Water Treatment Insulation & Trace Heating Case Study | Oswestry WWTW
The Result
Powertherm delivered a fully coordinated multidiscipline industrial services package at Oswestry Wastewater Treatment Works (WWTW), providing water treatment insulation, electrical trace heating, scaffolding access and bespoke flexible insulation systems. By delivering these services through a single contractor, the project benefited from streamlined coordination, improved programme efficiency and consistent quality standards throughout construction. The solution provided long-term frost protection, thermal efficiency, enhanced maintainability and reliable asset performance across critical process infrastructure.
Project Highlights:
- Multidiscipline service delivery
- Enhanced programme efficiency through a single-contractor solution
- 300m independent pipe bridge installation
- Approximately 150 scaffold structures active at peak
- 2,000+ lin/m of trace heating installed
- Frost protection provided to critical chemical dosing systems
- 680+ bespoke insulation jackets and enclosures manufactured in-house and installed on-site
- Engineered pipe rack insulation enclosure solution reduced installation time by approximately 50%
- Improved access for future inspection and maintenance
- 370 lin/m of thermal insulation and cladding installed across multiple process assets
- Long-term asset protection and thermal performance
- Safe and coordinated delivery across multiple site areas
Project Overview
Oswestry WWTW was undergoing a major upgrade programme to improve site capacity, operational efficiency, and long-term asset performance. As part of the works, new process infrastructure was being constructed alongside the refurbishment of existing assets.
Powertherm was appointed to deliver a coordinated multidiscipline package comprising scaffolding access, water treatment insulation, electrical trace heating, and bespoke flexible insulation jacket systems.
Project/ Site Details
- Site Name: Oswestry Wastewater Treatment Works
- Location: Oswestry, UK
- Industry: Water Treatment/ Utilities
- Contract Type: Construction
- Services: Scaffolding Access, Thermal Insulation, Flexible Insulation Jackets, Electrical Trace Heating
(Picture Credit: Murphy Group)
The Challenge – Scope of Works
The upgrade works at Oswestry WWTW involved the refurbishment of existing assets alongside the construction of new process infrastructure across multiple operational areas of the site. The scale and diversity of the project required a coordinated approach to support a range of specialist activities, including scaffolding access provision, thermal insulation, and trace heating works.
The scope covered a wide variety of process assets, from chemical dosing facilities, storage tanks and associated pipework networks. Each area presented its own technical and operational requirements, requiring solutions that could support construction activities while also meeting the long-term performance, maintenance, and protection needs of the completed installation.
A key challenge involved providing frost protection to eight dosing lines installed within a restricted 900mm-wide pipe rack, where conventional insulation methods were impractical and an engineered solution was required.
Successfully delivering the project required close coordination between disciplines, ensuring works were completed safely, efficiently, and in line with the wider construction programme.
What we Delivered – Technical Multidiscipline Solutions
Powertherm provided a coordinated multidiscipline industrial service package throughout the Oswestry WWTW project, combining scaffolding access, thermal insulation, electrical trace heating, and bespoke flexible insulation solutions. This integrated approach enabled Powertherm to support the construction programme while providing practical solutions to complex installation and maintenance challenges across the site.
Scaffolding Access
While on site at Oswestry WWTW, Powertherm’s access division delivered scaffolding support to provide safe access for all contractors on the construction site.
One of the most technical elements was the installation of a 300m pipe bridge. The independent pipe bridge provided full access to pipes and cable systems across its 6m width and stood at heights of three and four lifts. This phase alone utilised up to 200 tonnes of scaffolding materials, combining traditional tube and fitting with Layher system scaffolding to meet both structural and access requirements through an integrated scaffold system.
At peak activity, approximately 150 individual scaffold structures were in operation simultaneously, including TG20:21 compliant scaffolds like independents and birdcages as well as scaffolds that required designs. The site initially focused on shuttering works for new concrete structures, followed by the installation of modular staircases providing safe access in and out of newly constructed water cells as well as to the roof of various newly constructed buildings, all of which included edge protection.
This was then succeeded by a wide range of scaffolding solutions designed to support the installation of electrical systems, mechanical equipment, and extensive pipework, demonstrating a highly coordinated, efficient and adaptable approach throughout each stage of the build.
Water Treatment Insulation
Powertherm delivered thermal insulation and cladding services across a wide range of process assets at Oswestry WWTW. The scope covered chemical dosing systems, pipework networks, and associated process equipment across the following areas:
- Chemical Area & Building
- Chlorine Contact Tanks
- Salt Saturators
- Sodium Hydroxide Delivery Area & Tanks
- Sodium Hypochlorite Tanks
Pipework and associated fittings were insulated using 100kg/m³ mineral wool BCO pipe sections and clad with 0.6–0.8mm Aluzinc sheeting, depending on pipe diameter.
A total of 370 lin/m of pipework serving critical chemical process systems was insulated with 40mm thick mineral wool BCO pipe sections. The insulation system was subsequently clad with prefabricated Aluzinc sheeting to provide a durable protective finish and safeguard the insulation from environmental exposure and mechanical damage.
The water treatment insulation system reduced heat loss, helped maintain process temperatures, improved personnel safety by limiting exposure to hot surfaces, and provided long-term asset protection through a durable Aluzinc cladding finish.
Electrical Trace Heating
Over 2,000 lin/m of frost protection trace heating was installed to critical pipework and associated equipment within the chemical area of Oswestry WWTW. The system was designed (in accordance with BS EN 62395) to protect key process lines from the effects of low ambient temperatures, reducing the risk of freezing, process disruption, and asset damage to infrastructure essential to the operation of the plant.
8 dosing lines were installed on a 900mm pipe rack running from the static building into the chemical building, all 8 lines required trace heating for frost protection.
Considering there was insufficient room to apply the associated insulation to the individual pipes, our engineering design team had to come up with a suitable solution to minimise heat losses from the electrical trace heating system, whilst providing thermal insulating capabilities. After calculating the heat losses, our CompEx certified trace heating team calculated that trace heating each individual line and then enclosing the whole pipe rack in flexible insulation enclosures was the optimal solution and would actually cut the installation time in half, when compared to insulating each individual line.
In addition to the dosing lines 800 lin/m of frost protection trace heating was installed to process pipework in the chemical area. The system included a standby tracer on the Sodium Hydroxide and Sodium Hypochlorite lines.
Self-regulating trace heating cables were installed to protect pipework against potential damage from the external environment, monitored through temperature senses, should the ambient temperature drop below the specified level, the trace heating elements will energise, providing heat through the system and in turn protecting the dosing lines from freezing and potential damage.
Flexible Removable Insulation Jackets
Powertherm’s scope included the full site measurement, manufacture, and installation of over 680 bespoke insulation jackets and enclosures designed to suit varying pipe sizes, valves, flanges, and pipe rack configurations. Also 65+ removable insulation jackets fitted to valves and flanges associated with process pipework across the site.
Our custom in-house manufactured flexible insulation jackets were designed to meet the performance specifications of valves and flanges within the Chemical Area and Building, Chlorine Contact Tanks, Salt Saturators, Sodium Hydroxide Delivery Area and Tanks and Sodium Hypochlorite Tanks.
Dosing Pipework Insulation Jackets
To meet the operational and maintenance requirements of the dosing line systems, Powertherm provided removable insulation jacketed systems designed to maintain process temperatures while allowing easy access for inspections and maintenance.
- 32mm Armaflex pipe section insulation
- Grey silicone glass cloth inner and outer finish
- Velcro and drawcord fastening system
- Designed to suit 30mm & 70mm OD trace heated dosing lines
Pipe Rack Insulation Enclosures
To protect the trace-heated dosing lines installed on the pipe rack, Powertherm delivered bespoke removable insulation jackets designed to deliver reliable thermal performance while ensuring full accessibility for ongoing maintenance.
- 38mm Armaflex sheet insulation
- Grey silicone glass cloth inner and outer finish
- Velcro fastening for ease of removal
All insulation jackets and enclosures were installed by Powertherm’s trained operatives, working to site safety requirements and programme constraints.
The removable insulation jacket systems provided a practical maintenance solution, allowing valves, flanges and pipework to be accessed quickly without damaging insulation systems or compromising thermal performance.
Outcome & Benefits
The coordinated delivery of scaffolding access, thermal insulation, electrical trace heating, and bespoke flexible insulation systems enabled the successful completion of works across multiple operational areas at Oswestry WWTW.
By engaging Powertherm as a single multidiscipline contractor, the client benefited from improved coordination across trades, and a more efficient delivery programme within a complex and active construction environment.
The integrated approach ensured that safe access was maintained throughout all phases of the project, while critical assets were protected and prepared for long-term operation. Thermal performance requirements were achieved across key process systems through the application of water treatment insulation and electrical trace heating solutions.
The inclusion of removable insulation systems provided a practical long-term advantage, allowing essential maintenance and inspection activities to be carried out without disruption or damage to installed systems.
The engineered pipe rack enclosure solution reduced installation time by approximately 50% compared with insulating each dosing line individually.
Overall, the project delivered:
- Fully coordinated multidiscipline service delivery.
- Improved programme efficiency.
- Enhanced safety through controlled scaffolding access and planned installation sequencing.
- Reliable trace heating frost protection and thermal stability for critical process systems.
- Durable, maintainable asset protection across a wide range of water treatment works infrastructure.
- A consistent standard of workmanship across all disciplines and site areas.
The project demonstrates Powertherm’s ability to deliver complex multidiscipline packages within the water treatment sector. Through the integration of scaffold access, insulation and trace heating services, the project achieved safe construction access, reliable frost protection and maintainable long-term asset performance while supporting the successful delivery of a major wastewater treatment infrastructure upgrade.