Leonari – Central London Cooling Tower Refurbishment | Vistech
Complete Engineered Refurbishment Delivering Improved Performance Without Full Replacement
Two ageing Visco cooling towers serving a high-value Central London commercial property required upgrading to meet revised duty requirements. Vistech delivered a complete engineered refurbishment that avoided cranage, road closures and structural modifications while exceeding typical new galvanised replacement standards in key areas.
The Challenge
The site comprised two ageing Visco cooling towers serving a high-value Central London commercial property. The towers featured 316 stainless steel casings, mild steel centrifugal fans, gravity-fed distribution, and ageing packing and drift eliminators.
While structurally sound, performance and compliance standards had evolved. The towers required upgrading to meet revised thermal duty requirements without full replacement. Traditional replacement would have introduced significant logistical challenges: road closures and cranage, structural loading reviews, pipework re-routing, control system modifications, and major programme disruption – all highly problematic in a constrained Central London environment.
The Solution
Vistech delivered a complete engineered refurbishment of both towers, demonstrating capability to modernise towers manufactured by other OEMs.
The project required increased thermal performance, upgrade from gravity to spray distribution, replacement of pack and drift eliminators to anti-legionella standard (ACOP L8 and HSG274), improved access and maintainability, new high-efficiency stainless steel fan assemblies, and safe internal working platforms – all delivered sequentially to maintain site resilience with one tower operational at all times.
Scope of Works
Stainless Steel Fan Upgrade
Replacement of mild steel centrifugal fans with 316 stainless steel split casings, DIDW impellers, precision-ground shafts, auto-lubrication and Siemens IE4 motors.
Spray Distribution Conversion
Conversion from gravity-fed to high-efficiency spray distribution system in GRP-reinforced uPVC with stainless steel fittings.
Anti-Legionella Packing
Installation of modular 12mm flute PP packing (800mm depth) with low pressure drop, easy inspection removal, and UV/chemical resistance.
Drift Eliminators
New stainless-framed cellular drift eliminators achieving less than 0.0005% drift loss with T-bar air seals for ACOP L8 compliance.
GRP Lining & Casing
Internal GRP lining, surface cleaning, resealing of horizontal casing joints to extend casing service life.
Access & Safety
GRP Cleansafe flooring, new stainless steel access doors, sump door replacement, creating safe internal maintenance platforms.
Programme
Week 1
Site mobilisation, isolations and initial strip-out of existing cooling tower internals.
Week 2
Removal of existing fan assemblies, distribution system and redundant components.
Week 3
Mechanical preparation and GRP lining of casing, surface cleaning and resealing of horizontal joints.
Week 4
Installation of new stainless steel fan assemblies and drive systems.
Week 5
Installation of high-efficiency spray distribution system and pipework modifications.
Week 6
Installation of anti-legionella packing, drift eliminators and Cleansafe flooring.
Week 7
Installation of access upgrades, doors, heaters and instrumentation.
Week 8
Commissioning, performance testing and staged handover of cooling tower systems.
“Vistech provided a technically sound and commercially pragmatic alternative to full cooling tower replacement. Their ability to refurbish our existing towers within a constrained Central London site significantly reduced programme risk and disruption. The upgraded system has delivered improved performance and confidence in long-term compliance.”
— Kristian Gjetani, Leonari