Tanks and Custom Fabrication

Chicago Boiler Company has designed and fabricated quality metal tanks and pressure vessels for over a century. Our extensive design capabilities, vast experience and production resources enable us to meet challenging custom metal fabrication requirements.

We custom metal fabricate ASME tanks, air tanks, pressure tanks, acid tanks, fuel/oil tanks, storage tanks, condensate receivers, blow-down tanks, reactor vessels, hydro-pneumatic tanks, filter tanks, scrubbers, separators, portable tanks, cyclone tanks and even therapeutic pools. The majority of the tanks that are available from Chicago Boiler Company are steel or stainless steel. If you have a tank design in mind we are up to the challenge!


  • ASME tanks code & non-code
  • API-650 & API-620
  • CRN
  • UL-142
  • Minimum of 6 inch Diameter; Maximum of 12.5 Foot Diameter
  • Minimum of 18 inch Length; Maximum of 110 Foot Length

Vessel Types:

  • Compressed Air Tanks
  • Pressure Vessels
  • Storage Tanks
  • Acid Tanks
  • Reactor Vessels
  • Mixing Tanks
  • Portable Tanks
  • Blow-Down Tanks
  • Filter Tanks
  • Cyclone Tanks

Blasting & Coatings:

  • Glass Bead Blasting
  • FDA Approved Coatings
  • Potable & Non-potable Coatings
  • Powder Coatings
  • Chemical Resistant Coatings

Additional information regarding Chicago Boiler's custom metal products can be found in this brochure.

Shown below are a couple tanks of different sizes displaying our versatility of products. Please visit our Custom Metal Fabrication Gallery to view some of our unique tanks.

click for larger image click for larger image
Small Air Tank Large Fuel Storage Tank

ASME Tanks

Tanks and vessels manufactured by Chicago Boiler Company can be constructed to a variety of codes and standards. Chicago Boiler Company is an ASME certified manufacturer. We manufacture pressure vessels to every aspect of the standard. Code vessels can be supplied for vacuum or pressure service and for use in aggressive environments.

The ASME code(American Society of Mechanical Engineers) is a quality standard assuring the highest quality product that insures safety, reliability and economy. Manufacturing a vessel per code guidelines requires multiple reviews and inspections by an independent certified inspector and the use of certified, pressure vessel-rated, materials. Most vessels will undergo three reviews/inspections. These are reviews of the design calculations and material certifications, reviews and inspections of the initial assembly and finally a witnessed non-destructive test prior to shipment of the vessel. All of this insures quality and safety of the vessel for the designed service.

Here at Chicago Boiler Company, we have been fabricating custom ASME code tanks since 1891. If you have questions regarding a tank design, our engineering/design department has solutions to help you comply with regulations. They are also available for assistance in making your tank design as cost effective and functional as possible.

ASME Construction Process

A tank manufactured to ASME standards requires a series of inspections and careful planning. Even the simplest vacuum or pressure rated tank design must follow these strict steps. Following these steps will completely ensure the safety and service life of the vessel.

Step 1) Design review
All vessels are designed to meet the latest edition of the ASME Boiler and Pressure Vessel Code, Section VIII Division 1. Engineering calculations are performed to verify or determine the material thickness required for the design pressure and temperature of the vessel. A simple vessel design calculation will examine the circumferential welds, the longitudinal welds, joint design, joint bonding efficiency, type of metal selected, working pressure and vessel size. If the vessel has openings, the size, type, location, and number are also included inthe original design review. After this design review is complete, a set of working drawings will be created. All custom tanks will require subsequent review and approval by the purchaser. Since this is a custom product manufactured to meet a specific application, no work will be started until the purchaser agrees to the tank design. Once the design is approved by the purchaser, the next step is fabrication.

Step 2) Fabrication
Fabrication is the process of creating the components of a metal tank. Flat plate stock is rolled to the required diameter. This diameter is based on the diameter of the tank ends (also known as heads), because the tank heads can vary slightly in diameter. By checking this diameter, a smooth transition to the tank end to tank end can be achieved. The tank heads are also prepared to be joined to the vessel. All of the openings are then drilled or burned into their locations. This is now the beginning of a basic tank. Once all of these pieces of the tank have been created, the process moves to the next step: Fit Up.

Step 3) Fit Up
Fit Up is the initial assembly of the tank. It involves joining together the vessel, heads and major openings. Once these pieces are assembled, work is stopped and the vessel will be inspected by an independent inspection service. The inspector will review initial welding, metal to metal contact points and the overall construction of the tank. Once this step is completed, the vessel will move on to welding.

Step 4) Welding
The next step to completion of the tank requires the vessel to be welded by certified welders. Prior to this step, each welder must pass a series of semi-annual qualifying test welds to prove his ability to properly bond the components. Additionally, each step of this procedure from design to fabrication is documented and noted with the individual performing the task. In the case of welding, each welder must sign off indicating the welding function was performed to the best of his or her individual skills and when that function was performed. When the welding step is completed, the next step is a non-destructive evaluation of the vessel.

Step 5) Non-Destructive Testing (NDT)
The non-destructive testing of the vessel involves filling the vessel with water and then applying pressure to the vessel. This is the safest and most reliable method to discover failures of the welds (pinholes, cracks, and missed welds). If a pinhole is discovered the leak usually drips or, in very rare cases, water will squirt out of the hole. Testing with water is the preferred method because of water’s resistance to compression and is commonly referred to as hydrostatic testing. A witnessed hydrostatic test is conducted with the independent ASME pressure vessel inspector. Following the witnessed hydrostatic test, a permanently attached label is installed on the vessel, and final paperwork is signed and submitted to the customer and to the National Board of Boiler and Pressure Vessel registers. The internal paperwork procedure is completed and the vessel is prepared for painting and shipping.

Read more: ASME Tanks


API-650 and API-620 Tanks

Chicago Boiler Company builds custom shop fabricated vessels designed for oil storage according to the API-650 Appendix J and API-620 standards. The API standards establish minimum requirements for material, design, fabrication, erection, and testing. This is done for vertical, cylindrical, above ground, closed- and open-top, welded storage tanks of various sizes and capacities for internal pressures. The Standard is designed to provide the industry with tanks of adequate safety and reasonable economy for use in the storage of liquid products. Unlike ASME, this standard does not require independent inspection. It is considered self-regulating, requiring the purchaser and/or the manufacturer to demonstrate code compliance. Some of the typical design requirements are opening size, type and location, welded joint requirements, material thicknesses, venting, piping and flame arrestors when required.

Read more: API-650 and API-620 Tanks


UL 142 Tanks

Chicago Boiler Company is  also in compliance with manufacturers compliance standard UL-142. Underwriters Laboratories has long been recognized as a world leader in safety, setting standards and codes providing safe and reliable products. The UL 142 standard is a regulated and inspected standard that establishes the minimum requirements for material, design, fabrication, erection and testing. This is done for vertical and horizontal above ground atmospheric storage tanks of various sizes and capacities for internal working pressures not exceeding 1 PSIG.

Read more: UL 142 Tanks


Carbon Steel Tanks

Carbon steel is the most economical choice for a construction material. Low cost materials, flexibility, and reliable service make carbon steel tanks a good all-around choice. There are many conditions that may not allow the effective use of carbon steel. Aggressive chemicals, harsh environments, service temperatures, and weight restrictions may be factors in the decision of whether or not to use use carbon steel vessels. A variety of coating materials are also available with the purchase of any carbon steel tank.

Read more: Carbon Steel Tanks


Stainless Steel Tanks

Probably the most popular material choice for almost any application is Stainless Steel. We currently fabricate an equal number of stainless steel tanks as we do all other materials. Many customers are recognizing the benefits of using stainless steel over carbon steel in their manufacturing process. In many cases, using stainless steel improves clean up resulting in lower manufacturing costs. Most tanks internal finish requirements are intended to assist in cleaning the vessel. Stainless steel vessels also improve the overall appearance of the work area, by promoting a cleaner and neater work environment, again because of the ease of cleaning.

Read more: Stainless Steel Tanks


Reconditioned Tanks

Repair or reconditioning of a vessel is a very subjective choice by the customer. It is well known that reusing existing resources conserves precious natural resources by saving raw materials and reducing environmental footprints, as well as conserving corporate resources. The final decision is usually made by weighing the cost of repair vs. the new replacement cost and the length of available downtime to remove and install a new vessel. Chicago Boiler works as a partner by assisting in the evaluation of the existing vessels and providing economical alternatives to new purchases. Additionally, if the original vessel is an ASME Code rated vessel, we are a fully licensed ASME repair facility. Full inspection of the vessel can be executed at our shop, with the repair usually costing a fraction of the price of a new tank.

Read more: Reconditioned Tanks


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Call us: 847-662-4000

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Call us now at (847) 662-4000 and talk to your experts to learn more. Jim x 331 or Denny x 313.