wp3 design solutions for fire and firebombssecuremetro.inrets.fr/fileadmin/depository... ·...

SECUREMETRO

Inherently Secure Blast Resistant and Fire Safe Metro Vehicles

Grant Agreement no.: 234148

WP3

– Design solutions for fire and firebombs–

DELIVERABLE: D3.01 Critical inventory of technologies for firebomb mitigation

Version : 1

Authors : Suncove, INRETS, Inasmet ‐‐‐‐ Tecnalia, UNEW

Partners : MDM, RATP,

Date : 5 Oct 2010

D3.01: – Critical Inventory of Technologies for

Firebomb Mitigation

Document History

Issue Date Pages Comment 1 5 October 2010 All Initial Issue

2

3

4

5

6

7

8


Firebomb Mitigation

TABLE OF CONTENTS

1. CEN‐‐‐‐TS‐‐‐‐45545 ....................................................................................................................................... 5

1.1. INTRODUCTION ............................................................................................................................... 5 1.2. CEN TS 45545 FIRE PROTECTION OF RAILWAY VEHICLES .............................................................. 6

2. FIRE SUPPRESSION TECHNOLOGIES .......................................................................................... 8

3. WATER MIST SYSTEMS .................................................................................................................. 11

3.1. GENERAL ...................................................................................................................................... 11

3.2. DEFINITIONS OF WATER MIST ........................................................................................................ 11 3.3. DESIGN OF WATER MIST NOZZLES ................................................................................................. 12

3.3.1. Single‐fluid mist nozzles .......................................................................................................... 12 3.3.2. Twin‐fluid mist nozzles ............................................................................................................ 12

3.4. WATERMIST APPLICATION FOR TRAINS ......................................................................................... 12

4. FIRE AND SMOKE DETECTION TECHNOLOGIES .................................................................. 14

4.1. THE PROBLEM OF DETECTION ........................................................................................................ 14 4.2. ARGE DIRECTIVE ......................................................................................................................... 15 4.3. EXISTING DETECTION TECHNOLOGIES ........................................................................................... 16

4.3.1. Ionisation smoke detectors ...................................................................................................... 17 4.3.2. Scattered‐light optical smoke detectors ................................................................................... 18 4.3.3. Projected light (beam) smoke detectors ................................................................................... 19 4.3.4. Aspirating smoke detectors (ASDs) ......................................................................................... 20 4.3.5. Heat detection .......................................................................................................................... 21

4.3.6. Flame detection ....................................................................................................................... 22

4.3.7. Video‐based flame / smoke detection ....................................................................................... 22 4.4. FIRE HAZARD DETECTORS ............................................................................................................. 23 4.5. EXAMPLES OF FIRE DETECTION IN ROLLING STOCK ....................................................................... 23

4.5.1. The VAL Underground system ................................................................................................. 23 4.5.2. The Channel Tunnel................................................................................................................. 24

5. FIRE BARRIERS ................................................................................................................................ 25

5.1. BARRIER TECHNOLOGIES .............................................................................................................. 25 5.1.1. Explosion or Fire Isolation Systems ........................................................................................ 25 5.1.2. Materials Selection .................................................................................................................. 27

6. CONCLUSION .................................................................................................................................... 31

7. BIBLIOGRAPHY ................................................................................................................................ 32


Firebomb Mitigation

LIST OF TABLES

TABLE 1: HAZARD LEVELS CLASSIFICATION ..................................................................................................... 7

TABLE 2: HAZARD LEVELS SPECIFICATION ........................................................................................................ 7

TABLE 3: HAZARD RISK SPECIFICATION ............................................................................................................ 8

LIST OF FIGURES

FIGURE 1: THE AIR SEPARATION MODULE (ASM) NASA (2004). .................................................................... 9 FIGURE 2: THE COMPONENTS OF EXPLOSION ISOLATION SYSTEMS (RELIABLE FIRE, 2012) ............................ 10

FIGURE 3: EXPLOSION MECHANICAL ISOLATION SYSTEMS (FENWAL PROTECTION SYSTEMS, 2012)............... 10 FIGURE 4: EXPLOSION CHEMICAL ISOLATION SYSTEMS (FENWAL PROTECTION SYSTEMS, 2012) ................... 11 FIGURE 5: WATER MIST SYSTEM ...................................................................................................................... 13 FIGURE 6: DETECTION AND ACTIVATION SYSTEMS FOR WATER MIST SYSTEM .................................................. 13

FIGURE 7: EFFECT OF WATER MIST ON FLAME INTENSITY AND TEMPERATURE ................................................. 14

FIGURE 8: SMOKE AND TEMPERATURE DEVELOPMENT OF A FIRE, FROM SMOULDERING FIRE TO THE FULL

FLAME FIRE (ARGE, 2010). .................................................................................................................... 15 FIGURE 9: PRINCIPLE OF AN IONISING SMOKE DETECTOR (BRAZZEL, 2008)..................................................... 17 FIGURE 10: PRINCIPLE OF A SCATTERED LIGHT SMOKE DETECTOR (SIEMENS OP320A) ................................... 18

FIGURE 11: TRANSMITTER / RECEIVER (LEFT) AND PRISM REFLECTOR (RIGHT) CONSTITUTING A PROJECTED

LIGHT SMOKE DETECTOR (SIEMENS FDL241‐9). .................................................................................... 19

FIGURE 12: GENERAL SCHEMATIC OF AN ASPIRATING SMOKE DETECTOR (BRAZZEL, 2008)............................. 20

FIGURE 13: FIRE THRESHOLDS ON A ASD FIRE DETECTOR (XTRALIS VESDA). (BRAZZEL, 2008). ................. 21 FIGURE 14: A FLAME DETECTOR (SIEMENS FDF241‐9) .................................................................................... 22

FIGURE 15 ONE OF THE SMOKE DETECTORS INSTALLED IN THE VENTILATION EXHAUSTS IN TURIN VAL

CARRIAGES. ............................................................................................................................................ 24

FIGURE 16: DIVINYCELL CORES (DIAB, 2012) ................................................................................................ 28

FIGURE 17: LAYING UP A COMPOSITE TRAIN WITH DIVINYCELL CORES (RAILWAY TECHNOLOGY, 2012A) ..... 28 FIGURE 18: CORE SUPPLIER DIAB IDENTIFIES THE MULTIPLE INTERIOR AND EXTERIOR APPLICATIONS FOR ITS

DIVINYCELL CORE PRODUCTS IN SANDWICH CONSTRUCTED COMPOSITES FOR RAIL CARRIAGES. (MCCONNELL, 2008) .............................................................................................................................. 29

FIGURE 19: KTK GROUP INTERIOR COMPONENTS UTILISE DIAB CORE MATERIALS ON THE NEW SHANGHAI

METRO (MCCONNELL, 2008). ................................................................................................................. 29 FIGURE 20: INTERIOR SMC COMPONENTS FOR RAIL CARRIAGES IN CHINA MAY PROVIDE A NEW GROWTH

SEGMENT IN THIS MARKET (MCCONNELL, 2008). ................................................................................... 30

FIGURE 21: ON THE SIEMENS DESIRO TRAIN, FRP INTERIOR COMPONENTS USING MENZOLIT’S SMC 2400 MEET

HIGH FST STANDARDS THROUGH THE ADDITION OF ALUMINIUM TRIHYDRATE. ...................................... 31


Firebomb Mitigation

1. CEN‐‐‐‐TS‐‐‐‐45545

1.1. Introduction The reality of life in Europe today is that statistically the main cause of fires in trains is that of arson involving vandalised seats. It is not surprising that fire standards for components have been developed to cope with this risk to passenger safety. As a consequence, today there are different fire standards across Europe that apply to the use of composites in mass transit. In railway applications the British Standard 6853, 1999, whose highest categories are probably the most demanding in the world. BS 6853 has introduced the concept of an R‐Index, which is a single number quantification of the toxic gas risk associated with candidate composite materials for use in railway rolling stock. The R‐Indices are split into the following categories:

Category 1a Trains which predominantly use tunnels R < 1.0 Category 1b Trains which use tunnels, but infrequently R < 1.6 Category 2 Trains which run, predominantly, overground R < 3.6

The R‐Index is generated by analysing eight gases of combustion, for which critical concentrations have been established by NIOSH/OSHA and reported as IDLH, (Immediately Dangerous to Life and Health), values. These values have been recently revised and confirm the further tightening of the criteria associated with toxic fume emissions. Note that the inclusion of nitrogen oxides was only made in 1997 and that the toxic risk associated with the use of nitrogen compounds as fire retardants is the highest of all. New trains in the UK are required to meet the BS 6853 standard that defines what category of fire performance is needed for each end component based on the risks posed. In France the French Railway’s standard NFF 16‐101 combines reaction to fire, (M rating), with smoke and toxicity, (F rating), to provide a true FST evaluation of the fire safe properties of a composite material. As with the UK BS 6853 standard, the M/F rating required in NFF 16‐101 is dependent on the type of rolling stock, the extent to which it uses tunnels and the position and orientation of the part in the vehicle. In Germany, for example, the fire standards requirements in railways are defined by the DIN 5510, which does not include any measurement of toxic gases but focuses only on reaction to fire and smoke produced in a fire scenario. This older standard’s categories are not as demanding as more recent ones and equivalent parts would typically compare to those of the lower classifications such as category 2 on BS 6853. The European commission set up a project, FIRESTARR, with a view to establishing a European standard CEN TS 45545 specifying the ‘Fire Protection on Railway Vehicles’. The FIRESTARR project has been active since 1997 identifying fire risks in European trains, defining relevant, frequently recurring, fire scenarios and selecting suitable test methods for the assessment of reaction to fire behaviour. This assessment has considered fire initiation, time to flashover, time to loss of visibility and time to lethal conditions for passengers. For structural, furniture and electrical railway parts, performance has been compared against the existing national tests and FIRESTAR is shortly due to propose classifications and test methods, which will evaluate parts against these defined criteria.


Firebomb Mitigation

This deliverable (D3.01) provides an inventory of fire suppression technologies and detectors. In addition, it discusses fire barrier or isolation measures aimed at presenting fire from spreading. Some fire retardant materials used as fire barriers in railway vehicles are also discussed.

1.2. CEN TS 45545 Fire protection of railway vehicles This European Standard specifies the measures on railway vehicles for fire protection and the verification of these measures. The objective of the measures and requirements specified in this European Standard is to protect passengers and staff in railway vehicles in the event of a fire on board although it is not within the scope of this standard to describe measures which ensure the preservation of the vehicles in the event of a fire. In order to establish the requirements for testing it is required first to define the operational categories for railway vehicles. The railway vehicles to be considered are classified using the EC categories and by interior design under the following operation categories (EC, 2009a): Operation Category 1 Vehicles that are not designed or equipped to run on underground sections, tunnels and/or elevated structures and which may be stopped with minimum delay, after which immediate side evacuation to a place of ultimate safety is possible. Operation Category 2 Vehicles that are designed or equipped to run on underground sections, tunnels and/or elevated structures, with side evacuation available and where there are stations or emergency stations that offer a place of ultimate safety to passengers, reachable within a short running time. Operation Category 3 Vehicles that are designed or equipped to run on underground sections, tunnels and/or elevated structures, with side evacuation available and where there are stations or emergency stations that offer a place of ultimate safety to passengers, reachable within a long running time. Operation Category 4 Vehicles that are designed or equipped to run on underground sections, tunnels and/or elevated structures, without side evacuation available and where there are stations or emergency stations that offer a place of ultimate safety to passengers, reachable within a short running time. Design categories Railway vehicles are additionally classified under the following design categories: A: vehicles forming part of an automatic train having no emergency trained staff on board; D: double decked vehicles; S: sleeping and couchette vehicles; N: all other vehicles (standard vehicles).


Firebomb Mitigation

Vehicle classification The classification of the railway vehicle into the relevant categories contains the operation and design categories. It is also specified in the procurement documents. For each category and design feature, a specific Hazard Level (HL) is defined according to the following table Shown in Table 1 is the CEN/TS 45545 Part 2 classification of fire hazard risk according to vehicle category (EC, 2009b).

Table 1: Hazard Levels Classification

Design Category Operation Category

N: Standard Vehicles

A: Automatic vehicles having no emergency trained staff on board

D: Double decked vehicle

S: Sleeping and couchette cars, double decked or single deck

1 HL1 HL1 HL1 HL2 2 HL2 HL2 HL2 HL2 3 HL2 HL2 HL2 HL3 4 HL3 HL3 HL3 HL3

Each Hazard Level specifies predetermined specification levels of several features, as determined in Table 2.

Table 2: Hazard Levels Specification

Each specification is tested according to Table 3.


Firebomb Mitigation

Table 3: Hazard Risk Specification

2. FIRE SUPPRESSION TECHNOLOGIES Explosion/fire protection technology include: explosion prevention and suppression systems using reticulated foam inserts, fine water mist, on-board oxygen concentration reduction; explosion isolation systems and flameless deflagration venting devices (Zalosh, 2005). These are further detailed below as follows:

1. Inerting Technology Inerting requires that the oxygen concentration be reduced below the Limiting Oxygen Concentration for a particular fuel at a specified temperature and pressure. The LOC is the smallest concentration of oxygen that can support flame propagation at the stated temperature and pressure. The cost of commercially purchased compressed nitrogen and the need for high pressurize gas piping have been deterrents for widespread use of nitrogen inerting until recently. One new development that may eliminate these deterrents for some applications is the availability of new air separation technology to produce oxygen-vitiated air on site. The "safety kit" shown in Figure 1 is composed of air separation. The arrows show the direction of air flow through the ASM. Nitrogen-enriched air flows out the other end while the oxygen-enriched waste air stream comes out the side.


Firebomb Mitigation

Figure 1: The Air Separation Module (ASM) NASA (2004).

2. Deflagration Venting Technology

The most widely used deflagration protection technology is deflagration venting. In order for deflagration venting to be effective, the vent area must be sufficiently large to accommodate the rate of pressure increase due to combustion. Guidelines for deflagration vent design are provided in 4NFPA 68 (NFPA, 2002), other national and regional standards such as the CEN/TC 305 draft standard for dust explosion venting (EC, 2002).

3. Explosion Suppression Technology Explosion/fire suppression is the interruption of an incipient deflagration by quenching the propagating flame before destructive pressures have developed. Most explosion suppression systems are active in the sense that they respond actively to the developing deflagration, and then inject the suppression agent into the enclosure. Other types of suppression systems are passive in that they are pre-installed throughout the enclosure. Commercially available active explosion suppression systems are provided with explosion detectors (either flame sensors or pressure transducers), a suppression agent stored under high pressure in one or more agent containers, a rapid activation device to trigger the discharge of agent upon explosion detection, and a control unit to monitor the system during standby and send the trigger signal upon detection. A possible alternative for expensive suppression agents is the use of water spray surge systems with a supply of water and spray nozzles distributed throughout the enclosure. Energy is rapidly extracted from the fire by the enormous surface that is formed by the huge number of very small droplets. In many cases, the water spray significantly mitigates the explosion but may not completely suppress it. Passive explosion suppression systems use reticulated metal or polymer foams preinstalled in the enclosure for portable flammable liquid containers. The large specific surface area due to the reticulated foam configuration can provide ample surface area for flame quenching during an incipient gas explosion. Gas Systems can be installed for smaller electric installations. The extinguishing gas used mostly is nitrogen which dos not generate any toxic combustion


Firebomb Mitigation

by‐products as compared to chemical extinguishing gases. Aerosol Systems apply the principle of interruption of the oxidation process at the molecular level. Aerosol fire extinguishing technology is based on a pyrotechnical extinguishing charge.

4. Explosion/Fire Isolation Systems Although explosion venting and explosion suppression can be very effective for protecting a single enclosure, both methods can be defeated when there is explosion propagation between enclosures. The two most common active types of explosion isolation devices are fast-acting mechanical barriers and chemical isolation systems.

Figure 2: The Components of Explosion Isolation Systems (Reliable Fire, 2012)

Figure 3: Explosion Mechanical Isolation Systems (Fenwal Protection Systems, 2012)


Firebomb Mitigation

Figure 4: Explosion Chemical Isolation Systems (Fenwal Protection Systems, 2012)

Since the objective of project SecureMetro is the protection of people we will describe this system in more detail in the following pages. 3. WATER MIST SYSTEMS 3.1. General Interest in water sprays for fire‐fighting has undergone something of a renaissance in recent years and this has been stimulated largely by two global legislative acts, namely:

• The International Maritime Organisation (IMO) regulations which required the retrofit of fire suppression systems on most commercial maritime vessels;

• The Montreal Protocol which required the phase‐out of ozone‐depleting Halons for fire suppression.

The former led to the rapid development of lightweight, low impact, high efficiency (low water demand) mist systems to replace existing shipboard sprinkler systems while the intended phase‐ out of Halon fire suppressants prompted an ongoing search for alternative technologies which preserve the benefits of a clean ‘total flooding’ agent yet are environmentally benign. 3.2. Definitions of water mist The definition of a water mist adopted in the NFPA 750 standard is: ‘a water spray for which the DV99 (99% volume diameter) as measured at the coarsest part of the spray in a plane 1 m from the nozzle, at its minimum operating design pressure, is less than 1000 µm ’. By comparison, in a conventional sprinkler system DV99 may be of the order of 5000 µm


Firebomb Mitigation

3.3. Design of water mist nozzles The physical nature of water presents a fundamental problem in nozzle design: water possesses a high surface tension which makes it relatively difficult to atomise effectively because the consolidating influence of this force must be disrupted through the action of other internal and/or external forces. In the absence of such disruptive forces, an isolated liquid droplet in equilibrium assumes a spherical shape to satisfy the minimum surface energy condition. Any change in system geometry promoted by external distorting forces, such as aerodynamic forces, is resisted by a combination of stabilising internal viscous forces and surface tension. Atomisation occurs only when the magnitude of the external forces exceeds the surface tension force. Nozzles originally designed for agricultural or industrial applications have been adopted or modified for use in fire suppression applications and the various designs may be subdivided broadly into ‘single‐fluid’ and ‘twin ‐fluid’ types: 3.3.1. Single‐‐‐‐fluid mist nozzles Hollow cone–single fluid: a swirling motion is induced in the liquid within the nozzle producing a plume where most of the droplets are concentrated at the outer edge. Solid cone–single fluid: an approximately homogeneous concentration of droplets is distributed over a round, square or rectangular ‘footprint’. Flat spray–single fluid: an elliptical orifice produces a sheet spray with a relatively uniform distribution of droplets, which is particularly suitable for protecting equipment in narrow voids. Single‐ fluid systems are also known as ‘simplex’ or ‘hydraulic’ types. For these, the resulting spray is influenced by the water pressure. 3.3.2. Twin‐‐‐‐fluid mist nozzles The alternative to single‐ fluid mist production is the dual fluid head, also known as ‘air atomising’, ‘duplex’ or ‘pneumatic’ nozzles. In these systems a gas, commonly nitrogen, is mixed with water in a highly turbulent environment, producing a fine mist which is then expelled through single or multiple outlets. Effective atomisation occurs at low operating pressures (0,5–6 bar), with average droplet diameter decreasing with increasing gas to liquid pressure ratio. These systems may also provide high initial droplet velocities and good horizontal projection characteristics. Disadvantages are a high gas demand and the need for a twin supply manifold, resulting in an increased cost over single‐ fluid systems. Single‐ fluid nozzles can produce droplets as small as 90–100µm at pressures around 5–6 bar, but to achieve smaller droplets (down to 30µm), twin‐fluid systems are required. In addition, despite the theoretical and experimental evidence that such small droplets are extremely effective in combustion suppression, the production of sprays containing the bulk of their water in droplets smaller than 30µm remains problematic.

3.4. Watermist application for trains Water mist system (Figure 5) is the most commonly used fire suppression in trains, although not for passenger trains. It has the following characteristics:

• Cooling and smothering water extinguishant • Antifreeze extinguishant (‐35° C)


Firebomb Mitigation

• Harmless to people, engines and equipment • Minimum requirements for cleaning‐up after the fire • Anodised, high pressure containers, corrosion protected for even the

toughest environments. • Mechanical, manual and automatic actuation

Figure 5: Water mist system

Detection and activation takes place pneumatically (Figure 6). A pressurised detector pipe burst if there is a fire. The drop in pressure activates the valve on the extinguishing agent container.

Fire Extinguisher

Detector gas bottle

Figure 6: Detection and activation systems for water mist system


Firebomb Mitigation

A pressure indicator that produces a sound and activates the alarm is installed on the detector gas bottle. The system operates independently of power supply. High pressure water mist at 100 bar and the special nozzles, atomising the water into micro drops, the average size is 50 µm. One litre of water absorbs 540 000 calories during the evaporation resulting in a decrease of ‐500 °C in less then 3 seconds. Figure 7 illustrates the effect of applying the water mist on the flame propagation and temperature.

Figure 7: Effect of water mist on flame intensity and temperature

4. FIRE AND SMOKE DETECTION TECHNOLOGIES

4.1. The problem of detection If we omit the case of fires caused by incendiary bombs or highly flammable substances such as hydrocarbons, a typical fire begins by a smouldering phase, during which it burns slowly and can remain unnoticed, except for the growing release of smoke and odour. Then, after a time depending on several factors, flames appear and start spreading, and the temperature rises at a steady pace, yielding a fully developed fire (refer to Figure 8).


Firebomb Mitigation

Figure 8: Smoke and temperature development of a fire, from smouldering fire to the full flame fire (ARGE, 2010).

The issue is then to detect the fire as soon as possible, in order to allow both evacuation and extinction at an early stage, while they are still comparatively easy. As regards detection, the evolution of a fire can grossly be decomposed into 4 stages (Brazzel, 2008):

• Stage 1: Incipient stage. Inconspicuous (invisible) smoke release.

• Stage 2: Visible smoke.

• Stage 3: Flaming fire.

• Stage 4: Intense heat. We will discuss below the capability of the various detection techniques to deal with these stages.

4.2. ARGE directive The ARGE directive (ARGE, 2010) (German acronym for “Detection Equipment Working Party”) specifies a test procedure and equipment for the functional testing of fire alarm systems, for the determination of the response time of the fire detector at the installation location variables such as smoke, heat, radiation, etc., assuming possible fire events in rolling stock. ARGE is established by the German certification and normalisation orgnisation TÜV, and accepted by the regulatory authorities in Germany, Austria and Switzerland. It does not make requirements for the installation of fire detection systems, but aims at developing an


Firebomb Mitigation

uniform, reproducible test procedure for fire detection onboard trains. As such, it does not target specifically Underground rolling stock. This test specification focuses exclusively on the location of the fire detectors with respect to the potential starting points of fires, taking into consideration:

• Detection using smoke as guiding variable.

• Detection using temperature as guiding variable. For this detection technique, only control cabinets or equipment compartments are taken into consideration.

The smoke‐based detection functionality is tested using specified smoke release conditions, simulated with cold smoke, increasing during the test, heat‐driven for thermal lift (i.e. the smoke rises towards the ceiling due to the rising temperature). In order to pass the test, the detection system must respond within 1 minute after the beginning of smoke release in all possible conditions of service. For a detection system located in equipment areas, the time limit is raised to 2 minutes. This time includes not only the detection time, but also the time to communicate the alarm to people. It is interesting to note that this 1 or 2 minutes delay is close to the time of travel between stations in Underground systems (see Section 4.5.1). Recognising that temperature‐based detectors fail to meet the requirements for early fire detection, the “temperature” variable activates immediate fire fighting measures. Finally, the equipment must be certified to comply with the relevant standards, notably EN 54 (fire detection and fire alarm systems) and rail worthiness (notably regarding electromagnetic compatibility, shock and vibrations, and environmental testing) as a prerequisite to obtain the ARGE certificate.

4.3. Existing detection technologies Several techniques exist for fire and smoke detection, and are implemented, alone or together, according to the nature of the expected fire as well as cost, sensitivity and false alarm rate requirements, and environmental conditions. This section provides a comparative list of the commonly used techniques, regardless of their effective use in trains. Most commercially available fire detectors use smoke as criterion to trigger the alarm. In “ordinary” fires, smoke is usually the first available clue that something is burning (phases 1 and 2). Flames comes next, along with heat (phase 3), at which point the fire spreads very quickly to the fully developed state (phase 4). In such a scenario, smoke detectors offer the earliest detection. Another scenario is the sudden burst of highly flammable substances. In this case, flame detectors provide the fastest detection, as smoke reaches the smoke detectors only later under the effect of thermal lift. These two examples show that the nature of the fire determines the criterion used to detect fire.


Firebomb Mitigation

The sensitivity and false alarm rate are very important features related to the detection technology, which will be stated when data is available. The sensitivity of smoke detectors is always expressed in % obscuration due to smoke per metre separating a light source from a photo receiver. Another important consideration is the air flow that can cross the detectors. We will see that the performances of the various types of detectors are more or less affected by the air velocity, depending on their technology.

4.3.1. Ionisation smoke detectors This is a popular spot‐type (i.e. sensitive only at the place it is physically installed) smoke detector (Figure 9).

Figure 9: Principle of an ionising smoke detector (Brazzel, 2008).

4.3.1.1. Principle: An ionisation smoke detector consists of two chambers: an open, outer chamber and an semi‐ sealed reference chamber within, containing a small (typically 0.2 µg) low‐activity radioactive source of Americium 241 (FEMA, 2009). When the detector is powered up, the alpha particles from the source yield a current flow between the two chambers. When smoke enters the outer chamber, the smoke particles are attached to the ions, causing the current to decrease. This current is monitored and, when below a preset threshold, triggers the alarm.

4.3.1.2. Characteristics: Sensitivity: 3‐6% obscuration / m (assuming smoke coming from a fire) – more sensitive than “ordinary” photo‐electric detectors. False alarm rate: high, especially in high air velocities. Notoriously prone to false alarms in kitchens when cooking.


Firebomb Mitigation

Air velocity range: not suitable above 6 km/h, up to 30 km/h for some models Capture range: spot‐type (will not detect unless the smoke enters the chamber under the effect of thermal lift or of air flow).

4.3.1.3. Pro/cons: These are inexpensive general purpose detectors that respond well to flaming fires, but

high rate of false alarms and not really usable close to HVAC or other environments with

air movement. NB: the radioactive source used by these detectors is really small, and specific disposal measures are not considered necessary. On the other hand, the half‐life of Americium 241 is 470 years, which does not impair the useful lifetime of those detectors (Canadian Nuclear Society, 2008).

4.3.2. Scattered‐‐‐‐light optical smoke detectors

Figure 10: Principle of a scattered light smoke detector (Siemens OP320A)

4.3.2.1. Principle: The scattered‐light smoke detectors use a pulsed infrared LED located in a dark chamber, designed to let the air in, but exclude any light coming from the outside. A photodiode is located at an angle that prevents it from seeing the direct light from the LED. On the other hand, when smoke is present in the chamber, it scatters light which is recorder by the photodiode. When the scattered light exceeds a preset threshold, the alarm is triggered.

4.3.2.2. Characteristics: Sensitivity: 6‐12% obscuration / m, less sensitive than ionising detectors. There are high sensitivity models, but their characteristics are close to ionising types: higher false alarm rate, and not suitable for air flows above 6 km/h. False alarm rate: very low. In domestic environment, these are nicknamed “toast‐proof


Firebomb Mitigation

detectors” as opposed to the ionising detectors. Air velocity range: not suitable above 35‐70 km/h, or less for the high sensitivity models. Combined with their lower sensitivity, scattered light detectors often will not detect fires in high airflow environments. Capture range: as all spot‐type detectors, they need the smoke to enter the chamber under the effect of thermal lift or of air flow.

4.3.2.3. Pro/cons: These detectors are more robust to false alarms than the ionising type, but their lower sensitivity does not usually allow them to detect smoke until late, well into phase 2 of a fire, in which smoke becomes visible. A 2008 NIST investigation (Bukowski et al, 2008) found that, in domestic environment, the tested photo‐electric detectors consistently reacted faster to smouldering fire, whereas ionising detectors consistently reacted faster to flaming fires. This confirms that the fire scenario is an important criterion in the choice of a detection technology. Several commercially available detectors take this aspect into account by combining ionising and photoelectric chambers. This study also highlights the importance of the placement of the detector as regards the detection performances.

4.3.3. Projected light (beam) smoke detectors The principle of detection is the same as for the detectors based on scattered light, but instead of using a chamber, these detectors operate in open air. They use either separate emitter and receiver boxes, or an integrated emitter / receiver box with a reflector, and monitor the obscuration along the path of the infrared beam. These detectors are mentioned only for exhaustiveness, as they are not really suitable for small spaces such as trains. They are, however, convenient for large spaces such as warehouses, arenas, etc.

Figure 11: Transmitter / receiver (left) and prism reflector (right) constituting a projected light smoke detector (Siemens FDL241‐9).


Firebomb Mitigation

4.3.3.1. Characteristics:

Sensitivity: Less sensitive than scattered light detectors. May depend on the installation parameters (emitter / receiver distance, etc.). Capture range: as the two spot‐type detectors above, they need the smoke to cross the light beam under the effect of thermal lift or of air flow. The main difference is that the zone can be much wider, the whole length of the carriage if needed, at the cost of a sensitivity reduced by the dispersion of the beam.

4.3.3.2. Pro/cons: The risk of the beam being obstructed by a passenger or a piece of luggage reduces the use of these detectors to places inaccessible to people. Besides, the installation and maintenance are complicated by the need to align the beam and keep the optical surfaces clean. However, they are convenient in large spaces (museums, warehouses, etc.) where spot‐type detectors are too cumbersome due to the required number of detectors, or are difficult to maintain due to high ceilings.

4.3.4. Aspirating smoke detectors (ASDs) These detectors work by actively sampling air through a network of holes and pipes, and delivering it to a centralised detection chamber. The latter consists of a gas‐phase nephelometer, a calibrated laser‐based scattered‐light detector which provides extremely sensitive detection, and analyses simultaneously all the air samples. An air filter is integral part of the system, as it is required to avoid mistaking dust particles for smoke, and contaminating the chamber.

Figure 12: General schematic of an aspirating smoke detector (Brazzel, 2008).


Firebomb Mitigation

Sensitivity: 0.005 ‐ 20% / m obscuration, programmable (figures provided by Xtralis for their VESDA system). Several thresholds can be set for gradual response.

Figure 13: Fire thresholds on a ASD fire detector (Xtralis VESDA). (Brazzel, 2008).

Capture range: The aspirating systems provide a constant air flow allowing to capture smoke in the surrounding of the air inlets. Moreover, the multiple inlets allow a wide coverage of the monitored area. This advantage has a drawback however: in the case of a localised fire, the air sample containing smoke is diluted with all the smoke‐free samples, and the concentration in the detector chamber is lowered; however this is compensated by the very sensitive detection chamber. Another detrimental consequence of centralised detection is that, in case of detection, the origin of the fire cannot be known, contrary to spot‐type detectors with which the first detector to react can be assumed to be close to the origin of the fire.

4.3.4.1. Pro/cons: The aspirating principle allows avoiding the sensitivity of passive systems to air flow, and makes ASD an attractive technology for smoke detection in high air velocity environments. The high sensitivity of ASD also allows very early warning, and the use of several thresholds allows monitoring the evolution of a fire, and reacting gradually according to the emergency level (Ming and Yun, 2005).

4.3.5. Heat detection These detectors are sensitive to heat rather than smoke, and thus offer an alternative method of detecting fires. As one can see on Figure 1, room temperature rises significantly only at a late stage in the development of a fire, so this type of detector is not suitable for detection of smouldering fire in phase 1 or 2 (Bukowski et al, 2008). Several manufacturers offer detectors incorporating heat detection and scattered‐light smoke detection for multi‐criteria detection.


Firebomb Mitigation

Two different heat‐based detection techniques exist, with different application fields according to the environment: static (which is a mere threshold) and Rate of Rise (which monitors the speed at which temperature rises). Some detectors use those two detection techniques simultaneously. Both types are robust to dirty or dusty environments in which spot‐type smoke detectors tend to generate false alarms and get contaminated, and are most suitable in areas with a fairly constant temperature.

4.3.5.1. Static temperature detection This type of detector is basically a thermometer: if its temperature exceeds a preset threshold, the alarm is triggered. However, it is not really suitable for places subjected to high temperature variations, such as a public transport vehicle, where the need to set a high threshold only allows detecting fire at a very late stage. This kind of detector is widely seen as a property‐saving device, in the sense that it tends to trigger an alarm only at stage 3 (flaming fire), which can be good enough for e.g. inhabited warehouses, but not necessarily for houses or passenger carrying vehicles where early detection is a requirement.

4.3.5.2. Rate‐of‐rise detection Heat detection can be performed by detecting a sharp or more gradual rise in the temperature, in which case a threshold (expressed in °C / min) is set to trigger the alarm. In rolling stock, however, this type of detection is more likely to cause false alarms as doors open and close, for instance in an air conditioned vehicle on a hot summer day: the difference between inside and outside temperatures, as well as the constantly changing number of passengers, are sufficient to cause temperature gradients that can far outperform the gradient caused by a smouldering fire at an early stage.

4.3.6. Flame detection At stages 3 and 4, direct flame detection is possible using their optical properties as light emitters, in UV and/or IR wavelength domains. Flame detectors are particularly suitable for highly flammable materials causing smokeless fires or fire which start directly at stage 3: in this case, a flame detector reacts much earlier than a smoke detector. However, such materials are not usually found in Underground trains, in which the regulations prevent the use of flammable material for equipment and furniture.

Figure 14: A flame detector (Siemens FDF241‐9)

4.3.7. Video‐‐‐‐based flame / smoke detection Since several years, artificial vision researchers have been devising algorithms to detect


Firebomb Mitigation

smoke (Ugur Töreyin et al, 2005) or flames (Liu and Ahuja, 2004) in video images. One can point out that surveillance cameras are unlikely to see phase 1 smoke that remains invisible to the human eye, so the potential of video in early smoke detection appears doubtful. However, video detection has the major advantage of offering volumetric detection, being able to “see” smoke close to the ground, unlike spot‐type and even air sampling detectors that require smoke to reach at least near‐ceiling height: if smoke is visible at low level, it may be visually detected earlier. A standard does exist UL 268B (video image smoke detectors), to which at least one manufacturer1 claims approval. Unfortunately, we have not found any study comparing the performances of video based sensors to other technologies.

4.4. Fire hazard detectors Although not directly related to the detection of fire, but rather to the detection of risk, it is interesting to mention explosiveness sensors in this review. Based on detection of specific explosive materials, notably hydrocarbons, these sensors are able to detect explosion hazard. Such devices are for instance installed in the Eurotunnel shuttles wagons to detect fuel leaking from a car, and react accordingly to avoid a possible fire in tunnel (Whitaker, 1992). Other fire risks are detected by placing temperature sensors in technical equipment cabinets, on wheels or brakes. Historically placed on the trackside (“hot box” detectors), such detectors are now installed on the brakes and wheels themselves (refer to Section 4.5.1) and used by the train’s onboard control systems, to trigger alarms or to automatically activate fire avoidance procedures ranging from turning off the overheating equipment to stopping the train.

4.5. Examples of fire detection in rolling stock

4.5.1. The VAL Underground system Underground systems such as VAL represent a somewhat extreme case in which the vehicle runs for only a minute or two between stations. As such, fire detection means are not usually considered necessary. Indeed, great care is applied in the selection of materials to prevent a fire from developing, let alone in the short time between stations, and the structure itself is validated to stand a 30 minute fully developed, externally fuelled fire. As a result, the main fire detection system is the passengers themselves, and the emergency intercom which allows them to communicate with the Control Centre in case of incident, along with the smoke detection existing in the tunnels. The onboard fire suppression system itself is restricted to a hand‐operated fire extinguisher in each carriage, and a water‐spray fire extinguisher in the inter‐carriage space, outside the train, accessible to the rescue teams. All this is in line with the consideration that a fire is not able to spread in the short interval

during stations, and the best response to a fire is to evacuate the carriage when the train 1 http://www.axonx.com/01_26_10.htm


Firebomb Mitigation

stops.

On the first VAL generations, a scattered‐light smoke detector is installed to detect smoke entering the carriage from the tunnel. Its activation turns off the ventilation system and sends an alarm to the onboard automatic control system. Temperature probes are placed in critical electrical equipments, their activation triggers a suitable reaction of the vehicle (isolate the equipment, turn off the power, stop the train, etc.). On newer generations (VAL 208), an additional hot‐brake detector is provided. An improvement exists in the Turin VAL network, in which three scattered‐light type smoke detectors are installed in the ventilation exhausts of each carriage to detect smoke generated within the carriage, but these detectors are not part of the control system, they just generate alarms.

Figure 15 One of the smoke detectors installed in the ventilation exhausts in Turin VAL carriages.

4.5.2. The Channel Tunnel At the other extreme is the Channel Tunnel, in which trains run for 30 minutes in a tunnel between stations, hence widely different safety requirements. We find it interesting to describe the fire detection and suppression systems installed in the Shuttle wagons as an example of train designed to run in tunnels with the best possible fire protection systems available. These systems were designed taking into account both Eurotunnel’s original propositions and the Channel Tunnel Safety Authority, taking into account the results of full ‐scale fire tests. Those systems are many and complex, taking into consideration many aspects of safety, and we will describe only the systems dealing directly with fire detection and suppression.

4.5.2.1. Explosiveness detection and handling Although the engines are stopped during the travel, the most potentially dangerous situation in the Shuttle is a fuel leak from one of the vehicles in the wagon. This is why detection and suppression of this risk is handled by several measures:

• A drainage system is located at the centre of the deck to evacuate spilled fuel in


Firebomb Mitigation

order to minimise the surface of the spill, and direct it to an underfloor tank to minimise the risk and size of potential fire.

• A hydrocarbon gas detector is installed to detect spilled fuel. • Should the gas concentration reach a predefined level, the sensor triggers an AFFF

foam spray system located at floor level, in order to prevent the ignition of liquid fuel and stop any increase of the vapour concentration.

• The system is moreover connected to the ventilation system, which increases the air output in order to decrease the vapour concentration in the train.

4.5.2.2. Fire detection and suppression The fire detection system uses three types of sensors:

• Ionic smoke detectors. • Photo‐electric opacimeters to measure smoke density. • Flame detectors.

These sensors, along with the vapour detectors, assess the situation and if necessary activate the suppression system using Halon 1301. Fire doors and ventilation shutdown are used to maintain a sufficient Halon concentration in the area concerned by the fire. The objective is to allow evacuation of the passengers to other areas while maintaining effective fire suppression and reducing as much as possible the risk of intoxication and fire spreading for the whole duration of the 30 minute travel in the tunnel. Full scale fire tests, involving all types of fire, were carried out successfully to validate the system before commissioning.

5. FIRE BARRIERS

A fire barrier is an element that is intended for use in maintaining separation between two adjacent areas of a railway vehicle in the event of a fire which resists the passage of flame and/or heat and/or effluents for a period of time under specified conditions. The design of rolling stock and products used is aimed at limiting fire development should an ignition event occur in order that a sufficient level of safety is achieved (CEN 45455-Part3).

5.1. Barrier Technologies

5.1.1. Explosion or Fire Isolation Systems Origin of fire in a metro could be outside/exterior, inside/interior (passenger area), driver cab and under carriage not accessible. Each of these areas can be isolated to prevent fire spreading to the other areas. Isolation is best achieved by introducing fire barriers between them. Fire barrier design characteristics should conform to CEN 45545 Part 3, depending on the origin of the fire. For firebombs, the likelihood is that the fire is coming from the passenger area. The fire resistance performance of fire barriers are determined using standard fire test procedures in accordance with the general requirements specified in EN 1363-1.


Firebomb Mitigation

5.1.1.1. Fire resistance requirements for fire barriers

The objective of barriers is to protect passengers and staff in railway vehicles in the event of a fire on board by containing fire. In reducing the risk of fire development,

1. Fire and smoke barriers shall be installed in vehicles to delay the spread of fire and its combustion products. These barriers shall be sited in a vehicle such that they:

a. Delay the spread of fire and combustion products between vehicles with a vehicle / vehicle performance according to the category of the vehicles. (side walls, ceiling, floor)

b. Delay the penetration of fire from underneath the floor of a vehicle into the vehicle interior. Floor fire barriers shall achieve a 20 minute integrity and insulation in accordance with BS 476 Part 20 and Part 22 or BS EN 1363-1:1999 partition test. (floor)

c. Delay the spread of fire and combustion products into areas where the driver and traincrew carry out their operational duties under emergency conditions (such as driving the train to a safe place for evacuation and initiating an evacuation), and to safeguard their escape routes from those areas on completion of those duties. The fire barrier performance shall be in accordance with the category of the vehicles (doors, partitions).

2. Doors in fire barriers shall be self-closing. However, the passage of people through such doors shall not be impeded by that feature.

5.1.1.2. Classification of fire barriers

Fire barriers may have performance in one of the three parameters: 1. The lowest performing barrier is E = Integrity 2. The next level of performance would be requested EW = Integrity and Radiation

Transfer. 3. The top level is E I = Integration and insulation requirement

In the event of a fire developing, the vehicle design configuration and the materials used in its construction shall ensure, as far as reasonably practicable, that:

a) The required mechanical strength of the vehicle main structure is retained. b) The rates of fire propagation, of flame spread, heat release and of smoke and toxic

gas emissions are sufficiently low as to: i. Enable people not to be unduly hindered in their escape and evacuation to a

position of ultimate safety, taking account of the specific operational characteristics of the category of vehicles.

ii. Reduce as far as is reasonably practicable the effects on the railway infrastructure and on railway operations.

Currently, fire barriers applied in passenger areas include roofing, side walls, partitions, floor and doors. The materials used to make these components should have inherent fire resistance properties. Materials applied as fire barriers include:

• Sandwiches / Cavity barriers • Laminates • Composites (e.g. phenolic composites) • Foam


Firebomb Mitigation

5.1.2. Materials Selection In a rail vehicle a fire, smoke spread is more life threatening than flame spread (Chow et al, 2011). The fire standards EN 45455 (and the most stringent BS 6853) favours highly fire retardant composites that burn with low levels of toxic gas emission. The reaction to fire performance requirements of materials and components depend on their intrinsic nature but also on the,

• Location of materials or components within the design; • Shape and the layout of the materials; and • Direction surface exposed and relative mass and thickness of the materials

Fire resistance is the ability of an item to fulfil for a stated period of time the required stability and/or integrity and/or thermal insulation, and/or other expected duty specified in a standard fire-resistance test. For metros barriers should achieve 20 minute integrity. On the recent past, Fibre Reinforced Polymer (FRP) composites have been applied in rail vehicle construction to achieve this requirement. They not only offer light weight/high strength solutions, but also reduce maintenance costs. The following sections present examples of current composite solutions for rail vehicle con

5.1.2.1. Sandwich Composite Solutions

A sandwich-structured composite is fabricated by attaching two thin but stiff skins to a lightweight but thick core. The core material is normally low strength material, but its higher thickness provides the sandwich composite with high bending stiffness with overall low density. As an example, DIAB’s transport cores are used in rail vehicle construction (Figure 16 and Figure 17). They are thermoplastic, recyclable, compatible with polyester, vinyl ester, epoxy and phenolic resins, and have been designed for FST performance at elevated temperature. Divinycell F shows excellent heat aging at 180° C (356° F) and is compatible with most common composite manufacturing processes up to 220° C (428° F) cure cycles, including prepregs and infusion. (McConnell, 2008). Examples are shown in Figure 16 and Figure 17. Rail vehicles capitalising on the benefits of DIAB’s core materials in composite rail components are the Austrian Bayerische Oberlandbahn (flooring), Siemens Combino tram (front panel incorporating bumper), Bombardier’s Talent and Regina trains (front, sides and roof) and the Adtranz Regio Shuttle (front panel).


Firebomb Mitigation

Figure 16: Divinycell Cores (DIAB, 2012)

Figure 17: Laying up a composite train with Divinycell Cores (Railway Technology, 2012a)

Figure 18 and Figure 19 give examples of components that could be manufactured using sandwich components.


Firebomb Mitigation

Figure 18: Core supplier DIAB identifies the multiple interior and exterior applications for its Divinycell core products in sandwich constructed composites for rail carriages. (McConnell, 2008)

Figure 19: KTK Group interior components utilise DIAB core materials on the new Shanghai metro (McConnell, 2008).

5.1.2.2. Sheet Moulding Compound

Sheet moulding compoundreinforced polyester material primarily used in increasingly being used in rail vehicles to meet FST requreinforced sheet moulding compound (SMC) in its Desiro trains running in Europe, specifically SMC 2400 from Menzolitbased compound meets the strongest fire safety standard in Eur6853 for railways – and is also used in interior components on the Tucheng rail line in China and street cars in Berlin (McConnell, 2008). In wall claddings, window frames, door and seat structures, SMC 2400 (based on unsaturated polyester resin) is easily moulded in large panels. A key FST ingredient is aluminium-trihydrate (ATH), a mineral filler that acts as a quenching element in the SMC by releasing water at elevated temperature up to 200° C like a built in fire extinguisher.Under fire conditions, SMC components do not generate poisonous gases, collapse, or spread molten material or droplets keeping escape ways open for passengers to get out. In case of fire smoke is released to a small extent. Smoke is, except for carbon monnon-toxic. This makes SMC 2400 suitable for railway interior or exterior applications, like wall panels, window frames, luggage bins, seat shells and structures or similar rail way components. Fire safe furniture or sanitary furniture on ships, trainanother typical use. Shown in Figure 20 and Figure

Figure 20: Interior SMC components for rail carriages in China may provide a new growth segment in this


Firebomb Mitigation

Sheet Moulding Compound

Sheet moulding compound (SMC) or sheet moulding composite is a ready to mould fibrematerial primarily used in compression moulding. The compound is

increasingly being used in rail vehicles to meet FST requirements. Siemens uses glass reinforced sheet moulding compound (SMC) in its Desiro trains running in Europe, specifically SMC 2400 from Menzolit-Fibron GmbH. Introduced in 2005, this polyesterbased compound meets the strongest fire safety standard in Europe – British standard BS

and is also used in interior components on the Tucheng rail line in China and street cars in Berlin (McConnell, 2008).

In wall claddings, window frames, door and seat structures, SMC 2400 (based on polyester resin) is easily moulded in large panels. A key FST ingredient is

trihydrate (ATH), a mineral filler that acts as a quenching element in the SMC by releasing water at elevated temperature up to 200° C like a built in fire extinguisher.Under fire conditions, SMC components do not generate poisonous gases, collapse, or spread molten material or droplets keeping escape ways open for passengers to get out. In case of fire smoke is released to a small extent. Smoke is, except for carbon mon

toxic. This makes SMC 2400 suitable for railway interior or exterior applications, like wall panels, window frames, luggage bins, seat shells and structures or similar rail way components. Fire safe furniture or sanitary furniture on ships, trains or prison cells are

Figure 21 are some application of SMC rail vehicle

Interior SMC components for rail carriages in China may provide a new growth segment in this market (McConnell, 2008).

Critical Inventory of Technologies for

is a ready to mould fibre-. The compound is Siemens uses glass

reinforced sheet moulding compound (SMC) in its Desiro trains running in Europe, Fibron GmbH. Introduced in 2005, this polyester-

British standard BS and is also used in interior components on the Tucheng rail line in

In wall claddings, window frames, door and seat structures, SMC 2400 (based on polyester resin) is easily moulded in large panels. A key FST ingredient is

trihydrate (ATH), a mineral filler that acts as a quenching element in the SMC by releasing water at elevated temperature up to 200° C like a built in fire extinguisher. Under fire conditions, SMC components do not generate poisonous gases, collapse, or spread molten material or droplets keeping escape ways open for passengers to get out. In case of fire smoke is released to a small extent. Smoke is, except for carbon monoxyde

toxic. This makes SMC 2400 suitable for railway interior or exterior applications, like wall panels, window frames, luggage bins, seat shells and structures or similar rail way

s or prison cells are

are some application of SMC rail vehicle

Interior SMC components for rail carriages in China may provide a new growth segment in this

Figure 21: On the Siemens Desiro train, FRP interior components using Menzolit’s SMC 2400 meet high FST standards through the addition of aluminium trihydrate.

An example of a material with particularly low toxicity levels is filled polyester system has a very low R value.thixotropic, non-halogenated, non SMC technology also enables application for the structural laminate and the cosmetic pigmented surface, therefore eliminating the need for painting the components and providing a through colour. This offers technical advantages over painted systems, firstlany minor damage due to graffiti or scratches can be polished out to produce a refurbishedcomponent and secondly, there is no negative effect on the fire performance properties of the composite which is the case with painted systems.

5.1.2.3. Phenolic Prepregs

A large range of interior rail components can be made from phenolic prepregs including seating, ceilings, floorings, bulkheads, vestibules, fire barriers, wall panels, window surrounds, doors, corridor adapter frames, staircases, luggage bins/racks, fairingtoilet modules. E-glass reinforced phenolic prepregs from Gurit’s Aerospace and Rail divisions in Switzerland and Germany, feature good surface finish achieved in short cure cycles (10 minutes at 160° C) with 63 The prepregs have been used in interior components aboard the Siemens high speed AVE S103 in Spain and in the exterior front end for the Combino Plus in Portugal. Gurit’s PH840-300-42 prepreg is available in 8H satin woven fabric with 42% phenolic resin, whereas PH840-600-40 comes in satin HD special with 40% phenolic resin.

6. CONCLUSION Many fire detection technologies exist, using several different criterions and each technology or criterion is more or less suitable according to the nature of the fire that is expected. In Underground rolling stock, the risk of fire is usually detected using more or less sophisticated means, but the detection of fire itself is seldom done, due to its


Firebomb Mitigation

On the Siemens Desiro train, FRP interior components using Menzolit’s SMC 2400 meet high FST standards through the addition of aluminium trihydrate.

An example of a material with particularly low toxicity levels is Synolite 5001filled polyester system has a very low R value. Synolite 5001-T-1 is a DCPD based,

halogenated, non-pre-accelerated unsaturated polyester resin.

SMC technology also enables application for the structural laminate and the cosmetic pigmented surface, therefore eliminating the need for painting the components and providing a through colour. This offers technical advantages over painted systems, firstlany minor damage due to graffiti or scratches can be polished out to produce a refurbishedcomponent and secondly, there is no negative effect on the fire performance properties of the composite which is the case with painted systems.

Phenolic Prepregs

large range of interior rail components can be made from phenolic prepregs including seating, ceilings, floorings, bulkheads, vestibules, fire barriers, wall panels, window surrounds, doors, corridor adapter frames, staircases, luggage bins/racks, fairing

glass reinforced phenolic prepregs from Gurit’s Aerospace and Rail divisions in Switzerland and Germany, feature good surface finish achieved in short cure cycles (10 minutes at 160° C) with 63–68% glass loading.

e been used in interior components aboard the Siemens high speed AVE S103 in Spain and in the exterior front end for the Combino Plus in Portugal. Gurit’s

42 prepreg is available in 8H satin woven fabric with 42% phenolic resin, 40 comes in satin HD special with 40% phenolic resin.

Many fire detection technologies exist, using several different criterions and each technology or criterion is more or less suitable according to the nature of the fire that is

Underground rolling stock, the risk of fire is usually detected using more or less sophisticated means, but the detection of fire itself is seldom done, due to its

Critical Inventory of Technologies for

On the Siemens Desiro train, FRP interior components using Menzolit’s SMC 2400 meet high

Synolite 5001-T-1 ATH, a 1 is a DCPD based,

accelerated unsaturated polyester resin.

SMC technology also enables application for the structural laminate and the cosmetic pigmented surface, therefore eliminating the need for painting the components and providing a through colour. This offers technical advantages over painted systems, firstly any minor damage due to graffiti or scratches can be polished out to produce a refurbished component and secondly, there is no negative effect on the fire performance properties of the

large range of interior rail components can be made from phenolic prepregs including seating, ceilings, floorings, bulkheads, vestibules, fire barriers, wall panels, window surrounds, doors, corridor adapter frames, staircases, luggage bins/racks, fairings, and

glass reinforced phenolic prepregs from Gurit’s Aerospace and Rail divisions in Switzerland and Germany, feature good surface finish achieved in short cure

e been used in interior components aboard the Siemens high speed AVE S103 in Spain and in the exterior front end for the Combino Plus in Portugal. Gurit’s

42 prepreg is available in 8H satin woven fabric with 42% phenolic resin, 40 comes in satin HD special with 40% phenolic resin.

Many fire detection technologies exist, using several different criterions and each technology or criterion is more or less suitable according to the nature of the fire that is

Underground rolling stock, the risk of fire is usually detected using more or less sophisticated means, but the detection of fire itself is seldom done, due to its


Firebomb Mitigation

being seen as unnecessary because of the short distance between stations and the fireproof, non‐flammable design of the trains. A point that needs to be emphasised is that studies have found that the placement of the detector with respect to the fire is at least as important as its technology (Bukowski et al, 2008). This point is particularly considered in the ARGE validation process (ARGE, 2010). Materials used for metro interior and exterior body parts should exhibit good FST properties. Such materials are now readily available on the market in form of sandwich composites, Sheet Moulding Compounds (SMC) and phenolic prepregs.

7. BIBLIOGRAPHY

1. ARGE directive “Fire detection in rolling stock” – procedure for the proof of function concerning the placement of fire detectors in rooms accessible to people, electric control cabinets and areas of combustion engines – Guidelines / Inspection procedures. Available at http://www.tuev‐sued.de/uploads/images/1221831811714457190203/ARGE‐ Richtlinie_Branderkennung_in_Schienenfahrzeugen_Version_2.0‐Eng.pdf (accessed 10/02/2010).

2. Canadian Nuclear Society (2008): Smoke detectors and americium‐241 fact sheet. Available at http://media.cns‐snc.ca/pdf_doc/ecc/smoke_am241.pdf (accessed 10/02/2010).

3. D. Brazzell, The Effects of High Air Velocity and Complex Airflow Patterns on Smoke Detector Performance (2008). Available at http://www.afcom8‐21.afcom‐miami‐ admin.com/AFCOM%20%20‐ %20Effects%20of%20High%20Airflow%20and%20Complex%20Airflow%20Patt.pdf (accessed 10/02/2010).

4. EC (2002): EN/TC305/WG 3, “Dust Explosion Venting Protective Systems,” Draft prEN 14491, 2002.

5. EC (2009a): Railway applications — Fire protection on railway vehicles. Part 1: General. DD CEN/TS 45545-1:2009. CEN/TS 45545-1:2009 (E). Standards Policy and Strategy Committee on 30 April 2009. © BSI 2009. ISBN 978 0 580 53472 0.

6. EC (2009b): Railway applications — Fire protection on railway vehicles. Part 2: Requirements for fire behaviour of materials and components. CEN/TS 45545-4:2009. Standards Policy and Strategy Committee on 31 May 2009. © BSI 2009. ISBN 978 0 580 53473 7.

7. FEMA (2009): Disposal of Fire/Smoke Detectors. Tech Talk. Vol. 1, Non. 2. December 2009. Available at http://www.usfa.dhs.gov/downloads/pdf/techtalk/techtalk_v1n2_1209.pdf.

8. Fenwal Protection Systems (2012): Explosion Isolation Systems. http://www.fenwalprotection.com/ utcfs/Templates/Pages/Template-54/0,8063,pageId=1135&siteId=391,00.html.

9. Liu C. B. and Ahuja N. (2004): Vision Based Fire Detection, Proc. of Int. Conf. on Pattern Recognition, ICPR ’04, Vol. 4, 2004. Available at http://www.computer.org/portal/web/csdl/doi/10.1109/ICPR.2004.1333722 (accessed 10/03/2010).


Firebomb Mitigation

10. McConnel V. P. (2008): Rail – an Evolving Market for FRP Components. Reinforced Plastics. Volume 52. Issue 11. December 2008. Pages 24 – 29.

11. Ming H. and Yun J. (2005): Use of FDS to Assess the Effectiveness of an Air Sampling‐Type Detector for Large Open Space Protection. Fire Protection Engineering, 3rd quarter 2005. Available at http://www.fpemag.com/archives/article.asp?issue_id=27&i=154 (accessed 10/03/2010).

12. NASA (2004): Non-Flammable Fuel? http://www.nasa.gov/missions/research/ f_fuel-safety.html.

13. NFPA (2002): NFPA 68, “Guide for Venting of Deflagrations,” National Fire Protection Association, 2002

14. Reliable Fire (2012): About Explosion Isolation Systems. Available at http://www.reliablefire.com/explsupfolder/expl-isolation-systems.html.

15. Ugur Töreyin B., Dedeogl Y. and Enis Cetin A. (2005): Wavelet based real‐time smoke detection in video, 13th European Signal Processing Conference EUSIPCO 2005, Antalya, Turkey. Available at http://www.ee.bilkent.edu.tr/~ugur/eusipco2005.pdf (accessed 10/03/2010).

16. Whitaker, E. H. (1992): Eurotunnel’s Specification for Halon 1301 Replacement. NIST Special Publication 984‐4. Available at http://www.bfrl.nist.gov/866/HOTWC/HOTWC2006/pubs/R0301013.pdf. (accessed 10/03/2010).

17. Zalosh R. (2005): New Developments in Explosion Protection Technology. For Presentation at Fire and Emergency Services Asia 2005. Singapore. February 22– 26, 2005.

18. Railway Technology (2012a): DIAB - Sandwich Composite Cores. Available at http://www.railway-technology.com/contractors/passenger/diab/diab3.html.

19. DIAB (2012): DIAB Divinycell. http://pdf.nauticexpo.com/pdf/diab/the-ultimate-core-for-sandwich-structures-divinycell/22285-931.html.

20. Railway-technology.com (2012b): Interior of one of Seoul metro's trains on line 1. Available at http://www.railway-technology.com/projects/seoul-metro/images/4-seoul-metro-train.jpg.

21. Chow W.K., Lam K. C. Fong, N.K., Li S.S. and Gao Y. (2011): Numerical Simulations for a Typical Train Fire in China. Modeling and Simulation in Engineering. Volume 2011, Article ID 369470. Hindawi Publishing Corporation.

wp3 design solutions for fire and firebombssecuremetro.inrets.fr/fileadmin/depository... ·...

Documents