1、Designation: E2923 13E2923 14Standard Practice forLongevity Assessment of Firestop Materials UsingDifferential Scanning Calorimetry1This standard is issued under the fixed designation E2923; the number immediately following the designation indicates the year oforiginal adoption or, in the case of re
2、vision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This practice covers a standardized procedure for quantitatively assessing the longevity of materi
3、als used in firestop systems,by the use of data obtained from differential scanning calorimetry.1.2 This practice is intended to differentiate firestop materials that are expected to maintain performance characteristics overtime from those that are expected to degrade in performance characteristics
4、over time. DSC experimental curve evaluation can alsodeliver indifferent results, where an interpretation of sample properties is not possible without additional testing using conventionaldurability testing. It evaluates the extent of chemical reactions that will occur within the firestop material u
5、nder specified conditionsof temperature and humidity. This practice does not measure longevity under specific severe environmental conditions or buildingoperation that might be experienced by an individual firestop system.1.3 This practice is intended to be used to test the materials used within a f
6、irestopping system. The practice is not intended tobe used to test the properties of assembled firestopping systems.1.4 This practice is intended to evaluate the following types of materials used in through-penetration fire stops:1.4.1 Endothermic,1.4.2 Intumescent,1.4.3 Insulation,1.4.4 Ablatives,
7、and1.4.5 Subliming.1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this stan
8、dard to establish appropriate safety and health practices and determine the applicability of regulatorylimitations prior to use. Some specific hazards are given in Section 8 on Hazards.2. Referenced Documents2.1 ASTM Standards:2E814 Test Method for Fire Tests of Penetration Firestop SystemsE2041 Tes
9、t Method for Estimating Kinetic Parameters by Differential Scanning Calorimeter Using the Borchardt and DanielsMethod3. Terminology3.1 Definitions:3.1.1 firestop material, nthe part of a firestop system that provides the necessary seal to prevent the passage of flame and hotgases when tested in acco
10、rdance with Test Method E814. This includes any material that serves the purpose of closing and sealingthe gap(s) created in a fire-resistance rated wall or floor to accommodate a through-penetration.3.1.2 longevity, na measure of the length of time a product meets specified performance requirements
11、.3.1.2.1 Discussion1 This practice is under the jurisdiction of ASTM Committee E06 on Performance of Buildings and is the direct responsibility of Subcommittee E06.21 on Serviceability.Current edition approved April 1, 2013May 1, 2014. Published April 2013May 2014. Originally approved in 2013. Last
12、previous edition approved in 2013 as E292313.DOI: 10.1520/E29231310.1520/E2923142 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Document Summary page o
13、n the ASTM website.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may not be technically possible to adequately depict all changes accurately, ASTM recommends that user
14、s consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1Longevity is not intended to
15、be a measure of how long a product retains the precise properties that it had at the time of manufacture.Most materials will change over time to some extent, so a measurement of time before discernible change occurs would notgenerally be realistic or useful. Rather, longevity is intended to be a mea
16、sure of how long a product retains its properties to asufficient degree to be deemed as meeting the purpose(s) for which it was manufactured.4. Summary of Practice4.1 Asmall sample of the firestop material is tested by differential scanning calorimetry in accordance with Test Method E2041to determin
17、e the following information:4.1.1 Calculation of total released energy.4.1.2 Determination of reaction order.4.1.3 Determination of activation energy and Arrhenius frequency factor.4.1.4 Calculation of the conversion rate for 270 days at 70C.4.1.5 Calculation of the conversion rate for 30 years (10
18、950 days) at 50C.4.2 Using the kinetic data, the chemical conversion rate for the material can be calculated for any time duration and temperaturecombination. The conversion rate for that time and temperature is then compared to the predetermined threshold of acceptability.That threshold shall be ex
19、pressed as the largest fraction of the original material that shall be permitted to undergo change throughchemical reaction(s) while still allowing the material to adequately perform its design function.5. Significance and Use5.1 Firestop systems are exposed to fire tests and classified using materi
20、als that have been, in all likelihood, quite recentlymanufactured. The testing provides a fire resistance rating for the firestop system that is measured in hours. The goal of firestopsystem testing is to identify and list firestop systems that will have a fire resistance rating that is no less than
21、 the fire resistancerating of the classified wall or floor assembly in which it is installed. A building fire that could put the firestop system to the testcan occur at any time during the life of the building. By that time, the firestop system is composed of materials that have aged.Some assurance
22、is desired to establish quantitatively that the firestop system will continue to have a fire resistance rating that isno less than that of the wall or floor assembly.5.2 This practice provides one method for examining whether any changes are to be expected in the characteristics of a firestopmateria
23、l during its design life, as gauged by any chemical reactions that occur within the material to change it. The measurementof conversion rate provides a standard measure of how much a material will change over its design life. This provides an objectiveindication of whether the bulk of the material i
24、s likely to exhibit the desirable properties for which it was chosen in the firestopsystem.5.3 Measurement of conversion rate allows different firestop materials used for similar purposes to be compared with respectto their ability to remain unchanged during their design life.5.3.1 This allows mater
25、ials with an unusually high conversion rate to be questioned and possibly rejected early on during theresearch and development process.5.3.2 This allows materials to be screened by testing and listing agencies to ensure that they do not provide a listing for productsthat are not likely to have adequ
26、ate performance for the full length of the intended design life.5.3.3 This allows formulation changes that have no apparent impact on the results of the fire testing to be evaluated for anypossible long-term consequences on performance.5.3.4 Re-calculation of the conversion rate (other than for the
27、standard time and temperature specified in Section 11) allowsmaterials to be evaluated for suitability in applications where they may be regularly exposed to unusually high temperatures, orfor suitability in installations which are intended to have an unusually long design life, or both.5.4 Measurem
28、ent of conversion rate allows longevity of firestop materials to be compared to the longevity of the classified wallor floor assemblies in which the firestop system is installed, by measuring the conversion rate for each. This comparison can ensurethat the firestop system does not degrade significan
29、tly faster, thus possibly deeming it to be unacceptable. The comparison can alsoensure that the firestop system is not unjustifiably held to a higher standard of longevity than the floor or wall itself.5.5 The fundamental assumption inherent in making use of DSC conversion rate data for assessing lo
30、ngevity of firestopmaterials is that if the material has a chemical stability that keeps it from changing much over time in a certain environment, thenit is reasonable to expect it to adequately perform its design function if subjected to an actual fire many years after installation.6. Interferences
31、6.1 Because of its simplicity and ease of use, the Borchardt and Daniels method is often the method of choice forcharacterization of the kinetic parameters of a reaction system. The Borchardt and Daniels method, like all tools used to evaluatekinetic parameters, is not applicable to all cases. The u
32、ser of this method is expressly advised to use this method and its resultswith caution.6.2 Tabulated below are some guidelines for the use of the Borchardt and Daniels method.E2923 1426.2.1 The approach is applicable only to exothermic reactions.NOTE 1Endothermic reactions are controlled by the kine
33、tics of the heat transfer of the apparatus and not by the kinetics of the reaction.6.2.2 The reaction under investigation must have a constant mechanism throughout the whole reaction process. In practice, thismeans that the reaction exotherm upon heating must be smooth, well shaped with no shoulders
34、, multiple peaks or discontinuoussteps.6.2.3 The reaction must be nth order. Confirmation of an nth order reaction shall be made by an isothermal experiment suchas that described in Appendix X1 in Test Method E2041.6.2.4 Typical reactions which are not nth order and to which Borchardt and Daniels ki
35、netic shall not be applied for predictivepurposes include many thermoset curing reactions and crystallization transformations.6.2.5 The nth order kinetic reactions anticipate that the value of n will be small, non-zero integers, such as 1 or 2. Values ofn 2 or which are not simple fractions, such as
36、 = 0.5, are highly unlikely and shall be viewed with caution.6.2.6 The Borchardt and Daniels method assumes temperature equilibrium throughout the whole test specimen. This means thatlow heating rates, (that is, 10 K/min), small specimen sizes (5 mg) and highly conductive sealed specimen containers,
37、 forexample, aluminum, gold, platinum, etc., shall be used.6.3 Since milligram quantities of specimen are used, it is essential that the specimen be homogeneous and representative of thetest sample from which they are taken.7. Apparatus7.1 Differential Scanning Calorimeter (DSC), the instrumentation
38、 required to provide the minimum differential scanningcalorimetric capability for this practice includes the following:7.1.1 DSC Test Chamber, composed of the following:7.1.1.1 Furnace(s), to provide uniform controlled heating of a specimen and reference to a constant temperature at a constantrate w
39、ithin the applicable temperature range of this practice.7.1.1.2 Temperature Sensor, to provide an indication of the specimen/furnace temperature to 60.01 K.7.1.1.3 Differential Sensor, to detect heat flow difference between the specimen and reference equivalent to 1 W.7.1.1.4 A means of sustaining a
40、 test chamber environment of purge gas at a rate of 10 to 50 6 mL/min.NOTE 2Typically, 99.9+ % pure nitrogen, helium, or argon is employed. Use of dry purge gas is recommended and is essential for operation atsubambient temperatures.7.1.2 Temperature Controller, capable of executing a specific tempe
41、rature program by operating the furnace(s) between selectedtemperature limits, that is, 170 to 870 K, at a rate of temperature change of up to 10 K/min constant to 60.1 K/min.7.1.3 Recording Device, capable of recording and displaying any fraction of the heat flow signal (DSC curve), including thesi
42、gnal noise, on the Y-axis versus temperature on the X-axis.7.2 Containers (pans, crucibles, vials, etc.), that are inert to the specimen and reference materials, and which are of suitablestructural shape and integrity to contain the specimen and reference in accordance with the specific requirements
43、 of this practice.7.3 While not required, the user will find useful calculator or computer and data analysis software to perform the necessary leastsquares best fit or multiple linear regression data treatments required by this practice.7.4 Balance, to weigh specimens, or containers, or both, to 610
44、 g with a capacity of at least 100 mg.8. Hazards8.1 This practice uses equipment that alters a materials state that may create noxious gases that may be harmful. Care shall betaken to provide adequate ventilation for all equipment capable of producing this effect.9. Sampling, Test Specimens, and Tes
45、t Units9.1 Material tested shall be as commercially supplied by the manufacturer.9.2 Materials such as, but not limited to, sealants, putties, coatings, sprays, mortars and foams, which are normally shipped anddispensed at the time and place of final use from an air-tight or near air-tight container
46、, shall be cast, formed, sprayed or otherwiseapplied as they normally would to create a sample of thickness which is considered by the test sponsor and laboratory to representa typical field installation. The sample shall be allowed to cure or dry before testing. Curing or drying time shall be in ac
47、cordancewith manufacturers published instructions for the product.9.3 Inhomogeneous materials.9.3.1 Due to the possibility that a milligram-sized sample might not include one or more constituents of an inhomogeneousmaterial, multiple samples shall be taken and tested so as to ensure that the kinetic
48、 data (Arrhennius coefficients) of all constituentsof the material have been measured.NOTE 3It is not intended that samples should be prepared and tested that would test each individual component as a pure material. The intent is thatsufficient samples should be tested that each component has appear
49、ed in at least one test.E2923 1439.4 The samples to be used for DSC testing shall be excised from the material prepared as specified in 9.2.10. Procedure10.1 DSC testing shall be conducted on three samples prepared as specified in Section 9. The two tests and subsequent dataanalysis shall be as described in Test Method E2041, with exceptions as described in 10.1.1 and 10.1.2.10.1.1 In one test, the sample shall be in an open container that is exposed to a pure dry air atmosphere.10.1.2 In one test, the sample shall be in an open container that is exposed to an air
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