Here - Polyurethanes - Bayer

Issue 1/2005 

Baydur ® / Bayflex ® – Polyurethanes for Design and Functionality

Editorial 

Dear Readers, 

In 1835, Charles Darwin discovered 14 

different species of finch in the Galapagos 

Islands, all of which had evolved from a 

single finch species. Darwin later developed 

his theory of evolution on the basis of this 

discovery. 

We might ask ourselves: what is the 

equivalent of Darwin’s finches in the world 

of plastics? In my opinion, it’s polyurethanes. 

Their versatile structure has enabled them 

to undergo such a process of “evolution” that 

they are now found in a number of different 

rail transport applications. 

Let’s start by considering the driver’s cab in 

a train. Here, the use of Baydur 110 FRS and 

Baydur 60 FRS allows the interior to be 

designed in a functional and modern style – 

with impressive looking, high-quality 

materials and a level of fire performance that 

meets the requirements of DIN 5510. Rail 

damping with Bayflex ® effectively reduces 

vibration, allowing trains to run more quietly 

over the track. 

When conventional railway sleepers fail, 

concrete suffers frost damage and wood rots 

away, glass fibre-reinforced Baydur sleepers 

are still going strong. They maintain their 

high mechanical strength for an estimated 

lifetime of over 50 years. That’s what a highly 

envolved material called polyurethane can do! 

Sincerely, 

Dr. Stephan Schleiermacher 

Polyurethanes Business Unit 

Baydur ®/Bayflex ® – Polyurethanes for Design and Functionality 

IS FLYING REALLY BETTER? 

If you want to get from A to B in Germany quickly and in comfort, taking a plane is by no means 

your only option. These days, Deutsche Bahn’s high-speed trains offer a standard of service 

which, until recently, could only be experienced above the clouds. And it’s not just in the 

passenger facilities that you can draw this parallel. The driver’s cab in the ICE ® 3 looks just 

like the cockpit of a plane. It is only divided from the passenger carriages by a glass screen, 

so anyone who’s interested can see their “pilot” at work at any time during the journey ! 

Featuring soft contours, a clear layout and 

quality-finish surfaces, large areas of the 

driver’s control panel in the ICE ® 3 are made up 

of large, lightweight molded parts produced by 

polyurethane specialist Thieme GmbH & Co. KG 

of Teningen, Germany, using the Baydur ® 60 

and Baydur ® 110 systems. 

Thieme designs cladding 

for the cockpit of the ICE ® 3 

Thieme supplies the molded parts to Dornier 

GmbH, which in turn supplies them to the 

ICE ® Siemens/Bombardier consortium. This 

consortium has developed and built the ICE ® 3 

in a project led by the Transportation Systems 

Division of Siemens AG and run in cooperation 

with Deutsche Bahn AG. 

The advantages of using 

polyurethane in rail transport 

When it comes to implementing ambitious 

design concepts, polyurethane has repeatedly 

proven itself to be an excellent material in 

many fields. The railway sector is no exception. 

A total of 27 different parts are produced for 

the ICE ® 3 cockpit. 

They include everything from cladding sections 

to high-quality panels fitted with recesses 

for switches and levers. They can also be 

screen-printed. It is vital that the materials 

used in this project meet the strict guidelines 

of Deutsche Bahn and other national and 

international fire safety standards. Baydur ® 

complies with the required classifications S4, 

SR2 and ST2 of DIN standard 5510. 

(For information about fire protection standards 

in the rail sector, see the final article in this 

edition of InForm, which is entitled “Guide to 

Polyurethanes”)


The cockpit of the ICE ® 3 generation of trains is another example of how polyurethanes 

can be used to combine design with functionality and cost-effectiveness. 

Why use polyurethane? 

Polyurethane offers advantages over other 

plastics which are particularly relevant when 

designing trains. 

Materials are required to be: 

- Light 

- Easy to clean 

- Robust 

- Distortion-free 

Polyurethane meets all these requirements. 

This material also gives designers and 

engineers a great deal of room for manoeuvre 

in developing their ideas. For example, inserts 

or threaded bushings can be integrated directly 

at the time of manufacture while sound 

absorption holes and grille openings can also 

be molded into the design. Geometries can 

be selected at will. Thanks to their excellent 

flow properties, Baydur ® 60 and 110 make it 

possible to design even very complex molded 

parts. Even when the walls of components are 

very thin, the parts retain excellent rigidity and 

their integral skin foam (Baydur ® 60) or microcellular 

structure (Baydur ® 110) makes them 

light yet stable. Moreover, both materials offer 

an excellent surface finish to which high-quality 

coatings can be applied. They are thus ideally 

suited to the cutting-edge design of the cockpit. 

Since Baydur is processed using aluminum 

tools, it is cost-effective to produce small and 

medium-sized series. 

So far, over 150 ICE ® trains featuring cockpits 

produced by Thieme have already been brought 

into service. One place you’re guaranteed to see 

them is on the new ICE ® line between Frankfurt 

and Cologne, where they run regularly. 

For further information about Thieme go to: 

www.thieme-products.com


A MATERIAL THAT 

POINTS THE WAY FORWARD 

Wood, one of the oldest materials known to man, is also one of the most fascinating. 

However, this popular material does have its limits in terms of what it can be used for. 

Being a natural raw material, wood is not resistant to weathering. Its high tendency 

to warp has also forced engineers to look for alternatives in some areas where wood is 

traditionally used. 

“Eslon Neo Lumber FFU” is an extremely dimensionally 

stable composite material based on 

Baydur ® 60 reinforced with long glass fibers. It 

is produced by Sumika Bayer Urethane Co. Ltd., 

a subsidiary of Bayer MaterialScience AG. 

The Japanese company Sekisui Chemical has 

been successfully selling this product for over 

20 years as a construction material for the 

Asian market. There, the sophisticated composite 

material has proved its worth in a wide 

variety of applications, particularly where 

technical considerations mean that it is not 

practical to use wood, but where the engineers 

would still like to benefit from the ease of 

processing associated with wood. Common 

applications include pools for fish farming, 

silos, walkways, soil anchors (where it is used 

as a substitute for concrete) and, above all, 

railway sleepers. 

European debut: The Zollamt bridge 

in Vienna has been fitted with 

polyurethane railway sleepers 

Now, this versatile material has made its debut 

in Europe. As part of a renovation project, the 

tracks on the Zollamt bridge in Vienna have 

been laid on sleepers made from polyurethane. 

“Eslon Neo Lumber is particularly well suited to 

use on bridges as it offers clear advantages over 

wood,” says Max Nakai from Sekisui Chemical 

Deutschland. “Changes in temperature, UV radiation 

and in particular the fact that the air is 

always humid mean that wooden sleepers 

weather more quickly here than in other 

applications. The problem is that carrying out 

structural repairs to railway tracks not only 

involves considerable inconvenience but is 

also very expensive.” 

The Zollamt bridge in Vienna 

This is also the case with the Zollamt bridge, 

which was designed by the Viennese art 

nouveau architect Otto Wagner and was 

constructed in 1898 when the Viennese city 

rail network was built. Materials with a long 

service life quickly pay for themselves in 

applications like this. Sekisui produces the 

polyurethane-glass fiber compound FFU (FFU


stands for fiber-reinforced foamed urethane) 

using the pultrusion process. The material can 

be produced to almost any length, it looks like 

wood and combines all the positive attributes 

of the natural product with those of a modern 

composite material. 

Eslon Neo Lumber sleepers can be screwed 

together, nailed or sawn using conventional 

woodworking tools, and also adhere together 

superbly, achieving an even stronger bond 

than wood. Other positive features of the material 

include its low coefficient of linear thermal 

expansion and low thermal conductivity. 

Thanks to the closed-cell structure of the lightweight 

polyurethane-glass fiber compound, 

the sleepers absorb only a minimal amount of 

water. The fiber reinforcement provides the 

material with high compressive and tensile 

strength, making it one of today’s leading hightech 

construction materials. The material’s 

excellent resistance to hydrolysis, greases and 

oils is another quality which makes the “polyurethane 

wood” a very reliable material, even 

when exposed to long-term weathering. 

Unlike natural wood, Eslon Neo Lumber FFU 

loses none of its favorable mechanical properties, 

even after prolonged service in the open 

air. Being light in weigthand simple to process 

on site, it is also superior to concrete. Special 

techniques for installing sleepers are often 

required when working on old bridges. Moreover, 

the statics of these bridges normally 

mean that only lightweight materials can be 

used. In Japan, polyurethane sleepers are not 

only used on bridges but also on stretches that 

are frequently washed by seawater and exposed 

to an aggressive microclimate. In tunnels, 

due to the limited amount of space available, 

work is very difficult and costly, which is why 

in tunnels situated close to the sea, polyurethane, 

which is light and resistant to salt water, 

is generally preferred. 

Stable and weather-resistant 

alternative to wood 

Sleepers of varying length are used for the 

manufacture of points. When concrete sleepers 

are cast, a separate mold is needed for each 

length. With the pultrusion process, on the 

other hand, it is easy to make any individual 

length. Polyurethane sleepers are significantly 

lighter than concrete ones. This is a particular 

advantage with points sleepers, which can be 

up to 10 meters long. In addition, polyurethane 

sleepers do not break as easily as concrete 

ones. 

The excellent electrical insulation properties 

of the plastic sleepers is particularly effective 

in winter when the points have to be heated 

in order to prevent them from freezing solid. 

The material is also resistant to frost and deicing 

salt. 

For further information go to: 

www.sekisui.de


THE WHISPERING 

STREETCAR 

Streetcar systems are a wonderful thing. 

Many city centers are much easier to reach 

by streetcar than by car. The streetcar takes 

you straight to where the action is, and 

there’s no need to worry about finding somewhere 

to park. Unfortunately, however, 

streetcars have their downside too. It’s not 

uncommon for people living along the 

routes to be bothered by the noise of streetcars 

squeaking and rumbling past their 

homes, particularly at night, and stray current 

from the tracks can cause corrosion damage 

to water and gas pipes. 

Fortunately, there’s an effective means of solving 

these problems. The underside of the tracks can 

be encased in an elastic, non-conducting plastic 

foam, a technique mastered by Polyplan GmbH 

of Strasslach, Germany. The materials used are 

polyurethane systems with tailor-made cell 

structures formulated specially for this application 

by Büfa Polyurethane GmbH & Co. KG 

of Oldenburg, Germany, a systems house of 

Bayer MaterialScience AG. They boast outstanding 

mechanical performance in long-term 

use and are very easy to work with. 

“There are two main sources of noise from streetcars,” 

says Lutz Ohmstede, who was part of the 

team at Büfa which developed the polyurethane 

system for this unusual application. “Firstly, 

there’s the rolling noise from the wheels and 

secondly, there’s the impact noise produced 

when the streetcar hits weld joints and points 

on the track. Both sources of noise can be re- 

duced by dampening the rail webs which emit 

the noise to provide effective acoustic insulation. 

Elastic plastics are perfect for the job.” 

Compared to conventional solutions using filled 

solid plastics, rigid polyurethane foams offer 

particular advantages. “Instead of controlling 

the dampening effect, and in turn the noise 

reduction performance of the grouting material 

by altering its hardness, we can optimize both 

properties using a tailor-made pore structure 

that literally swallows up sound,” continues 

Lutz Ohmstede “Moreover, using polyurethanes 

here means that we can completely do 

away with plasticizers. That’s particularly 

important, since these auxiliary substances 

are known to leach out of many other noisereducing 

materials over time, which can cause 

the material to become brittle.” The Büfaflex ® 

systems, which are based on Bayflex ® systems 

from Bayer MaterialScience AG, boast excellent 

long-term stability and maintain their vital 

dampening properties very well. Foams produced 

using these systems are highly weatherresistant 

and are also suitable for use in 

groundwater protection zones. Even adverse 

environmental conditions don’t affect them. 

Foam-coated rails minimize running 

noise and problems with stray current 

Büfaflex ® is also more cost-effective to process 

than conventional rail grouting systems. The 

rail is simply “floated” in a special framework 

on site and then encased in the foamed polymer 

material using a mobile, computer-controlled 

polyurethane grouting system so that the grout 

comes up to the lower edge of the rail head. 

The foam automatically expands to fill any space. 

“Grouting the rail in this way provides it with 

complete support,” explains Jürgen Huber from 

Polyplan GmbH, which specializes in rail grouting.


Another advantage is the fact that the polyurethane 

grouting system allows continuous 

operation, which is far quicker and more costeffective 

than the “bucket-by-bucket” approach 

used with conventional systems. 

“However, the elastic mounting does more than 

just significantly reduce structure-borne noise,” 

says Huber. “The complete, seamless coating 

also ensures that the rail is electrically isolated 

from the ground below. That provides the best 

possible protection against stray current.” 

To ensure that the rail fasteners do not conduct 

electricity into the ground, both elements can 

additionally be electrically isolated from one 

another by inserting plastic plates or anchor 

screws with plastic inserts. 

The whispering rail SILENCE is already ensuring 

peace and quiet on test tracks in major cities 

like Munich, Frankfurt and Zurich, and further 

projects are on the agenda – not least because 

new legislation to combat the problem of stray 

current is in the pipeline. “We believe that our 

role involves far more than simply providing 

the engineering technology on the ground,” 

continues Huber “We also intend to develop 

special frameworks and components and come 

up with cost-reducing strategies. We will in 

particular be working with our partner Büfa to 

adapt the polyurethane material to the specific 

needs of transport companies, which may vary 

greatly from one region to the next.” 

Once again, the versatility of polyurethane 

is really paying off – making 

streetcars an even more environmentally 

friendly mode of transport 

than they already are. 


lutz.ohmstede@buefa.de / www.buefa.com 

or visit www.fluesterschiene.de 

contact@polyplangmbh.de


ELECTRONIC EYES FOR 

FLOATING TRAINS 

Regardless of whether or not it comes into 

service in Germany in the foreseeable future, 

the Transrapid is internationally recognized 

as an outstanding achievement of German 

engineering. As with all modes of mass 

transportation, it is vital that all the system 

components in this “maglev” (magnetic 

levitation) train be totally reliable. That goes 

for the moving parts as well as the fixed 

system components, which also require 

effective protection from the specific environmental 

conditions they will encounter when 

the train goes into service in China. 

The GST 24 VT voltage sensors in the Transrapid 

linear motor produced by Duromer Kunststoffverarbeitungs-GmbH 

of Ottendorf-Okrilla, 

Germany, on behalf of the Transrapid Consortium 

are encapsulated in Baydur ® E, a 

specially designed polyurethane molding 

system using two liquid components. Despite 

its appearance, the Transrapid has little in 

common with a conventional high-speed train. 

Rather than running on rails, it “floats” to its 

destination on strong magnetic fields without 

coming into contact with the ground. This makes 

for a very smooth, energy-efficient action. 

Unlike conventional trains, the drive assembly 

on the maglev train is located in the track rather 

than in the train itself. The magnetic fields 

which “carry” the train are switched on and off 

in a fraction of a second by a system of linear 

motors. To ensure that the control electronics 

in these motors have an accurate picture of 

the condition of the railway track at all times, 

high-performance sensors are built into the 

track at regular intervals to relay vital information 

about factors such as the voltage and 

current conditions. “These sensors play a 

key role in the drive assembly of the Transrapid, 

so it’s vital that they are totally reliable,” says 

Dr. Axel Georgi, Managing Director of Duromer 

Kunststoffverarbeitungs-GmbH. “That’s why 

these modules are encased in polyurethane 

cast resin. This material not only isolates the 

electrical components, it also prevents dust, 

dirt and water penetrating the modules under 

sub-tropical conditions, thereby ensuring high 

operating reliability.” The casting compounds 

used are extremely resistant to hydrolysis, a 

factor which is important in the often warm, 

humid climate of Asian countries, and offers some 

clear technical advantages over epoxy resins. 

Polyurethane molding systems: 

Reliability is key to the drive concept 

“Polyurethane cast resins can be processed at 

comparatively low temperatures of around 100 

degrees Celsius,” explains Friedhelm Fähling, 

an expert in electrical casting compounds at 

Bayer MaterialScience AG. “That allows even 

large parts like the cylindrical sensor, which 

measures around 150 x 250 mm, to be produced 

quickly without lengthy heating uptimes.” 

Vacuum technology is used to create a bubblefree 

casting which will not cause any unevenness 

in the magnetic field. There is no need to anneal 

the casting compound afterwards. The moderate 

casting temperature also means that only 

slight shrinkage pressure is exerted on the 

delicate sensor electronics. This allows even 

components made of electrical conductors and 

semi-conductors with widely divergent thermal 

expansion coefficients to be sealed without 

sustaining any damage. The excellent flow 

properties of the polyurethane and the fact 

that it will adhere to a wide range of materials 

also ensure gap-free bonding. Moreover, when 

used with the appropriate fillers, these 

polyurethane resins conduct heat away very 

effectively. 

Polyurethanes have significant economic 

advantages over epoxy resins, shorter cycle 

times, lower energy costs and easier storage 

because different degrees of hardness can be 

achieved using one and the same raw material 

system. 

Foto: Transrapid Int. GmbH & Co. KG 


www.duromer.de

Bayer and its Partners 

BÜSING & FASCH GMBH & CO. 

Founded more than 120 years ago, Büsing & Fasch is an outstanding example of 

how entrepreneurial spirit, innovation and perseverance combined with an eye for the 

future and a willingness to embrace change can turn a modest regional business 

into an international enterprise. 

In 1883, Ludwig Büsing and Friedrich Fasch 

founded their dye, chemical and oil wholesale 

business in Oldenburg. Before the turn of the 

century, the dyewoods, plant dyes and tree 

oils which the company started out importing 

were joined by new products from Germany’s 

burgeoning chemical industry. These included 

synthetic dyes, mineral oils and all kinds of 

liquid and solid chemicals. 

New ideas for over 120 years 

In 1935, Johann Dietrich Kolwey became the 

sole owner of the firm, and a new era in the 

company’s history began under his leadership. 

He commenced production of dry dyes, coatings 

and textile auxiliaries in an effort to produce 

a portfolio which would allow him to serve his 

customers better, faster and more cost-effectively. 

In the 1960s, the company also began 

producing reactive resins and polyurethanes. 

Today, the BÜFA Group is majority-owned by 

the Wuppermann family (the grandchildren 

and great-grandchildren of J. D. Kolwey). 

Progress is a corporate goal 

BÜFA has always insisted on remaining a midsize 

company. The BÜFA Group has a modern 

structure with a strategic holding company 

comprising five independent subsidiaries at 11 

sites in Germany and overseas. It employs 

more than 500 people and records annual sales 

of approximately 150 million Euros. Operational 

business is led by the subsidiaries. 

The Group’s business activities include: 

- Chemical trading 

- Cleaning systems 

- Specialty glass 

- Reactive resins 

- Polyurethane systems. 

BÜFA Polyurethane & und Co. KG of Oldenburg-Etzhorn 

is a specialist in the field of 

formulating polyurethane system components. 

Since 2003, it has been a joint-venture under- 

taking of Büsing & Fasch GmbH & Co. KG and 

Bayer MaterialScience AG of Leverkusen, the 

inventor and market leader in the field of polyurethanes. 

Bayer and BÜFA have been cooperating 

for much longer than that, however. 

Bayer has been a supplier of raw materials and 

a strategic partner ever since polyurethane 

activities began in Oldenburg in 1969. Bayer 

MaterialScience AG appreciates the flexible 

approach which small and midsize companies 

take to business, and therefore sees BÜFA 

Polyurethane as an important building block 

for central and northern Europe in the worldwide 

BaySystems systems house network 

which it is developing. 

Polyurethane processors require customized 

solutions. BÜFA Polyurethane is therefore an 

active partner during the development stage 

of these materials. It assists its customers in 

optimizing process technology, tools and all 

the processes which lead up to the start of 

series production. The company boasts laboratories 

and cutting-edge application technology 

with a full range of machinery for this purpose. 

The systems are produced in a high-tech automated 

formulation plant, tested to the very 

highest quality standards and delivered to the 

customer in drums, IBCs or tankers. It goes 

without saying that BÜFA Polyurethane also 

holds ISO 9001 and 14001 certification. 

Combining expertise and flexibility for 

the benefit of the customer is the stated 

objective of the company. 


www.buefa.com

Guide To Polyurethanes 

Fire protection standards (part 2) 

RAILWAY VEHICLES 

A variety of national fire protection standards for railway vehicles is in force across 

Europe (see table for examples). These have developed as a result of differing historical 

experiences, evolving concepts of protection and different vehicle designs. Different 

countries still use different types of track. This is a reflection of their geography and degree 

of urbanization. The passenger evacuation conditions where railway routes feature 

large numbers of tunnels or bridges differ from those running across wide open spaces. 

Because of these differences, individual countries have different ways of assessing the 

various fire risks. 

These risks can best be explored from the 

point of view of the passenger. When a fire 

breaks out on a train, passengers may be 

endangered in a variety of ways. 

It may be difficult for them to escape or be 

rescued if the fire spreads rapidly and there is 

a lot of smoke. Smoke gases can have a toxic 

effect. In the worst-case scenario, heat may 

cause flammable gases to vaporize and collect 

under the roof of the train. This gas can spontaneously 

ignite in what is known as a “flashover”, 

spreading the fire to other parts of the 

train. 

Different countries use different fire testing 

procedures to assess these potential risks. 

Our assessment shows that different countries 

have independently identified similar types of 

risk. In general, flammability, flame spread 

patterns and smoke gas density are assessed. 

Some testing procedures also assess heat 

development and the toxic potential of smoke 

gases. 

The testing methods used vary widely. 

In France and Spain, for example, flame spread 

patterns are assessed by looking at the effect 

of heat radiation on materials using the 

Epiradiateur test. In Germany, on the other 

hand, the materials are subjected to a direct 

flame in a large test chamber in accordance 

with DIN standard 54837 (see photo). 

Fire protection standards specify which of the 

aforementioned tests a material must pass 

and what performance criteria apply to it. 

They take account of where a component will 

be installed in the vehicle and how large it is. 

Additional requirements are also set out for 

specific parts such as electrical encapsulation 

components. 

Based on the fire protection categories of the 

vehicle, different material requirements may 

be applied to reflect different levels of risk 

associated with ease of escape from the vehicle 

in question. 

For example, passengers can escape more 

quickly from a streetcar than they can from 

a high-speed train or a vehicle that passes 

through tunnels. In Germany, all these factors 

are taken into account by fire protection standard 

DIN 5510. This standard covers all finished 

components and divides trains into four fire 

protection categories. 

Test results are translated into classes based 

on one or more criteria. In Germany, materials 

are classified according to three criteria: 

A Flammability Class (S1 to S5), a Smoke Development 

Class (“SR1 not achieved”, “SR 1” or 

“SR2”) and a Drip Class (ST1 or ST2). The fire 

protection standard determines the classification 

of a material, which in turn governs 

the applications for which it can be used. The 

This information and our technical advice – whether verbal‚ in writing or by way of trials – are given in good faith but without warranty‚ and this also 

applies where proprietary rights of third parties are involved. Our advice does not release you from the obligation to verify the information currently 

provided – especially that contained in our safety data and technical information sheets – and to test our products as to their suitability for the intended 

processes and uses. The application‚ use and processing of our products and the products manufactured by you on the basis of our technical advice 

are beyond our control and‚ therefore‚ entirely your own responsibility. Our products are sold in accordance with the current version of our General 

Conditions of Sale and Delivery. 

Bestell-Nr.: MS 006045, Printed in Germany KL 

Bayer MaterialScience AG 

51368 Leverkusen, Germany 

www.bayermaterialscience.com 

Baydur 60 FRS in a DIN 54837 testing chamber 

standard lists the class ratings which must be 

fulfilled for specific applications. 

In an effort to ensure uniform assessment of 

materials throughout the European Union, 

standard EN 45545 “Fire protection on railway 

vehicles” has been drafted. 

Objections to Part 2 of this draft standard are 

currently being filed, and will be assessed soon. 

Part 2 deals with the issue of assessing the 

fire behavior of materials and components, 

and will probably set out four main tests. 

These will involve determining the amount of 

heat released, the flame spread, the smoke 

gas density and the toxicity of the combustion 

gases. 

Fire protection standard 

DIN 5510 1) 

AFNOR NF F 16-101 

DT-PCI/5A 

BS 6853 

UNIFER E 10.02.977.3 

prEN 45455 

Country 

Germany 

France 

Spain 

United Kingdom 

Italy 

European Union 

1) also applies in Austria, Switzerland and China 

Contact: 



Tel.: ++ 49 214 30 - 3 94 95 

stephan.schleiermacher@bayerbms.com 

If you have any questions or suggestions, 

please contact: 

Martin Sixsmith 

Tel. +44 1635 563 811 

Fax +44 1635 563 272 

ukqueries@bayermaterialscience.com

Guide To Polyurethanes 

Fire protection standards (part 2) 

RAILWAY VEHICLES 

A variety of national fire protection standards for railway vehicles is in force across 

Europe (see table for examples). These have developed as a result of differing historical 

experiences, evolving concepts of protection and different vehicle designs. Different 

countries still use different types of track. This is a reflection of their geography and degree 

of urbanization. The passenger evacuation conditions where railway routes feature 

large numbers of tunnels or bridges differ from those running across wide open spaces. 

Because of these differences, individual countries have different ways of assessing the 

various fire risks. 

These risks can best be explored from the 

point of view of the passenger. When a fire 

breaks out on a train, passengers may be 

endangered in a variety of ways. 

It may be difficult for them to escape or be 

rescued if the fire spreads rapidly and there is 

a lot of smoke. Smoke gases can have a toxic 

effect. In the worst-case scenario, heat may 

cause flammable gases to vaporize and collect 

under the roof of the train. This gas can spontaneously 

ignite in what is known as a “flashover”, 

spreading the fire to other parts of the 

train. 

Different countries use different fire testing 

procedures to assess these potential risks. 

Our assessment shows that different countries 

have independently identified similar types of 

risk. In general, flammability, flame spread 

patterns and smoke gas density are assessed. 

Some testing procedures also assess heat 

development and the toxic potential of smoke 

gases. 

The testing methods used vary widely. 

In France and Spain, for example, flame spread 

patterns are assessed by looking at the effect 

of heat radiation on materials using the 

Epiradiateur test. In Germany, on the other 

hand, the materials are subjected to a direct 

flame in a large test chamber in accordance 

with DIN standard 54837 (see photo). 

Fire protection standards specify which of the 

aforementioned tests a material must pass 

and what performance criteria apply to it. 

They take account of where a component will 

be installed in the vehicle and how large it is. 

Additional requirements are also set out for 

specific parts such as electrical encapsulation 

components. 

Based on the fire protection categories of the 

vehicle, different material requirements may 

be applied to reflect different levels of risk 

associated with ease of escape from the vehicle 

in question. 

For example, passengers can escape more 

quickly from a streetcar than they can from 

a high-speed train or a vehicle that passes 

through tunnels. In Germany, all these factors 

are taken into account by fire protection standard 

DIN 5510. This standard covers all finished 

components and divides trains into four fire 

protection categories. 

Test results are translated into classes based 

on one or more criteria. In Germany, materials 

are classified according to three criteria: 

A Flammability Class (S1 to S5), a Smoke Development 

Class (“SR1 not achieved”, “SR 1” or 

“SR2”) and a Drip Class (ST1 or ST2). The fire 

protection standard determines the classification 

of a material, which in turn governs 

the applications for which it can be used. The 

This information and our technical advice – whether verbal‚ in writing or by way of trials – are given in good faith but without warranty‚ and this also 

applies where proprietary rights of third parties are involved. Our advice does not release you from the obligation to verify the information currently 

provided – especially that contained in our safety data and technical information sheets – and to test our products as to their suitability for the intended 

processes and uses. The application‚ use and processing of our products and the products manufactured by you on the basis of our technical advice 

are beyond our control and‚ therefore‚ entirely your own responsibility. Our products are sold in accordance with the current version of our General 

Conditions of Sale and Delivery. 

Bestell-Nr.: MS 006045, Printed in Germany KL 

Bayer MaterialScience AG 

51368 Leverkusen, Germany 

www.bayermaterialscience.com 

Baydur 60 FRS in a DIN 54837 testing chamber 

standard lists the class ratings which must be 

fulfilled for specific applications. 

In an effort to ensure uniform assessment of 

materials throughout the European Union, 

standard EN 45545 “Fire protection on railway 

vehicles” has been drafted. 

Objections to Part 2 of this draft standard are 

currently being filed, and will be assessed soon. 

Part 2 deals with the issue of assessing the 

fire behavior of materials and components, 

and will probably set out four main tests. 

These will involve determining the amount of 

heat released, the flame spread, the smoke 

gas density and the toxicity of the combustion 

gases. 

Fire protection standard 

DIN 5510 1) 

AFNOR NF F 16-101 

DT-PCI/5A 

BS 6853 

UNIFER E 10.02.977.3 

prEN 45455 

1) also applies in Austria, Switzerland and China 

Contact: 



Tel.: ++ 49 214 30 - 3 94 95 

stephan.schleiermacher@bayerbms.com 

If you have any questions or suggestions, 

please contact: 

Monika Brandt 

Tel. ++ 49 214 30 - 3 30 13 

Fax ++ 49 214 30 - 5 53 52 

monika.brandt@bayerbms.com 

Country 

Germany 

France 

Spain 

United Kingdom 

Italy 

European Union

Here - Polyurethanes - Bayer

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