Conveyor belts - Fire simulation flammability testing - Part 1: Propane burner tests

EN 12881-1 describes four methods for measuring the propagation of a flame along a conveyor belt which has been exposed to a relatively high localized heat source such as a fire. The damage suffered by the conveyor belt, as well as its tendency to support combustion, is measured by observing the extent to which the fire spreads along the test piece.
Method A uses a test piece 2 m in length and consumes propane gas through the burner at the rate of (1,30 ± 0,05) kg per 10 min.
Method B uses a test piece 2,5 m in length and consumes propane gas through two burners mounted above and below the test piece trestle at the rate of (1,30 ± 0,05) kg per 10 min for each burner.
Method C uses a test piece 1,5 m in length and consumes propane gas through the burner at the rate of (565 ± 10) g per 50 min.
Method D uses a test piece 1,2 m in length and consumes propane gas through the burner at the rate of
150 l/hr (D1) or 190 l/hr (D2).

Fördergurte - Brandtechnische Prüfungen - Teil 1: Prüfungen mit dem Propanbrenner

Dieser Teil der EN 12881 legt drei Verfahren zur Bestimmung der Ausbreitung einer Flamme entlang eines Fördergurtes fest, der einer örtlichen Wärmequelle, wie Feuer, ausgesetzt war. Es wird sowohl die Beschädigung des Fördergurtes gemessen als auch seine Neigung, die Verbrennung zu unterstützen, wobei das Fortschreiten der Flamme entlang des Probekörpers beobachtet wird.
Für Verfahren A wird ein 2 m langer Probekörper verwendet, wobei der Propangasverbrauch des Brenners (1,30 ± 0,05) kg in 10 min beträgt.
Für Verfahren B wird ein 1,5 m langer Probekörper verwendet, wobei der Propangasverbrauch des Brenners (565 ± 10) g in 50 min für jeden Brenner beträgt.
Für Verfahren C wird ein 1,2 m langer Probekörper verwendet, wobei der Propangasverbrauch des Brenners 150 l je h (D1) oder 190 l je h (D2) beträgt.

Courroies transporteuses - Essais de simulation d'inflammation - Partie 1: Essais avec brûleur propane

L’EN 12881 1 décrit quatre méthodes de mesurage de la propagation d’une flamme sur une courroie transporteuse qui a été exposée à une source de chaleur localisée relativement élevée, comme par exemple un feu. La détérioration de la courroie transporteuse est mesurée, ainsi que sa tendance à entretenir la combustion, en observant le degré de propagation du feu sur l’éprouvette.
La méthode A utilise une éprouvette de 2 m de long et consomme du gaz propane à l’aide du brûleur, avec un débit de (1,30  0,05) kg par 10 min.
La méthode B utilise une éprouvette de 2,5 m de long et consomme du gaz propane à l’aide de deux brûleurs montés au-dessus et en-dessous du tréteau de l’éprouvette, avec un débit de (1,30  0,05) Kg par 10 min pour chaque brûleur.
La méthode C utilise une éprouvette de 1,5 m de long et consomme du gaz propane à l’aide du brûleur, avec un débit de (565  10) g par 50 min.
La méthode D utilise une éprouvette de 1,2 m de long et consomme du gaz propane à l’aide du brûleur, avec un débit de 150 l/h (D1) ou 190 l/h (D2).

Naprave za kontinuirni transport - Trakovi tračnih transporterjev - Požarnovarnostni preskusi - 1. del: Preskusi s propanskim gorilnikom

Standard EN 12881-1 opisuje štiri metode za merjenje širjenja ognja po traku tračnega transporterja, ki je bil izpostavljen razmeroma visoki koncentraciji lokaliziranega toplotnega vira, kot je ogenj. Tako škoda, ki jo utrpi trak tračnega transporterja, kot tudi težnja k zgorevanju se meri z opazovanjem tega, v kakšnem obsegu se ogenj razširi po preskušancu. Metoda A uporablja preskušanec z dolžino 2 m in propan skozi gorilnik porablja s hitrostjo (1,30 ± 0,05) kg na 10 minut. Metoda B uporablja preskušanec z dolžino 2,5 m in propan skozi dva gorilnika, nameščena nad in pod oporo preskušanca, porablja s hitrostjo (1,30 ± 0,05) kg na 10 minut za posamezni gorilnik. Metoda C uporablja preskušanec z dolžino 1,5 m in propan skozi gorilnik porablja s hitrostjo (565 ± 10) g na 50 minut. Metoda D uporablja preskušanec z dolžino 1,2 m in propan skozi gorilnik porablja s hitrostjo 150 l/uro (D1) ali 190 l/uro (D2).

General Information

Status
Published
Publication Date
13-May-2014
Withdrawal Date
29-Nov-2014
Current Stage
9093 - Decision to confirm - Review Enquiry
Completion Date
22-Sep-2020

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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.NRPFördergurte - Brandtechnische Prüfungen - Teil 1: Prüfungen mit dem PropanbrennerCourroies transporteuses - Essais de simulation d'inflammation - Partie 1: Essais avec brûleur propaneConveyor belts - Fire simulation flammability testing - Part 1: Propane burner tests53.040.20Deli za transporterjeComponents for conveyors13.220.40Sposobnost vžiga in obnašanje materialov in proizvodov pri gorenjuIgnitability and burning behaviour of materials and productsICS:Ta slovenski standard je istoveten z:EN 12881-1:2014SIST EN 12881-1:2014en,fr,de01-julij-2014SIST EN 12881-1:2014SLOVENSKI

STANDARDSIST EN 12881-1:2006+A1:20081DGRPHãþD
SIST EN 12881-1:2014
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 12881-1

May 2014 ICS 13.220.40; 53.040.20 Supersedes EN 12881-1:2005+A1:2008English Version

Conveyor belts - Fire simulation flammability testing - Part 1: Propane burner tests

Courroies transporteuses - Essais de simulation d'inflammation - Partie 1: Essais avec brûleur propane

Fördergurte - Brandtechnische Prüfungen - Teil 1: Prüfungen mit dem Propanbrenner This European Standard was approved by CEN on 15 February 2014.

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-CENELEC 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-CENELEC Management Centre has the same status as the official versions.

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

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre:
Avenue Marnix 17,

B-1000 Brussels © 2014 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 12881-1:2014 ESIST EN 12881-1:2014

EN 12881-1:2014 (E) 2 Contents Page

Foreword ..............................................................................................................................................................3 Introduction .........................................................................................................................................................4 1 Scope ......................................................................................................................................................5 2 Normative references ............................................................................................................................5 3 Propane gas supply ...............................................................................................................................5 4 Method A – Two metre single burner test ...........................................................................................6 4.1 Apparatus ...............................................................................................................................................6 4.2 Preparation of test pieces .....................................................................................................................9 4.3 Temperature at commencement of test ..............................................................................................9 4.4 Number of tests ......................................................................................................................................9 4.5 Procedure ...............................................................................................................................................9 4.6 Termination of tests............................................................................................................................ 10 4.7 Measurement of damage to test pieces ........................................................................................... 10 4.8 Test report ........................................................................................................................................... 11 5 Method B – Double burner test ......................................................................................................... 12 5.1 Apparatus ............................................................................................................................................ 12 5.2 Preparation of test pieces .................................................................................................................. 13 5.3 Temperature at commencement of test ........................................................................................... 13 5.4 Number of tests ................................................................................................................................... 13 5.5 Procedure ............................................................................................................................................ 14 5.6 Termination of tests............................................................................................................................ 14 5.7 Measurement of damage to test pieces ........................................................................................... 14 5.8 Test report ........................................................................................................................................... 15 6 Method C – Mid-scale fire propagation test ..................................................................................... 15 6.1 Apparatus ............................................................................................................................................ 15 6.2 Preparation of test pieces .................................................................................................................. 23 6.3 Installation of the test pieces and burner ........................................................................................ 23 6.4 Temperature at commencement of test ........................................................................................... 23 6.5 Number of tests ................................................................................................................................... 23 6.6 Procedure ............................................................................................................................................ 23 6.7 Termination of tests............................................................................................................................ 24 6.8 Measurement of damage to test pieces ........................................................................................... 24 6.9 Exhaust temperature calibration ....................................................................................................... 25 6.10 Test report ........................................................................................................................................... 25 7 Method D Laboratory scale Fire Propagation Test ......................................................................... 26 7.1 Apparatus ............................................................................................................................................ 26 7.2 Preparation of test pieces .................................................................................................................. 27 7.3 Installation of the test piece and burner .......................................................................................... 27 7.4 Test Conditions ................................................................................................................................... 27 7.5 Procedure ............................................................................................................................................ 27 7.6 Termination of tests............................................................................................................................ 28 7.7 Measurement of damage to test pieces ........................................................................................... 28 7.8 Test report ........................................................................................................................................... 28 Annex ZA (informative)

Relationship between this European Standard and the Essential Requirements of EU Directive 2006/42/EC ....................................................................................... 33 Bibliography ..................................................................................................................................................... 34

SIST EN 12881-1:2014

EN 12881-1:2014 (E) 3 Foreword This document (EN 12881-1:2014) has been prepared by Technical Committee CEN/TC 188 “Conveyor belts”, the secretariat of which is held by SNV. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by November 2014 and conflicting national standards shall be withdrawn at the latest by November 2014. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights. This document supersedes EN 12881-1:2005+A1:2008. 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. The main changes with respect to the previous edition are listed below: — ‘Laboratory scale fire propagation test' was added (Method D); — 'Mid-scale fire propagation test' (Method C, 6.1.1 Test gallery) thermal conductivity of the refractory material was included; — 'Mid-scale fire propagation test' (Method C, 6.1.4 Gas burner) the diameter of the bore jets used was added. 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, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. SIST EN 12881-1:2014

EN 12881-1:2014 (E) 4 Introduction This European Standard is a type B1 standard as stated in EN ISO 12100. The provisions of this European Standard may be supplemented or modified by a type C standard. The machinery concerned and the extent to which hazards, hazardous situations and events are covered are indicated in the scope of this European Standard. NOTE For machines which are covered by the scope of a type C standard and which have been designed and built according to the provisions of that standard, the provisions of that type C standard take precedence over the provisions of this type B1 standard. The methods of test described in EN 12881-1 are intended to provide an indication of the reaction of a conveyor belt to a fire situation. However, in doing so attention is drawn to the fact that in assessing the overall flammability characteristics of conveyor belting for specific installations, it is not sufficient to rely solely on any single method of test but consideration has also to be given to the individual site location. WARNING — The tests described in EN 12881-1 can generate large amounts of smoke and heat. It is therefore essential to conduct the tests with caution, having due regard to health and safety considerations and to terminate any test immediately if at any time it is considered advisable to do so. In this regard it is recommended that no test should be supervised by only one person. SIST EN 12881-1:2014

EN 12881-1:2014 (E) 5 1 Scope EN 12881-1 describes four methods for measuring the propagation of a flame along a conveyor belt which has been exposed to a relatively high localized heat source such as a fire. The damage suffered by the conveyor belt, as well as its tendency to support combustion, is measured by observing the extent to which the fire spreads along the test piece. Method A uses a test piece 2 m in length and consumes propane gas through the burner at the rate of (1,30 ± 0,05) kg per 10 min. Method B uses a test piece 2,5 m in length and consumes propane gas through two burners mounted above and below the test piece trestle at the rate of (1,30 ± 0,05) kg per 10 min for each burner. Method C uses a test piece 1,5 m in length and consumes propane gas through the burner at the rate of (565 ± 10) g per 50 min. Method D uses a test piece 1,2 m in length and consumes propane gas through the burner at the rate of

150 l/hr (D1) or 190 l/hr (D2). 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 10088-3, Stainless steels — Part 3: Technical delivery conditions for semi-finished products, bars, rods, wire, sections and bright products of corrosion resisting steels for general purposes EN 22768-1, General tolerances — Part 1: Tolerances for linear and angular dimensions without individual tolerance indications (ISO 2768-1) ISO 65, Carbon steel tubes suitable for screwing in accordance with ISO 7-1 ISO 9162, Petroleum products — Fuels (class F) — Liquefied petroleum gases — Specifications 3 Propane gas supply The burners used in each method shall be supplied from bottled propane gas complying with ISO 9162 which shall be fed to each burner, using high pressure propane hose having a minimum internal diameter of 6,3 mm, either: a) through a pressure reducing valve, a non-return valve and an orifice plate 1,7 mm thick with a 2,5 mm diameter hole; or b) through a pressure reducing valve and a non-return valve followed by a flow meter calibrated to ensure that the correct mass of gas is consumed. Before and during the test, immerse each gas cylinder to approximately two-thirds of its height in a bath of water at a temperature of (25 ± 3) °C. Ensure that each gas cylinder is not emptied at the end of a test by more than 90 % of its gas mass capacity. SIST EN 12881-1:2014

EN 12881-1:2014 (E) 6 4 Method A – Two metre single burner test 4.1 Apparatus 4.1.1 Gallery (see Figure 1) having a cross section not greater than 6 m2, a height of not less than 1,9 m and not greater than 2,25 m and a width of not less than 1,9 m and not greater than 2,75 m through which air is drawn by an adjustable fan. The gallery shall have a concrete floor and shall be not less than 15,0 m long measured from the gallery entrance. 4.1.2 Trestle (see Figure 2) comprising a framework having internal dimensions 2,25 m long x 1,25 m wide and constructed of steel tubing complying with ISO 65, having a bore designation of DN 15 heavy series. The upper sides of the trestle frame shall be fitted with rod retainers to position and retain 15 steel bars manufactured from an austenitic chrome/nickel steel of an appropriate quality, such as 1.4310X10CrNi18-8 complying with EN 10088-3, resistant to rust, acid and heat. The bars shall be 10 mm diameter x 1,4 m in length and form the frame on which the belting rests. The upper surface of the bars shall be 350 mm from the floor. 4.1.3 Burner, constructed in accordance with Figure 3, comprising a square having side dimensions of

(450 ± 9) mm and an overall height of (220 ± 5) mm. The burner shall be made of welded steel tube complying with ISO 65, having a bore designation of DN 15 medium or heavy series. The tubing shall have

52 holes, each having a diameter of (1,5 ± 0,1) mm, spaced at 50 mm intervals. 4.1.4 Anemometer, or other means of measuring the air velocity in the gallery, which shall be located at a height of 350 mm on the centreline of the gallery, at least 7,25 m inside the gallery entrance and 750 mm from the end of the trestle nearest the gallery entrance. It is important that the air flow in the gallery is laminar and to this end equipment to assist in producing laminar flow may be used. 4.1.5 Thermocouple, to measure the temperature of the incoming air, located as shown in Figure 1. SIST EN 12881-1:2014

EN 12881-1:2014 (E) 7 Dimensions in millimetres
a) Plan view of gallery

b) Cross-section of front of gallery Key 1 rear of gallery 2 position of thermocouple on centre line 3 front of gallery Figure 1 — Location of thermocouple for measuring the temperature of incoming air General manufacturing tolerances shall be according to EN 22768-1, unless otherwise stated. SIST EN 12881-1:2014

EN 12881-1:2014 (E) 8 Dimensions in millimetres

Key 1 direction of air flow 8 gallery entrance 2 additional bar 9 test piece 3 to be clear of any cross bracing 10 edge of test piece flush with front of trestle 4 propane burner 11 350 mm to flow line 5 DN 15 heavy series tube 12 rod retainers 6 detail of trestle 13 DN 15 heavy series trestle 7 bars made of austenitic chrome/nickel steel, 14 detail of rod retaining angle

diameter 10 mm, length 1,4 m

Figure 2 — Propane burner trestle showing positions of burner and test piece SIST EN 12881-1:2014

EN 12881-1:2014 (E) 9 Dimensions in millimetres
a) Elevation

b) Plan view Key 1 threaded 2 hole (x 52) Figure 3 — Burner for Method A 4.2 Preparation of test pieces Cut two test pieces, each 2 m long × 1 200 mm wide or of full width if the conveyor belt is less than

1 200 mm wide. Lay the test pieces out for 24 h in dry conditions at any ambient temperature above 0 °C immediately prior to testing to remove residual curvature. 4.3 Temperature at commencement of test The ambient temperature at the commencement of the test shall be between 5 °C and 30 °C. 4.4 Number of tests Carry out two tests, one on each side of the belt, so that both covers are tested. 4.5 Procedure 4.5.1 Weigh the propane gas bottle prior to the test. SIST EN 12881-1:2014

EN 12881-1:2014 (E) 10 4.5.2 Install the trestle (4.1.2) centrally on the longitudinal axis of the gallery (4.1.1) with the burner end facing the direction of the ventilation flow. The burner end of the trestle shall be at least 8 m from the gallery entrance. 4.5.3 Place each test piece in turn centrally on the trestle with its transverse edge flush with the burner end of the trestle. 4.5.4 Adjust the air current in the gallery to give an average velocity of (1,5 ± 0,1) m/s at a height of 350 mm. Take the measurement on the centreline of the trestle and at a distance of 750 mm from the end of the trestle nearest the gallery entrance (see Figure 1). 4.5.5 Place the burner centrally with the four parallel burner tubes in line with the longitudinal axis of the test piece, and position it so that the distance from the top of the burner to the top of the bars on which the belt rests is (130 ± 5) mm, with the transverse end row of burner holes 50 mm inside the vertically projected transverse edge of the test piece. Light the burner and adjust the rate of gas consumption immediately to (1,30 ± 0,05) kg per 10 min. The rate of gas consumption may be regulated by controlling the gas pressure at the high pressure side of the orifice plate to approximately 0,16 MPa for a gas consumption rate of 0,13 kg/min. The pressure reducing valve, the non-return valve and the orifice plate should be positioned as close to each other as possible. A sensitive precision pressure gauge should be used to monitor the pressure at the high pressure side of the orifice plate. 4.5.6 After 10 min switch off the gas. Leave the test piece on the trestle until all flame and glowing have ceased (see also 4.6). However, terminate the test early if the extent of the fire appears to be a danger to persons or equipment. 4.5.7 Re-weigh the gas bottle at the end of the test. 4.5.8 Measure the damage to the test piece as described in 4.7. 4.6 Termination of tests 4.6.1 Normal termination A test shall be terminated, and shall be deemed to be terminated normally, when a period of at least 10 min has elapsed after all flaming and glowing on the test piece and debris has ceased. 4.6.2 Premature termination Any test terminated for safety reasons shall be deemed to be terminated prematurely and shall be recorded on the test report (see 4.8) as 'test terminated prematurely'. 4.7 Measurement of damage to test pieces 4.7.1 Criteria for assessment of damage After testing and in order to determine, for the purposes of damage assessment, the length of the test piece which remains undamaged, any embrittlement or hardening, cracking, blistering or other blemishes not originally present shall be regarded as damage. SIST EN 12881-1:2014

EN 12881-1:2014 (E) 11 4.7.2 Length of belting undamaged Measure the length of the test piece which remains undamaged over its full width from the trailing edge, as shown in Figure 4, on both the upper and lower surfaces. Record the lower of the two measurements as the length of belting that remains undamaged. Measurement in each case shall be made in a direction parallel to the longitudinal axis of the belt. If the edges of the test piece are not parallel because of uneven shrinkage, the direction of the longitudinal axis shall be judged by eye. Measurement shall be made along the surface of the test piece even if the test piece has become curved.

Key 1 length of undamaged belting 2 trailing edge 3 damaged belting Figure 4 — Measurement of length of undamaged belting 4.8 Test report The test report shall include the following: a) reference to this part of EN 12281 and method, i.e. “EN 12881-1:2014, Method A”; b) name of institution carrying out the test; c) name of belt manufacturer; d) date of test; e) identification of the belt under test; f) for each test piece, the minimum length measured as being undamaged (4.7.2); g) mass of gas consumed; h) signature and name of person responsible for the test; i) any deviations from the procedure, including whether the test was terminated prematurely; SIST EN 12881-1:2014

EN 12881-1:2014 (E) 12 j) the following statement: “The test results relate only to the behaviour of the test pieces of a product under the particular conditions of test; they are not intended to be the sole criterion for assessing the potential fire hazard of the product in use”. 5 Method B – Double burner test 5.1 Apparatus 5.1.1 Gallery, as described in 4.1.1. 5.1.2 Trestle (see Figure 5), as described in 4.1.2, except that its length shall be 2,70 m instead of 2,25 m and it shall retain 18 steel bars of 12 mm diameter instead of 15 steel bars of 10 mm diameter. 5.1.3 Burner, constructed in accordance with Figure 6, comprising two squares, having side dimensions of (450 ± 9) mm, situated one above the other in two parallel planes 280 mm apart. The centreline of the lower part of the burner shall be situated at a height of (210 ± 5) mm. The burner shall be made of welded steel tube complying with ISO 65, having a bore designation of DN 15 medium or heavy series. The tubing shall have 104 holes (52 in each element), each having a diameter of (1,5 ± 0,1) mm, spaced at 50 mm intervals. Each element of the burner shall have its own gas supply. 5.1.4 Anemometer, or other means of measuring the air velocity in the gallery, which shall be located at a height of 350 mm on the centreline of the gallery, at least 750 mm from the end of the trestle nearest the gallery entrance. Dimensions in millimetres

Key 1 test piece 2 direction of air flow 3 double burner 4 trestle Figure 5 — Positions of trestle, double burner and test piece for Method B SIST EN 12881-1:2014

EN 12881-1:2014 (E) 13 Dimensions in millimetres

Key 1 supports 2 hole (x 52) 3 centre line of burner Figure 6 — Burner for Method B 5.2 Preparation of test pieces Cut two test pieces, each 2,5 m long × 1 200 mm wide or of full width if the conveyor belt is less than

1 200 mm wide. Lay the test pieces out for 24 h in dry conditions at any ambient temperature above 0 °C immediately prior to testing to remove residual curvature. 5.3 Temperature at commencement of test The ambient temperature at the commencement of the test shall be between 5 °C and 30 °C. 5.4 Number of tests Carry out two tests, one on each side of the belt, so that both covers are tested. SIST EN 12881-1:2014

EN 12881-1:2014 (E) 14 5.5 Procedure 5.5.1 Weigh the propane gas bottle prior to the test. 5.5.2 Install the trestle (5.1.2) centrally on the longitudinal axis of the gallery (5.1.1) with the burner end facing the direction of the ventilation flow. The burner end of the trestle shall be at least 8 m from the gallery entrance. 5.5.3 Place each test piece in turn centrally on the trestle with its transverse edge flush with the burner end of the trestle. 5.5.4 Adjust the air current in the gallery to give an average velocity of (1,5 ± 0,1) m/s at a height of 350 mm. Take the measurement on the centreline of the trestle and at a distance of 750 mm from the end of the trestle nearest the gallery entrance (see Figure 1). 5.5.5 When the air velocity has stabilized at (1,5 ± 0,1) m/s, place the burner centrally with the four parallel burner tubes on each burner in line with the longitudinal axis of the test piece, and position it so that the transverse end row of burner holes is 50 mm inside the vertically projected transverse edge of the test piece. 5.5.6 Light the burners and adjust the rate of gas consumption immediately to (1,30 ± 0,05) kg per 10 min for each burner. The rate of gas consumption may be regulated by controlling the gas pressure at the high-pressure side of the orifice plate to approximately 0,16 MPa for a gas consumption rate of 0,13 kg/min. The pressure reducing valve, the non-return valve and the orifice plate should be positioned as close to each other as possible. A sensitive precision pressure gauge should be used to monitor the pressure at the high pressure side of the orifice plate. 5.5.7 After 20 min switch off the gas to both burners. Leave the test piece on the trestle until all flame and glowing have ceased (see also 5.6). However, terminate the test early if the extent of the fire appears to be a danger to persons or equipment. 5.5.8 Re-weigh the gas bottle at the end of the test. 5.5.9 Measure the damage to the test piece as described in 5.7. 5.6 Termination of tests 5.6.1 Normal termination A test shall be terminated, and shall be deemed to be terminated normally, when a period of at least 10 min has elapsed after all flaming and glowing on the test piece and debris has ceased. 5.6.2 Premature termination Any test terminated for safety reasons shall be deemed to be terminated prematurely and shall be recorded on the test report (see 5.8) as 'test terminated prematurely'. 5.7 Measurement of damage to test pieces 5.7.1 Criteria for assessment of damage After testing and in order to determine, for the purposes of damage assessment, the length of the test piece which remains undamaged, any embrittlement or hardening, cracking, blistering or other blemishes not originally present shall be regarded as damage. SIST EN 12881-1:2014

EN 12881-1:2014 (E) 15 5.7.2 Length of belting undamaged Measure the length of the test piece which remains undamaged over its full width from the trailing edge, as shown in Figure 4, on both the upper and lower surfaces. Record the lower of the two measurements as the length of belting that remains undamaged. Measurement in each case shall be made in a direction parallel to the longitudinal axis of the belt. If the edges of the test piece are not parallel because of uneven shrinkage, the direction of the longitudinal axis shall be judged by eye. Measurement shall be made along the surface of the test piece even if the test piece has become curved. 5.8 Test report The test report shall include the following: a) reference to this part of EN 12281 and method, i.e. “EN 12881-1:2014, Method B”; b) name of institution carrying out the test; c) name of belt manufacturer; d) date of test; e) identification of the belt under test; f) for each test piece, the minimum length measured as being undamaged (5.7.2); g) mass of gas consumed; h) signature and name of person responsible for the test; i) any deviations from the procedure, including whether the test was terminated prematurely; j) the following statement: “The test results relate only to the behaviour of the test pieces of a product under the particular conditions of test; they are not intended to be the sole criterion for assessing the potential fire hazard of the product in use”. 6 Method C – Mid-scale fire propagation test 6.1 Apparatus 6.1.1 Test gallery (see Figures 7 and 8), comprising a chamber made from 25 mm thick refractory material, with an opening measuring 460 mm × 460 mm and a length of 1 676 mm, connected to a 300 mm diameter ex

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