The CB Frost Guide to Hazard Levels, Fire Safety, and Material Selection for the Rail Industry.

Passenger safety is at the centre of every design decision for the modern rail industry. Since the mandatory adoption of EN45545-2 (the European standard for fire protection on rail vehicles) across Europe in 2016, gasket materials designed for the mass transit sector are a necessity. 

For engineers designing interior applications for rolling stock, including HVAC systems, lighting enclosures, and doors seals, the challenge is finding a material with the necessary balance of mechanical durability and the strictest fire, smoke and toxicity standards required by EN45545-2. With this balance considered, high-performance grades of Silicone rubber, sponge and foam are the clear winner.

To ensure you are selecting the best suited materials for various sealing and cushioning applications within rail interiors, this guide explores why Silicone materials, including the Rogers BISCO® family and MF775 Silicone rubber, are outperforming other gasket materials when it comes to rail industry compliance.

Understanding EN45545-2 Hazard Levels

To select the right rail material for your application, it’s important to understand the classification system. EN45545-2 classifies rail vehicles based on the environment they operate in and the difficulty of evacuation, categorised into Hazard Levels.

• HL1 & HL2: Hazard Levels 1 and 2 typically apply to standard operation rail vehicles, such as trams or subways, where evacuation is generally straightforward.

• HL3: This is the strictest category, required for vehicles that operate in tunnels, or environments where evacuation is much more difficult.

The most important thing to remember is that compliance is mandatory. If your interior gasket material fails to meet the relevant EN45545-2 Hazard level for its use, then the entire rail carriage can fail compliance. At CB Frost, we supply Silicone grades specifically formulated to meet these rigorous HL3 requirements.

Silicone Rubber, Sponge and Foam for Rail Applications

The table below features our top Silicone rubber, sponge and foam grades commonly used for rail interiors, outlining their application suitability and compliance.

Silicone or EPDM for Rail?

Since the introduction of EN45545-2, one of the most common questions we have been asked by Engineers designing new rail vehicles is whether they can use EPDM for its lower cost and weather resistance. Low Smoke Low Toxicity (LSLT) grades of EPDM are EN45545-2 (HL3) compliant and are well suited to some rail applications. However, Silicone rubbers are frequently preferred due to these three distinct advantages:

• Fire resistance: Silicone naturally self-extinguishes and does not release the toxic smoke associated with standard grades of EPDM or Neoprene. LSLT grades of EPDM are engineered specifically to prevent the release of toxic smoke.
• Temperature range: Silicone materials for the rail industry function effectively from -55°C to +200°C (and -60°C to +230°C for CBF Sil-V0), ensuring seals do not crack in freezing conditions or melt or deform in high temperatures.
• Compression set resistance: Materials like HT800 have excellent “memory”, which means they return to their original shape even after years of compression. This characteristic is essential for preventing rattling doors and drafty windows that can be an issue for aging rail carriages.

Common Rail Applications

Silicon rubber, foam and sponge materials are frequently used for rail applications including:

• Acoustic barriers
• Doors seals
• Gap fillers
• HVAC seals
• LCD and lighting enclosure gaskets
• Seating cushioning
• Smoke seals
• Vibration isolation
• Partitioning

Don’t Gamble with Rail Industry Compliance

When it comes to mass transit, you can’t gamble with compliance. The cost of a failed safety audit, or worse, a safety incident, far outweighs the cost difference between generic rubber and high performance Silicone engineered for the rail industry.

As a preferred converter of Rogers BISCO® materials for over 30 years, we have the materials and expertise to manufacture bespoke gaskets and seals through processes including cutting, extruding, moulding and fabrication.

Need help selecting the right grade of Silicone for your next rail project? Speak to our team today or browse our rubber, sponge and foam materials.