avoiding peak power prices, and
  • It increases the efficiency of the system by running at night when temperatures are cooler.

Although the TES energy-saving technology has been available for decades, it has never before seen the far-reaching potential for application that it does now.



Thermal energy storage (TES), with its load-shifting operation technique, is a proven energy-saving technology that cost-effectively regulates plant load requirements. Large-scale developers are increasingly aware of the significant returns from rate off-setting, and reduced capital costs provided by thermal energy storage (TES).

Take advantage of rate offsets – If a new power plant is an infrastructure component of a large-scale development that integrates load regulation (shifting), the power plant has the ability scale back, thus reducing not only its construction and maintenance costs, but also minimizing the overall carbon footprint. In many cases, power providers offer incentives for facilities that utilize TES. These offsets are significant enough that the majority of new TES projects pay themselves off within 5 years.

Minimize capital costs – In addition to savings from rate offsets, adding TES can also reduce initial costs by using chillers more efficiently.

  • New chiller plant projects can benefit from TES because it reduces the peak load requirement, thus fewer or smaller chillers are required.
  • For chiller plant expansion projects, TES can be integrated into the existing infrastructure seamlessly to enhance efficiency by allowing for useful generation during times when the plant would otherwise be dormant.

Preload offers value assessments including capital planning budget estimates, plant opticase2mization, and capital return period based on project-specific analysis.


Storing chilled water and keeping it chilled


The key to maintaining the temperature of the chilled water over long periods of time is to minimize heat transfer with warmer surroundings. Any heat transferred to the chilled water increases the temperature and releases some of the stored energy. Although Preload carefully designs an insulation system to minimize ambient heat gain from the outside air, most significant potential for heat gain actually occurs inside the tank. We install diffusers inside the tank to keep warm water from invading the cold water at the bottom of the tank.

Eliminating turbulence and maintaining the thermocline – As a part of a closed loop system, a TES tank also stores warm water that is returned from the heat exchanger (air conditioning unit). Warm and chilled water enter and exit the tank through diffusers located at the top and bottom of the tank, respectively. These diffusers are designed to eliminate turbulence and provide a stable, sharply defined transition layer, or “thermocline,” which allows for the natural stratification of warm water at the top of the tank and chilled water at the bottom.


Diffuser piping arrangements


The diffuser piping is arranged in such a way that it “spreads” flow equally over a large area in order to minimize mixing. There are a number of ways to accomplish laminar flow within the tank and Preload offers unmatched experience with a variety of arrangement options to suit projects of all types.

Octagons for typical applications – Most TES systems utilize an octagonal arrangement. This type of system is perfect for larger-volume applications, such as district and turbine inlet cooling (TIC). As the name suggests, piping in this system is constructed with a number of concentric octagonal “rings,” each having evenly spaced inlet slots which distribute flow. For higher-flow applications, additional rings may be added to ensure adequate distribution. By adding more rings, the initial flow is split several times, which reduces the velocity through each pipe slot.

diffuser3 copy

“H” pipe for smaller applications – For such smaller applications as emergency cooling for data centers, an “H” configuration is optimal. In this case, the smaller tank diameters often associated with emergency cooling limit the number of rings that can be constructed practically. Also, since flows tend to be higher for these applications, the straight pipe sections cover more plan area than a ring configuration might allow.


Industries rely on Preload for safe prestressed concrete storage tank construction

Since 1930, industries have relied on Preload to safely construct high quality liquid storage tanks which exceed the stringent demands of the industrial environment. Preload has constructed wire-wrapped prestressed concrete tanks for some of the largest industries and engineering procurement construction (EPC) clients in the world including applications for process water storage and treatment, fire protection storage, and petroleum and crude storage.

Our expertise even extends to the design and construction of wire-wrapped prestressed concrete storage tanks for liquids stored at cryogenic temperatures well below minus-260 degrees Fahrenheit.

Whatever the difficulty level, Preload is prepared to design and safely construct a high quality liquid containment structure.


Preload leads in design and construction of LNG prestressed concrete tanks

Preload was the first company to introduce the design and construction of prestressed concrete tanks for the storage of liquid natural gas (LNG), in which the stored cryogenic product comes in direct contact with the concrete wall. Our engineers have spearheaded the formation of ACI Committee 376, “Design and Construction of Prestressed Concrete Tanks for the Containment of Refrigerated Liquefied Gases (RLG).” Preload tanks are proven to be ideal for the storage of crude oil and petroleum distillate products, both above and below ground.

Preload prestressed tanks feature a versatile material with properties capable of providing safe solutions to cryogenic storage containers and protective systems. The use of prestressed concrete for low-temperature applications offers designers a wide variety of concept options.

We have constructed some of the largest tanks in the world for LNG applications.


Over 80 years of reliable industrial storage for process and fire protection… and still going

As the pioneer of wire-wrapped prestressed concrete tanks, industries have relied on Preload for the safe construction of high quality prestressed concrete storage tanks for over 80 years. Preload has more tanks in successful use in industrial applications than any other prestressed concrete tank manufacturer. Our unique understanding of the stringent safety requirements of industrial sites is second to none. The number of tanks in use today in industrial applications is a testament to the long-term durability of tanks designed and constructed by Preload.

Industrial customers choose wire-wrapped prestressed concrete tanks for critical process and fire water applications because Preload tanks require zero downtime for maintenance over the life of the structure. Therefore, gaps in fire protection or processes are practically eliminated.


With the price of energy on the rise, the need for biofuel storage is ever increasing

Preload prestressed concrete tanks provide the durability, flexibility, and safety to store liquid biofuels and biogases. Depending on the storage need, a Preload tank can be built to various height-to-diameter ratios with flat or dome roofs, or open top. As with all our digester tanks, we can incorporate the necessary conical floors and mixing equipment utilized for the treatment of biofuels.


Our extensive industry experience offers many different solutions for your project’s needs.

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