Promain are one of the lead suppliers of paint to TfL and London Underground. We would like to introduce the Sherwin Williams system below for the painting of Tower Bridge in London. This is as part of our extensive industrial coatings available. The system requirement was for 25 year protection to first maintenance. The project began in 2008.
Introducing Tower Bridge
Tower Bridge has stood over the River Thames in London since 1894. Henceforth, it is one of the most recognisable landmarks in the world. It is also the only bridge on the Thames which can be raised.
Before its restoration in the 2010s, the bridge’s colour scheme dated from 1977. It was originally painted red, white and blue for Queen Elizabeth II’s Silver Jubilee. Its colours were subsequently restored to blue and white.
The restoration of the bridge is vital to protect this landmark for the future.
Requirements
The original specification prior to Sherwin Williams involvement required total removal of the existing paintwork. This would have had to done via abrasive blast cleaning. Because of this, the bridge would need to be closed for three months. As Tower Bridge is a vital piece of infrastructure in the capitals network, this proposal was not ideal.
Firstly, Transport for London wanted to keep the structure open to prevent disruption. This was magnified as the proposal required painting Tower Bridge during the busy summer period. Henceforth, alternative ideas were explored with Sherwin Williams. A C5M specification was required.
System Proposal
Initially, repainting from cradles could keep the structure open. However, blast cleaning from cradles is not possible. After discussions, a Network Rail approved system was agreed. This meant that mechanical methods of surface preparation was possible. This would enable the contractors to remove all the unsound existing paintwork.
- Substrate: Steel, cast and wrought iron
- Requirements: 25 years protection against high humidity and salinity levels
- Specifications: Macropoxy M902, Macropoxy M905 and Acrolon C137V2 Acrylic Urethane Finish
- Coating Required: 22,00 Litres
- Applicator: Pyeroy
A surface tolerant epoxy coating system was chosen. The system comprises of Macropoxy M902, Macropoxy M905 and Acrolon C137V2.
Sherwin Williams Macropoxy M902 – This product was formerly known as Leighs Epigrip M902. M902 is an epoxy MIO surface tolerant epoxy protective coating. It is suitable for low temperature curing on Network Rail, TfL or Ministry of Defence applications. You can see more MIO products here >>
Sherwin Williams Macropoxy M905 – This product was formerly known as Leighs Epigrip M905. M905 is a winter fast hi build undercoat. This paint can cure down to 0°C.
Sherwin Williams Acrolon C137V2 – This product was formerly known as Leighs Resistex and Transgard TG168. C137V2 is a high performance, fast drying, acrylic urethane gloss finish. It is for use where long term exterior gloss and colour retention characteristics are required.
You can find more Sherwin Williams specifications for Network Rail here.
Preparation
Initially scaffolding and special polythene wraps around the bascules were installed. Consequently, they had to suspend the raising of the immense bascules. This from November 2010 to allow the contractors to carry out the work.
You can modify this special shrink wrap material using heat. This forms a seamless enclosure around the scaffolding. The shrink wrap will prevent particles of paint or dust escaping into the environment. For instance, they need to encapsulate the bascules to catch old paintwork as it falls. Subsequently, this in turn protects Thames river life.
For in depth restoration, you can see more on Tower Bridge’s restoration website here.
Application
In conclusion, the full restoration took three years to complete.
Successful trials were carried out under the watchful eye of Sherwin Williams technical service team. Transport For London accepted the proposal.
The new paintwork, which has a life expectancy of 25 years, was essential to protect the steelwork. Protecting by painting Tower Bridge will preserve the iconic structure for future generations. More than 22,000 litres of paint were used to maintain the original iconic white and blue colour scheme.
Furthermore, in the below video you can see a small fraction of the prestigious bridge jobs from Sherwin Williams:
Promain specify comprehensive assessments to determine appropriate surface cleaning, preparation and coating systems.
Would you like further information regarding specifications for bridges? Contact our technical team on 01462 421333 to discuss your requirements with our technical team.
