| Process requirements | Working fluid, operating temperature range, required heat-transfer duty, batch size, and expected heating or cooling time. | Are the design assumptions based on the actual fluid, process load, and operating cycle? | Size the tank and heat-transfer surface for the process duty. Confirm operating limits with the equipment designer; avoid selecting by volume alone. |
| Pressure and venting | Whether the tank is atmospheric or designed to operate under pressure or vacuum; the applicable design pressure and vent arrangement. | Is the vessel intended for the actual pressure conditions? Can it be safely vented during filling, heating, and draining? | Do not treat an atmospheric tank as a pressure vessel. Where pressure or vacuum is possible, verify the vessel rating and required protective devices against applicable local requirements. |
| Overtemperature protection | Temperature control limits, independent high-temperature cut-out, alarm behavior, and the safe response to sensor or controller failure. | Can a separate protective device stop heating if the primary controller or sensor fails? | Look for a clearly defined high-limit protection strategy and a documented reset procedure. Setpoints must suit the fluid and process; there is no universal safe temperature. |
| Pressure relief and expansion | Thermal expansion provisions and, where applicable, correctly selected pressure-relief devices and discharge routing. | Could trapped liquid expand during heating? Is any relief device appropriate for the vessel and its service? | Confirm the system cannot be unintentionally isolated with liquid trapped between closed valves. Relief arrangements should be designed and reviewed for the specific system. |
| Materials and fluid compatibility | Tank, coil, gasket, seal, and fitting materials in contact with the process fluid and heat-transfer medium. | Are materials compatible with the fluids, temperatures, cleaning chemicals, and expected corrosion conditions? | Obtain material specifications and compatibility guidance for the actual service. Consider corrosion, contamination limits, and cleaning requirements. |
| Temperature and level monitoring | Sensor location, measurement range, display or alarm visibility, and low-level or dry-heating protection where relevant. | Does the sensor represent the process temperature? What happens if the tank level drops below the safe operating point? | Choose monitoring points that reflect the process, and verify that alarms or interlocks respond to foreseeable low-level and sensor-fault conditions. |
| Controls and interlocks | Controller functions, alarm indication, heating enable conditions, restart behavior after power loss, and manual override access. | Can operators identify a fault promptly? Does the system return to a safe state after an interruption? | Review the control sequence and failure responses before purchase. Require clear alarm meanings and controlled restart procedures appropriate to the process risk. |
| Operator protection | Insulation, hot-surface guarding, accessible valves and drains, spill management, and safe access for sampling or cleaning. | Can routine tasks be performed without unnecessary exposure to hot surfaces, hot fluid, or unexpected discharge? | Check the installed layout as well as the tank itself. Insulation and guarding should suit the operating environment and remain serviceable. |
| Inspection and maintenance | Access for inspecting the vessel, coils, connections, seals, instruments, and any installed protective devices. | Are inspection points accessible? Are maintenance intervals and functional tests documented? | Request operating and maintenance instructions, recommended inspection tasks, and records for protective-device checks. Follow applicable regulations and the equipment documentation. |
| Cleaning and drainage | Drainability, clean-out access, dead spaces, surface finish where relevant, and compatibility with the cleaning method. | Can the tank be emptied and cleaned effectively for the process and fluid being handled? | Confirm that drain connections and access points suit the actual cleaning procedure. Hygienic or contamination-sensitive service may require additional design criteria. |
| Documentation and installation | Drawings, nameplate limits, wiring information, commissioning checks, utility requirements, and site-specific installation constraints. | Can the supplier provide enough information for safe installation, operation, inspection, and troubleshooting? | Verify the tank’s rated limits and installation requirements before commissioning. Confirm local code, permitting, and inspection obligations for the site and service. |