Cold weather can create challenges for chemical storage operations, but freezing isn’t the only concern. As temperatures drop, some chemicals become more viscous, begin to crystallize, or solidify. These changes can interfere with pumping, piping, and transfer operations, potentially affecting the reliability of the entire storage system.
Heat tracing can help address these challenges by maintaining chemicals within a specified temperature range. However, not every chemical storage tank requires supplemental heating. The need for chemical storage heat tracing depends on the chemical, its concentration, ambient conditions, tank location, and operating requirements. Understanding these factors helps determine when heat tracing is appropriate and when it may be unnecessary.
What Is Heat Tracing for Chemical Storage Tanks?
Heat tracing uses heating elements to compensate for heat loss and maintain stored chemicals at a specified temperature. In chemical storage applications, heating elements are typically installed along the tank’s exterior, with temperature controls regulating the system to maintain the desired conditions.
Heat tracing is primarily intended to maintain temperature rather than rapidly reheat a large volume of chemical that has already cooled below its required operating range. The system must be selected based on the chemical’s temperature requirements, tank size, and expected environmental conditions.
Assmann offers heat tracing and insulation systems (https://assmann-usa.com/tank-accessories/) for select polyethylene chemical storage tanks. These systems combine water-resistant, adhesive-backed heating elements with polyurethane foam insulation, a protective mastic coating, and temperature controls to help maintain the conditions required for temperature-sensitive chemicals.
How Chemical Properties Determine the Need for Heat Tracing
The chemical itself is the starting point when evaluating heating requirements. Different chemicals respond differently to temperature changes, and some require more controlled conditions to maintain their properties during storage and transfer.
Viscosity Changes at Lower Temperatures
Viscosity describes a liquid’s resistance to flow. Many chemicals become more viscous as temperatures decrease, potentially increasing pumping requirements, reducing flow rates, and making transfer operations more difficult. The extent of these changes depends on the chemical and its concentration. For applications where viscosity affects handling or processing, maintaining a minimum temperature may be necessary to support reliable operations.
Crystallization and Freezing Risks
Complete freezing isn’t always the first concern. Some chemical solutions begin forming crystals as temperatures decrease, potentially restricting flow through piping, valves, and pumps. Even when the liquid inside a storage tank remains usable, crystallization in smaller components can interfere with chemical transfer.
Heat tracing may be appropriate when a chemical must remain above its crystallization or solidification temperature to maintain normal operation.
Why Chemical Concentration Matters
Chemical concentration can significantly affect viscosity, freezing points, and crystallization temperatures. Sodium hydroxide, for example, behaves differently depending on its concentration. A storage temperature suitable for one solution may not be appropriate for another.
Certain sodium hydroxide solutions can begin solidifying as temperatures decrease, making supplemental heating necessary in some applications. Assmann recommends heat tracing and insulation for sodium hydroxide storage applications (https://assmann-usa.com/solutions/applications/sodium-hydroxide-storage/) where maintaining the chemical above its solidification temperature is necessary. Because temperature requirements vary by concentration, the appropriate storage range should always be established using the chemical supplier’s technical information.
How Location and Climate Affect Chemical Tank Heat Tracing
Environmental conditions also influence whether supplemental heating is necessary. Two facilities storing the same chemical at the same concentration may have different requirements because of their locations and operating environments.
Outdoor vs. Indoor Chemical Storage
Outdoor tanks experience seasonal temperature changes and potentially prolonged cold weather. A tank installed in a mild climate may face different conditions than one exposed to extended periods of freezing temperatures.
Indoor installations often provide more stable conditions, particularly in temperature-controlled facilities. However, tanks inside unheated buildings may still experience temperatures low enough to affect certain chemicals. The deciding factor is the actual temperature range the tank and its contents will encounter, not simply whether the installation is indoors or outdoors.
Regional Temperatures and Environmental Exposure
Average winter temperatures don’t always reflect the conditions a storage system must withstand. Evaluations should consider the lowest anticipated ambient temperatures, the duration of cold exposure, and environmental factors such as wind and temperature fluctuations.
Wind can increase heat loss from tank surfaces when the contents are warmer than the surrounding air. Repeated daytime and nighttime temperature changes, along with prolonged cold periods, can also influence stored chemical temperatures. These conditions help determine whether supplemental heat is needed and how much heating capacity may be required.
For additional information about protecting chemical storage systems during winter conditions, see Assmann’s article, Deicing Chemicals: Proper Storage for Maximum Effectiveness During Winter Storms (https://assmann-usa.com/knowledge-base/blog/deicing-chemicals-proper-storage-for-maximum-effectiveness-during-winter-storms/).
Determining the Right Chemical Storage Temperature
Preventing freezing and maintaining an appropriate operating temperature are not always the same thing. A chemical may remain liquid but become too viscous for efficient pumping, while another may require a higher minimum temperature to prevent crystallization.
The required temperature should account for the chemical supplier’s storage recommendations, transfer requirements, and any upper temperature limits. Excessive heating can also affect chemical stability, making temperature control important in both directions.
Understanding Temperature Differential (Delta T)
An important factor in evaluating chemical tank heat tracing is the temperature differential, or Delta T, between the required maintenance temperature and the lowest anticipated ambient temperature.
Delta T = Required Maintenance Temperature − Minimum Ambient Temperature
For example, if a chemical must remain at 70°F and the lowest expected ambient temperature is 10°F, the temperature differential is 60°F.
This calculation provides a starting point for determining heating requirements, but it does not establish the complete system design. Tank capacity, insulation, heat loss, and operating conditions must also be considered.
Assmann uses tank capacity and Delta T when evaluating heating requirements. Its heat tracing and insulation specifications (https://assmann-usa.com/wp-content/uploads/2021/09/Assmann-Specs-HeatTracingInsulation-2021.pdf) provide additional information about available configurations and temperature-maintenance capabilities.
Heat Tracing and Insulation: Why They Work Together
Heat tracing and insulation serve different but complementary purposes. Heat tracing supplies supplemental heat to maintain the required chemical temperature, while insulation reduces heat transfer between the tank and its surroundings.
Without adequate insulation, more heat may escape into the surrounding environment, increasing the heating capacity needed to maintain the desired temperature. Insulation helps reduce this loss and limit temperature fluctuations, but it does not generate heat. It cannot indefinitely maintain a chemical above ambient temperature without an additional heat source.
For some applications, insulation alone may provide sufficient protection. Others require both heating and insulation to maintain appropriate storage conditions. Assmann’s heat tracing systems combine heating elements with a nominal two-inch layer of polyurethane foam insulation, a protective mastic coating, and temperature controls. Together, these components help maintain temperatures within the required range.
Why the Entire Chemical Storage System Matters
Heat tracing should never be evaluated independently of the rest of the chemical storage system. Tank materials, fittings, piping, valves, and transfer equipment must all be compatible with the chemical and the temperatures they may encounter.
Tank Material and Temperature Compatibility
Polyethylene chemical storage tanks provide chemical resistance for many industrial applications, but material selection must account for both chemical compatibility and operating temperature.
Assmann manufactures vertical chemical storage tanks (https://assmann-usa.com/tanks/vertical-storage-tanks/) using crosslinked polyethylene (XLPE) and linear polyethylene. Both materials have temperature limitations that must be considered when selecting a heating system.
The appropriate operating temperature depends on the tank material, chemical compatibility, concentration, and application requirements. Any heat tracing system must operate within the acceptable temperature range of both the chemical and the tank material. Assmann’s manufacturing specifications identify resin-related temperature limits, but the suitability of a particular tank must be evaluated for its intended application.
Fittings, Piping, and Transfer Equipment
Chemicals inside exposed piping can cool at a different rate than those inside a large storage tank. As a result, a tank may maintain its required temperature while unprotected transfer lines, valves, or other components become cold enough to experience crystallization or solidification.
Heating the tank alone may not prevent these problems. Fittings, gaskets, pumps, piping, and other equipment should be evaluated for chemical compatibility and temperature exposure. Additional insulation or heating may be needed for components outside the tank to maintain reliable transfer operations.
When Is Heat Tracing Unnecessary?
Not every chemical storage application requires supplemental heating. If a chemical maintains acceptable viscosity and does not crystallize or freeze within the expected temperature range, heat tracing may provide little benefit.
Temperature-controlled indoor installations may already provide suitable conditions, while insulation alone may be sufficient for certain applications. The decision should reflect the chemical’s requirements and actual operating conditions rather than an assumption that every outdoor or cold-weather installation needs heating.
Installing heat tracing where it isn’t needed can add equipment and operating costs without providing a meaningful benefit.
Questions to Ask Before Selecting a Chemical Tank Heat Tracing System
Evaluating the complete application is essential before selecting a heat tracing system. Important questions include:
1. What chemical and concentration will be stored? Identify temperature-dependent properties and compatibility requirements.
2. What storage temperature is required? Review supplier recommendations and operating limits.
3. How does the chemical respond to cold? Consider changes in viscosity, crystallization, and freezing behavior.
4. What environmental conditions are expected? Evaluate minimum ambient temperatures, wind exposure, and prolonged cold periods.
5. Where will the tank be installed? Consider indoor, outdoor, and unheated locations.
6. What tank material and capacity are appropriate? Confirm chemical compatibility and temperature limitations.
7. Will piping and accessories need protection? Evaluate the complete transfer system.
8. What temperature differential must be maintained? Determine Delta T using the required maintenance and minimum ambient temperatures.
9. Is insulation sufficient, or is heating necessary? Consider heat loss and temperature-maintenance requirements.
10. What temperature controls are needed? Ensure the system can maintain the required range without exceeding established limits.
Answering these questions can help identify whether heat tracing is necessary and what the storage system may require. Assmann’s technical documents library (https://assmann-usa.com/technical-documents-library/) offers additional information about tank specifications, materials, and available accessories.
Plan Chemical Storage Temperature Control with Assmann
Heat tracing can help maintain the performance of temperature-sensitive chemicals during cold weather, but it isn’t necessary for every application. Chemical properties, concentration, environmental exposure, tank materials, and transfer requirements must all be considered when determining whether supplemental heating is appropriate.
Assmann Corporation of America manufactures polyethylene chemical storage tanks and offers heat tracing and insulation options for select vertical, conical bottom, and horizontal cylindrical configurations. Our team can help evaluate tank selection, heating options, and the specific requirements of your application.
Planning a chemical storage installation or reviewing an existing system for cold-weather operation? Contact Assmann (https://assmann-usa.com/contact-us/) to discuss your requirements and explore the appropriate storage options.
Frequently Asked Questions About Chemical Storage Heat Tracing
Do all outdoor chemical storage tanks need heat tracing?
No. Heat tracing requirements depend on the chemical being stored, its concentration, expected ambient temperatures, and operating requirements. Some chemicals remain suitable for storage and transfer without supplemental heating, even in outdoor installations.
Can insulation replace heat tracing on a chemical storage tank?
Insulation reduces heat loss but does not generate heat. In some applications, insulation alone may provide sufficient temperature protection. When a chemical must remain above ambient temperature for extended periods, supplemental heating may be necessary.
Can heat tracing prevent chemicals from crystallizing?
A properly designed heat tracing system can help maintain temperatures above the crystallization range of certain chemicals. The required temperature depends on the chemical and its concentration. The heating system must also remain within the acceptable temperature limits of the chemical and storage equipment.