1、Designation: E2923 13Standard 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 revision,
2、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 quan-titatively assessing the longevity of materials use
3、d in firestopsystems, by the use of data obtained from differential scanningcalorimetry.1.2 This practice is intended to differentiate firestop mate-rials that are expected to maintain performance characteristicsover time from those that are expected to degrade in perfor-mance characteristics over t
4、ime. DSC experimental curveevaluation can also deliver indifferent results, where an inter-pretation of sample properties is not possible without addi-tional testing using conventional durability testing. It evaluatesthe extent of chemical reactions that will occur within thefirestop material under
5、specified conditions of temperature andhumidity. This practice does not measure longevity underspecific severe environmental conditions or building operationthat might be experienced by an individual firestop system.1.3 This practice is intended to be used to test the materialsused within a firestop
6、ping system. The practice is not intendedto be used to test the properties of assembled firestoppingsystems.1.4 This practice is intended to evaluate the following typesof materials used in through-penetration fire stops:1.4.1 Endothermic,1.4.2 Intumescent,1.4.3 Insulation,1.4.4 Ablatives, and1.4.5
7、Subliming.1.5 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to esta
8、blish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. Some specifichazards are given in Section 8 on Hazards.2. Referenced Documents2.1 ASTM Standards:2E814 Test Method for Fire Tests of Penetration FirestopSystemsE2041 Test Method fo
9、r Estimating Kinetic Parameters byDifferential Scanning Calorimeter Using the Borchardtand Daniels Method3. Terminology3.1 Definitions:3.1.1 firestop material, nthe part of a firestop system thatprovides the necessary seal to prevent the passage of flame andhot gases when tested in accordance with T
10、est Method E814.This includes any material that serves the purpose of closingand sealing the gap(s) created in a fire-resistance rated wall orfloor to accommodate a through-penetration.3.1.2 longevity, na measure of the length of time a productmeets specified performance requirements.3.1.2.1 Discuss
11、ionLongevity is not intended to be a mea-sure of how long a product retains the precise properties that ithad at the time of manufacture. Most materials will changeover time to some extent, so a measurement of time beforediscernible change occurs would not generally be realistic oruseful. Rather, lo
12、ngevity is intended to be a measure of howlong a product retains its properties to a sufficient degree to bedeemed as meeting the purpose(s) for which it was manufac-tured.4. Summary of Practice4.1 A small sample of the firestop material is tested bydifferential scanning calorimetry in accordance wi
13、th TestMethod E2041 to determine the following information:4.1.1 Calculation of total released energy.4.1.2 Determination of reaction order.1This practice is under the jurisdiction of ASTM Committee E06 on Perfor-mance of Buildings and is the direct responsibility of Subcommittee E06.21 onServiceabi
14、lity.Current edition approved April 1, 2013. Published April 2013. DOI: 10.1520/E2923132For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summar
15、y page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.1.3 Determination of activation energy and Arrheniusfrequency factor.4.1.4 Calculation of the conversion rate for 270 days at70C.4.1.5 Calculation of the conv
16、ersion rate for 30 years (10 950days) at 50C.4.2 Using the kinetic data, the chemical conversion rate forthe material can be calculated for any time duration andtemperature combination. The conversion rate for that time andtemperature is then compared to the predetermined threshold ofacceptability.
17、That threshold shall be expressed as the largestfraction of the original material that shall be permitted toundergo change through chemical reaction(s) while still allow-ing the material to adequately perform its design function.5. Significance and Use5.1 Firestop systems are exposed to fire tests a
18、nd classifiedusing materials that have been, in all likelihood, quite recentlymanufactured. The testing provides a fire resistance rating forthe firestop system that is measured in hours. The goal offirestop system testing is to identify and list firestop systemsthat will have a fire resistance rati
19、ng that is no less than the fireresistance rating of the classified wall or floor assembly inwhich it is installed. A building fire that could put the firestopsystem to the test can occur at any time during the life of thebuilding. By that time, the firestop system is composed ofmaterials that have
20、aged. Some assurance is desired to establishquantitatively that the firestop system will continue to have afire resistance rating that is no less than that of the wall or floorassembly.5.2 This practice provides one method for examiningwhether any changes are to be expected in the characteristics of
21、a firestop material during its design life, as gauged by anychemical reactions that occur within the material to change it.The measurement of conversion rate provides a standardmeasure of how much a material will change over its designlife. This provides an objective indication of whether the bulkof
22、 the material is likely to exhibit the desirable properties forwhich it was chosen in the firestop system.5.3 Measurement of conversion rate allows different firestopmaterials used for similar purposes to be compared withrespect to their ability to remain unchanged during their designlife.5.3.1 This
23、 allows materials with an unusually high conver-sion rate to be questioned and possibly rejected early on duringthe research and development process.5.3.2 This allows materials to be screened by testing andlisting agencies to ensure that they do not provide a listing forproducts that are not likely
24、to have adequate performance forthe full length of the intended design life.5.3.3 This allows formulation changes that have no apparentimpact 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 th
25、an forthe standard time and temperature specified in Section 11)allows materials to be evaluated for suitability in applicationswhere they may be regularly exposed to unusually hightemperatures, or for suitability in installations which areintended to have an unusually long design life, or both.5.4
26、Measurement of conversion rate allows longevity offirestop materials to be compared to the longevity of theclassified wall or floor assemblies in which the firestop systemis installed, by measuring the conversion rate for each. Thiscomparison can ensure that the firestop system does notdegrade signi
27、ficantly faster, thus possibly deeming it to beunacceptable. The comparison can also ensure that the firestopsystem is not unjustifiably held to a higher standard oflongevity than the floor or wall itself.5.5 The fundamental assumption inherent in making use ofDSC conversion rate data for assessing
28、longevity of firestopmaterials is that if the material has a chemical stability thatkeeps it from changing much over time in a certainenvironment, then it is reasonable to expect it to adequatelyperform its design function if subjected to an actual fire manyyears after installation.6. Interferences6
29、.1 Because of its simplicity and ease of use, the Borchardtand Daniels method is often the method of choice for charac-terization of the kinetic parameters of a reaction system. TheBorchardt and Daniels method, like all tools used to evaluatekinetic parameters, is not applicable to all cases. The us
30、er ofthis method is expressly advised to use this method and itsresults with caution.6.2 Tabulated below are some guidelines for the use of theBorchardt and Daniels method.6.2.1 The approach is applicable only to exothermic reac-tions.NOTE 1Endothermic reactions are controlled by the kinetics of the
31、heat transfer of the apparatus and not by the kinetics of the reaction.6.2.2 The reaction under investigation must have a constantmechanism throughout the whole reaction process. In practice,this means that the reaction exotherm upon heating must besmooth, well shaped with no shoulders, multiple pea
32、ks ordiscontinuous steps.6.2.3 The reaction must be nth order. Confirmation of an nthorder 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 whichBorchardt and Daniels kinetic shall not
33、be applied for predic-tive purposes include many thermoset curing reactions andcrystallization transformations.6.2.5 The nth order kinetic reactions anticipate that thevalue of n will be small, non-zero integers, such as 1 or 2.Values of n 2 or which are not simple fractions, such as =0.5, are highl
34、y unlikely and shall be viewed with caution.6.2.6 The Borchardt and Daniels method assumes tempera-ture equilibrium throughout the whole test specimen. Thismeans that low heating rates, (that is, 10 K/min), smallspecimen sizes (5 mg) and highly conductive sealed specimencontainers, for example, alum
35、inum, gold, platinum, etc., shallbe used.E2923 1326.3 Since milligram quantities of specimen are used, it isessential that the specimen be homogeneous and representativeof the test sample from which they are taken.7. Apparatus7.1 Differential Scanning Calorimeter (DSC), the instru-mentation required
36、 to provide the minimum differential scan-ning calorimetric capability for this practice includes thefollowing:7.1.1 DSC Test Chamber, composed of the following:7.1.1.1 Furnace(s), to provide uniform controlled heating ofa specimen and reference to a constant temperature at aconstant rate within the
37、 applicable temperature range of thispractice.7.1.1.2 Temperature Sensor, to provide an indication of thespecimen/furnace temperature to 60.01 K.7.1.1.3 Differential Sensor, to detect heat flow differencebetween the specimen and reference equivalent to 1 W.7.1.1.4 A means of sustaining a test chambe
38、r environmentof purge gas at a rate of 10 to 50 6 mL/min.NOTE 2Typically, 99.9+ % pure nitrogen, helium, or argon isemployed. Use of dry purge gas is recommended and is essential foroperation at subambient temperatures.7.1.2 Temperature Controller, capable of executing a spe-cific temperature progra
39、m by operating the furnace(s) betweenselected temperature limits, that is, 170 to 870 K, at a rate oftemperature change of up to 10 K/min constant to 60.1 K/min.7.1.3 Recording Device, capable of recording and display-ing any fraction of the heat flow signal (DSC curve), includingthe signal noise, o
40、n the Y-axis versus temperature on theX-axis.7.2 Containers (pans, crucibles, vials, etc.), that are inert tothe specimen and reference materials, and which are of suitablestructural shape and integrity to contain the specimen andreference in accordance with the specific requirements of thispractice
41、.7.3 While not required, the user will find useful calculator orcomputer and data analysis software to perform the necessaryleast squares best fit or multiple linear regression data treat-ments required by this practice.7.4 Balance, to weigh specimens, or containers, or both, to610 g with a capacity
42、 of at least 100 mg.8. Hazards8.1 This practice uses equipment that alters a materialsstate that may create noxious gases that may be harmful. Careshall be taken to provide adequate ventilation for all equipmentcapable of producing this effect.9. Sampling, Test Specimens, and Test Units9.1 Material
43、tested shall be as commercially supplied by themanufacturer.9.2 Materials such as, but not limited to, sealants, putties,coatings, sprays, mortars and foams, which are normallyshipped and dispensed at the time and place of final use froman air-tight or near air-tight container, shall be cast, formed
44、,sprayed or otherwise applied as they normally would to createa sample of thickness which is considered by the test sponsorand laboratory to represent a typical field installation. Thesample shall be allowed to cure or dry before testing. Curing ordrying time shall be in accordance with manufacturer
45、s pub-lished instructions for the product.9.3 Inhomogeneous materials.9.3.1 Due to the possibility that a milligram-sized samplemight not include one or more constituents of an inhomoge-neous material, multiple samples shall be taken and tested so asto ensure that the kinetic data (Arrhennius coeffi
46、cients) of allconstituents of the material have been measured.NOTE 3It is not intended that samples should be prepared and testedthat would test each individual component as a pure material. The intentis that sufficient samples should be tested that each component hasappeared in at least one test.9.
47、4 The samples to be used for DSC testing shall be excisedfrom the material prepared as specified in 9.2.10. Procedure10.1 DSC testing shall be conducted on three samplesprepared as specified in Section 9. The two tests and subse-quent data analysis shall be as described inTest Method E2041,with exce
48、ptions as described in 10.1.1 and 10.1.2.10.1.1 In one test, the sample shall be in an open containerthat is exposed to a pure dry air atmosphere.10.1.2 In one test, the sample shall be in an open containerthat is exposed to an airflow that is saturated with water.NOTE 4Test Method E2041 specifies t
49、hat a sample to be tested byDSC is to be contained within a hermetically sealed container. The twoindependent tests specified here place the sample in an open container,each of which is exposed to a different atmospheric condition. These twoconditions represent extremes of environmental conditions that a firestopproduct might be exposed to during its design life: very dry air, and veryhumid air.11. Calculation or Interpretation of Results11.1 For each DSC test conducted, the conversion rate ofthe material shall be calculated for the following two time andtemperature co
