Seminar on Fire Safety by ramesh

8/13/2019 Seminar on Fire Safety by ramesh

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FIRE SAFETY IN

RAIL VEHICLE

DESIGN


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FIRE SAFETY IN TRAINS

SHOULD BEGIN WITH VEHICLEDESIGN PROCESS ITSELF.


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THIS IS A NOVELSTEP IN FIRE SAFETY

THINKING


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CONVENTIONAL FIRE PREVENTION

PRACTICES HAVE TO BE ABOLISHED

We have ensure that material supplierswill accept the need for this new design

review approach to fire safety.


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APPROACH USING ARGEGUIDELINES

ARGE guidelines focuses on fulfilling

the utmost safety objective

SAFETYOF PASSENGERS


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This guideline is already accepted in manycountries as acknowledged code of practice

and is being applied Europewide.

This guideline helps for designing and proofing

the functionality of fire detectors, fire fighting

and fire extinguishing systems.


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DETECTION OF FIRE IN A MOVING TRAIN AND

INSTALLATION OF FIRE DETECTORS

Here the aim is to provide complete

planning for the installation of fire

detection systems in rolling stock.

To achieve this aim , system specificrequirements for design,

construction and proof are needed.


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The main objective is to create

health conditions acceptable

for a safe evacuation ofpassengers and staff from the

train.


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In this context, FIRE can be classified into

a) Flaming fire.

b) Smoldering fire.

Flaming fire can be defined as fire having a little smoke and

more flame.

Smoldering fire can be defined as fire having a little fire and

more smoke.

IMPORTANCE OF FIRE DETECTION.

A fire event should be detected already during the formation

phase itself, that is in the smouldering phase itself or quickly as

possible after ignition is set up.


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A SMOLDERING FIRE IF LEFT UNNOTICED CAN DEVELOP INTO A BIG

FIRE AND MAKE THE SAFE EXIT OF PASSENGERS DIFFICULT.

THE INTERIORS OF ALL TRAINS ARE MADE OF MANY MATERIALS

INCLUDING POLYMERS ,ELASTOMERS,AND NATURAL PRODUCTS.

THE EFFECT OF SMOLDERING FIRE ON THIS MATERIALS RESULTS IN

THE EMISSION OF TOXIC GASES.

NOW LET US ANALYSE THE MAJOR COMPONENTS THAT ENSUES FIRE

AND ITS IMPACT ON THE HUMAN LIVES .


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Table: Indices and reference values for quantitative protection objectives

Smoke gaspercentage Threshold value

Exposure time

about 15 minincl. safety

factor

Exposure time

about 5 minincl. safety

factorCarbon monoxide < 1400 ppm 200 ppm 500 ppm

Carbon dioxide < 6.0 vol.-% 2 vol.-% 3 vol.-%Oxygen > 12 vol.-% 14 vol.-% 12 vol.-%

Smoke gastemperature < 65 C 50 C 50 C

The measurements are performed in the area affected by the fire in a height of about

1.6m and in about 2.0 m distance from the ignition source..


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THE MEASURING POINTS ARE TO BE ARRANGED AT A HORIZONTAL DISTANCE OF 2

METRES FROM THE FIRE SOURCE IN THE CENTRE OF THE ESCAPE ROUTE AT A

HEIGHT OF APPROXIMATELY 1.6METRES. ( ie, THE HEIGHT OF OUR RESPIRATORY

SYSTEM ).

REFER TO THE ILLUSTRATION BELOW..


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Schematic of smoke and temperature development of a fire

(development starting with a smoldering fire to the full flame fire)


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Parameters for detection of fire.

1) SMOKE .

2) TEMPERATURE.

Areas of test.

1) PASSENGER AND STAFF.

2) ELECTRICAL AND TECHNICAL AREAS.

3) TECHNICAL AREAS WITH COMBUSTION ENGINES.


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PARAMETERS FOR

DETECTION

AREAS OF APPLICATION RESPONSE TIME OF THE

DETECTOR

SMOKE PASSENGER/STAFF AREAS 1 MINUTE

SMOKE ELECTRICAL/TECHNICAL AREAS 2 MINUTES

SMOKE TECHNICAL AREAS WITH COMBUSTION

ENGINES

1 MINUTE

Note: In technical areas with combustion engines, smoke should generally NOTbe used as parameter for fire detection; due to the risk of contamination by dirtand thus low system availability.

o The specif ied time period also includes the alarm transmission from

detector to perso ns (passengers and/ or train staff).


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THE SIMULATION TESTOF SMOKE RELEASE IN

PASSENGER AREAS CAN BE CARRIED OUT EITHER

BY

a) BURNING OF A TRAVEL BAG.

b) THERMALLY DRIVEN COLD SMOKE .

c) FOG GENERATED FROM A FLUID.


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The simulation of smoke release in passenger areas is based on the test fire

"burning of a travelling bag ignited by an UIC paper cushion.

Design fire "travel bag":

Fixed bag size (commercial medium size fabric travel bag; dimensions:

0.40 x 0.30 x0.30 m) including mixed bag contents with respect to the usual

travel items.

Exemplary compilation of the contents of a travel bag*(used for proofing the determination of the design fire)

Compilation mBag [g]Bag 100% Nylon 565Sweater vest 100% polyacrylate 3012 sheets 100% Cotton 1001toothbrush cup 100% polyethylene 24Newspaper 100% paper 282Gumboots Cotton, polyvinyl chloride 9011 StandardWood 310Total mass 3384*Alignment with R-32


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PICTURE OF A TYPICAL TRAVEL BAG


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BESIDES THE SMOKE SIMULATION TEST USING TRAVEL BAG , SIMULATION

OF SMOKE RELEASE USING THERMALLY DRIVEN COLD SMOKE OR FOG

GENERATED FROM A FLUID IS ALSO USED FOR DETECTION OF FIRE

USING SMOKE AS PARMETER IN PASSENGER AREAS.

IN THIS METHOD, SMOKE RELEASE IS INCREASED IN ACCORDANCE WITH

THE DEFINED TEST FIRE CRITERIA.


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Test fog generation for performing the function test

on fire detectors (smoke detection)

Fog volume/ fog duration

Passenger and staff areas (Release time max 1 minute):

Fog duration: 60 seconds with totally 10 ml +/- 1 ml)

Of this 30 seconds with totally 4 ml +/- 0.5 ml30 seconds with totally 6 ml +/- 0.5 ml

Equipment area (Release time max 2 minutes):

In non-ventilated equipment areas or equipment areas with passive ventilation (e.g.control cabinets or machine rooms), a fog heater [see Appendix 5] is necessary.

Test duration: 120 seconds with totally 15 ml +/- 1 ml


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Thermal lift in areas accessible to

passengers. Different types Thermal liftTest in areas accessible

for persons with methanol container

Thermal liftTest in areas accessible

for persons with methanol container

and stack.


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Specification of test equipment for function tests of fire

detectors

Thermal liftTest in electrical / technical compartments

For testing smoke detectors in electrical / technical areas, a thermal lift of

the fog is needed. Because in technical areas SMOKE should NOT be used

as a parameter. This can be achieved by a fog heater at the tube exit. It

consists for example of a copper sheet of about 10 x 10 cm which is twisted

into a tube shape. Glued onto this is a heating foil of 10 x 10 cm size, 12 W,

10 V. This foil is powered by an AC adapter, and reaches a temperature of

80 to 90 C. A pre-warming period of about 5 min has to be taken into

account. The through-streaming fog is heated and thus rises as it leaves the

tube.


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Thermal liftTest in Electrical /

Technical Compartments


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Test fog generation for performing the function test on fire detectors (smoke detection)

With a fog generator, the below described volume of test fog is generated. This

requires to know the fog generator's consumption of fluid to produce the required volumes of

fog. This is done by a protocolled measuring equipment calibration (consumptionmeasurement).

If different intensity levels cannot be set, the required fog volume is produced by setting

intervals (blow-out and pause times).

It is recommended to use a fog fluid with medium half-life (e.g. Regular-Fog -

Distributor: Look-Solution).

Example of fog volume generation with fog generators Viper NT and Viper 2.6 from OTTEC

Technology

GmbH:

- Fog volumes can be set in 1 % increments up to

100 %.- Switching levels / percentage of maximum possible

conversion:

Level 1 or 1% with about 7.5 ml / min (Viper NT) and 10.0 ml / min

(Viper 2.6) Level 5 or 5%, with about 8.5 ml / min (Viper NT) and 15.0

ml / min (Viper 2.6)Smaller fog volumes should be assessed as conservative, however, the prescribed maximum

response times must be observed here as well.

Measuring instrument calibration (fog generator) measuring methods of fluid


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Measuring instrument calibration (fog generator) measuring methods of fluidconsumption:

One of the following measuring methods must be applied for the relevant level settings(if available) of the fog generator.

Example log

Parameters SpecificationsFog generatorModel No.Level setting optionFluid designationMeasuring methodMethod a)

1. Fluid aspiration from a measuring cup during a selected time, e.g. 2 min2. Operation of the machine with a fluid volume of 20 ml with time measurement

From time and fluid volume, the fluid consumption in ml/min is calculated. From this,the necessary level setting for the simulation during 1 minute in passenger areas ormore than 2 minutes in equipment areas is determined.Deviat ing from this, in technic al areas with combust ion engines, the maximum

allowed t ime unt i l respon se is 1 minute; due to the risk of huge damage.

Note: A possibly differing quality of the main energy supply might influence thegenerator function.

Example log

Level setting Measuringtime [s] Fluid volume[ml] Consumption [ml/min]


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POSITIONING OF THE TEST EQUIPMENT AND THE

REALIZATION OF THE TEST SMOKES THERMAL LIFT

IN PASSENGER AREAS

a) At the place where quick detection of fire is difficult.

b) Place where there are chances of hidden ignition.

c) Place where larger items of travel luggage are stored in trains.

These tests are to be performed with all possible air circulation

situations in service. Ex: ventilation both in ON and OFF positions.

Also by heating and cooling of circulating air.


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POSITIONING OF THE TEST EQUIPMENT AND

THE REALIZATION OF THE TEST SMOKES

THERMAL LIFT IN TECHNICAL AREAS

a) At the place where quick detection of fire is difficult.

b) Place where air volume is lowest for heat removal.c) Likely places of hot surfaces due to liquid fire loads. (diesel

engine rooms).

These tests are to be performed with all possible air circulationsituations in service.

Note: Thermal lift is the convection flow of heat generated by a

heat source.


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TEMPERATURE AS PARAMETER FOR PLACING OF FIRE DETECTORS.

The simulation of temperature development in installation areas using

technical testing equipment is impracticable, complex and partially

hazardous. Numerical field simulations hve to be carried out with a field model model

(e.g.Kobra 3D or FDS).

For the assessment, the FDS and Kobra 3D programs have beenvalidated using real fire tests and requires validation by experts.

DETECTION OF FIRE TEST AREAS (IN LARGE INSTALLATION

COMPARTMENTS)

RESPONSE TIME

TEMPERATURE AS

PARAMETER.

PASSENGER AREAS TEMPERATURE IS

NOT USED AS

PARAMETERTEMPERATURE AS

PARAMETER.

TECHNICAL /ELECTRICAL AREAS 2 MINUTES

TEMPERATURE AS

PARAMETER.

TECHNICAL AREAS WITH COMBUSTIBLE

ENGINES

1 MINUTE


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USING TEMPERATURE AS PARAMETER SIMULATION TESTS ARE PARTIALLY

DANGEROUS IN NATURE

DETECTION OF FIRE IS USUALLY ACHIEVED BY USING HEAT DETECTORS .

THE INSTALLATION AND GEOMETRICAL ARRANGEMENT IS DONE BY CAREFULLYVERIFYING THE AERODYNAMICS OF THE AREA CONCERNED. THIS IS DONE DUE

TO THE FACT THAT THE AIR FLOW IN THE AREA CAN HAVE A SERIOUS IMPACT ON

THE SURROUNDING TEMPERATURE


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The installation of heat detectors was specified on the basis of 1:1 fire tests inelectrical cabinets The correct geometrical arrangement of the detectors,

also taking into account the aerodynamics in the monitored area, is thusvisually verifiable.

. In large techical areas with forced ventilation (e.g. engine rooms) and inmachine systems installed outside of the vehicle body (e.g. underfloor areas),the correct spatial arrangement of the detectors must be demonstrated in

terms of the aerodynamic conditions in the monitored space or area bynumerical fire simulations or equivalent methods (e. g. fire test). Thesimulations are subject to determined inputs and / or simulation boundary

conditions.

.

. In case of the installation of linear heat detectors in underfloor risk areas, aproof can be omitted, if the risk areas determined by the fire hazard analysisare monitored completely and directly. Operational influences (e.g.

aerodynamics) have to be taken into account.


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Specification of the detector positioning in smallinstallation spaces / control cabinets (temperaturesensing)

1. Combustion will be limited in enclosed and non-ventilated installationspaces.Installation requirement above potential ignition sources up toapprox. 0.5 m.

2. Combustion with normal thermal lift occurs in installation spaces withstatic ventilation.Installation requirement above potential sources of

ignition until approximately 2 m and in the ceiling area of the room.

3. Combustion with deflected thermal lift occurs in strongly ventilatedinstallation spaces.Installation requirement at the bottom flow-off edgeof the air-outlet of the installation area.

4. If the installation spaces include extensive obstructions or separating elements,

the detectors for fire risk areas have to be positioned below these obstructions.In case of a forced ventilation a separate positioning can possibly be omitted.

The installation requirement additionally depends on required maintainingof functionalities of the components installed in the installation space.

Detector positioning (temperature sensing) in large


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Detector positioning (temperature sensing) in largeinstallation compartments (e.g. engine rooms) and atequipment installed outside (e.g. underfloor areas) bynumerical fire simulation.

1. The numerical fire simulations have to be carried out with a field model(e.g.Kobra 3D or FDS). Full fire models are no t su itable he re.

2. For the assessment, the FDS and Kobra 3D programs have beenvalidated using real fire tests . The use of different programs requiresvalidation by an independent authorized evaluator with expert knowledge invehicle fire prevention.

3. For the fire simulation, the basic conditions for the particular application haveto be determined and described exactly. In particular, the heat release rate(HRR), the heat transfer to the components enclosing the installation spaceand to the installed components as well as the ventilation conditions in theroom/ area are considered.

4. At least two fire scenarios have to be calculated for installationcompartments of combustion engines:

1. Spray fire by rupture of an injection line with a heat release rate whichcorresponds to the released fuel volume per time of the respectiveengine. Example underfloor engine leak in an injection line: 0.0033 l/s

2. Pool fire with an area of 0.25 m2 underneath the engine (heat release rateof

347 kW for diesel fuel). For other installation areas, the fire scenariosmust be discussed and agreed upon with the authorized expert.

5. When interpreting the results of the simulation, the following shouldbe considered concerning the spatial arrangement of the detectors:

For the assessment, the temperature distribution 2 min after start of thesimulation is determining. Deviating from this, in equipment areas withcombustion engines, the maximum allowed time until response is 1minute; due to the risk of huge damage.

The release temperature of the sensor should be 80% of thecalculated temperature at the detector position.


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ARGE Guideline - Part 2"Fire fighting in Rolling Stock"

The guideline focuses on the inspection of the effectiveness of fire fighting and fire

extinguishing systems and on the selection of the extinguishing agent.

DEFINITION OF FIRE FIGHTING

Fire protection system for the passenger area, staff areas, WCs and driver cabs.Fire events are limited to the formation location, the ambient temperature is kept

at an acceptable level for survival and the toxic gas concentration is minimized.

DEFINITION OF FIRE EXTINGUISHING

Fire protection system for areas not accessible for persons (e.g. electricalequipment areas, areas of combustion engines).. The fire event must be

extinguished reliably to reduce the necessary emergency scenarios. .


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For fire fighting in areas accessible for passengers,

water-based extinguishing agents are suitable.

Other firefighting agentsshould as far as possible

be omitted.

For fire extinguishing in equipment rooms,

aqueous extinguishing agents (with or without

improving additives), extinguishing gases as well asfine powders or aerosols are suitable; regarding the

respective fire loads (liquids and solids).


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General fire development (fire incident without and with fire fighting/

extinguishing. IMPORTANCE OF FIREFIGHTING


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BOUNDARY CONDITIONS FOR FIRE FIGHTING IN THE POTENTIAL AREAS

PASSENGER AND STAFF AREAS

WITH THE PRIME OBJECTIVE BEING RELATIVE SAFETY OF PASSENGERS , THE

DURATION OF FIRE FIGHTING IN THIS AREAS SHOULD BE BASED ON THE FACT

THAT THE PRESENCE OF PASSENGERS IS POSSIBLE IN THE FIRE AFFECTED AREA

WHILE THE VEHICLE IS RUNNING.AFTER FIRE FIGHTING THE FIRE SHOULD NOT

FLARE UP AGAIN.

TECHNICAL /ELECTRICAL AREAS

IN SUCH AREAS FIRE EXTINGUISHING SHOULD ENSURE THAT THE VEHICLE IS

STILL CAPABLE OF RUNNING , AND THE EFFECT OF FIRE ON FIRE LOADS LIKE

DIESEL FUEL TANKS AND ELECTRICAL IGNITIONS IS COMPLETELY WIPED OUT.


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ASSESSMENT TEST FOR THE VERIFICATION OF THE FIRE FIGHTING IN

PASSENGER AREAS

AS REFERENCE FIRE LOAD TWO IMO FOAM CUSHIONS ARRANGED ONE ABOVE

THE OTHER HAVE TO BE USED AS FIRE OBJECT.

FOR THE 1: 1 SPACE MODEL THE ORIGINAL MATERIALS INSTALLED IN THE

VEHICLE CAN BE USED.

( THAT IS ORIGINAL SEATS WITH SIDE PANELS.)

IF SUCH A TEST WAS PERFORMED WITH ONLY THE ORIGINAL MATERIALS THEN

THE FIRE TEST IS ONLY VALID FOR THE VEHICLE.

THE SIMULATION FIRE EVENT IS STARTED BY INFLAMING UIC PAPER CUSHION AS

FIRE STARTER.

THE FIRE LOAD CAN BE POSITIONED ,

a) ON THE FLOOR BETWEEN TWO SEATS AT THE SIDE WALL.

b) ON THE SEAT.

c) BETWEEN THE SEAT BACKS ON THE FLOOR.

IF THE CONFIRMATION TESTS HAS TO BE FULFILLED , THE REFERENCE FIRE

LOAD HAS TO BE A TRAVEL BAG AS BURNING OBJECT.


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The simulated fire event is started by inflaming an

UIC paper cushion (UIC 564-29) as activator (firestarter). The fire is started by inflaming the four

corners of the UIC paper cushion placed on the fire

object.

From a conservative point of view, the fire model has

to be equipped with non-flame- resistant materials.

The sidewall is to be emulated by plywood and theseat cushions and seat backs by IMO foam cushions .


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For the plywood the following recommendations should be noticed:

Plywood according to the EN 636-1 G . Continuous bonding.

3 to 5 mm thick and a maximum of three layers.

Material concentration around 550 to 700 kg/m.

The plywood should not be prepared with any material protection or protection against

inflammability.

Storage for at least 72 hours at a temperature of 20C, +/-5C and an air humidity of ca.50%, +/- 10%.

The arrangement of the fire loads should be in accordance with the figures with a focus onthe actual dimensions of the passenger space including the seat arrangement. The position

of the available activation (fire starter) has to be selected according to section.

Before planning the assessment tests the test procedure, test room, and test materials

should be presented to the assessor.


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THE FOLLOWING ILLUSTRATIONS

SHOWS THE ARRANGEMENT OF

THE TRAIN INTERIOR WITH

POSITION OF THE FIRE OBJECTS .


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CONDITIONS FOR FIRE FIGHTING TEST IN PASSENGER AREAS


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CONDITIONS FOR FIRE FIGHTING TEST IN PASSENGER AREAS

PASSENGERS MUST BE ABLE TO STAY OUTSIDE AN AREA OF 2 METERS

AROUND THE FIRE LOCATION.

AIR TEMPERATURE AND THE GASEOUS CONCENTRATIONS OF

OXYGEN , CARBON MONOXIDE AND CARBONDIOXIDE IN THE AIR

SHOULD BE FOUND OUT DURING THE ENTIRE TEST OR REQUIRED

PRESENCE PERIOD.

THE EXTINGUISHING AGENT APPLIED SHOULD BE SPREAD UNIFORMLY

IN CONCENTRATION AROUND THE FIRE INCIDENT AREA OF ATLEAST 2METRES.

A FIRE FIGHTING DURATION OF ATLEAST 10 MINUTES IS PRESCRIBED.

DURING A PERIOD OF 30 MINUTES FROM THE TEST START (

EQUIVALENT TO THE RESCUE TIME FOR FIRE BRIGADE) THE AFORESAID

TEST CRITERIA HAVE TO BE MET.


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BEFORE GOING FOR THE TEST CONDITIONS FOR EMPLOYING GASEOUS

EXTINGUISHERS IN ELECTRICAL AREAS LET US SEE SOME DEFINITIONS.

EXTINGUISHING CONCENTRATION: IT IS THE CONCENTRATION OF THE

EXTINGUISHING AGENT IN THE ATMOSPHERE OF THE FIRE AREA TO ENSURE A

SUCCESSFULEXTINGUISHING.

MINIMUM DESIGN CONCENTRATION: EXTINGUISHING CONCENTRATION WHICH

ENSURES A SUCCESSFUL EXTINGUISHING PLUS SAFETY VALUE.

RETENTION TIME : IT IS THE TIME UPTO WHICH THE GASEOUS EXTINGUISHING

AGENT IS PRESENT IN THE AIR NEAR TO FIRE AREA.

PRE-BURN TIME : IT IS THE TIME TAKEN BY FIRE TO DEVELOP ITSELF FROM

IGNITION TO DETECTION BY THE DETECTOR.

EXTINGUISHER OUTLET TIME: TIME REQUIRED BY THE EXTINGUISHING AGENT TO

LEAVE THE EXTINGUISHER NOZZLE AND START ITS ACTIVATION BY PUTTING OUT

THE FIRE.


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CONDITIONS FOR FIRE FIGHTING TEST IN ELECTRICAL AREASWHEN GASEOUS EXTINGUISHING AGENTS ARE USED,

a) WE HAVE TO ENSURE THAT EXTINGUISHING CONCENTRATION AND MINIMUM

DESIGN CONCENTRATION ARE MET DURING THE RETENTION TIME IN THE FIRE

AFFECTED AREA.

b) TEMPERATURE INCREASE IN THE TEST AREA SHOULD NOT INCREASE 60DEGREE CELSIUS.

MINIMUM DESIGN CONCENTRATION IS 120SECONDS.

THE RETENTION TIME ALLOWED IS 180SECONDS.


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THE FIRE ASSESSMENT TEST IN ELECTRICAL AREAS ISDONE BY,

BY IGNITING A FIREPAN OF THE SIZE OF 15X15 CM

IS FILLED WITH 18 ml OF HEPTANE AND 2 ml OF

TOLUENE , THE TEST IS CARRIED OUT AND THE

LIKELY DAMAGE CAUSED BY FIRE IS NOTED.


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UNDER THE FOLLOWING USING WATER MIST EXTINGUISHING SYSTEMS AND

OTHER NON GASEOUS EXTINGUISHING AGENTS IN ELECTRICAL AREAS A 1:1

PROOF BASIC CONDITIONS HAVE TO BE FOLLOWED:

Simulation of a developing fire, consisting of a fire pan filled with 50 ml of heptane (base

area 15 x 15 cm) which thermally loads and ignites the cable harness 5 cm above (7 cables

per level with a length of 25 cm) or the plastic electrical components (e.g. 2 to 3

enclosures of electrical components).

The selection of the cable is done according to CEN / TS 14972:2011 and defined for

rolling stock specific handling as follows:

Cable Type CU number Number of cables

per level

NYY-O 2x1,5 12 mm 29 1

J-Y(St)Y 12x2x0,8 14 mm 123 2

NYY-J 4x10 20 mm 384 2

NYY-J 3x50/25 31 mm 1680 1

NYY-J 4x120 42 mm 4608 1

The pre-burn time ends when at least 50% of the cable or component area burns.


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e p e bu t e e ds e at east 50% o t e cab e o co po e t a ea bu s

The tests should be carried out in a fire zone which simulates at least the usual cabinet size

of (0.5 x 0.5 x 2.0) m3.

2.Simulation of a container fire based on a fire pan with a base area of 15 cm x 15 cm; filled

with 18 ml of heptane and 2 ml of toluene.

This test should be performed in the electrical cabinet or container. .

The complete filling of the area by the extinguishing agent is determined over the defined

period of release, e.g. thermal lift conditions in the affected fire area cause of "suction" of

the water mist by the fire. Between the potential fire location, identified in the fire risk

assessment and the nozzle position no flat separations should be installed.

In areas with combustion technology, the possible accumulation (e.g. fuel, oil) or the outlet

of coolant in connection with potential evaporation on hot surfaces has to be considered

for design and for positioning of extinguishing nozzles.

The assessment for extinguishing capability and the required exposure time for

extinguishing agent is principally based on 1:1 fire tests. Here, the real fire situation can be

simulated using a model with appropriate internals (obstructions).


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Test parameters Dimension

Cable channel length 250 mm

Cable channel width 150 mm

Cable length 250 mm

Number of cables per level 7

Cable distance (cable middle) 20 mm

Proportion of the hole area in the total area ofthe cable channel 20-30%

Thickness cable channel approx. 1 mm

Cable channel spacing 20 mm

Distance of lower channel from fire pan 65 mmAmount of n-heptane 50 ml


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TEST LAYOUT OF FIRE FIGHTING IN

ELECTRICAL EQUIPMENT AREAS


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CONDITIONS FOR FIRE FIGHTING TEST IN ELECTRICAL

AREASWHEN LIQUIFIEDGASEOUS EXTINGUISHING AGENTS ARE USED,

a) WE HAVE TO ENSURE THAT EXTINGUISHING CONCENTRATION AND

MINIMUM DESIGN CONCENTRATION ARE MET DURING THE RETENTION

TIME IN THE FIRE AFFECTED AREA.

b) TEMPERATURE INCREASE IN THE TEST AREA SHOULD NOT INCREASE 60DEGREE CELSIUS.

MINIMUM DESIGN CONCENTRATION IS20 SECONDS.

THE RETENTION TIME ALLOWED IS 30 SECONDS.

EXTINGUISHER OUTLET TIME IS 10SECONDS.


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USING WATER MIST EXTINGUISHING SYSTEMS AND OTHER NON GASEOUS

EXTINGUISHING AGENTS IN COMBUSTION ENGINE AREAS A 1:1 PROOF BASIC

CONDITIONS HAVE TO BE FOLLOWED. THEY ARE

1. Simulation of a spray fire by rupture of an injection line with a heat releasethat corresponds to the amount of fuel leaving one line of the respective

engine. Here, at least a leak in one injection line of 0.0033 l/s has to be

simulated.

As pre-burn time, 15 seconds are specified in order to achieve a heating up of

the surfaces which are reached by the spray fire. An additional direct preheating

using manual flaming should be performed when liquid fire loads can

accumulate (e.g. puddles in depressions). It shall be proven that re- ignition at

the overheated surfaces after extinction by the emerging fuel is prevented.


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2. Simulation of a pool fire with an area of 1/3 of the drip pan, but at least 1

m2

; centered below the engine (1,800 kW heat release for diesel fuel). Toachieve a stable thermal lift, the fire area and the surfaces have to be heated up

during a pre-burn time of 60 seconds.

3. Simulation of a pool fire with an elongated area of at least 0.25 m2

above the

engine and centered between the arranged nozzles (Heat release 347 kW for

diesel; layout example 0.9 m x 0.3 m, i.e. 0.27 m = ca. 380 kW). To achieve a

stable thermal lift, the fire room and the surfaces have to be heated up

during a pre-burn time of 30 seconds when the distance of coverage is up to 500mm and during a period of at least 60 seconds when the distance is larger.

If there are re-ignition hazards at operationally heated surfaces, they have to

be simulated.


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3.1 Basic function of alarm

The following requirements for the alarm are defined:

The fire alarm must be transmitted to the staff (driver and/or train staff) visuallyand acoustically, according to the operating concept.

A local alarm has to be signalized in the passenger area when a limitednoticeability of a fire by the passengers can be assumed. In sleeping orcouchette cars, in double-deck coaches and in WCs, an acoustic signal has tobe provided; in sleeping and couchette cars additionally a visual signal.

The driver has to be informed about the triggering of a fire fighting or fireextinguishing system (e.g. in connection with the shutdown of devices affectedby the fire).

For transmission to the leading vehicle, alarm messages may be combined.


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Basic Function System Operation

The following points are required for the technical facilities:

Monitoring of system state, signal output concerning operation, transmission

to interface

required for the vehicle's unlimited operation.

Monitoring of system state, signal output concerning potential faults in

the system, transmission to interfacelimited operation is still possible, or operation state is withdrawn.

Monitoring of system state, signal output of fire alarms, transmission to

interface

Basis for subsequent operational processes according to the

vehicle operator's instructions for staff.

Internal processing of the alarm signal and providing the signal at the

interface for possible external switching operations.

For transmission to the leading vehicle, fault messages may be combined.


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CONTROLLING THE FIRE

BEHAVIOUR OF MATERIALS


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IDENTIFYING FIRE HAZARDS USING DESIGN REVIEW

APPROACH.

THE PARAMETERS USED ARE

a) VISIBILITY FACTOR K.

b) GAS SAMPLING TO FIND TOXIC GAS

CONCENTRATION.

c) IMPORTANCE OF FIRE LOAD AND ITS CALCULATIONS .

d) OXYGEN LIMITING INDEX AND TEMPERATURE INDEX.


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e) RATE OF HEAT RELEASE.

f) FLAME SPREAD PROPERTIES.

g) TOXIC PRODUCTS FROM COMBUSTION.

COLLECTING LOCATION INFORMATION FOR


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COLLECTING LOCATION INFORMATION FOR

DESIGN REVIEW APPROACH

a) DIRECT VISIT TO THE MANUFACTURING SITE WHERE

MATERIALS ARE TO BE USED.

b) CAREFUL STUDY OF THE DRAWINGS TOGETHER WITH

THE PHYSICAL EXAMINATION OF A COMPARABLE SITE,

VEHICLE, MOCK UP OR SIMULATION.

BY THIS LOCATION INFORMATION THE


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BY THIS LOCATION INFORMATION THE

FOLLOWING DATA IS OBTAINED:

1) REGARDING VENTILATION TO ASSESS SMOKE

DISPERSION.

2) LIGHTING AND NATURE OF EXIT SIGNS, ie COLOURS

USED AND WHETHER EXIT SIGNS ARE EXTERNALLYILLUMINATED OR SELF ILLUMINATED.

3) DIMENSIONS OF COMBUSTIBLE MATERIALS.

4) THE NATURE OF MATERIALS IN USE OR PROPOSED.

5) ORIENTATION AND MOUNTING OF MATERIALS.


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NOW THE PARAMETERS IN EACH LOCATION ARE

DETERMINED IN TERMS OF

a) COMPARTMENTATION.

b) AIR VOLUMES FOR SMOKE AND GASDISPERSAL.

c) PROBLEMS WHICH PREVENT SAFE ESCAPE

OF PASSENGERS.


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NOW THESE LOCATION INFORMATION

ARE EVALUATED IN ACCORDANCE WITHTHE REQUIRED PARAMETERS.


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VISIBILITY FACTOR K VISIBILITY DISTANCE IS THE GREATEST DISTANCE

AT WHICH EXIT SIGNS CAN BE SEEN OR 10METRES WHICHEVER IS GREATEST.


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Visibility Basic Concepts Visibility -the maximum distance at which an object of

defined size can be seen and recognised .

Standardised object in fire emergenciesEXITsign.

Visibility depends on the obscuration along the line of

sightpath dependent.


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For design purposes it is often assumed that

Occupants unfamiliar with their exit routes are reluctant to

evacuate through smoke which is denser than 10m visibility.

Occupants familiar with their exit routes have been shown to

evacuate through more dense smoke at


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An example photo

The EXITsign is obscured, though smoke only spreads

to one end of the corridor.

HOMOGENOUS DISTRIBUTION OF SMOKE


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HOMOGENOUS DISTRIBUTION OF SMOKE

ALONG THE LINE OF SIGHT. EXITSIGN IS VISIBLE

CRAWLING TO FIND A SAFE WAY OUT IN DENSE


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CRAWLING TO FIND A SAFE WAY OUT IN DENSE

SMOKE


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USING SMOKE EMISSION TEST ,

THE EXPECTED ABSORBANCE OF LIGHT BY SMOKE IS ,

Ae = SUM OF ALL ( Ao x u/V ) values.

Where Ao IS THE STANDARD ABSORBANCE.

u is the number of units of material in a vehicle or construction.Themagnitude of a unit depends on the amount burnt during testing,and

its unit may be in kg, area, or length burned.

V is the dispersal volume

= (visibility distance ) x 2 x cross sectional area at the point.


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De =K/ Ae where De is the expected distance.

If De less than D,

Then the smoke emitted by the test material is more than normal.

D is the standard visibility distance calculated using normal test

conditions.

Therefore usage of the material needs reconsidering with the

objective of reducing smoke output.


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GAS SAMPLING

THIS IS USED TO DETERMINE THE RATE ATWHICH THE TOXIC GASES ARE EMITTED

FROM THE BURNING MATERIAL.


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TEST METHOD

USING DRAEGER TUBES, GAS CONCENTRATION , L t IS FOUND IN PARTS PER

MILLION ie, PPM.

STANDARD GAS CONCENTRATION L0 = Lt /TEST CHAMBER VOLUME.

NOW CHECK WHETHER,

IFSUM OF ALL (L0 x u/V /THRESHOLD )IS LESS THAN OR EQUAL TO UNITY,

IF THE VALUE IS GREATER THAN UNITY THEN THE MATERIAL EMIITS MORE TOXIC GASES

THAN THE THRESHOLD VALUE AND THE MATERIAL USAGE HAS TO BE RECONSIDERED.

IMPORTANCE OF FIRE LOAD AND ITS CALCULATION


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IMPORTANCE OF FIRE LOAD AND ITS CALCULATION

THIS IS CALCULATED TO LIMIT THE AMOUNT OF COMBUSTIBLEMATERIAL IN VEHICLES.

FIRE LOAD DENSITY = MASS OF THE MATERIAL PRESENT x ITS CALORIFIC VALUE

TOTAL FLOOR AREA

IF THE ABOVE VALUE OF FIRE LOAD DENSITY IS LESS THAN 1100 MJ/m2

THEN,THE MATERIALS USED ARE ACCEPTABLE AS PER THE FIRE SAFETY POINT

OF VIEW.

LIMITING OXYGEN INDEX ( LOI)


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MOST MATERIALS HAVE AN LOIOF 21% VOLUME.

THIS IS THE VALUE AT WHICH MOST MATERIALS

BURN WHEN IGNITED. BUT THERE ARE SOME

MATERIALS WHICH HAVE LOIABOVE OR BELOW

21. IF LOI IF ABOVE 21 THEN THE MATERIAL

POSSESSES EXCELLENT FIRE RETARDANCY.


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TEMPERATURE INDEX (TI) IT IS THE MINIMUM TEMPERATURE AT WHICH THE MATERIAL

SUPPORTS COMBUSTION IN AIR CONTAINING 21% OXYGEN.

COMBINING BOTH , A NEW TERM CALLED TEMPERATURE OXYGEN

INDEX IS COINED.


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IN THE MANUFACTURING SIDE , THE ACCEPTABLE VALUES OF LOI

AND TI WITHOUT COMPROMISING THE MECHANICAL PROPERTIESARE,

LOIGREATER THAN OR EQUAL TO 30.

TI EQUAL TO OR GREATER THAN 260DEGREE CELSIUS.


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RATE OF HEAT RELEASE

IT IS THE GAS TEMPERATURE CREATED WHEN A MATERIAL IS EXPOSED TO

HEAT SOURCES.THE DIFFERENCE BETWEEN THE GAS TEMPERATURE FROM ATEST MATERIAL AND A COMBUSTIBLE MATERIAL GIVES THE MEASURE OF

HEAT RELEASE.

EXPERIMENTS PROVE THAT THE INTEGRATED RATE OF HEAT RELEASE UPTO

3 MINUTES, SUMMED FOR ALL SURFACES EXPOSED TO HEAT FLUX AND

CONVERTED INTO HEAT POTENTIAL PER UNIT VOLUME GIVES AN

INDICATION FOR POTENTIAL FLASHOVER. RESULTS PROVE THAT THE

LOWEST LIMITING VALUE IS 3MJ/m3 AT THREE MINUTES.


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NORMALLY THE HEAT RELEASE FOR AN ALLOTTED TIME OF 3

MINUTES IS TAKEN(CAN BE MARKED AS i ) . ALSO THE

HEAT RELEASE OF THE MATERIAL FOR THE WHOLE TEST PERIOD

IS ALSO NOTED DOWN. CAN BE MARKED AS I.

BY SPECIFYING MAXIMUM VALUES FOR BOTH i AND I

SOME CONTROL CAN BE BROUGHT IN THE HEAT OUTPUT OF

MATERIALS BY JUDICIOUSLY SELECTING THEM FOR VEHICLE

DESIGN.


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FLAME SPREAD PROPERTIES

FLAME SPREAD PROPERTY OR SURFACE

BURNING CHARACTERISTICS OF A MATERIAL IS

THE PROPENSITY OF A MATERIAL TO BURN

RAPIDLY AND SPREAD FLAMES.


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BY NFPA 286 STANDARD METHOD OF FIRE TESTS FOR EVALUATING

CONTRIBUTION OF WALL AND CEILING INTERIOR FINISH TO ROOM

FIRE GROWTH,THE TEST MEASURES FLAME SPREAD IN A ROOM

CONFIGURATION ,INCLUDING FIRE SPREAD ALONG WALLS , CEILINGS,

AND COMBINATIONS OF BOTH.THIS METHOD IS MORE INDICATIVE OF

REAL WORLD FIRE HAZARDS,BUT MORE EXPENSIVE.

CLASS OR TYPE FLAME REMARKS


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SPREAD

RATING(FSR)

CLASS 1 OR

CLASS A

0-25 INORGANIC MATERIALS

SUCH AS BRICK OR TILE

FALLS IN THIS CLASS.

CLASS 2 OR

CLASS B

26-75 WHOLE WOOD

MATERIALS FALLS INTO

THIS CLASS.

CLASS 3 OR

CLASS C

76-200 RECONSTITUTED WOODMATERIALS SUCH AS

PLYWOOD,CARDBOARD

.

TOXIC PRODUCTS FROM COMBUSTION.


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AS PER THE DESIGN POINT OF VIEW THE TOXIC

PRODUCTS CAN BE DIVIDED INTO THREE CATEGORIES.

1) ASPHYXIANTSWHICH CAUSES OXYGEN

DEPLETION OF CARBONDIOXIDE

2) PHYSICAL AGENTSSUCH AS SMOKE, HOT AIR AND

GASES.

3) POISONOUS GASESCARBONMONOXIDE , OXIDES

OF NITROGEN, HYDROGEN CYANIDE AND OTHER

GASES.


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TOXICITY TEST.THIS TEST IS DONE TO MEASURE THE RELEASE OF TOXIC

GASES BY COMBUSTIBLE MATERIALS USED IN TRAIN

INTERIORS.

METHOD OF TEST.


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A SAMPLE OF THE MATERIAL IS BURNED IN A SEALED TEST CHAMBER.WITHTHE HELP OF SOME COLORIMETRIC OR OTHER ANALYTICAL INSTRUMENTS

THE CONSTITUENT GASES AND ITS CONCENTRATION ARE FOUND OUT.

THE MEASURED CONCENTRATION OF EACH GAS IS THEN CALCULATED TOGIVE A VALUE FOR 100 GRAMS OF MATERIAL BURNING IN ONE CUBIC

METRE.

THE ABOVE VALUE IS IS THEN DIVIDED BY THE MAXIMUM PERMISSIBLECONCENTRATION.

THIS GIVES THE TOXICITY INDEX.

CONCLUSION


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CONCLUSION

THIS IS A SCIENTIFIC APPROACH TO

REDUCE THE DANGERS CAUSED BY FIRE IN

TRAINS, THE EMPHASIS BEING ON THESAFETY OF PASSENGERS.

MANY UNKNOWN VARIABLES STILL

CONTRIBUTE TO SERIOUS FIRE HAZARDS.


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Seminar on Fire Safety by ramesh

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