Rotomolded Chemical Storage Tank Manufacturers: 10 Suppliers

Technology and applications

Rotational molding starts with a measured charge of polymer inside a closed hollow mold. The mold turns through a heating cycle so the softened material coats its internal surfaces, then continues through controlled cooling before the product is removed. For a typical polyethylene tank, this produces a hollow body without joining two separately formed shells.

That process is different from thermoforming, which shapes a heated sheet. This guide currently appears in the portal's Thermoforming navigation, but the vessels discussed here are rotationally molded. It is also different from extrusion blow molding, where a hot parison is inflated inside a mold.

Chemical storage is only one duty. A stationary atmospheric tank, a dosing reservoir, a mixing vessel and a transport container should not be specified as though they face the same loads. A suitable storage design does not automatically qualify for agitation, road transport, burial, pressure or vacuum. Define the duty before comparing suppliers.

Capacity also needs a clear definition. Ask for the nominal volume, intended working volume and required headspace. A quotation based on the vessel's maximum geometric volume may not provide the usable storage your process requires. Include filling and emptying rates, planned operating cycles and any cleaning procedure in the application brief.

Materials and process control

Polyethylene is available in different formulations, including linear and crosslinked grades used for rotational molding. Those labels alone do not establish chemical compatibility. The stored substance, concentration, temperature, exposure time and mechanical loading all matter. A general resistance chart is a screening tool; use the manufacturer's written assessment for the specified tank system.

Review every wetted component. A compatible body does not compensate for an unsuitable gasket, valve, fitting or level instrument. Ask the supplier to list the proposed materials, including seals and fasteners exposed to the liquid or vapor. Changes in chemical supply, cleaning agents or concentration should trigger another compatibility review.

Wall distribution deserves attention as well as average thickness. Corners, transitions and connection areas can experience different loads from the straight cylindrical wall. Request the manufacturer's inspection approach and acceptance criteria for the chosen design. For crosslinked products, ask how the production process and required material properties are verified; avoid assuming that the resin label proves the finished tank's condition.

Venting is a system-design issue, not just a hole in the lid. Filling, emptying and temperature changes can create pressure differences, while some applications also require vapor treatment. Have the tank supplier and process designer agree the venting arrangement for the actual service. Do not pressurize an atmospheric vessel or adopt a generic vent size from an unrelated installation.

Supplier selection and quality

Start with a written application sheet and ask every supplier to respond to the same information. It should identify the chemical and mixture, operating and upset temperatures, liquid density, working volume, indoor or outdoor location, and expected service conditions. Mark unknowns clearly. A quotation that fills them in silently can make two apparently similar offers impossible to compare.

Next, review the general-arrangement drawing. Check the support surface, tank dimensions, access, connection locations and space needed for replacement or inspection. Pipework and heavy valves should not impose unreviewed loads on the tank wall. Agree how expansion and movement will be accommodated, and who is responsible for the supporting structure.

Ask for an inspection and documentation package proportionate to the service: product identification, material traceability, dimensional checks and the agreed tests. Do not substitute a company-wide quality certificate for evidence about the supplied vessel. Equally, a test result from a different tank size or configuration may not answer the project requirement.

Secondary containment needs its own review. A double-wall product, a separate bund and a site-built containment area differ in access, drainage, leak detection and available volume. Confirm the arrangement with the responsible site engineer and the applicable local requirements. Neither an editorial shortlist nor a manufacturer's general brochure establishes regulatory compliance for a particular installation.

Costs and procurement

Compare the installed scope rather than the tank-body price alone. Quotations can differ in the resin, duty rating, outlet arrangement, fittings, venting, containment, testing, freight and installation support. Ask suppliers to identify exclusions explicitly. An inexpensive vessel can become a costly project if the quotation leaves critical accessories and design work unresolved.

Standard tooling usually changes the procurement conversation: buyers select from established geometries and then agree the permitted configuration. Custom molding adds tooling ownership, design approval, sampling and validation. Before paying for a mold, establish the expected production quantity, revision process, storage arrangements and what happens if the project moves to another manufacturer.

For large tanks, freight and site handling can materially affect installed cost. Check shipping dimensions, lifting instructions, site access and unloading responsibility before committing. An installation drawing should be available early enough to coordinate civil works and pipework; the delivery date alone is not a complete project schedule.

Finally, agree the handover and maintenance documents. Record the approved contents and duty so a later operator does not assume the tank can be reassigned to another chemical. Define the inspection responsibilities, replacement-parts route and the process for reporting damage. Warranty terms deserve a separate review alongside the operating and installation limits.

Frequently asked questions

Are rotomolded chemical tanks the same as water tanks?

No. They may look similar, but the specified resin, wall design, density rating, connections and intended duty can differ. Tell the manufacturer exactly what will be stored and under which conditions. Do not fill a water tank with a chemical simply because polyethylene appears compatible in a general chart.

Is crosslinked polyethylene always the better choice?

There is no universal choice for every chemical-storage project. The resin, chemical exposure, tank design and lifecycle requirements must be assessed together. Ask the manufacturer to explain its proposed material for your application, including any constraints on fabrication, repair or end-of-life handling, rather than selecting by a broad material label.

Can a storage tank be used for mixing?

Only when the selected tank and its supporting arrangement are designed for that service. An agitator introduces loads and operating conditions that a simple storage specification may not cover. Confirm the support for the mixer, baffles if required, connections, cleaning procedure and process conditions with the equipment and tank suppliers.

What should I send with a request for quotation?

Send the chemical identity and concentration, temperature range, density, working volume, filling and emptying rates, site location, connection schedule and containment requirements. Include a layout drawing if available and identify the responsible process engineer. State which assumptions are unresolved so suppliers can qualify their offers without inventing operating conditions.

Related supplier guides

For a process comparison involving smaller hollow industrial products, see extrusion blow molding companies. If the project instead needs welded hollow structures made from two heated sheets, review twin sheet thermoforming companies. Neither process should be substituted solely because the finished parts are hollow; application, material, geometry and production requirements determine the useful shortlist.

Image credit

PlasticParts Hub editorial illustration.