Beneath the Thames: MC-Color T 21 tunnel coating in action

Optimal light reflection, high durability and quick application

MC-Color T 21 was specifically engineered to meet the needs of next generation tunnel infrastructure. Its high light reflectance value (LRV) ≥ 70% not only enhances visibility within the tunnel but also exceeds the requirements of the British Standard BS 5489-2:2016, which mandates a minimum wall reflectance of 60%. This improved brightness contributes directly to road safety by reducing blinding due to sudden changes in light levels and increasing reaction times, while also enabling more energy-efficient lighting systems. On-site reflectivity and luminescence measurements, conducted by an independent third party in April 2024, confirmed that MC-Color T 21 met the prescribed reflectivity threshold under BS 5489-2:2016.

From a practical standpoint, the product’s single-component formulation ensures ease of application, eliminating mixing errors and allowing unlimited working time. Compared to conventional resin coatings, MC-Color T 21 cures independently of ambient humidity and condensation during the curing phase, allowing for consistent results even under challenging site conditions. Coupled with a touch-dry and overcoating time of just one hour and a full curing time of one day, the system helps to meet tight construction schedules and deliver projects on time. Its fast-curing properties and ease of use ensured seamless application and smooth progress, despite concurrent traffic and equipment activity inside the tunnel.

Integrated 3D Technology: strength and breathability in one system

MC-Color T 21 incorporates an advanced 3D crosslinking technology, forming a dense three-dimensional microstructure within the coating matrix. In this system, acrylate elements are densely cross-linked in a similar manner to reaction resin systems. This intensive internal network significantly strengthens the macromolecular cohesion of the coating film, making it far more robust than traditional dispersion paints and standard concrete protection coatings. The result is an exceptionally high resistance to cleaning and abrasion, comparable to that of two-component reaction resins, making it ideal for high-demand infrastructure environments such as tunnels.

Another key advantage of MC-Color T 21 is its high water vapour diffusion capability. While traditional epoxy and polyurethane resins tend to trap residual moisture, which can lead to blistering or delamination, MC-Color T 21 allows moisture from the substrate to escape. This "breathable" property reduces the risk of blisters and detachment, thereby significantly extending the coating’s service life. This is a crucial factor in tunnel maintenance, where coating renewal usually requires partial tunnel closures – resulting in considerable logistical challenges and high costs.

Proven long-term performance: UV-resistant, fire-safe and easy to clean

MC-Color T 21 also offers outstanding long-term benefits. Its UV-resistant formulation prevents yellowing and fading, even under exposure to tunnel lighting and sunlight at entrance and exit zones. Its smooth, dense finish repels dirt and allows for effortless cleaning with jet washing. Critically, the product is classified as non-flammable according to A2-s1-d0 for fire behaviour, placing it in the best-in-class category among conventional tunnel coatings and further enhancing tunnel safety. These properties were essential requirements for Riverlinx in selecting a coating that could maintain both functionality and appearance over many years with minimal maintenance effort.

Faster. Brighter. Safer. MC-Color T 21 sets new benchmarks in tunnel protection

The Silvertown Tunnel showcases how MC-Color T 21 delivers tangible benefits in demanding infrastructure projects, from high reflectivity and durability to fast curing and long-term cleanability. Thanks to its 3D technology, high vapour diffusion permeability and hydrophobic properties, it is a reliable solution for enhancing tunnel safety and maintenance efficiency. The tunnel stands as a landmark reference that truly embodies the promise behind MC-Color T 21: fast application, high reflectivity and best-in-class fire safety in modern tunnel infrastructure.