EN-45545-2 simply explained​


EN-45545-2 simply explained​

When designing rail vehicles, a primary focus is on ensuring safety for passengers and staff, especially in the extremely rare event of a train fire. In addition to the obvious risks such as flames and heat, the resulting smoke and toxic gases pose a significant danger in the event of a fire. Reducing these risks is a central component of the EN 45545-2 standard. Historically, various national standards have already specified requirements for rail vehicle materials. As part of European harmonization, EN 45545 was introduced in July 2013. After a transition period of three years, national standards are no longer valid since April 1, 2016, and only EN 45545 is binding. This standard defines the fire protection requirements for all materials used in rail vehicles across Europe.

Determining the applicable fire protection standard looks very complex at first glance, but is very simple and logical once it has been done a few times. We will give you a little insight into the necessary steps

Determination of the applicable fire standard

The structure of the standard is carefully structured and is oriented along the entire production chain, starting with the end product (the rail vehicle) through the assemblies to the individual components. This approach is due to the fact that the potential danger posed by a particular rail vehicle to passengers and staff can vary greatly depending on its intended use. A substructure for transporting wood, for example, requires a lower fire protection standard than a fully occupied subway. The requirements for the fire behavior of materials and components specified in the standard depend on various factors. (See listing on the right) 

Influencing factors

  • Operating class and operating mode
  • Installation location of the component
  • shape, exposed surface
  • Combustible mass
  • thickness

Requirement definition process

1. Determine design class .


2. Determine risk level

3. Listed/unlisted components

4. Define R-phrase and select correct material

1. Determine the operating and design class

First, we must identify the operating and design class of the rail vehicle in question. The corresponding classifications are specified in Section 5 of EN 45545-1. The operation category is determined primarily based on the required evacuation time due to use on open routes (OC 1) or underground (short tunnel, long tunnel, side evacuation possible). The design class, in turn, takes into account whether the vehicles are part of an automatic train (Class A, without trained emergency personnel on board), double-decker vehicles, sleeping cars (Class S), couchette cars or other vehicles (standard vehicles, Class N). This classification is often not carried out by the component or material supplier itself, but is specified by the end customer. 

2. Danger level

The combination of operating class and design class of the rail vehicle determines the corresponding hazard level (HL). This identified risk level determines the necessary fire protection requirements (requirement sets) for materials and components. 

3.1 Listed components

The listed components are listed in Table 2 of EN 45545-2. For each of these components, the table shows the corresponding requirements (R phrase = a set of several requirements such as the amount of toxic gases, smoke development and associated measurement methods). The standard contains an extensive list of components, 5 of which are listed on the right as an example:

3.2 Unlisted components

Any product that is not listed in the table for listed components is considered an unlisted product and is to be classified as in the regulations attached. Alternatively, an assembly can be evaluated using the following set grouping rules. (See decision diagram)

3.2 Decision matrix for unlisted components/assemblies

If you stick to the table above for components that are not listed, you are definitely in the right place. However, it is often not possible to achieve these very high requirements. The standard therefore provides a process for classifying assemblies with individual qualified subcomponents. This includes, among other things, the distance to other unqualified components, the weight, the surface, etc. decisive.