Bsi bs en 14591 2 2007 (2010)

24Annex E informative Example for marking of water trough barriers ...44 Annex F normative Instructions for water trough barriers ...45 Annex ZA informative Relationship between this Eur

This British Standard is the UK implementation of

EN 14591-2:2007, incorporating corrigendum September 2008

The UK participation in its preparation was entrusted to Technical Committee FSH/23, Explosion and fire precautions in industrial and chemical plant

A list of organizations represented on this committee can be obtained

on request to its secretary

This publication does not purport to include all the necessary provisions of a contract Users are responsible for its correct application

Compliance with a British Standard cannot confer immunity from legal obligations.

This British Standard was

published under the authority

of the Standards Policy and

28 February 2010 Implementation of CEN corrigendum September 2008;

row inserted in Table ZA.1 for 1.2.1

EUROPÄISCHE NORM March 2007

ICS 13.230; 73.100.99

English Version

Incorporating corrigendum

September 2008

Explosion prevention and protection in underground mines

-Protective systems - Part 2: Passive water trough barriers

Protection contre l'explosion dans les mines souterraines

-Systèmes de protection - Partie 2: Arrêts-barrages passifs

à bacs à l'eau

Explosionsschutz in untertägigen Bergwerken Schutzsysteme - Teil 2: Passive Wassertrogsperren

-This European Standard was approved by CEN on 4 February 2007.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN Management Centre or to any CEN member.

This European Standard exists in three official versions (English, French, German) A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

EUROPEAN COMMITTEE FOR STANDARDIZATION

C O M I T É E U R O P É E N D E N O R M A L I S A T I O N

E U R O P Ä I S C H E S K O M I T E E F Ü R N O R M U N G

Management Centre: rue de Stassart, 36 B-1050 Brussels

© 2007 CEN All rights of exploitation in any form and by any means reserved

worldwide for CEN national Members. Ref No EN 14591-2:2007: E

Contents Page

Foreword 5

Introduction 6

1 Scope 7

2 Normative references 7

3 Terms and definitions 7

4 Construction requirements of water troughs 10

4.1 General 10

4.2 Dimensions, specifications 10

5 Testing of water troughs 11

5.1 General 11

5.2 Construction tests 11

5.2.1 Shape, capacity, dimensions 11

5.2.2 Strength, shape retention 11

5.2.3 Water level indicator 11

5.3 Testing of electrostatic properties 12

5.3.1 Test method 12

5.3.2 Assessment 12

6 Additional fittings for water troughs 12

7 Marking of water troughs 12

8 Construction of concentrated and distributed water trough barriers 12

8.1 General 12

8.2 Framework structures 12

8.3 Arrangement of troughs in the roadway cross-section 13

8.4 Configuration of water trough barriers in mine workings 13

9 Marking of water trough barriers 15

10 Information for use 16

Annex A (normative) Construction of quick-deploy passive water trough barriers 17

A.1 General 17

A.2 Trough frames 17

A.3 Ropes and chains 17

A.4 Attachment supports 17

A.5 Arrangement of the quick-deploy water trough barriers in the roadway 17

A.6 Volume of water to be contained by quick-deploy water trough barriers 18

Annex B (normative) Example of acceptable test procedure for water troughs 19

B.1 Testing of heat reaction properties 19

B.1.1 Test procedure 19

B.1.2 Test arrangement 19

B.1.3 Procedure 20

B.1.4 Assessment 20

B.2 Testing of explosion properties 20

B.2.1 Testing of water dispersion 20

B.2.2 Testing the extinguishing efficiency in full-scale tests 22

B.3 Testing of fire-resistance properties 22

Annex D (informative) Examples for configuration of water troughs 24

Annex E (informative) Example for marking of water trough barriers 44

Annex F (normative) Instructions for water trough barriers 45

Annex ZA (informative) Relationship between this European Standard and the Essential Requirements of EU Directive 94/9/EC 46

Bibliography 48

Figures Figure 1 — Trough group, plan view 9

Figure 2 — Water trough type A (side elevations) 10

Figure 3 — Water trough type B (side elevations) 10

Figure 4 — General rules for water trough barriers in mine workings 15

Figure A.1 — Quick-deploy water trough barrier (example) 18

Figure B.1 — Test arrangement for determining heat reaction properties 19

Figure B.2 — Test arrangement for investigating water dispersion 21

Figure D.1 — Location of water troughs, sectional view 24

Figure D.2 — Arrangement of troughs in roadway cross-section – coverage 25

Figure D.3 — Arrangement of troughs in roadway cross-section – horizontal distances 26

Figure D.4 — Arrangement of troughs in the roadway cross-section – vertical distances 27

Figure D.5 — Arrangement of troughs in the roadway cross-section – vertical distances 27

Figure D.6 — Arrangement of troughs in the roadway cross-section – transverse and longitudinal position 28

Figure D.7 — Arrangement of troughs in the roadway cross-section – Obscurement by supports or fixtures 29

Figure D.8 — Arrangement of troughs in the roadway cross-section – Obscurement by supports or fixtures 30

Figure D.9 — Arrangement of troughs in the roadway cross-section – Obscurement by troughs 30

Figure D.10 — Arrangement of vertically-offset troughs in the roadway cross-section, distance < 1.2 m 31

Figure D.11 — Barrier cordon for a roadway intersection 32

Figure D.12 — Barrier cordon for shafts and insets 33

Figure D.13 — Barrier cordon for closely spaced roadway intersections 34

Figure D.14 — Barrier cordon for closely spaced junctions – Calculation examples for explosion-barrier setting distances 35

Figure D.15 — Barrier cordon for closely spaced junctions – Calculation examples for

explosion-barrier setting distances 36

Figure D.16 — Setting distances for concentrated and distributed water trough barriers 37

Figure D.17 — Roadway drivage with concentrated water trough barriers 38

Figure D.18 — Roadway drivage with concentrated water trough barriers – Calculation examples a) and b) 39

Figure D.19 — Roadway drivage with dispersed water trough barrier 40

Figure D.20 — Roadway drivage with concentrated and dispersed water trough barrier 41

Figure D.21 — Water trough barriers at the face/gate intersection 41

Figure D.22 — Explosion barriers in advance gate-roads 42

Figure D.23 — Arrangement of water trough barriers when retreating to the main seam road 43

Figure E.1 — Example for marking of water trough barriers 44

Tables Table 1 — Maximum container dimensions and water content for 40 litre water troughs 11

Table 2 — Container dimensions and water content for 90 litre water troughs 11

Table ZA.1 — Relationship between this European Standard and Directive 94/9/EC 46

This document has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association, and supports essential requirements of EU Directive(s)

For relationship with EU Directive(s), see informative Annex ZA, which is an integral part of this document

EN 14591 Explosion prevention and protection in underground mines — Protective systems consists of the

following parts:

Part 1: 2-bar-explosion-proof ventilation structure

Part 2: Water trough barriers

Part 4: Automatic extinguishing systems for road headers

According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom

Introduction

Water trough barriers are autonomous protective systems by reducing the effects of combustible dust and/or firedamp explosions in underground mines to a sufficient level of safety They are used for preventing the propagation of explosions in roadways in underground coal mines The purpose of water trough barriers is to extinguish explosion flames in roadways in underground mines and in this way to limit propagation of explosions

Water trough barriers are designed and arranged in such a way that explosions are prevented from spreading through dangerous chain reactions and incipient explosions do not become detonations

Water trough barriers will only be effective as a configuration of individual water troughs in accurately defined arrangements Water troughs are the components for this protective system

Their effectiveness in the event of explosions is based on the distribution of water acting as a extinguishing medium held in individual water troughs, with the blast wave preceding an explosion destroying individual water troughs, thus evenly distributing water, the extinguishing medium, throughout the cross-section of a roadway and extinguishing the explosion flame that follows

fire-The water trough barriers described in this standard are the result of research and testing of many years above ground and underground The results of these tests can be used as a basis for type examination

1 Scope

This standard specifies the requirements for concentrated and distributed passive water trough barriers, and quick-deploy water trough barriers

This standard specifies the requirements and test methods for water troughs which are used as components

of the "water trough barrier" protective system for underground coal mines

This standard does not apply to active water trough barriers

2 Normative references

The following referenced documents are indispensable for the application of this document For dated references, only the edition cited applies For undated references, the latest edition of the referenced document (including any amendments) applies

EN 13463-1, Non-electrical equipment for potentially explosive atmospheres — Part 1: Basic method and

requirements

EN ISO 4589-2, Plastics — Determination of burning behaviour by oxygen index — Part 2:

Ambient-temperature test

ISO 554, Standard atmospheres for conditioning and/or testing — Specifications

3 Terms and definitions

For the purposes of this document, the following terms and definitions apply:

3.1

explosion barrier

device intended effectively to suppress coal-dust and firedamp explosions and to limit their physical impact

3.2

water trough barrier

explosion barrier in which the extinguishing medium, namely water, is contained in water troughs

any troughs located within a roadway section of no more than 3 m in length in the distributed barrier

NOTE See Figure 1 A group can be composed of 1 to 3 rows of troughs

3.5

roadway cross-section

area bounded by the roadway floor and lagging or, where no lagging is installed, by the surrounding rock

3.6

volume of roadway section

product of the mean roadway cross-section and relevant length

NOTE In the case of concentrated water trough barriers, the relevant length is the distance between the start and the end of the water trough barrier In the case of distributed water trough barriers, the relevant length is the distance between two adjacent trough groups

3.7

passive water trough barrier

fixed or mobile water trough barrier in which the extinguishing medium, namely water, is dispersed solely by the blast pressure of the explosion

3.8

active water trough barrier

fixed or mobile water trough barrier in which the extinguishing medium, namely water, is dispersed independently of the blast pressure of the explosion

3.9

concentrated water trough barrier

water trough barrier which contains a minimum of 200 l of water per square metre of roadway cross-section and which has a length of at least 20 m

NOTE The concentrated water trough barrier contains a minimum of 5 l of water per cubic metre of roadway section between the start and the end of the water trough barrier

3.10

distributed water trough barrier

water trough barrier which contains a minimum of 1 l of water per cubic metre of roadway section in each trough group measured up to the adjacent trough group

NOTE The clear interval between adjacent trough groups does not exceed 30 m (or 50 m in case of cross-sections

up to 10 m2)

3.11

quick-deploy water trough barrier

quick-deploy water trough barriers are used in the case of rescue action, when concentrated or distributed water trough barriers are not provided between areas where the rescue teams are working and the potential fire source

NOTE Quick-deploy water trough barriers contain at least 60 l of water per square metre of roadway cross-section

3.12

blast pressure

pressure exerted by a current of air on a free-standing static plate positioned at right angles to the direction of flow

Dimensions in metres

Key

1 Trough group of one trough row

2 Trough group of two trough rows

3 Trough group of three trough rows

Figure 1 — Trough group, plan view

4 Construction requirements of water troughs

Water troughs shall be of sufficient strength and stability of shape

Water troughs shall remain functional for as long as possible under the effect of high temperatures

Water troughs shall be made of plastic

Water troughs shall be composed of a material which does not burn spontaneously when subjected to a defined level of exposure to flames

Water troughs shall be designed so that the rate of evaporation of the extinguishing medium, namely water, is

as low as possible

4.2 Dimensions, specifications

Figure 2 — Water trough type A (side elevations)

Table 1 — Maximum container dimensions and water content for 40 litre water troughs

Container dimensions – max

mmWater

The covers shall be designed to give a flush fit with the outer rim of the containers

5 Testing of water troughs

5.1 General

The test pieces for the tests described below comprise one or several water troughs which shall come from the same production run The number of test pieces required is determined by the respective testing station When issuing contracts for testing, each testing station shall be provided not only with descriptions and drawings of the equipment (e.g containers, covers, floats and lid holders), but also with precise data on the composition of the material used For an example of acceptable test procedures, see Annex B

NOTE Other test procedures are under consideration

5.2 Construction tests

5.2.1 Shape, capacity, dimensions

The specifications laid down in 4.2 shall be used as a basis for testing the shape, dimensions and capacity of the water troughs

5.2.2 Strength, shape retention

When a uniform static load is applied to a stack of water troughs, composed of five containers fitted one inside

the other, by a force of 500 N (direction of force at right angles to the container bottoms), the containers shall

not suffer damage or permanent deformation During subsequent unstacking, the containers shall not be wedged together and shall not be damaged

5.2.3 Water level indicator

The minimum water level indicator shall be checked for correct operation and accuracy The maximum margin

of indicator error shall be ± 5 %

5.3 Testing of electrostatic properties

5.3.1 Test method

The surface resistance shall be tested in accordance with EN 13463-1

The test voltage shall be 100 V The measured value shall be read 60 s after the test voltage has been applied The measurement shall be carried out in standard atmosphere 23/50-2 according to ISO 554

5.3.2 Assessment

Containers and matching covers, together with all attachments, shall be fitted together in a conductive manner Conduction shall take place both externally and internally The water trough being tested meets the

6 Additional fittings for water troughs

Water troughs may be provided with additional fittings, such as level indicators and filling and draining devices These additional fittings shall not conflict with the construction requirements laid down in clause 4

7 Marking of water troughs

Water troughs (containers and covers) shall be marked An example is given in Annex C

8 Construction of concentrated and distributed water trough barriers

The framework structures, beams or shelves shall be attached to the supports or to the roadway fixtures by means of suitable mountings Chains, steel ropes or suspension rods can also be used for this purpose The framework structures shall be designed in such a way that suspended troughs can be supported on all sides by the full width of their edges, or failing that at least by the full width of their long sides, or that the troughs can be constructed where necessary using battens

8.3 Arrangement of troughs in the roadway cross-section

The number of water troughs in a trough group shall be sufficient to comply with 3.9 and 3.10

The trough groups shall cover the greatest width of the roadway cross-section (floor width or roadway diameter) at the point of installation The achieved coverage is as follows:

This calculation is based on measurements taken between the edges of the outer troughs of the trough group

at the sides of the roadway

The horizontal distance measured at right angles to the roadway direction

 between the roadway wall and the nearest trough shall not exceed 1,2 m and

 between two troughs shall not exceed 1,5 m

The total distances shall not exceed 1,8 m

The vertical distance between the bottom of any trough and the boundary of the roadway cross-section shall not exceed 2,6 m in a downward direction nor 2,0 m in an upward direction If the distance measured in an upward direction from a trough has to be greater than 2,0 m, an additional trough shall be installed In this case, the vertical distance between the bottoms of the troughs in each row shall be less than 2,0 m

Troughs are normally installed with their long sides at right angles to the roadway direction (transverse arrangement) As a deviation from this, individual troughs can be arranged longitudinally (longitudinal arrangement), though the number shall not exceed half of all the troughs in the group where this is necessary

in order to provide cover for the roadway width and to reduce the intermediate spaces

It is permitted to arrange more than 50 % of the troughs in the longitudinal direction if the extinguishing effectiveness is proved by experiments

Troughs shall be arranged so that they are not obscured by supports or by roadway fixtures Troughs which are spaced less than 1,2 m apart in the direction of the roadway shall not obscure one another

Troughs which are arranged at a distance of < 0,5 m above other troughs shall not obscure more than half the lid area of any trough located beneath them

8.4 Configuration of water trough barriers in mine workings

The distance between the water trough barriers and the intersections or junctions shall be kept as small as possible and shall not exceed 75 m in the case of concentrated water trough barriers and 30 m in the case of distributed water trough barriers

The maximum distances of 75 m and 30 m between intersections and junctions do not apply when there are

no distances greater than 200 m between adjacent concentrated water trough barriers designed to cordon off the intersection and junction areas

The distance requirements do not apply either between closely-spaced intersections and junctions provided that in any circumstance which may arise the distance between a distributed water trough barrier and an adjacent distributed or concentrated water trough barrier designed to cordon off the intersection and junction areas does not exceed 120 m In this zone, the erection of water trough barriers can be dispensed with This means that points where roadways intersect with surface shafts, shaft insets or staple shafts are treated as

intersections or junctions The trough groups of these distributed water trough barriers shall contain a quantity

of at least 200 l of water per square metre of roadway cross-section

Concentrated water trough barriers constructed in roadways shall be arranged in such a way that the distance between one water trough barrier and another does not exceed 400 m

Distributed water trough barriers constructed in roadways shall be arranged in such a way that the distance between the trough groups does not exceed 30 m

Within a roadway, the distance between a concentrated water trough barrier and the first trough group of a distributed water trough barrier shall not exceed 30 m

By contrast, the distance between a concentrated water trough barrier and the first trough group of a distributed water trough barrier, when measured through an individual roadway intersection or junction, can be

as much as 105 m (30 m + 75 m)

NOTE 1 Usually, in gate-roads and in mechanized in-seam drivages, water trough barriers are erected as distributed barriers Where no mining is being carried out in the gate-road zone, or when no mechanized heading operation is under way in this area, distributed water trough barriers can be replaced with concentrated barriers if this proves necessary for transport activities and the like

When concentrated water trough barriers are used in roadway drivage operations, the distance from the heading face to the nearest water trough barrier in the roadway shall be as small as possible; this distance shall not exceed 320 m, though the first water trough barrier shall be erected at the very latest on reaching a drivage length of 200 m When distributed barriers are used in roadway drivage operations, the distance from the heading face to the nearest trough group in the roadway shall be as small as possible This distance shall not exceed 120 m, though the first trough group shall be erected at the very latest on reaching a drivage length of 120 m

As a deviation from this, the drivage length in gate-roads can also be allowed to reach 200 m before constructing the first water trough barrier, provided that the latter is designed as a concentrated barrier

In gate-roads, the distance from the face-gate intersection to the nearest trough group shall be as small as operating conditions permit; under no circumstances shall this distance exceed 120 m

Where the advance heading section of a non-interconnected gate-road is longer than 120 m, distributed water trough barriers are to be erected at this point in accordance with 3.10 In addition, the water content of all the

NOTE 2 The location where water trough barriers are to be constructed, e.g at roadway intersections, roadway junctions and mine excavation (working), can be defined in national legislation concerning the safety of work places NOTE 3 Where the distance between the face/gate intersection and the roadway junction is less than 120 m during coal winning, usually a concentrated water trough barrier is constructed in the gate-road at the roadway junction or intersection This concentrated water trough barrier can be omitted when the structural explosion protection provided in the main seam road is in the form of distributed water trough barriers The ability to provide structural explosion protection

in such cases should be taken into account during the roadway and coal face planning phase The above-mentioned requirements are not valid if the working face is protected by concentrated water trough barriers

Due to local conditions the above-mentioned maximum distances can be reduced

Figure 4 — General rules for water trough barriers in mine workings

For examples of water trough arrangements, see Annex D

9 Marking of water trough barriers

Water trough barriers shall be marked

For marking, panels shall be arranged in visible places at least at the beginning of a barrier, in the direction of the firedamp flow, and also for any distributed water trough barriers at the end of the barrier Marking shall include the following details:

 name and address of manufacturer;

 actual water volume;

 number of water troughs;

 date of construction;

 date of acceptance;

 the number of this European Standard, i.e EN 14591-2

An example is contained in Annex E

10 Information for use

Information included in Annex F shall be considered in the instructions

Quick-deploy water trough barriers are composed of hanger units with suspension gear and water-filled troughs which are fitted into the carrying frame in such a way that the empty troughs and hanger units can be transported as a stacked system and fixed to the roadway supports at the point of application (see Figures A.1) The troughs can be used without covers

A.2 Trough frames

Trough frames shall be designed so that water troughs can be suspended from them The troughs are immovably suspended in the support frame and at least the full edge width of their long sides shall rest on the longitudinal beams of the support frame The projecting ends of the support beams are provided with drill holes for the guides and for the attachment of suspension ropes or chains

A.3 Ropes and chains

Six or more support frames are combined to form a hanger unit, depending on the height of the roadway The individual support frames are immovably attached to the ropes or chains at an interval of at least trough height + 30 mm The loadbearing capacity of an individual rope or chain shall be greater than the total weight of the hanger unit when filled with water

The length of the ropes or chains is such that suspension is still possible even in unusually high roadways (see also A.5)

A.4 Attachment supports

The hanger units are attached to the supports in such a way that the long sides of the water troughs lie at right angles to the roadway axis

A.5 Arrangement of the quick-deploy water trough barriers in the roadway

A quick-deploy water trough barrier shall comprise at least 3 hanger units which shall be constructed as far as possible in a staggered arrangement in a roadway section of 10 m in length The hanger units are constructed

in a staggered arrangement in such a way that as uniform a coverage of water troughs as possible is achieved over the roadway cross-section The number of water troughs employed per hanger unit depends on the height of the roadway at the point of suspension Approximately 3 troughs can be accommodated per metre of roadway height

The quick-deploy water trough barrier is located at least 200 m from the dam building site in the direction of the hazardous location

A.6 Volume of water to be contained by quick-deploy water trough barriers

The quick-deploy water trough barrier contains at least 60 l of water per square metre of roadway section

cross-Key

a) Stacked troughs

b) Suspended troughs

Annex B

(normative)

Example of acceptable test procedure for water troughs

B.1 Testing of heat reaction properties

The suspended water trough is to be supported between two hangers by its long edges in such a way that it

The temperature outside the water trough (air temperature) shall be established at two points at least and the temperature inside the water trough (water temperature) shall be established at one point at least The measurement points for the air temperature shall be located centrally at the same level as the cover and container bottom

Dimensions in millimetres trough

suspended

trough fixed

Key

1 Measurement of air temperature

2 Measurement of water temperature

3 Holder

Figure B.1 — Test arrangement for determining heat reaction properties

B.1.3 Procedure

The water troughs shall be filled to the brim with water at a temperature of (45 ± 2) °C The air temperature is

to be set to (45 ± 2) °C within a period of 2 h and the humidity to at least 80 % relative humidity

After the test, the quantity of water remaining in the water trough shall be determined

B.1.4 Assessment

Water troughs meet the requirements if, after a period of 48 h, the 40 l water trough contains at least 35 l of water and the 90 l water trough at least 80 l of water During this test, there shall be no material damage which has resulted in leakage During the test, the suspended water troughs shall not slip through the trough hangers

B.2 Testing of explosion properties

B.2.1 Testing of water dispersion

B.2.1.1 Test procedure

In order to determine the quality of dispersion of the extinguishing agent under the effect of blast pressure of

approximately 5 kPa, the absorption of infrared light is measured using testing equipment

B.2.1.2 Test arrangement

The test shall be carried out in a tubular tunnel 25 m in length which is closed at one end and is circular in cross-section The tubular tunnel shall be 1,8 m in height and 1,4 m in width (see Figures B.2) A

1,5 kPa and 20 kPa which are required for the test

circular static plate 1,5 mm in thickness The force-sensing device is to be positioned in the centre of the open end of the tunnel (see Figures B.2)

Two rows of six and four iodine-quartz lamps, each of identical output, are to be mounted one row above the other outside the tunnel and opposite the tunnel entrance as an infrared radiation source All the lamps are to

be aligned so that they illuminate the entrance to the tunnel A photoconductive cell is to be positioned at each outer side wall, at mid-height level, at the entrance to the tunnel, in order to measure the infrared radiation from the iodine-quartz lamps and/or the infrared absorption The radiation spectrum of the infrared radiation source shall match that of the photoconductive cell

A carrier frame constructed from square steel tubing (40 mm x 40 mm x 2 mm) and capable of holding one water trough is to be rigidly fixed to the sides of the roadway at the entrance to the tunnel The frame comprises two supports positioned at right angles to the roadway axis and two cross-members which lie at right angles to the supports

The CH4/air mixture described in B.2.1.2 shall be created in the explosion chamber and then ignited by means

of an electrical spark; the blast pressure and infrared absorption level shall then be measured The tests shall

be carried out at pressures which are distributed across the entire pressure range of 1,5 kPa to 20 kPa

Dimensions in metres

Key

3 Photoconductive cell

Figure B.2 — Test arrangement for investigating water dispersion B.2.1.4 Assessment of water dispersion

The exponential quotient b for the infrared absorption/blast pressure relationship shall be determined from the

measurement results of at least 20 tests using the method of least squares (regression) The infrared absorption required for assessing the water dispersion shall be determined using equation (B.1):

Where:

achieved with the measurement arrangement);

A water trough is considered to be sufficiently effective as an extinguishing device when the infrared

absorption A (see equation B.1) reaches the value 70 % at a blast pressure p of 5 kPa

B.2.2 Testing the extinguishing efficiency in full-scale tests

If a water trough fails to satisfy the above requirements, its adequate extinguishing efficiency as part of a water trough barrier can be established by means of full-scale tests

B.3 Testing of fire-resistance properties

The flammability of the materials shall be tested according to EN ISO 4589-2

The oxygen index value shall be higher than 27

the specific marking of explosion protection

Annex D

(informative)

Examples for configuration of water troughs

An arrangement of water trough barriers and trough groups suitable for a type of system is shown in the following pages:

 arrangement of water trough barriers in roadway cross-section (Figures D.1 to D.10);

 arrangement of water trough barriers in working (Figures D.11 to D.23)