ISO TR 22898-2006 Review of outputs for fire containment tests for buildings in the context of fire safety engineering《防火工程中建筑物用防火试验的效率评价》.pdf

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1、 Reference number ISO/TR 22898:2006(E) ISO 2006TECHNICAL REPORT ISO/TR 22898 First edition 2006-04-01 Review of outputs for fire containment tests for buildings in the context of fire safety engineering Examen des rsultats des essais dendiguement du feu pour les btiments, dans le contexte de lingnie

2、rie de scurit ISO/TR 22898:2006(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the

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5、 at the address given below. ISO 2006 All rights reserved. Unless otherwise specified, 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 either ISO at the address b

6、elow or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2006 All rights reservedISO/TR 22898:2006(E) ISO 2006 All rights reser

7、ved iii Contents Page Foreword. v Introduction . vi 1 Scope . 1 2 Normative references . 1 3 Executive summary and recommendations 2 4 Mechanisms of fire spread 3 4.1 Routes and mechanisms of fire spread 3 4.2 Review of mechanisms leading to secondary fire initiation, fire growth and damage in adjac

8、ent areas directly related to the behaviour of the structure . 7 4.3 Review of secondary indirect mechanisms threatening life safety. 12 5 Fire resistance testing Review of exposure conditions. 14 5.1 Thermal exposure. 14 5.2 Pressure conditions . 16 5.3 Specimen size . 16 5.4 Restraint conditions .

9、 16 5.5 Furnace turbulence. 17 5.6 Atmosphere . 17 5.7 Conditioning 18 5.8 Quality of construction. 18 6 Fire resistance testing Review of the current measurements and criteria 18 6.1 Loadbearing capacity. 25 6.2 Integrity 25 6.3 Insulation . 27 6.4 Radiation 27 6.5 (Hot gas) leakage 28 6.6 Other da

10、ta collected . 28 6.7 Pre-test and post-test measurements and observations . 29 7 Comparison between exposure conditions used in the test and conditions likely to prevail in a real fire and recommendations for changes to the test procedures. 30 7.1 Thermal exposure. 30 7.2 Pressure differentials . 3

11、3 7.3 Specimen size . 34 7.4 Boundary conditions (load actions) . 35 7.5 Furnace turbulence. 36 7.6 Furnace atmosphere. 38 7.7 Conditioning 38 7.8 Quality of tested construction. 38 8 Comparison between data measured in the test and data required by the fire engineer and recommendations for changes

12、in the test procedure(s). 38 8.1 Behaviour of the load-bearing structure in fire safety engineering 39 8.2 Leakage of fire into protected space 41 8.3 Temperature rise on the unexposed face. 42 8.4 Heat flux received in the protected space 43 8.5 Smoke leakage into the protected space . 45 8.6 Other

13、 life safety and property protection consideration 46 8.7 Ensuring the construction . 46 9 Conclusions 46 ISO/TR 22898:2006(E) iv ISO 2006 All rights reservedAnnex A (informative) Decision tree for evaluating the compatibility of elements in respect of maintaining the fire tightness of the compartme

14、nt . 48 Annex B (informative) Background information on factors that affect life safety. 54 Bibliography . 56 ISO/TR 22898:2006(E) ISO 2006 All rights reserved v Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodie

15、s). The work of preparing International Standards is normally 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 n

16、on-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Pa

17、rt 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies castin

18、g a vote. In exceptional circumstances, when a technical committee has collected data of a different kind from that which is normally published as an International Standard (“state of the art”, for example), it may decide by a simple majority vote of its participating members to publish a Technical

19、Report. A Technical Report is entirely informative in nature and does not have to be reviewed until the data it provides are considered to be no longer valid or useful. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not

20、 be held responsible for identifying any or all such patent rights. ISO/TR 22898 was prepared by Technical Committee ISO/TC 92, Fire safety, Subcommittee SC 2, Fire containment. ISO/TR 22898:2006(E) vi ISO 2006 All rights reservedIntroduction Fire resistance test methods have been in existence for m

21、any decades and they permit various forms of structure to be evaluated and classified for regulatory purposes with respect to their fire containment capabilities, against conditions that reproduce one of the many possible fire scenarios that can exist in practice. Because of the changing use of mate

22、rials and the design of modern buildings, even this one scenario is becoming less relevant to the performance expected in practice. The criteria of failure used in these standardized tests sometimes reflect pseudo-life risk and sometimes a property risk. More recently, tests have been developed to m

23、easure the smoke containment potential of doors at ambient temperatures. When a fire engineer is designing a structure to resist the spread of fire and the products of combustion in order to satisfy a fire strategy that is responding to actual conditions and known exposure variations, both with resp

24、ect to the life safety of persons and the limitation of damage to the structure, the output of the standard fire tests are not deemed to be relevant in most situations. This Technical Report reviews the relevance of the standard tests and their outputs for the benefit of committees and working group

25、s developing specifications for structure that can satisfy a functionally derived fire safety strategy. In considering the effectiveness of the test for life safety purposes, it is solely with respect to the ability of the element to contain the fire to the enclosure/compartment of origin so that pe

26、ople outside of that space, including fire fighters, are not harmed indirectly by the fire or the behaviour of the building. By the time the “flashover” condition exists, it is assumed that the life safety of the persons within the enclosure is no longer a matter of concern because the measures put

27、into the design to ensure escape have achieved their objective. Once initiated, a fire within an enclosure, during this phase, initially burns in what is known as a “fuel-bed” controlled state. In this condition, in simplistic terms, the rate of combustion (and hence heat release) is controlled by t

28、he nature and geometry of the fuel at the seat of the fire. The predominant means of fire spread within the enclosure is by direct flame impingement on other combustible materials or by heat radiation from the flames onto materials positioned very close by. Provided that the hot gases of combustion

29、can vent easily into the open air from the enclosure or compartment (and that the elements of structure forming the compartments boundaries are not of a highly insulative nature), then it is conceivable that, for very well ventilated spaces, the fire will continue growing in a fuel-bed controlled st

30、ate until all combustible material within the enclosure or compartment is either on fire, or has been completely combusted. In large, well ventilated compartments, it has been shown by means of large scale “natural fire” tests that the fire can “leap frog” to adjacent parts of the compartment and th

31、at by the time fire reaches combustible materials remote from the original initiation point, the fuel at the initial location has been completely used up. Under such circumstances, the air/gas temperatures within the compartment are likely to be significantly stratified and are unlikely to exceed 50

32、0 C. In most fire containment applications, however, it is unlikely that there is an adequate supply of air via “natural” ventilation to support a fire in a persistently “fuel bed” controlled state. In these circumstances, the destination of the effluent gases of combustion plays a crucial role in t

33、he further development of fire. Once hot effluent gases are being produced by a fire at a rate faster than can be vented from the space, these gases start to collect under the roof or ceiling, thus forming a hot gas layer. As the layer deepens and gets closer to the seat of the fire, the amount of “

34、cold” ambient air drawn into the rising plume becomes less due to the shorter distance available for the plume to entrain the air. Consequently, the degree to which the smoke products are diluted, and hence cooled, becomes less. This, in turn, increases the temperature of the smoke layer, which also

35、 tends to darken due to the increased density of smoke particles. As the magnitude of this temperature approaches 600 C, the hot smoke layer is radiating significant quantities of heat in its own right and this energy is capable of causing pyrolysis, or even auto- ignition of combustible materials q

36、uite remote from the seat of the fire. This phenomenon marks the occurrence of flashover, and, once it occurs, all combustible materials within the enclosure rapidly become involved in the fire. ISO/TR 22898:2006(E) ISO 2006 All rights reserved vii The fire now enters the post-flashover, or “ventila

37、tion” controlled state, which is characterized by turbulent “swirling” flames throughout the entire space in conjunction with large flames from ventilation openings where superheated unburned volatiles escape and burn in the open air. Once a compartment fire is burning in a post-flashover ventilatio

38、n-controlled state, then temperatures within the compartment are quite likely to be of the order of 1 000 C. Whilst the fire-resisting elements of a structure provide a fire containment role during the “fuel-bed” controlled phase, they are primarily designed to provide fire separation with respect t

39、o a ventilation-controlled, post- flashover fire phase. The objective of many fire engineering strategies is to delay or suppress the potential of flashover. This can be achieved by the introduction of suppression measures, e.g. sprinklers (the most common method), smoke exhaust and ventilation, con

40、trol of contents and/or geometry of the space. Despite such controls, it is nave to believe that the enclosure boundary, say to a protected stair, or to areas of a different risk category, needs to have no fire-separating abilities. Currently, the fire engineers have no way of determining or measuri

41、ng the ability of a construction to withstand any condition other than that modelled by the standard fire-resistance test, which could represent an overprovision if the suppression system reliability is high. As previously stated, it is important to recognize that with the change of lifestyle since

42、the fire-resistance test was developed, there is frequent questioning of the validity of the standard-fire resistance exposure conditions. Few would question the validity of the current conditions for product classification periods, as the experiences of many decades have shown it to be adequate for

43、 environments where conventional furnishing materials have been used. Increasingly, though, the validity of the current exposure condition is questioned when using the outputs from a fire-resistance test in a fire-safety engineered strategy. If the rate of heating is increased, the temperature reach

44、ed could be greater or the pressure could be varied. This Technical Report considers the practicality of changing the exposure conditions, what they should be changed to, and what form the output should take. Similarly, ISO/TR 5925-1 represents only a limited number of fire scenarios due to the rang

45、e of pressures and temperatures used in the test. It also measures only the leakage of doorsets, ignoring the leakage of many other forms of construction. This Technical Report has been prepared to establish how the outputs generated by the tests developed and maintained within ISO/TC92/SC2, i.e. IS

46、O 834 (all parts) test methods, can be modified in due course to support the design codes produced by the working groups of ISO/TC92/SC4, in support of the fire-safety engineering designs of buildings, e.g. ISO 13387, in its various parts. The Technical Report is of value to the convenors of the wor

47、king groups developing and maintaining fire containment test procedures. It is also of value in the interim period to fire-safety engineers who wish to understand the limitations of products tested to the SC2-generated test procedures. It is anticipated that further Technical Reports will be prepare

48、d giving recommendations to the various working groups as to how their standards, and in particular their criteria, can be improved to reflect the needs of the fire-engineering community. TECHNICAL REPORT ISO/TR 22898:2006(E) ISO 2006 All rights reserved 1 Review of outputs for fire containment test

49、s for buildings in the context of fire safety engineering 1 Scope This Technical Report has been prepared in order to review whether the current ISO furnace-based fire resistance testing methods remain appropriate for establishing the performance of elements of structure when exposed to fully developed fire conditions in the context of a fire safety engineered strategy for a building. It identifies whether there is a difference between the data produced and the data required. Where there is, it reviews whether the test methods can be easily