The decision between on-site heat exchanger service and workshop service is not simply about which is cheaper or which is more convenient. Each approach is appropriate for a different set of circumstances, and the right choice depends on the equipment involved, the nature of the work required, and the plant’s operational and access constraints. On-site service is not an inferior alternative to workshop service; it is the correct approach in defined circumstances and the wrong approach in others.
Understanding when on-site heat exchanger service is the right option requires clarity about what can and cannot be achieved without removing the equipment. In-situ heat exchanger service covers everything that can be accomplished in the installed position without the capabilities of a controlled workshop environment, what the plant’s operational constraints are, and how on-site service fits into the longer-term maintenance programme for the asset. This article covers the scope of on-site service, when it is appropriate, its limitations, and how it can be combined with workshop service to achieve outcomes that neither approach alone would provide. Call +61 3 9761 7766 to discuss on-site service requirements for your heat exchanger installation.
What On-Site Heat Exchanger Service Involves
The Scope of On-Site Service
On-site heat exchanger service covers the cleaning, inspection, and limited repair work that can be carried out at the plant without removing the exchanger from its installed position. The scope includes tube-side cleaning using portable high-pressure equipment, shell-side cleaning where access is available, tube plugging for failed tubes identified during inspection, gasket replacement for flanged connections and header box covers, and chemical cleaning through temporary circulation connections.
The work is carried out using portable equipment brought to the site and set up in the vicinity of the exchanger. On-site service crews work within the plant’s permit-to-work system, safety management requirements, and access constraints. Heat exchanger servicing Australia-wide involves a range of site types, from compact urban facilities to large remote mining operations, and on-site service capability must adapt to the specific access and environmental conditions of each. The scope of what can be achieved on-site is inherently narrower than in a workshop environment, but for the right application, this scope is sufficient to restore the performance required.
How It Differs from Workshop Service
Workshop service offers capabilities that on-site service cannot replicate: full disassembly of the unit on an overhead crane, comprehensive access to all surfaces including the inside of the shell side with the bundle removed, controlled lighting and ventilation for detailed visual inspection, machining capability for tube sheet preparation, and full weld repair capability to documented procedures. Workshop service produces a more comprehensive assessment and a wider range of repair options.
On-site service in return offers advantages the workshop cannot: no removal, rigging, transport, or reinstallation of the exchanger and no transport damage risk; a shorter interruption to availability; and the ability to maintain equipment that is too large, heavy, or permanently integrated into the plant structure to be practically removed.
When On-Site Heat Exchanger Service Is the Right Choice
Large or Permanently Installed Equipment
Some heat exchangers are installed in positions where removal would require significant structural modification, extended crane operations, or the shutdown of surrounding equipment that is not otherwise in the maintenance scope. Very large shell and tube exchangers on elevated process structures, air cooled units built into a permanent structural steel framework, and heat exchangers with limited headroom above them for rigging are all examples of equipment where removal cost and risk can exceed the cost of the service work itself.
For equipment in this category, on-site heat exchanger service is the practical option regardless of the scope limitations. The economics of removal do not support workshop service at every maintenance interval, and on-site service between major turnarounds is how these assets are kept in a maintained condition.
Service and refurbishment includes on-site crew deployment for cleaning, inspection, and limited repair work at industrial sites across Australia. The on-site service capability covers both air cooled and liquid-cooled heat exchanger types and applies the same AS 9001 documented procedures on-site as are used in the workshop.
Operational Constraints and Short Outage Windows
Many Australian industrial operations run continuous processes where extended outages for heat exchanger removal and workshop service are not available between planned turnarounds. A short maintenance window of a few days allows on-site cleaning and inspection to be completed, identifying any tube plugging or gasket replacement required, without committing to the longer outage needed for workshop service.
On-site service during short planned outages extends the operating period to the next turnaround when a full workshop service can be scheduled. It is a bridge maintenance strategy, not a substitute for comprehensive service. The inspection data collected during on-site service informs the workshop service scope when the turnaround arrives.
Addressing a Specific Defect Without Full Service
On-site service is appropriate when the maintenance requirement is a specific, known defect rather than a comprehensive service. A tube that has failed and can be identified from the service history and process data can be plugged on-site during a short outage without removing the unit. An external flange leak from a deteriorated header box gasket can be corrected on-site by replacing the gasket. Chemical cleaning can be carried out on-site to address a performance decline attributed to fouling without committing to the full scope of a workshop visit.
On-Site Cleaning Methods
Tube-Side Hydroblasting on Site
Portable high-pressure water equipment allows tube-side hydroblasting to be carried out on-site. A flexible lance is inserted through the tube at one end and traversed to the opposite tube sheet, removing internal deposits as it passes. This method requires access to the tube ends at one header box end, either through a removable cover or through the existing nozzle if the nozzle geometry allows lance insertion.
Air cooled heat exchangers with accessible header box covers are well-suited to on-site tube-side hydroblasting. The header box covers are removed, the tube ends are exposed, and the hydroblast lance is inserted tube by tube. The process does not require removing the tube bundle from the unit or separating the air cooled unit from the structure.
Chemical Circulation Cleaning
Chemical cleaning is carried out on-site by connecting temporary hoses and a portable circulation pump to the existing process nozzles and circulating a compatible cleaning solution through the tube side or shell side. The cleaning solution is prepared at the appropriate concentration for the deposit type and circulated for the time required to achieve the target cleaning effectiveness. The solution is then flushed from the exchanger before it is returned to service.
The heat exchanger cleaning process for chemical circulation must account for the same chemical selection considerations as workshop chemical cleaning: compatibility with the tube and shell metallurgy, suitability for the deposit type, and safe handling and disposal of the spent cleaning solution at the site.
Air-Side and External Surface Cleaning
Air-side cleaning of fin surfaces on air cooled equipment is carried out on-site by directing high-pressure water, steam, or compressed air across the fin bundle face from the clean side. The cleaning direction is opposite to the normal airflow direction to push deposits out through the inlet face rather than further into the fin passages. The fan must be isolated and locked out before cleaning begins.
On-Site Inspection Capabilities
Eddy Current Testing on Site
Portable eddy current testing equipment allows tube wall condition assessment to be carried out on-site without removing the tube bundle. The probe is inserted through each tube end in the same way as in the workshop, producing wall thickness data for the full tube length. This makes in-situ heat exchanger service using portable eddy current equipment a practical option for plants that need tube condition data without removing the unit. On-site eddy current testing provides the same tube condition data as the workshop process, allowing a plugging or retubing decision to be made from on-site inspection results.
Shell and tube heat exchanger service that uses on-site eddy current data to define the repair scope can often complete the plugging scope on-site in the same outage as the inspection, without requiring removal to the workshop.
Visual Inspection and Pressure Testing On Site
Visual inspection on-site covers the accessible surfaces after cleaning: tube ends, tube sheet faces visible through the header box access, nozzle connections, and the external shell surface. Surfaces within the shell side that require bundle removal to access are not available for visual inspection on-site.
On-site pressure testing uses a portable hydraulic test rig connected to the exchanger nozzles to pressurise the tube side or shell side to the test pressure and confirm the integrity of accessible joints after repair. The scope of the test covers the joints that have been disturbed during the on-site service and confirms their leak-tightness before the exchanger is returned to service.
Limitations of On-Site Service
What Cannot Be Done On Site
Weld repairs to pressure-containing components, including shell seam repairs, tube sheet weld repairs, and nozzle attachment weld work, cannot be carried out to the standard required for pressure equipment in a typical on-site environment. The controlled conditions available in an accredited workshop, including overhead lighting, ventilation, calibrated inspection equipment, and crane access for positioning, are not replicable on-site in most cases.
Full bundle retubing requires removing the tube bundle from the shell to a workshop environment for tube removal, tube sheet preparation, new tube installation, and joint verification. Bundle retubing cannot be completed on-site for most shell and tube exchanger designs without removing the bundle.
Environmental and Safety Constraints
Chemical cleaning on-site requires containment and collection of the spent cleaning solution and rinse water, which must be disposed of in compliance with site environmental requirements. The volume of chemical waste generated by a large on-site chemical cleaning is significant and must be managed appropriately.
Internal inspection of shell-side spaces constitutes confined space entry in most plants, requiring a confined space entry permit, atmospheric monitoring, standby observer, and rescue equipment. This applies on-site but not in the workshop, where the exchanger can be fully opened and the confined space hazard eliminated before work begins.
Combining On-Site and Workshop Service
Removing Components for Workshop Service While Leaving the Shell in Place
For large shell and tube exchangers where the shell is permanently installed but the tube bundle can be withdrawn, the bundle can be removed and transported to the workshop for retubing while the shell remains on-site. The shell nozzles are temporarily blanked during the retubing period, and the refurbished bundle is reinstalled when it returns from the workshop.
Our Victorian engineering team coordinates combined on-site and workshop service programmes of this type, managing the logistics of bundle removal, workshop service, and reinstallation as an integrated project.
Planning On-Site Service Within a Turnaround Programme
On-site heat exchanger service is most effective when it is planned as a defined element of a broader turnaround or planned maintenance programme. Early identification of which exchangers will be serviced on-site in the current turnaround and which will be removed to the workshop allows resources, access, and outage time to be allocated appropriately.
Industrial heat exchanger maintenance planning that incorporates both on-site and workshop service as complementary tools produces better outcomes than treating one as the default and the other as the exception.
Related Equipment and On-Site Service Scope
Plate Heat Exchangers and On-Site Gasket Replacement
Gasketed plate units are particularly well-suited to on-site service. The plate stack can be disassembled in place by releasing the tie bolts, each plate can be cleaned and inspected individually, and new gaskets can be fitted before reassembly in position. The entire heat exchanger cleaning process for a gasketed plate unit can be completed on-site without removing the unit from its piping connections in most installations.
Oil/Air Coolers and On-Site Access
Oil/air coolers in hydraulic and lubrication systems are compact and often accessible from ground level or from a standard maintenance platform. On-site cleaning through temporary chemical circulation connections, visual inspection of accessible components, and connection gasket replacement can typically be carried out without removing the cooler from its installation. This makes on-site service a practical regular maintenance option for these units between workshop services.
Conclusion
On-site heat exchanger service is the right choice when equipment size or installation constraints make removal impractical, when short outage windows make workshop service timing infeasible, or when the maintenance requirement is a specific defect that can be addressed without full disassembly. It is not a substitute for workshop service when comprehensive inspection, weld repair, or retubing are required.
On-site and workshop service are complementary rather than competing approaches. Heat exchanger servicing Australia-wide requires both capabilities: on-site for the equipment and outage constraints that make removal impractical, and workshop for the comprehensive inspection and repair scope that on-site service cannot replicate. Effective industrial heat exchanger maintenance planning uses both, assigning each exchanger to the service approach that matches its condition, size, and the plant’s operational constraints.
Call +61 3 9761 7766 or contact us to discuss on-site service requirements for your heat exchanger installation.
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