This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: C920 − 18
Standard Specification for
Elastomeric Joint Sealants1 This standard is issued under the fixed designation C920; the number immediately following the designation indicates the year of original origin al adoption or, in the case of revis revision, ion, the year of last revision. revision. A number in paren parenthese thesess indicates the year of last reappr reapproval. oval. A superscript epsilon (´) indicates an editorial change since the last revision or reapproval. This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Sco Scope pe
C717 Terminology of Building Seals and Sealants C717 Terminology C719 T C719 Test est Met Method hod for Adhesio Adhesion n and Coh Cohesio esion n of Elas Elastotomeric Joint Sealants Under Cyclic Movement (Hockman Cycle) C793 Test C793 Test Met Method hod for Ef Effec fects ts of Lab Labora orator tory y Acc Acceler elerated ated Weather eathering ing on Elastom Elastomeric eric Joint Sealan Sealants ts C794 T C794 Test est Method for Adhesion-in-Peel of Elastomeric Joint Sealants C1183 Te C1183 Test st Method for Extrusion Rate of Elastomeric Sealants C1193 Guide C1193 Guide for Use of Joint Sealants C1246 T C1246 Test est Meth Method od for Ef Effec fects ts of Heat Aging Aging on Weig eight ht Loss, Los s, Crac Crackin king, g, and Cha Chalki lking ng of Ela Elasto stomer meric ic Sea Sealant lantss After Cure C1247 Test Method for Durability of Sealants Exposed to C1247 Continuous Immersion in Liquids C1442 Pra Practic cticee for Con Conduc ductin ting g Test estss on Seal Sealant antss Usi Using ng Artificial Weathering Apparatus
1.1 This ASTM spe specifi cificati cation on cov covers ers the pro proper perties ties of a cured single- or multicomponent cold-applied elastomeric joint sealan sea lantt fo forr sea sealin ling, g, cau caulki lking ng,, or gla glazin zing g op opera eratio tions ns on buildings, plazas, and decks for vehicular or pedestrian use, and typ types es of con constr structi uction on oth other er tha than n hig highwa hway y and air airfield field pavements paveme nts and bridg bridges. es. 1.2 A sealant sealant meeting the requirements requirements of this specifi specification cation shall be designated by the manufacturer to be one or more of the types, classes, grades, and uses defined in Section 7. 1.3 The values values stated in SI uni units ts are to be reg regard arded ed as the standard. The values given in parentheses are for information only. 1.4 This standard standard is similar, but not identical, identical, to ISO 11600 and ISO 11618. 1.5 This int intern ernati ationa onall sta standa ndard rd was dev develo eloped ped in acc accor or-dance with internationally recognized principles on standardizatio iza tion n es esta tabl blis ishe hed d in th thee De Decis cisio ion n on Pr Prin incip ciple less fo forr th thee Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
3. Terminology 3.1 Definitions—Refer to Terminology C717 Terminology C717 for for definitions of the fol follow lowing ing term termss use used d in thi thiss spe specifi cificati cation: on: adh adhesi esive ve failure, caulking, chemically curing sealant, cohesive failure, cure, cured, elastomeric, glazing, joint, primer, seal, sealant, and standard conditions.
2. Referenc Referenced ed Documents Documents 2.1 ASTM Standards:2 C510 Test C510 Test Method for Staining and Color Change of Singleor Multicomponent Joint Sealants C639 Test Met Method hod for Rhe Rheolo ologica gicall (Fl (Flow) ow) Pro Proper perties ties of Elastomeric Sealants C661 Test C661 Test Method for Indentation Hardness of ElastomericType Sealants by Means of a Durometer C679 Test C679 Test Method for Tack-Free Time of Elastomeric Sealants
4. Class Classifica ification tion of Sealants 4.1 A seal sealant ant qua qualify lifying ing und under er this specificat specification ion sha shall ll be classified as to type, grade, class, and use as follows: 4.1.1 Type S— A single-component sealant. 4.1.2 Type M— A multicomponent sealant. 4.1.3 Grade P— A pourable or selfleveling sealant that has sufficient flow to form a smooth, level surface when applied in a horizontal joint at 4.4°C (40°F). 4.1.4 Grade NS— A nonsag or gunnable sealant that permits application in joints on vertical surfaces without sagging or slumping when applied at temperatures between 4.4 and 50°C (40 and 122°F). 4.1.5 Class 100/50— A sealan sealantt that when tested for adhesion adhesion and cohesion under cyclic movement ( (8.8 8.8)) shall withstand an increase of at least 100 % and a decrease of at least 50 % of the joint width as measured at the time of application, and, in addition, meet all the requirements of this specification.
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This specification specification is under the juris jurisdictio diction n of ASTM Committee C24 on Building Seals and Sealants and is the direct responsibility of Subcommittee C24.10 on Specifications, Guides and Practices. Current Curre nt editio edition n approv approved ed Jan. 1, 2018. Published Published Janua January ry 2018. Originally Originally approved in 1979. Last previous edition approved in 2014 as C920 – 14a. DOI: 10.1520/C0920-18. 2 For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at
[email protected]. For Annual Book of ASTM Standards volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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C920 − 18 4.1.6 Class 50— A sealant that when when tested for adhesion adhesion and cohesi coh esion on und under er cyc cyclic lic mov movemen ementt (8.8 8.8)) sh shal alll wi with thsta stand nd an increase and decrease of at least 50 % of the joint width as measured at the time of application, and, in addition, meet all the requirements of this specification. 4.1.7 Class 35— A sealant that when when tested for adhesion adhesion and cohesi coh esion on und under er cyc cyclic lic mov movemen ementt (8.8 8.8)) sh shal alll wi with thsta stand nd an increase and decrease of at least 35 % of the joint width as measured at the time of application, and, in addition, meet all the requirements of this specification. 4.1.8 Class 25— A sealant that when when tested for adhesion adhesion and cohesi coh esion on und under er cyc cyclic lic mov movemen ementt (8.8 8.8)) sh shal alll wi with thsta stand nd an increase and decrease of at least 25 % of the joint width as measured at the time of application, and, in addition, meet all the requirements of this specification. 4.1.9 Class 121 ⁄ 2 — A sealant that when tested for adhesion and cohesion under cyclic movement (8.8 ( 8.8)) shall withstand an increase and decrease of at least 121 ⁄ 2 % of the joint width as measured at the time of application, and, in addition, meet all the requirements of this specification. Use T 1 — A se 4.1.10 Use seala alant nt de desig signe ned d fo forr us usee in jo join ints ts in pedestrian and vehicular traffic areas such as walkways, plazas, decks and parking garages where a higher durometer sealant is desired. 4.1.11 Use seala alant nt de desi sign gned ed fo forr us usee in jo join ints ts in Use T 2 — A se pedestrian and vehicular traffic areas such as walkways, plazas, decks and parking garages where a lower durometer sealant is desired.
shall be uniform and of a consistency suitable for immediate application by hand or pressure caulking gun, or by hand tool. The sealant when completely cured shall form an elastomeric solid capable of maintaining a seal. 6. General Requirements Requirements 6.1 Shelf-life— The The shelf-life of this sealant shall be determined by its manufacturer. When establishing the shelf-life, the manufa man ufactu cturer rer sho should uld also ide identi ntify fy acce accepta ptable ble con condit dition ionss of storage for the sealant. 6.2 Color— The The color of the sealant, after curing 14 days in a lab labora orator tory y con contro trolled lled at stan standar dard d con condit dition ions, s, sha shall ll be that color which has been agreed upon between the purchaser and the supplier. 6.3 The sealant shall shall be intended for use only on clean, clean, dry surfaces. Where a primer is recommended by a manufacturer for a specific surface, all tests on that surface shall include the primer. NOTE 2—The 2—The pro proper per use of pri primer merss (or sur surfac facee con condit dition ioners ers)) in connection with the applica connection application tion of sealan sealants ts is descr described ibed in detail in Guide C1193.. This guide also describes proper methods for joint design, back-up C1193 materials, mater ials, surface prepa preparation ration,, toolin tooling g of sealan sealant, t, and other important procedures proced ures in sealan sealantt applic application ation in build buildings. ings.
6.4 The same conditions conditions of time, temperature, and humidity humidity shall be used for cure of test specimens for Test Methods C661 C661,, C719,, C794 C719 C794,, and and C1247 C1247.. 7. Signi Significanc ficancee and Use
NOTE 1—Hardness alone does not correlate with joint performance. The joints in pedestrian and vehicular traff traffic ic areas such as walkways, plazas, decks, and parki parking ng garage garagess requir requiree approp appropriate riate design consi considerati derations ons including material selection, total joint design, manufacturer involvement and field testing.
7.1 This specification specification covers several several classifications classifications of sealantss as des ant descri cribed bed in Sec Section tion 4 for var variou iouss app applica lication tions. s. It should be recognized by the purchaser or design professional that not all sealants meeting this specification are suitable for all applications applications and all substr substrates. ates. It is essential, therefore, therefore, that the applicable type, grade, class, and use be specified so that the proper classification of sealant is provided for the intended use.. Test met use method hodss rel relate ate to spe special cial stan standar dard d spe specime cimen n sub sub-strates str ates of mor mortar tar,, gla glass, ss, and alu alumin minum. um. If test testss are req requir uired ed using substrates in addition to or other than the standard, they should be so specified for testing.
Use NT NT— — A se 4.1.12 Use seala alant nt de desi sign gned ed fo forr us usee in jo join ints ts in nontraffic areas. 4.1.13 Use I— A sealant designed designed for use in joints which are submerged continuously in a liquid. 4.1.14 Use M— A sealant that meets the requirements requirements of this specification when tested on mortar specimens in accordance with 9.9 with 9.9 and 9.10. 9.10 . 4.1.15 Use G— A sealant that meets the requirements requirements of this specific spe cificatio ation n whe when n tes tested ted on glas glasss spe specim cimens ens in acc accord ordanc ancee with 9.9 with 9.9 – 9.11. 9.11. 4.1.16 Use A— A sealant that meets this specification when tested test ed on alu alumin minum um spe specim cimens ens in acco accorda rdance nce with with 9.9 and 9.10.. 9.10 4.1.17 Use O— A sealant that meets this specification when tested tes ted on su subs bstr trate atess ot othe herr th than an th thee sta stand ndar ard d su subs bstr trate atess in accordance with 9.9 with 9.9 and 9.10. 9.10.
8. Physical Requirements Requirements 8.1 Rheological Properties: 8.1.1 Grade P (pourable (pourable or selflev selfleveling) eling) sealant sealant shall have flow characteristics such that when tested in accordance with Test Method Method C639 it sha shall ll exh exhibit ibit a smo smooth oth,, lev level el sur surfac face. e. (Refer to Types I and III in the test.) 8.1.2 8.1 .2 Gra Grade de NS (no (nonsa nsag) g) or gun gunnab nable le sea sealant lant shall hav havee flow characteristics such that when tested in accordance with Test Method C639 Method C639 it it does not sag more than 4.8 mm ( 3 ⁄ 16 16 in.) in ve vert rtic ical al di disp splac lacem emen ent. t. Als Also o th thee se seala alant nt sh shall all sh show ow no deformation in horizontal displacement. (Refer to Types II and IV in the test.)
5. Mate Material rialss and Manufacture Manufacture 5.1 A single-comp single-component onent sealant shall be a uniform mixture of a consistency suitable for immediate application by hand or pres pr essu sure re ca caul ulki king ng gu gun n or by ha hand nd to tool ol.. Th Thee sea sealan lantt wh when en completely cured shall form an elastomeric solid capable of maintaining a seal.
8.2 Extrusion Rate: 8.2.1 8.2 .1 Type Type S (si (singl nglee com compon ponent ent), ), Gra Grade de P (po (poura urable ble or selfleveling) sealant shall have an extrusion rate of not less than 10mL/min when tested in accordance with Test Method C1183 Method C1183,, Procedure A.
5.2 A mul multico ticompo mponen nentt che chemica mically lly cur curing ing sea sealan lantt sha shall ll be furnished in two or more components. The resulting mixture 2
C920 − 18 8.2.2 Type S (si 8.2.2 (singl nglee com compon ponent ent), ), Gra Grade de NS (no (nonsa nsag g or gunnable sealant) shall have an extrusion rate of not less than 10 mL mL/m /min in wh when en tes tested ted in acc accor orda danc ncee wi with th Tes estt Me Meth thod od C1183,, Procedure A. C1183
8.10.1 Exposure Apparatus— The The exposure apparatus shall be one of the three types of laboratory accelerated weathering devices described in Practice C1442 Practice C1442,, that use either xenon arc, fluores fluo rescen centt UV or ope open n flam flamee car carbon bon arc rad radiati iation. on. Con Consul sultt Practice C1442 Practice C1442 for for the differences in test parameters among the devices. Because of differences in test conditions, test results may differ with the type of device used. The choice of device shall be by mutual agreement among the interested parties. 8.10 8. 10.1 .1.1 .1 When When pe peel el ad adhe hesi sion on is to be te test sted ed on gl glas asss substrate subst rate specim specimens ens after ultraviolet exposure throu through gh glass, place the specimens in the weathering device with the sealant surface facing away from the light source after 21 days of cure at laboratory conditions. Test conditions in each type of device are in accordance with the procedures in C1442 C1442,, Section 7 on Apparatus, except that the xenon arc and open flame carbon arc devices shall be operated without the water spray. Expose the specimens for 200 h and then continue with 7 days of water immersion.
8.3 Application Life: 8.3.1 8.3 .1 Type Type M (mu (multic lticomp ompone onent) nt),, Gra Grade de P (po (poura urable ble or selfleve selfl evelin ling) g) seal sealant ant,, whe when n tes tested ted in acco accorda rdance nce wit with h Test Method C1183 Method C1183,, Proce Procedure dure A shall be extrudable extrudable at a rate of not not less than 10 mL/min 3 h after mixing. 8.4 Hardness: 8.4.1 8.4 .1 Use T1 (traffic) sealant shall have a hardness reading, after being properly cured, of not less than 25 when tested in accordance with Test Method C661 C661.. 8.4.2 8.4 .2 Use T2 (traffic) sealant shall have a hardness reading, after af ter be bein ing g pr prop oper erly ly cu cure red, d, of les lesss th than an 25 wh when en tes tested ted in accordance with Test Method C661 C661.. 8.4.3 8.4 .3 Use NT (no (nontr ntraf afffic) seal sealant ant sha shall ll hav havee a har hardne dness ss reading, after being properly cured, of less than 60 when tested in accordance with Test Method C661 C661..
NOTE 4—Although the xenon arc irradiance setting of 0.35 W/(m2·nm) at 340 mm is acceptable, Practice C1442 Practice C1442 specifies specifies 0.51 W/(m2·nm) at 340 mm as the pre prefer ferred red set settin ting. g. To acc accomm ommoda odate te tes testin ting g in xen xenon on arc weathering weath ering devices that cannot use the higher irradi irradiance ance setting, 0.35 W/(m2·nm) at 340 nm may be used if the length of the total exposure time is increased to provide the equivalent radiant exposure received at 0.51 W/(m2·nm) at 340 nm for 200 h exposure. See Annex A1 in Practice C1442 for C1442 for determining the exposure time.
8.5 Effects of Heat Aging— The The sealant shall not lose more than 7 % of its or than orig igin inal al we weig ight ht or sh show ow an any y cr crack ackin ing g or chalking when tested in accordance with Test Method C1246 C1246.. 8.6 Tack-Free T heree sh shal alll be no tr tran ansf sfer er of th thee Tack-Free Time— Ther sealan seal antt to th thee po poly lyet ethy hyle lene ne fil film m wh when en te test sted ed at 72 h in accordance with Test Method C679 C679..
8.10.2 Immedi 8.10.2 Immediately ately following the weather weathering ing cycle, completely immerse the specimen in distilled or deionized water for 7 days. Mortar specimens are placed in a separate container from the glass and aluminum specimens, because the highly alkali conditions generated could have an effect on the glass and aluminum.
8.7 Stain and Color Change— The The sealant shall not cause any visible stain on the top surface of a white cement mortar base when tested in accordance with Test Method C510 Method C510.. 8.8 Adhesion and Cohesion Under Cyclic Movement— The The total loss in bond and cohesion areas among the three specimens tested for each surface shall be no more than 9 cm 2 (11 ⁄ 2 in.2) when tested in accordance with Test Method C719 C719 with standard mortar, glass, and aluminum or any other specified substrates.
8.11 Effects of Accelerated Weathering— The The sealant shall show no cracks greater than those shown in Example #2 of Fig. 1 in Test Method C793 Method C793 after after the specifi specified ed ultrav ultraviolet iolet exposure and shall show no cracks greater than those shown in Example #2 of Fig Fig.. 2 in Test Test Me Meth thod od C793 after after exp exposu osure re at col cold d temperature and the bend test when tested in accordance with Test Method C793 Method C793..
8.9 Adhesion-in-Peel— The The peel strength for each individual test te st sh shal alll no nott be le less ss th than an 22 22.2 .2 N (5 lb lbf) f) wh when en te test sted ed in accorda acco rdance nce wit with h Test Meth Method od C794 with stand standard ard morta mortar, r, glass gl ass,, an and d alu alumin minum um or an any y ot othe herr sp speci ecifie fied d su subs bstr trate ate.. In addition, the sealant shall show no more than 25 % adhesive bond loss for each individual test.
8.12 Effects of Continuous Immersion for Use I Sealants: 8.12.1 Class 1— After After 6 weeks exposure, the total loss in bond and cohesion areas among the specimens tested for each substrate shall be no greater than 9.5 cm 2 (1.5 in.2) when tested accor acc ordin ding g to Test Met Metho hod d C1247 with sta stand ndard ard gla glass, ss, aluminum, or any other substrate specified. 8.12.2 Class 2— After After 10 weeks exposure, the total loss in bond and cohesion areas among the specimens tested for each substrate shall be no greater than 9.5 cm 2 (1.5 in.2) when tested accor acc ordin ding g to Test Met Metho hod d C1247 with sta stand ndard ard gla glass, ss, aluminum, or any other substrate specified.
NOTE 3—Curing conditions are specified by all of the test methods cited. The manufacturer may request other conditions than those specified for the curing period provided they meet the following requirements: (1) the curing period shall extend for 21 days; (2) the temperature temperature during the curing period shall not exceed 50°C (122°F); and (3) the amend amended ed curing conditions recommended by the manufacturer shall also be applied to the durability, adhesion in peel, and ultraviolet radiation exposure tests.
Adhesion-i n-in-P n-Peel eel for Use G Exp Expose osed d to Ultr Ultravi aviole olet t 8.10 Adhesio The peel str streng ength th for each ind indii Exposure Through Glass— The vidu vi dual al tes testt sh shall all not ha have ve le less ss th than an 22 22.2 .2 N (5 lbf) and th thee compound shall be no more than 25 % adhesive bond loss for each eac h in indi divi vidu dual al te test st wh when en tes teste ted d in acc accor orda danc ncee wi with th Tes estt Method C794 modified modified to inc includ ludee 200 h in an acc acceler elerated ated weathering device followed by 7 days immersion in distilled water.
9. Test Methods Methods 9.1 Standa All test testss Standard rd Cond Conditions itions for Labor Laboratory atory Tests— All described in the following paragraphs shall be performed in a laborato labo ratory ry con control trolled led at stan standar dard d con conditi ditions ons.. The seal sealant ant sample shall be conditioned at standard conditions for at least 24 h before laboratory tests are made. 9.2 Rheological Properties— Test Test Method C639 Method C639.. 3
C920 − 18 9.3 Extrusion Rate— Test Test Method C1183 Method C1183,, Procedure A.
9.12 Effects Test Meth Method od Effects of Acce Accelera lerated ted Weath eatherin ering— g— Test C793.. C793
9.4 Application Life— Test Test Method C1183 Method C1183,, Procedure A. 9.5 Hardness— Test Test Method C661 Method C661..
Sealants nts Exp Expose osed d to Co Conti ntinu nuou ouss Im Immer mersio sion— n— Test 9.13 Seala Test Method C1247 Method C1247..
9.6 Effects of Heat Aging— Test Test Method C1246 Method C1246
10. Pack Packagin aging g and Marki Marking ng
9.7 Tack-Free Time— Test Test Method C679 Method C679..
10.1 Packag Packaged ed materials that are certified by the manufacturer to be in compliance with this specification shall be labeled as to type, class, grade, and use, in accordance with Section 7 7..
9.8 Stain and Color Change— Test Test Method C510 Method C510.. Adhesion and Cohesion After Cyclic Movement— Test 9.9 Adhesion Method C719 Method C719..
10.2 10. 2 All cer certific tificatio ation n to thi thiss spe specific cificatio ation n sha shall ll stat statee time time,, temperature, and humidity of cure used in the tests.
9.10 Adhesion-in-Peel— Test Test Method C794 Method C794..
11. Keywords
9.11 Adhesion-in-Peel After Ultraviolet Exposure Through Glass— Test Test Method C794 Method C794..
11.1 contin 11.1 continuous uous immersion; immersion; elastomeric elastomeric sealant sealants; s; joint sealants; sealant sealants; s; specific specification ation
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