SIST EN 61482-1-2:2007
Live working - Protective clothing against the thermal hazards of an electric arc -- Part 1-2: Test methods -- Method 2: Determination of arc protection class of material and clothing by using a constrained and directed arc (box test)
Live working - Protective clothing against the thermal hazards of an electric arc -- Part 1-2: Test methods -- Method 2: Determination of arc protection class of material and clothing by using a constrained and directed arc (box test)
This part of IEC 61482 specifies methods to test material and garments intended for use in heat- and flame-resistant clothing for workers exposed to electric arcs. In contrast to the test methods in IEC 61482-1-11) a directed and constrained electric arc in a low voltage circuit is used to classify material and clothing in defined arc protection classes. The test methods specified in this document are aimed at rendering a decision whether arc thermal protection is met under defined conditions. Two protection classes are tested. Protection class 1 and protection class 2 are safety requirements covering actual risk potentials due to electric fault arcs. The test methods are not directed toward measuring the arc thermal performance value (ATPV). Methods determining the ATPV are prescribed in IEC 61482-1-1. This standard specifies tests with which it is possible to evaluate materials and protective clothing based on the use of a directed and constrained electric arc under defined laboratory conditions (box-test). A practical scenario concerning test set-up and test conditions, electrical and constructional parameters is selected. For the tests a low voltage procedure is used. The tests can optionally be carried out in two fixed test classes, selected by the amount of prospective short circuit current: - Class 1 4 kA; - Class 2 7 kA. The defined duration of the electric arc is 500 ms in both test classes. Materials and clothing will be tested with two methods: the material box test method and the garment box test method. The material box test method is used to measure and find material response to an arc exposure when tested in a flat configuration. A quantitative measurement of the arc thermal performance is made by means of the energy transmitted through the material. The garment box test method is used to test the function of the protective clothing after an arc exposure, including all the garment findings, sewing tread, fastenings and other accessories; no heat flux will be measured. Testing refers to the thermal arc effects; it does not apply to other effects like noise, light emissions, pressure rise, hot oil, electric shock, the consequences of physical and mental shock or toxic influences.
Arbeiten unter Spannung - Schutzkleidung gegen die thermischen Gefahren eines elektrischen Lichtbogens -- Teil 1-2: Prüfverfahren -- Verfahren 2: Bestimmung der Lichtbogen-Schutzklasse des Materials und der Kleidung unter Verwendung eines gerichteten Prüflichtbogens (Box-Test)
Travaux sous tension - Vêtements de protection contre les dangers thermiques d'un arc électrique -- Partie 1-2: Méthodes d'essai -- Méthode 2: Détermination de la classe de protection contre l'arc de matériaux et de vêtements au moyen d'un arc dirigé et contraint (enceinte d'essai)
La présente partie de la CEI 61482 spécifie des méthodes d'essai des matériaux et des articles d'habillement destinés à être utilisés pour les vêtements résistant à la chaleur et à la flamme, pour les travailleurs exposés aux arcs électriques. Par opposition aux méthodes d'essai de la CEI 61482-1-1, un arc électrique dirigé et contraint dans un circuit basse tension est utilisé pour classer les matériaux et les vêtements dans les classes de protection contre l'arc définies. Les méthodes d'essai spécifiées dans le présent document ont pour objectif de statuer si la protection thermique contre l'arc est satisfaite dans des conditions définies. Deux classes de protection sont soumises aux essais. La classe de protection 1 et la classe de protection 2 sont des exigences de sécurité traitant des risques potentiels réels dus aux arcs électriques sur défaut. Les méthodes d'essai ne sont pas destinées à mesurer la valeur de performance thermique de l'arc (ATPV; en anglais Arc Thermal Performance Value). Les méthodes déterminant la valeur de performance thermique de l'arc sont prescrites dans la CEI 61482-1-1. La présente norme spécifie des essais avec lesquels il est possible d'évaluer les matériaux et les vêtements de protection en se basant sur l'utilisation d'un arc électrique dirigé et contraint dans des conditions de laboratoire définies (enceinte d'essai). Un scénario pratique est choisi, concernant le montage d'essai et les conditions d'essai, ainsi que les paramètres électriques et de construction. Pour les essais, une procédure basse tension est utilisée. Les essais peuvent être effectués au choix selon deux classes d'essai fixes, choisies par la quantité de courant de court-circuit présumé: Classe 1: 4 kA; Classe 2: 7 kA. La durée de l'arc est définie à 500 ms dans les deux classes d'essais. Les matériaux et les vêtements seront soumis aux essais selon deux méthodes: la méthode de l'enceinte d'essai pour les matériaux et la méthode de l'enceinte d'essai pour les articles d'habillement. La méthode de l'enceinte d'essai pour les matériaux est utilisée pour mesurer et trouver une réponse des matériaux à une exposition à l'arc lors de l'essai en une configuration plane. Une mesure quantitative de la performance thermique à l'arc est effectuée au moyen de l'énergie transmise à travers le matériau. La méthode de l'enceinte d'essai pour les articles d'habillement est utilisée pour soumettre aux essais la fonction du vêtement de protection après une exposition à l'arc, y compris toutes les fournitures de confection, le fil de couture, les fermetures et les autres accessoires; aucun flux thermique ne sera mesuré. Les essais se rapportent aux effets thermiques de l'arc; ils ne s'appliquent pas aux autres effets tels que le bruit, les émissions de lumière, la montée de pression, l'huile chaude, les chocs électriques, les conséquences des chocs physiques et mentaux ou les influences toxiques.
Delo pod napetostjo - Zaščitna oblačila proti temperaturnim nevarnostim električnega obloka - 2-1.del: Preskusne metode - 2. metoda: Določanje zaščitnega razreda proti obloku za material in oblačila z uporabo omejenega in usmerjenega obloka (preskus v zaboju) (IEC 61482-1-2:2007)
General Information
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Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Live working - Protective clothing against the thermal hazards of an electric arc - Part 1-2: Test methods -- Method 2: Determination of arc protection class of material and clothing by using a constrained and directed arc (box test)QRVWLPTravaux sous tension - Vetements de protection contre les dangers thermiques d'un arc électrique - Partie 1-2: Méthodes d'essai - Méthode 2: Détermination de la classe de protection contre l'arc de matériaux et de vetements au moyen d'un arc dirigé et contraint (enceinte d'essai)Arbeiten unter Spannung - Schutzkleidung gegen die thermischen Gefahren eines elektrischen Lichtbogens - Teil 1-2: Prüfverfahren - Verfahren 2: Bestimmung der Lichtbogen-Schutzklasse des Materials und der Kleidung unter Verwendung eines gerichteten Prüflichtbogens (Box-Test)Ta slovenski standard je istoveten z:EN 61482-1-2:2007SIST EN 61482-1-2:2007en,fr,de13.340.10Varovalna oblekaProtective clothing13.260XGDURPProtection against electric shockICS:SIST-TS CLC/TS 50354:20071DGRPHãþDSLOVENSKI
STANDARDSIST EN 61482-1-2:200701-november-2007
EUROPEAN STANDARD EN 61482-1-2 NORME EUROPÉENNE
EUROPÄISCHE NORM March 2007
CENELEC European Committee for Electrotechnical Standardization Comité Européen de Normalisation Electrotechnique Europäisches Komitee für Elektrotechnische Normung
Central Secretariat: rue de Stassart 35, B - 1050 Brussels
© 2007 CENELEC -
All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 61482-1-2:2007 E
ICS 13.220.40; 29.260; 29.260.99 Supersedes CLC/TS 50354:2003
English version
Live working -
Protective clothing against the thermal hazards of an electric arc -
Part 1-2: Test methods -
Method 2: Determination of arc protection class of material and clothing by using a constrained and directed arc (box test) (IEC 61482-1-2:2007)
Travaux sous tension -
Vêtements de protection contre les dangers thermiques d'un arc électrique - Partie 1-2: Méthodes d'essai -
Méthode 2: Détermination de la classe
de protection contre l'arc de matériaux et de vêtements au moyen d'un arc dirigé et contraint (enceinte d'essai) (CEI 61482-1-2:2007)
Arbeiten unter Spannung -
Schutzkleidung gegen die thermischen Gefahren eines elektrischen Lichtbogens -Teil 1-2: Prüfverfahren -
Verfahren 2: Bestimmung der
Lichtbogen-Schutzklasse des Materials und der Kleidung unter Verwendung eines gerichteten Prüflichtbogens (Box-Test) (IEC 61482-1-2:2007)
This European Standard was approved by CENELEC on 2007-03-01. CENELEC 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 Central Secretariat or to any CENELEC 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 CENELEC member into its own language and notified to the Central Secretariat has the same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom.
EN 61482-1-2:2007
- 2 -
Foreword The text of document 78/657/CDV, future edition 1 of IEC 61482-1-2, prepared by IEC TC 78, Live working, was submitted to the IEC-CENELEC parallel Unique Acceptance Procedure and was approved by CENELEC as EN 61482-1-2 on 2007-03-01. This European Standard supersedes CLC/TS 50354:2003. The following dates were fixed: – latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement
(dop)
2007-12-01 – latest date by which the national standards conflicting
with the EN have to be withdrawn
(dow)
2010-03-01 Annex ZA has been added by CENELEC. __________ Endorsement notice The text of the International Standard IEC 61482-1-2:2007 was approved by CENELEC as a European Standard without any modification. __________
- 3 - EN 61482-1-2:2007 Annex ZA
(normative)
Normative references to international publications with their corresponding European publications
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.
NOTE
When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD applies.
Publication Year Title EN/HD Year
IEC 60584-1 -1) Thermocouples -
Part 1: Reference tables EN 60584-1 19952)
ISO 3175-2 -1) Textiles - Professional care, drycleaning and wetcleaning of fabrics and garments -
Part 2: Procedure for testing performance when cleaning and finishing using tetrachloroethene EN ISO 3175-2 19982)
ISO 6330 -1) Textiles - Domestic washing and drying procedures for textile testing EN ISO 6330 20002)
ISO 9151 -1) Protective clothing against heat and flame - Determination of heat transmission on exposure to flame - -
1) Undated reference. 2) Valid edition at date of issue.
NORME INTERNATIONALECEIIEC INTERNATIONAL STANDARD 61482-1-2Première éditionFirst edition2007-01 Travaux sous tension –
Vêtements de protection contre les dangers thermiques d'un arc électrique
– Partie 1-2: Méthodes d'essai – Méthode 2: Détermination
de la classe de protection contre l’arc
de matériaux et de vêtements au moyen
d’un arc dirigé et contraint (enceinte d’essai)
Live working –
Protective clothing against the thermal hazards
of an electric arc –
Part 1-2: Test methods – Method 2: Determination
of arc protection class of material and clothing
by using a constrained and directed arc (box test) Pour prix, voir catalogue en vigueur For price, see current catalogue© IEC 2007
Droits de reproduction réservés
⎯
Copyright - all rights reserved Aucune partie de cette publication ne peut être reproduite ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie et les microfilms, sans l'accord écrit de l'éditeur. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the publisher. International Electrotechnical Commission,
3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, SwitzerlandTelephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch
Web: www.iec.ch CODE PRIX PRICE CODE U Commission Electrotechnique InternationaleInternational Electrotechnical Commission
61482-1-2 © IEC:2007 – 3 – CONTENTS FOREWORD.7
1 Scope.11 2 Normative references.13 3 Terms, definitions and symbols.13 4 Principle of the test methods.23 4.1 Material box test method.23 4.2 Garment box test method.23 5 Significance and use of the test methods.23 6 Test apparatus.25 6.1 Test box for both methods.25 6.2 Material box test method.29 6.3 Garment box test method.33 6.4 Electric supply and electrodes.33 6.5 Electric arc characteristics.35 6.6 Measurement and data acquisition system.35 7 Precautions.37 8 Specimen preparation.37 8.1 Description of the test specimens.37 8.2 Laundry conditioning of test specimens.39 8.3 Pre-conditioning of the test specimens.39 9 Calibration.39 9.1 Data acquisition system pre-calibration.39 9.2 Calorimeter calibration check.39 9.3 Arc exposure calibration.39 9.4 Calibration of the electric test circuit and testing.41 9.5 Confirmation of test apparatus setting.41 9.6 Preparing and conditioning of the box.41 10 Apparatus care and maintenance.43 10.1 Surface reconditioning of the sensors.43 10.2 Care of test plate and mannequin.43 10.3 Care of electrodes.43 11 Test procedures.43 11.1 Test parameters.43 11.2 Number of tests.45 11.3 Test conditions and initial temperature.45 11.4 Specimen mounting.45 11.5 Specimen description.45 12 Interpretation of results.47 12.1 Heat transfer.47 12.2 Visual inspection.49 12.3 Test result.51 13 Test report.51
Bibliography.55
61482-1-2 © IEC:2007 – 5 –
Figure 1 – Test box .27 Figure 2 – Test set up .29 Figure 3 – Test plate with sensors (calorimeter in mounting board) .31
Table 1 – Statistically confirmed mean values of the direct exposure incident energy.41 Table 2 – Ranges of the permissible arc energy.41 Table 3 – Test parameters for Classes 1 and 2.43 Table 4 – Human tissue tolerance to heat, second degree burn.49 Table 5 – Acceptance criteria for tests on materials.51 Table 6 – Acceptance criteria for tests on garments.51
61482-1-2 © IEC:2007 – 7 – INTERNATIONAL ELECTROTECHNICAL COMMISSION ____________
LIVE WORKING – PROTECTIVE CLOTHING
AGAINST THE THERMAL HAZARDS OF AN ELECTRIC ARC –
Part 1-2: Test methods –
Method 2: Determination of arc protection class of material
and clothing by using a constrained and directed arc (box test)
FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with may participate in this preparatory work. International, governmental and non-governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for Standardization (ISO) in accordance with conditions determined by agreement between the two organizations. 2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international consensus of opinion on the relevant subjects since each technical committee has representation from all interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any misinterpretation by any end user. 4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications transparently to the maximum extent possible in their national and regional publications. Any divergence between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter. 5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any equipment declared to be in conformity with an IEC Publication. 6) All users should ensure that they have the latest edition of this publication. 7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and members of its technical committees and IEC National Committees for any personal injury, property damage or other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is indispensable for the correct application of this publication. 9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent rights. IEC shall not be held responsible for identifying any or all such patent rights. International Standard IEC 61482-1-2 has been prepared by IEC technical committee 78: Live working. The text of this standard is based on the following documents: Enquiry draft Report on voting 78/657/CDV 78/687/RVC
Full information on the voting for the approval of this standard can be found in the report on voting indicated in the above table.
61482-1-2 © IEC:2007 – 9 – This publication has been drafted in accordance with the ISO/IEC Directives, Part 2. A list of all parts of the IEC 61482 series, under the general title Live working – Protective clothing against the thermal hazards of an electric arc, can be found on the IEC website. The committee has decided that the contents of this publication will remain unchanged until the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in the data related to the specific publication. At this date, the publication will be • reconfirmed, • withdrawn, • replaced by a revised edition, or • amended.
61482-1-2 © IEC:2007 – 11 – LIVE WORKING – PROTECTIVE CLOTHING
AGAINST THE THERMAL HAZARDS OF AN ELECTRIC ARC –
Part 1-2: Test methods –
Method 2: Determination of arc protection class of material
and clothing by using a constrained and directed arc (box test)
1 Scope This part of IEC 61482 specifies methods to test material and garments intended for use in heat- and flame-resistant clothing for workers exposed to electric arcs. In contrast to the test methods in IEC 61482-1-11) a directed and constrained electric arc in a low voltage circuit is used to classify material and clothing in defined arc protection classes. The test methods specified in this document are aimed at rendering a decision whether arc thermal protection is met under defined conditions. Two protection classes are tested. Protection class 1 and protection class 2 are safety requirements covering actual risk potentials due to electric fault arcs.
NOTE 1 In practice there can be higher risks. A risk analysis should clarify the actual risk. The test methods are not directed toward measuring the arc thermal performance value (ATPV). Methods determining the ATPV are prescribed in IEC 61482-1-1. This standard specifies tests with which it is possible to evaluate materials and protective clothing based on the use of a directed and constrained electric arc under defined laboratory conditions (box-test). A practical scenario concerning test set-up and test conditions, electrical and constructional parameters is selected. For the tests a low voltage procedure is used. The tests can optionally be carried out in two fixed test classes, selected by the amount of prospective short circuit current: Class 1 4 kA; Class 2 7 kA. The defined duration of the electric arc is 500 ms in both test classes.
NOTE 2 These conditions represent e.g. low voltage environmental conditions during an electric fault. Materials and clothing will be tested with two methods: the material box test method and the garment box test method. ___________ 1)
IEC 61482-1, Ed.1 (2002) is currently under revision. The next edition will be numbered IEC 61482-1-1.
61482-1-2 © IEC:2007 – 13 – The material box test method is used to measure and find material response to an arc exposure when tested in a flat configuration. A quantitative measurement of the arc thermal performance is made by means of the energy transmitted through the material. The garment box test method is used to test the function of the protective clothing after an arc exposure, including all the garment findings, sewing tread, fastenings and other accessories; no heat flux will be measured. Testing refers to the thermal arc effects; it does not apply to other effects like noise, light emissions, pressure rise, hot oil, electric shock, the consequences of physical and mental shock or toxic influences. 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. IEC 60584-1, Thermocouples – Part 1: Reference tables ISO 3175-2, Textiles – Professional care, drycleaning and wetcleaning of fabrics and garments – Part 2: Procedure for testing performance when cleaning and finishing using tetrachloroethene
ISO 6330, Textiles – Domestic washing and drying procedures for textile testing ISO 9151, Protective clothing against heat and flame – Determination of heat transmission on exposure to flame 3 Terms, definitions and symbols For the purposes of this document, the following terms, definitions and symbols apply. 3.1
arc current
Iarc current actually flowing in the electric test circuit during arc duration (through the arc); as r.m.s. value the average during arc duration NOTE 1 Arc current is expressed in A. NOTE 2 The arc current flowing during arc duration fluctuates due to the non-linear arc impedance stochastically varying with time. 3.2
arc duration time duration of the arc NOTE Arc duration is expressed in s.
61482-1-2 © IEC:2007 – 15 – 3.3
arc energy
Warc electrical energy supplied to the arc and converted in the arc; sum of the instantaneous arc voltage values multiplied by the instantaneous arc current values multiplied by the incremental time values during the arc duration NOTE Arc energy is expressed in kJ or kW·s. 3.4
arc gap distance between the arc electrodes NOTE Arc gap is expressed in mm. 3.5
arc thermal protection degree of thermal protection offered against electric arc under specific arc testing conditions NOTE 1 For materials, the arc thermal performance is obtained from the measurement of the transmitted energy and by evaluation of other thermal parameters (burning time, hole formation, melting). NOTE 2 For garments, the arc thermal performance is obtained by evaluation of thermal parameters (burning time, hole formation, melting) and of the functioning of fasteners and accessories. 3.6
arc voltage voltage across the arc NOTE Arc voltage is expressed in V. 3.7
burning time time for which a flame is visible after arc exposition NOTE Burning time is expressed in s. 3.8
calorimeter
device for measuring the heat flux and incident energy 3.9
charring formation of carbonaceous residue as the result of pyrolysis or incomplete combustion 3.10
clothing assembly of garments worn by workers 3.11
delta peak temperature
ΔTp
difference between the maximum temperature and the initial temperature of the sensor during the test exposure time NOTE 1 Delta peak temperature is expressed in °C. NOTE 2 The symbol ΔTp is used without index when testing with material; an additional index “0” is used when testing without material for calibration (ΔTp0).
61482-1-2 © IEC:2007 – 17 – 3.12
direct exposure incident energy
Ei0 heat energy or incident energy emitted by the electric arc and received at a calorimeter directly exposed to the arc without material influence; used for calibration NOTE Direct exposure incident energy is expressed in kJ/m2 or kW·s/m2 (cal/cm²) 2). 3.13
dripping material response evidenced by flowing of the fibre polymer 3.14
electric arc
self-maintained gas conduction for which most of the charge carriers are electrons supplied by primary-electron emission [IEV 121-13-12] NOTE During live working, the electric arc is generated by gas ionisation arising from an unintentional electrical conducting connection or breakdown between live parts or a live part and the earth path of an electrical installation or an electrical device. During testing, the electric arc is initiated by the blowing of a fuse wire. 3.15
embrittlement formation of a brittle residue as the result of pyrolysis or incomplete combustion 3.16
exposure time total test time interval of observation and measurement NOTE Exposure time is expressed in s. 3.17
garment single item of clothing which may consist of single or multiple layers 3.18
heat flux thermal intensity of an electrical arc indicated by the amount of energy transmitted per unit area and time NOTE Heat flux is expressed in kW/m². 3.19
hole formation existence of holes in the test specimen material with minimum 5 mm in any direction 3.20
ignition initiation of combustion ___________ 2) Correlation:
1 cal/cm² = 41,868 kJ/m²; 1 kJ/m² = 0,023 885 cal/cm².
61482-1-2 © IEC:2007 – 19 – 3.21
incident energy
Ei heat energy (total heat) received at a unit surface area as a result of an electric arc; measured as a proportional peak temperature rise ΔTp of a calorimeter sensor NOTE Incident energy is expressed in kJ/m2 or kW·s/m2 (cal/cm2). 3.22
material
fabric or other substances of which the garment is made, this may consist of single or multiple layers 3.23
material response reaction of the material to an electric arc indicated by the following characteristics: burning time (afterflame, ignition), hole formation, melting, dripping, charring, embrittlement, shrinkage, transmitted energy
3.24
melting material response evidenced by softening and deformation of the fibre polymer 3.25
prospective short circuit current
predicted current flowing when the arc electrodes are connected by a conductor of negligible impedance (short-circuit of supply) NOTE 1 Prospective short circuit current is expressed in A. NOTE 2 There is in general a difference between the actual arc current and the test current as defined. The actual arc current flowing during the arc duration is smaller and fluctuates due to the non-linear arc impedance stochastically varying with time. Reproducible test conditions may only be defined by means of the prospective short-circuit current to be expected in case of impedance-less connected arc electrodes. This prospective short-circuit current is, by the way, also a parameter which describes the practically interesting points in the electrical systems or installations where arc exposure has to be considered. 3.26
protective clothing clothing which covers or replaces personal clothing and which is designed to provide protection against one or more hazards [Definition 3.4 of ISO 13688] 3.27
sensor assembly with a calorimeter and a non-conductive heat-resistant material in which the calorimeter is mounted 3.28
shrinkage material response evidenced by reduction in specimen size 3.29
Stoll curve curve of thermal energy and time produced from data on human tissue tolerance to heat and used to predict the onset of second-degree burn injury (see Table 4 and Equation (1))
61482-1-2 © IEC:2007 – 21 – 3.30
test current
Iarc, class
prospective short-circuit current of the electric test circuit (predicted current), characterising a test class, r.m.s. value (symmetrical AC component) NOTE Test current is expressed in A. 3.31
time to delta peak temperature
tmax time from beginning of the initiation of the arc to the time the delta peak temperature is reached NOTE Time to delta peak temperature is expressed in s. 3.32
transmitted energy
Eit
incident energy received at a calorimeter when testing material or clothing; fraction of the emitted incident energy which is transmitted through the specimen NOTE Transmitted energy is expressed in kJ/m2 or kW·s/m2 (cal/cm2). 3.33
X/R ratio ratio of system inductive reactance to resistance NOTE The X/R ratio is proportional to the L/R ratio of time constant, and is, therefore, indicative of the rate of decay of any d.c. offset. A large X/R ratio corresponds to a large time constant and a slow rate of decay. 3.34
Symbols and units used in this document
Ei incident energy
kJ/m2 or kW·s/m2 (cal/cm2) 1 cal/cm2 = 41,868 kJ/m2;
1 kJ/m2 = 0,023885 cal/cm2 Ei0 direct exposure incident energy
kJ/m2 or kW·s/m2 (cal/cm2) Eit transmitted energy
kJ/m2 or kW·s/m2 (cal/cm²) Iarc arc current A Iarc, class test current (prospective short circuit current) A tmax time to delta peak temperature
s Ta ambient temperature °C T0 initial temperature sensor °C Warc
arc energy
kJ, kW·s ΔTp delta peak temperature
°C ΔTp0 delta peak temperature by calibration °C
61482-1-2 © IEC:2007 – 23 – 4 Principle of the test methods
The material box test method and the garment box test method covered by this standard determine the behaviour of materials and garments when exposed to heat energy from electric arcs with specific characteristics. 4.1 Material box test method With the material box test method the amount of heat energy transferred by the flat material(s) is measured during and after exposure to a specified electric arc.
Material performance for this procedure is determined from the amount of heat transmitted through the specimen(s) and other thermal parameters.
The heat flux of the exposure and that transferred by the test specimen(s) are measured with copper calorimeters. The degree to which the temperature of the calorimeters increases is a direct measure of the heat energy received. Heat transfer data is used to assess the onset of a second-degree burn using the Stoll curve. Material response shall be further described by recording the observed effects of the electric arc exposure on the specimens using the characteristics mentioned in definition 3.23.
4.2 Garment box test method Garment performance for this procedure is determined by evaluating the function
...
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