BS ISO 14934-4-2014 Fire tests Calibration and use of heat flux meters Guidance on the use of heat flux meters in fire tests《燃烧试验 热流计的校准和使用 燃烧试验用热流计的使用指南》.pdf

1、BSI Standards PublicationBS ISO 14934-4:2014Fire tests Calibration and useof heat flux metersPart 4: Guidance on the use of heat fluxmeters in fire testsBS ISO 14934-4:2014 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 14934-4:2014.It supersedes DD ISO/TS 149

2、34-4:2007 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee FSH/21/-/5, Reaction to fire tests - Heat release andsmoke measurement.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not p

3、urport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2014. Published by BSI StandardsLimited 2014ISBN 978 0 580 82022 9ICS 13.220.40; 13.220.50Compliance with a British Standard cannot confer immunity fromleg

4、al obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 31 August 2014.Amendments issued since publicationDate Text affectedBS ISO 14934-4:2014 ISO 2014Fire tests Calibration and use of heat flux meters Part 4: Guidance on the use of he

5、at flux meters in fire testsEssais au feu talonnage et utilisation des appareils de mesure du flux thermique Partie 4: Lignes directrices pour lutilisation des fluxmtres thermiques dans les essais au feuINTERNATIONAL STANDARDISO14934-4First edition2014-08-15Reference numberISO 14934-4:2014(E)BS ISO

6、14934-4:2014ISO 14934-4:2014(E)ii ISO 2014 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2014All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or po

7、sting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrigh

8、tiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 14934-4:2014ISO 14934-4:2014(E) ISO 2014 All rights reserved iiiContents PageForeword ivIntroduction v1 Scope . 12 Normative references 13 Terms and definitions . 14 General information on heat flux meters . 14.1 General . 14.2 Principle of measu

9、rement . 24.3 Design of heat flux meter . 34.4 Measurement characteristics . 54.5 Physical shape of heat flux meter . 85 Attachments to heat flux meters 95.1 Air purging 95.2 Windows 105.3 Cooling system . 116 Selection of a suitable heat flux meter126.1 General 126.2 Range of measurement . 126.3 Ty

10、pe, dimensions and orientation 136.4 View angle 146.5 Response time. 146.6 Sensitivity to convective heat transfer. 147 Performing a measurement .147.1 Installation . 147.2 Target surface 157.3 Electronics . 157.4 Relationship between output voltage and total heat flux .158 Calibration .168.1 Second

11、ary standard heat flux meter . 168.2 Working standard heat flux meters . 168.3 Frequency of calibration 169 Maintenance .169.1 Absorber 169.2 Wiring 169.3 Water supply 1610 Use of heat flux meters in fire tests 1610.1 General 1610.2 Ignitability test: ISO 5657 . 1710.3 Spread of flame test: ISO 5658

12、 series . 1710.4 Heat release, smoke production and mass loss: ISO 5660 series and ISO 17554 1810.5 Full-scale room test for surface products: ISO 9705 and ISO 13784 series 1810.6 Faade tests: ISO 13785 series . 1810.7 Spread of flame test for floor coverings: ISO 9239 series .1810.8 Intermediate-sc

13、ale heat release calorimeter (ICAL): ISO 14696 .18Bibliography .19BS ISO 14934-4:2014ISO 14934-4:2014(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normal

14、ly carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the

15、 work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the d

16、ifferent approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).Attention is drawn to the possibility that some of the elements of this document

17、 may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/pa

18、tents).Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO princi

19、ples in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary informationThe committee responsible for this document is ISO/TC 92, Fire safety, Subcommittee SC 1, Fire initiation and growth.This first edition of ISO 14934-4 cancels and replaces ISO/TS 14934-4:2007, wh

20、ich has been technically revised.ISO 14934 consists of the following parts, under the general title Fire tests Calibration and use of heat flux meters: Part 1: General principles Part 2: Primary calibration methods Part 3: Secondary calibration methods Part 4: Guidance on the use of heat flux meters

21、 in fire testsiv ISO 2014 All rights reservedBS ISO 14934-4:2014ISO 14934-4:2014(E)IntroductionIn many fire test methods, the radiation level is specified and, therefore, it is of great importance that the radiative heat flux is well defined and measured with sufficient accuracy. Radiative heat tran

22、sfer is also the dominant mode of heat transfer in most real fires.In practice, radiative heat flux is usually measured with so-called total heat flux meters of the Schmidt-Boelter (thermopile) or Gardon (foil) type. Such meters register the combined heat flux by radiation and convection to a cooled

23、 surface. The contribution to the heat transfer by convection depends mainly on the temperature difference between the surrounding gases and the sensing surface and on the velocity of the surrounding gases. It will, however, also depend on the size and shape of the heat flux meter, its orientation,

24、and its temperature level, which is near the cooling water temperature. In many practical situations in fire testing, the contribution due to convection to the sensing surface of the instrument can amount to 25 % of the heat flux. Therefore, it is always necessary to determine and control this part.

25、To determine the fraction of total heat flux due to radiation, a calibration scheme has been developed where primary calibration is performed on two different types of heat flux meters: (1) a total hemispherical radiometer sensitive to radiation only, and (2) a total heat flux meter (most frequently

26、 used) sensitive to both radiant heat transfer and convective heat transfer.When using heat flux meters, it is important to realize that, provided that convective heat transfer is kept to a minimum, only incident radiant heat flux can be measured directly. The net radiant heat flux as well as the he

27、at transfer by convection to a body depend on, among other things, the temperature of the receiving surface, while the instrument responds to heat transfer to a cooled surface.This part of ISO 14934 provides guidance on how this type of instrument is used and how the results are interpreted. ISO 201

28、4 All rights reserved vBS ISO 14934-4:2014BS ISO 14934-4:2014Fire tests Calibration and use of heat flux meters Part 4: Guidance on the use of heat flux meters in fire tests1 ScopeThis part of ISO 14934 provides guidance on the use of heat flux meters in fire testing applications, including the desc

29、ription and working principles of common heat flux meters and methods for their selection and maintenance. The guidance can also be applied to measuring heat flux from radiant panels and other large heat sources used to simulate the heat flux from a fire. It is applicable for all common testing purp

30、oses when measuring heat flux from radiant sources.This part of ISO 14934 also provides basic theory and working principles of heat flux meters and methods for selection, use, and maintenance of heat flux meters. Although it is particularly aimed at the application of heat flux meters in fire tests

31、and experimental works of fire research, it can also serve as a guide for other research applications like research of boilers, combustion processes, etc.Instruments, which measure the transient temperature of a solid body of known mass and heat capacity to infer the heat flux (slug calorimeter type

32、), are not covered by this part of ISO 14934.2 Normative referencesThe 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 ame

33、ndments) applies.ISO 13943, Fire safety VocabularyISO 14934-1, Fire tests Calibration and use of heat flux meters Part 1: General principlesISO 14934-2, Fire tests Calibration and use of heat flux meters Part 2: Primary calibration methodsISO 14934-3, Fire tests Calibration and use of heat flux mete

34、rs Part 3: Secondary calibration method3 Terms and definitionsFor the purposes of this document, the terms and definitions given in ISO 13943 and ISO 14934-1 apply.4 General information on heat flux meters4.1 GeneralA heat flux meter is an instrument which measures the radiant and convective heat th

35、at is transferred from the fire environment to a sensing element. In practice, heat flux is most commonly measured with total heat flux meters of the Schmidt-Boelter (thermopile) or Gardon (foil) type. Although there are a wide variety of designs of heat flux meters, a typical design consists of a t

36、hermopile sensor, mounted on a metal body that is cooled by water. The body acts as a constant temperature heat sink. The thermopile sensor typically has a nearly black surface which is assumed to absorb all incident radiation, or which emissivity is given.INTERNATIONAL STANDARD ISO 14934-4:2014(E)

37、ISO 2014 All rights reserved 1BS ISO 14934-4:2014ISO 14934-4:2014(E)It is assumed that sensitivity does not depend on wavelength over the spectral range of the radiating sources. Deviations from the ideal directional response characteristics may normally be also disregarded.In a normal situation, th

38、e field of view is assumed to be 2 sr and the surface is assumed to be a perfect blackbody, both regarding the spectral characteristics and the directional response.In general, heat flux meters consist of an absorber of heat flux, body, water-cooling system, and wiring as shown in Figure 1. They oft

39、en also have a flange for mounting purposes.213456789Key1 absorber 6 cable2 body 7 heat flux meter signal3 flange 8 temperature sensor signal4 tube for water supply 9 incident heat flux5 tube for wiringFigure 1 General features of heat flux metersThe sensing surface shall remain free of deposition o

40、f soot or other particulates. It should be noted that soot may accumulate on the cool gauge surface and can affect the gauge output.4.2 Principle of measurementThe incident heat flux onto the absorber creates a local temperature difference. This difference is measured, resulting in an output signal

41、(voltage). As a first approximation, this voltage is linear with the heat flux received by the sensor. In most heat flux meters, the measurement of the temperature difference is based on thermocouples or thermopiles, which are passive and do not require any external power.Within a limited working ra

42、nge, the relationship between the heat flux received by the sensor and the output signal can be assumed to be linear. However, it should be noted that the output signal is not always linear to the incident heat flux (see 4.4.3).2 ISO 2014 All rights reservedBS ISO 14934-4:2014ISO 14934-4:2014(E)4.3

43、Design of heat flux meterThere are two types of heat flux meters that are widely used in fire tests: so-called Gardon (foil) type and Schmidt-Boelter (thermopile) type.The Gardon type heat flux meters have a very wide working range and a very fast response time. However, they have a low sensitivity

44、and therefore do not work with low heat fluxes.The Schmidt-Boelter type heat flux meters generally have a much higher sensitivity than Gardon gauges.Another type of heat flux meter is a hemispherical radiometer, sensitive to irradiance only, i.e. it is not sensitive to surrounding gas temperature an

45、d velocity and is used for estimating the convective part of the heat transfer measured with total heat flux meters.4.3.1 Gardon type heat flux meterThe Gardon type heat flux meters have an absorber, which is deposited on a thin foil. The absorbed heat is conducted radially along the foil into the b

46、ody, which is water-cooled. The absorber has an approximately parabolic temperature distribution. The temperature at the centre is high, varying with heat flux to the sensor, while the temperature at the edge is relatively low, remaining at the constant body temperature, i.e. the temperature of the

47、cooling water. The temperature profile is no longer parabolic when a significant convective cross-flow is present. Temperature difference between the centre and the edge is measured by a thermocouple. A schematic view of the Gardon type heat flux meter is shown in Figure 2.324156Key1 foil with black

48、 absorber (usually constantan) 4 cooling water2 incident heat flux 5 wire connected to the body (or edge of the foil)3 wire connected to the centre of the foil 6 thermocouple for body temperature measurementFigure 2 Gardon type heat flux meter4.3.2 Schmidt-Boelter type heat flux meterA Schmidt-Boelt

49、er type heat flux meter has a relatively thick thermopile mounted on a heat sink, the water-cooled body of the gauge. The absorbed heat is conducted perpendicular to the absorber surface through the sensor into the heat sink. The absorber has a relatively uniform temperature distribution. Temperature difference between the sensor and the body is measured by the multiple thermocouples connected in series in the thermopile. The schematic view of the Schmidt-Boelter type heat flux meter is shown in Figure 3. ISO 2014 All righ