© ISO 2016 Rubber or plastics coated fabrics — Determination of tensile strength and elongation at break Supports textiles revêtus de caoutchouc ou de plastique — Détermination de la force de rupture[.]
INTERNATIONAL STANDARD ISO 1421 Third edition 2016-12-01 Rubber- or plastics-coated fabrics — Determination of tensile strength and elongation at break Supports textiles revêtus de caoutchouc ou de plastique — Détermination de la force de rupture et de l’allongement la rupture Reference number ISO 1421:2016(E) I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n © ISO 2016 ISO 1421:2016(E) COPYRIGHT PROTECTED DOCUMENT © ISO 2016, Published in Switzerland All rights reserved Unless otherwise specified, no part o f this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission Permission can be requested from either ISO at the address below or ISO’s member body in the country o f the requester ISO copyright o ffice Ch de Blandonnet • CP 401 CH-1214 Vernier, Geneva, Switzerland Tel +41 22 749 01 11 Fax +41 22 749 09 47 copyright@iso.org www.iso.org ii I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n ISO 1421:2016(E) Contents Page Foreword iv Scope Normative references Terms and definitions Principle 5 Apparatus and reagents Atmosphere for conditioning and testing 6.1 6.2 For conditioning For testing 8.1 8.2 Sampling and preparation of test pieces Procedure 8.2.1 Mounting the test piece in place 8.2.2 Operation 8.2.3 Slippage 8.2.4 Jaw breaks and the breaks outside the reference marks 8.2.5 Test on wet test pieces Calculation and expression of results 10 Test report 10 Time-interval between manufacture and testing Method 1: Strip test method 8.3 8.4 Method 2: Grab test method 10 9.1 9.2 9.3 9.4 Sampling and preparation of test pieces 10 Procedure 11 9.2.1 Mounting the test piece in place 11 9.2.2 Operation 11 9.2.3 Slippage 11 9.2.4 Jaw breaks 11 9.2.5 Test on wet test pieces 11 Calculation and expression of results 13 Test report 13 © ISO 2016 – All rights reserved I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n iii ISO 1421:2016(E) Foreword I SO (the I nternational O rganiz ation for Standardiz ation) is a worldwide federation of national s tandards bodies (ISO member bodies) The work o f preparing International Standards is normally carried out through ISO technical committees Each member body interested in a subject for which a technical committee has b een es tablished has the right to b e represented on that committee I nternational organi zation s , governmental and non-governmental, in liaison with I SO, al so take p ar t in the work ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters o f elec trotechnical s tandardi z ation T he procedures used to develop this cument and those intended for its fur ther maintenance are describ ed in the I SO/I E C D irec tives , Par t I n p ar ticu lar the different approval criteria needed for the di fferent types o f ISO documents should be noted This document was dra fted in accordance with the editorial ru les of the I SO/I E C D irec tives , Par t (see www iso org/direc tives) Attention is drawn to the possibility that some o f the elements o f this document may be the subject o f patent rights ISO shall not be held responsible for identi fying any or all such patent rights Details o f any patent rights identified during the development o f the document will be in the Introduction and/or on the I SO l is t of p atent declarations received (see www iso org/p atents) Any trade name used in this document is in formation given for the convenience o f users and does not cons titute an endors ement For an explanation on the meaning o f ISO specific terms and expressions related to formity assessment, as well as information about I SO ’s adherence to the World Trade O rganization ( WTO) principles in the Technical B arriers to Trade (TB T ) see the following URL: www.iso.org/iso/foreword html T he committee res p ons ible for this cument is I SO/ TC 45 , Products (other than hoses) SC 4, Rubber and rubber products, Sub committee This third edition cancels and replaces the second edition (ISO 1421:1998), which has been technically revised T he changes are as fol lows — I n C lause , gauge length and reference p oints have b een added and Figures , , and have b een — T he title of C lause has b een changed — C laus e moved to clari fy the definitions has been subdivided in two subclauses and conditions have been clarified respectively by re ferring to the particulars specified in ISO 2231:1989 — A new clause has been added to speci fy the time-interval between manu facture and testing — I n , two narrower widths of 10 mm and mm have b een added for tes t piece and the pre-tens ion orces have been revised accordingly The procedure for the test pieces with re ference mark has f b een incorp orated — iv In 8.2 , the procedure for handling abnormal test results has been modified I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n INTERNATIONAL STANDARD ISO 1421:2016(E) Rubber- or plastics-coated fabrics — Determination of tensile strength and elongation at break WARNING — Persons using this International Standard should be familiar with normal laboratory practice This International Standard does not purport to address all of the safety problems, if any, associated with its use It is the responsibility of the user to establish appropriate safety and health practices and to ensure compliance with any national regulatory conditions Scope T h i s I nternationa l Sta nda rd s p e c i fie s two me tho d s for the de term i nation o f the ten s i le s treng th o f fabrics coated with rubber or plastics — Method — the strip test method, which is a method for the determination of tensile strength and elongation at break — M e tho d — the grab te s t me tho d, wh ich i s a me tho d for the de term i nation o f ten s i le s treng th on ly T he me tho d s apply to te s t pie ce s i n e qu i l ibrium with s p e c i fic s ta ndard atmo s phere s for te s ti ng a nd to wet test pieces Both methods require the use of a constant rate of extension (CRE) tensile-testing machine Normative references T he fol lowi ng i nd i s p en s able c u ments , i n whole or i n p ar t, are normatively re ference d i n th i s c u ment a nd are for its appl ic ation For date d re ference s , on ly the e d ition cite d appl ie s For u ndate d re ference s , the late s t e d ition o f the re ference d c u ment (i nclud i ng any amend ments) appl ie s ISO 2231:1989, Rubber- or plastics-coated fabrics — Standard atmospheres for conditioning and testing ISO 2286-2, Rubber- or plastics-coated fabrics — Determination of roll characteristics — Part 2: Methods for determination of total mass per unit area, mass per unit area of coating and mass per unit area of substrate ISO 7500-1, Metallic materials — Calibration and verification of static uniaxial testing machines — Part 1: Tension/compression testing machines — Calibration and verification of the force-measuring system Terms and definitions For the pu r p o s e s o f th i s c u ment, the fol lowi ng term s and defi n ition s apply 3.1 constant rate of extension CRE means of conducting a tensile test in which the rate of increase in the length of the test piece is uniform with time N o te to entr y: T he rate o f i nc re a s e o f the © ISO 2016 – All rights reserved I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n force i s dep endent up on the e x ten s ion ch a rac ter i s tic s o f the te s t p ie ce ISO 1421:2016(E) 3.2 elongation extension E increase in length of a test piece N o te to entr y: I t i s e x pre s s e d i n u n its o f leng th , e g c m o r m m 3.3 elongation at break elongation (3.2) of a test piece corresponding to the force at the breaking point N o te to entr y: S e e Figure I t i s u s u a l l y e xpre s s e d a s a p ercentage o f the nominal gauge length (3.9) Y Key X elongation, E Y force maximum force force at break elongation at maximum force elongation at break Figure — Tensile force at break 3.4 elongation at maximum force elongation (3.2 ) o f a te s t pie ce pro duce d by the ma xi mu m N o te to entr y: S e e I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n Figure 1, Figure and Figure force ISO 1421:2016(E) Y Key X Y elongation, E force maximum force elongation at maximum force Figure — Maximum force at break 3.5 force at break tensile force recorded at the moment of break Figure Figure N o te to entr y: S e e N o te to entr y: examples are: cor re s p ond s to the r up tu re o f o ne o f the elements s tituti ng the co ate d fab r ic: a “r igid” p o l ymer l ayer on a n e x ten s ib le b) a ver y e x ten s ib le , th ick p o l ymer l ayer on a we a k, le s s e x ten s ib le © ISO 2016 – All rights reserved I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n Typic a l r up tu re o f the p ol ymer l ayer; a) fabric or of the nonwoven fabr ic fab r ic or nonwo ven: r up tu re o f the woven ISO 1421:2016(E) Y Key X elongation, E Y force maximum force elongation at maximum force rupture of one element Figure — Rupture of one element of a coated fabric 3.6 gauge length length at a test piece prior to the addition of the pre-tension loaded, measured either from nip to nip of the j aws o f the hold i ng cl amp s or b e twe en the reference points (3.11) 3.7 grab test ten s i le s treng th te s t i n wh ich on ly the centra l p ar t o f the width o f the te s t pie ce i s gripp e d i n the j aws 3.8 maximum force maximum force recorded in extending the test piece to breaking point N o te to entr y: S e e Figure 1, Figure and Figure 3.9 nominal gauge length leng th o f a te s t pie ce u nder a s p e c i fie d pre -ten s ion, me as u re d either from nip to n ip o f the j aws o f the holding clamps with the clamps or between the reference points (3.11) in their starting position 3.10 percentage elongation elongation (3.2) expressed as a percentage of the nominal gauge length (3.9) 3.11 reference points two marks wh ich are u s ua l ly l i ne s p erp end ic u l arly acro s s the width o f 10 m m ap ar t marke d on the s u r face o f a te s t pie ce e qu id i s ta ntly I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n from the m idd le p oi nt ISO 1421:2016(E) 3.12 strip test tensile strength test in which the full width o f the test piece is gripped in the jaws Principle A test piece is extended at a constant rate of extension until it breaks For Method (see Clause 8), the maximum force and the elongation at maximum force and, if required, the force at break and the elongation at break are determined For Method (see Clause 9), only the maximum force is determined Apparatus and reagents 5.1 Constant rate of extension (CRE) tensile testing machine, having the following general characteristics The machine shall be provided with means for reading and recording both the force applied to the test piece in stretching it to the breaking point and the corresponding extension of the test piece It shall be provided with a strength indicator having several scales in order to ensure that the rupture of each test piece is obtained with a strength of 15 % to 85 % of the maximum of the scale used Under conditions of use, the accuracy o f the apparatus shall be class as defined in ISO 7500-1 The error o f the indicated or recorded maximum force at any point in the range in which the machine is used shall not exceed ±1 %, and the error o f the indicated or recorded jaw separation shall not exceed mm A fter the first s o f the test, the rate of increase in the distance between the clamps shall be uniform to within % If the orce and elongation are recorded by means o f data acquisition boards and so ftware, the frequency o f data collection shall be at least s−1 f 5.2 Clamping device, with the central point o f the two jaws o f the machine in the line o f pull, the ront edges at right angles to the line o f pull and their clamping faces in the same plane The jaws shall be capable o f holding the test piece without allowing it to slip They shall be designed so that they not damage the test piece or reduce its strength Smooth, flat or engraved corrugated jaws can be used for clamping Using suitable packing materials in the jaws, e.g paper, leather, plastics or rubber, avoids di fficulties in clamping in many cases f When tests are carried out and the test pieces either break at the jaws or tend to slip, the results may o ften be discarded In order to obtain legitimate results by avoiding jaw breaks and the e ffect o f slippage, the use o f capstan jaws or any other sel f-locking device can be a suitable alternative to ordinary flat jaws When in formation on strain is required, elongation measurements are made by means of an extensometer which follows the movements of two reference points on the test piece The use o f such jaws and an extensometer shall be reported in the test report; see 9.4 h) For the strip test method, the jaws shall be not less than the width o f the test piece and should pre ferably have a width of at least 60 mm For the grab test method, the dimensions o f one o f the jaws o f each clamp shall be 25 mm ± 0,5 mm by 25 mm ± 0,5 mm The other jaw o f each clamp shall be at least as wide as the one to which it is attached and should pre ferably be 50 mm wide 5.3 Equipment for cutting test pieces and fraying them down to the required width 5.4 Equipment in which the test pieces can be immersed in water prior to wet testing 5.5 Distilled or deionized water, for wetting out the test pieces 5.6 Wetting agent or surfactant © ISO 2016 – All rights reserved I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n ISO 1421:2016(E) Atmosphere for conditioning and testing 6.1 For conditioning The atmosphere shall be the method o f conditioning “1” specified in ISO 2231:1989 For fabrics coated on one side only, a minimum o f 16 h exposure is recommended For fabrics co ated on b oth s ides , a m inimum of h is recom mended 6.2 For testing The atmosphere shall be selected from A to E as specified in ISO 2231:1989 I f it is necessary to control both temperature and humidity, select the atmosphere from A to C NOTE The temperature 23 °C is normally the testing atmosphere in temperate countries and 27 °C is normally in tropical and subtropical countries Time-interval between manufacture and testing For al l tes t purp oses , the minimum time b etween manufac ture and tes ting shal l b e 16 h For nonpro duc t tes ts , the ma ximum time b etween manufac ture and tes ting shal l be weeks , and for evaluations intended to b e comp arable, the tes ts , as far as p os s ible, shal l b e carried out after the s ame time-inter val For pro duc ts , un les s other wise agreed b etween the interes ted p ar ties , the time b etween manufac ture and tes ting shal l not exceed months Method 1: Strip test method 8.1 Sampling and preparation of test pieces From each s ample, cut two sets of tes t pieces , one set in the longitudinal direc tion and the other in the transverse direction Each set shall consist o f not less than five test pieces I f, by agreement between the interes ted p ar ties , a higher degree of precis ion is required, tes t more tes t pieces S elec t the tes t pieces from the ful l us able width and length of the s ample in accordance with I SO 2 -2 An example o f how test pieces may be cut out is given in Figure Each test piece shall be 10 mm ± 0,5 mm, 30 mm ± 0,5 mm or 50 mm ± 0,5 mm wide and o f su fficient length to allow a distance o f 200 mm ± mm between the jaws o f the test machine I f the elongation exceeds 75 %, reduce the distance to 100 mm ± mm When a re ference mark is applied, the distance between the re ference points shall be 100 mm ± mm and the distance between the jaws shall be 150 mm ± mm or 200 mm ± mm The length o f the parts o f test piece clamped in the jaws is not less than the width of the tes t piece I f there is a woven s upp or t, take a wider s trip and reduce the width to 50 mm ± 0,5 mm by fraying, i f possible Should fraying not be possible, cut the test pieces in the direction o f testing as exactly as possible along a thread I f it is not possible to cut exactly along a thread because o f distortion o f the threads or the presence o f an invis ible s upp or t, use another tes t method, for example, Metho d I f there is a knitted support, cut the test pieces to their final dimensions by following a wale or course I f it is not p os s ible to cut a s uitable tes t piece b ecause of dis tor tion of the threads or the presence of an invis ible s upp or t, use another tes t metho d, for example, Method I f there is a nonwoven s upp or t s uch as felt, cut rec tangu lar tes t pieces in the longitudinal and trans verse directions with tidy edges I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n ISO 1421:2016(E) When it is required to determine the properties of wet material, immerse the test pieces for 24 h in water (5.5), or water containing no more than 0,1 % wetting agent or surfactant (5.6), of about 20 times the to ta l volume o f the te s t pie ce s at the ro om temp erature I m me d i ately a fter remova l from the water, ri n s e thorough ly i n water and pro ce e d to te s t with i n m i n 8.2 Procedure 8.2.1 Mounting the test piece in place 8.2.1.1 General S e t the j aws o f the te s t mach i ne 0 m m ± m m ap ar t, m m ± m m or 10 m m ± m m ap ar t i f more appropri ate C lamp a te s t pie ce i n the s tationar y j aws s o that its longitud i na l a xi s p a s s e s th rough the centre o f the front e dge o f e ach j aw Test pieces can be mounted under pre-tension or in the slack condition When test pieces are mounted under pre-tension, check that the pre-tension does not produce an elongation greater than % If these conditions cannot be met, mount the test piece in the slack condition © ISO 2016 – All rights reserved I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n ISO 1421:2016(E) L1 T1 L2 L3 T2 1 T3 T4 L4 L5 T5 Key L test pieces cut in the longitudinal direction T test pieces cut in the transverse direction selvedge usable width width length about m Figure — Example showing how test pieces may be cut out I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n ISO 1421:2016(E) 8.2.1.2 Pre-tension setting Apply the appropriate pre-tension from the values given in Table Table — Pre-tension force of each test piece width Mass of the test piece Less than 200 g/m2 Equal to or more than 200 g/m2 and less than 500 g/m Equal to or more than 500 g/m2 8.2.1.3 Test piece width 10 mm 30 mm 50 mm 0,4 N 1,0 N 2,0 N 1,2 N 3,0 N 6,0 N 2,0 N 5,0 N 10,0 N Slack mounting When test pieces are mounted in the slack condition, the starting point of the curve corresponds to the required pre-tension force Add the corresponding elongation to the gauge length and use it as the nominal gauge length Table — Pre-tension force of slack condition Test piece width Pre-tension 8.2.2 10 mm 0,1 N 30 mm 0,3 N 50 mm 0,5 N Operation Engage any device for reading the breaking strength and elongation Set the moving clamp in motion at a constant rate o f 100 mm/min ± 10 mm/min, unless otherwise agreed between the interested parties, and extend the test piece to the breaking point Repeat the procedure for each test piece 8.2.3 Slippage Disregard any test results where the test piece slips asymmetrically or slips by more than mm, or record them in the report when they are use ful in formation When results are discarded, repeat the test on a replacement test piece taken, if practicable, from the same part of the sample as the discarded test piece 8.2.4 Jaw breaks and the breaks outside the reference marks Disregard any test results where the test piece breaks within mm o f the face o f a jaw or outside the re ference marks on the test piece (outside the test length o f 100 mm) When the results are judged to be useful information at the user’s discretion, record them in the test report When results are discarded, repeat the test on a replacement test piece taken, if practicable, from the same part of the sample as the discarded test piece I f, in spite o f taking care, all breaks are within mm o f the face o f a jaw or outside the re ference marks, use Method 8.2.5 Test on wet test pieces Remove the test piece from the water (see 8.1 , last paragraph), press it lightly between two sheets of blotting paper and immediately carry out the test as described in 8.2.1 to 8.2.4, except that, for the wet test, apply hal f the normal pre-tension © ISO 2016 – All rights reserved I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n ISO 1421:2016(E) 8.3 Calculation and expression of results Record the maximum force and the force at break (this has to be recorded to ascertain whether it d i ffers from the ma xi mu m force or no t) for e ach o f the five te s t pie ce s i n b o th the longitud i na l a nd the transverse directions and calculate the mean value of the maximum force and the mean value of the force at break in each direction Round both the mean maximum force and the mean force at break to the ne are s t N or to % o f the c a lc u l ate d va lue C a lc u late the co e fficient o f vari ation i n e ach c a s e and, i f re qu i re d, the fidence l i m its o f the me an Record, to the nearest mm, the elongation at maximum force (and, if different, the elongation at break) o f e ach o f the five te s t pie ce s i n e ach d i re c tion E xpre s s the elongation at ma xi mum at break values as a percentage elongation (see 3.10) force a nd elongation Calculate the mean values of the elongation at maximum force and elongation at break Round these mean values to the nearest 0,2 % when the mean elongation does not exceed %, to the nearest 0,5 % when it i s % to % a nd to the ne a re s t % when it i s gre ater th an % C a lc u l ate the co e fficient o f variation i n e ach c as e a nd, i f re qui re d, the fidence l i m its o f the me a n 8.4 Test report The test report shall include the following particulars: a) a re ference to th i s I nternationa l Standard, i e I S O 142 ; b) the me tho d u s e d (M e tho d : Strip te s t me tho d) ; c) the s ampl i ng s cheme u s e d; d) the nu mb er o f te s t pie ce s te s te d e) the cond ition i ng a nd te s t atmo s phere u s e d; f) the gauge leng th and the way i n wh ich the te s t pie ce s were mou nte d ( pre -ten s ion or s lack) ; g) the s tate o f the te s t pie ce s (cond itione d or we t) and the ti me o f cond ition i ng or i m mers ion; h) the typ e o f ten s i le te s ti ng mach i ne u s e d a nd its lo ad c ap ac ity; i) e ach s ample; the values of the maximum force and, if different, the force at break, for each test piece and the mean maximum force and force at break, in newtons, and the width of the test piece tested, for e ach s ample, vari ation j) from for for the longitud i na l a nd tra n s vers e d i re c tion s s ep arately, as wel l a s the co e fficient o f e ach force and e ach d i re c tion and , i f re qu i re d, the fidence l i m its o f the me an; the va lue s o f the elongation at ma xi mu m force and , i f d i fferent, the elongation at bre a k o f e ach test piece and the mean elongation at maximum force and elongation at break, in millimetres, for e ach s ample, for the longitud i na l a nd tra n s vers e d i re c tion s s ep arately, as wel l a s the co e fficient o f vari ation a nd, i f re qu i re d, the fidence l i m its o f the me a n; k) de tai l s o f any deviation l) the date of the test from the s p e ci fie d pro ce du re; Method 2: Grab test method 9.1 Sampling and preparation of test pieces From each sample, cut two sets of test pieces, one set in the longitudinal direction and the other in the tra n s vers e d i re c tion E ach s e t sha l l s i s t o f no t le s s th an five te s t pie ce s I f, b y agre ement b e twe en the interested parties, a higher degree of precision is required, test more test pieces 10 I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n ISO 1421:2016(E) Select the test pieces from the full usable width of the sample The width of each test piece shall be 10 m m ± m m a nd its leng th s l l no t b e le s s th an m m On each test piece, draw a line 37 mm from one of the long edges, parallel to the edge, along the full length of the test piece (see Figure 5) When it is required to determine the properties of wet material, immerse the test pieces for 24 h in water (5.5), or water containing no more than 0,1 % wetting agent or surfactant (5.6), of about 20 times the to ta l volume o f the te s t pie ce s at the ro om temp erature I m me d i ately a fter remova l from the water, ri n s e thorough ly i n water and pro ce e d to te s t with i n m i n 9.2 Procedure 9.2.1 Mounting the test piece in place S e t the j aws o f the te s t mach i ne either 10 m m ± m m or 75 m m ± m m ap ar t, b y agre ement b e twe en the i ntere s te d p ar tie s C lamp a te s t pie ce i n the s tationa r y j aws ( th rough the centre o f the front 5.2) so that its longitudinal axis passes Figure 5) f e dge o f e ach j aw and i s p erp end ic u lar to the e dge s o f the j aws , and s o that the l i ne d rawn on the te s t pie ce coi ncide s with the appropriate e dge o 9.2.2 e ach j aw (s e e Operation E ngage any device for re ad i ng the ma xi mum force S e t the movi ng cla mp i n mo tion at a s ta nt rate o f 10 m m/m i n ± 10 m m/m i n, u n le s s o ther wi s e agre e d b e twe en the i ntere s te d p ar tie s , and e xtend the test piece to the breaking point Repeat the procedure for each test piece 9.2.3 Slippage D i s c ard the te s t re s u lts where the te s t pie ce s l ip s a s ym me tric a l ly or s l ip s b y more th an m m Re cord the te s t re s u lts i n the rep or t when they a re j udge d to b e u s e fu l i n formation at the u s er ’s d i s cre tion When results are discarded, repeat the test on a replacement test piece taken, if practicable, from the same part of the sample as the discarded test piece 9.2.4 Jaw breaks D i s c ard the te s t re s u lts where the te s t pie ce bre a ks with i n m m o f the face o f a j aw Re cord the te s t re s u lts i n the te s t rep or t when they are j udge d to b e u s e fu l i n formation at the u s er ’s d i s c re tion When results are discarded, repeat the test on a replacement test piece taken, if practicable, from the same part of the sample as the discarded test piece 9.2.5 Test on wet test pieces Remove the test piece from the water (see 9.1 , la s t p aragraph) , pre s s it l ightly b e twe en two s he e ts o f blo tti ng p ap er a nd i m me d iately c arr y out the te s t as de s crib e d i n © ISO 2016 – All rights reserved I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n 9.2.1 to 9.2.4 11 ISO 1421:2016(E) Key ≥1 mm 100 mm 37 mm 25 mm 100 mm or 75 mm top j aw bottom j aw Figure — Test piece for grab test method 12 I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n ISO 1421:2016(E) 9.3 Calculation and expression of results Re cord the ma xi mu m force for e ach o f the five te s t pie ce s i n b o th the longitud i na l a nd the tran s vers e directions and calculate the mean value in each direction Round the mean maximum force to the ne a re s t N or to % o f the c a lc u l ate d va lue C a lc u late the co e fficient o f vari ation a nd, i f re qu i re d, the fidence l i m its o f the me a n 9.4 Test report The test report shall include the following particulars: a) a re ference to th i s I nternationa l Sta nda rd , i e I S O 142 ; b) the me tho d u s e d (Me tho d : Grab te s t me tho d) ; c) the s ampl i ng s cheme u s e d; d) the nu mb er o f te s t pie ce s te s te d e) the cond ition i ng and te s t atmo s phere u s e d; f) the gauge leng th; g) the s tate o f the te s t pie ce s (cond itione d or we t) a nd the ti me o f cond itioni ng or i m mers ion; h) the typ e o f ten s i le te s ti ng mach i ne u s e d and its lo ad c ap acity; from e ach s ample; i) the values of the maximum force for each test piece and the mean maximum force, in newtons, for e ach s a mple, for the longitud i na l and tran s vers e d i re c tion s s ep a rately, a s wel l as the co e fficient o f va riation a nd , i f re qu i re d, the fidence l i m its o f the me an; j) de ta i l s o f a ny deviation from the s p e c i fie d pro ce dure; k) the date of the test © ISO 2016 – All rights reserved I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n 13 ISO 42 : 01 6(E) ICS 9.080.40 Price based on 13 pages © ISO 2016 – All rights reserved I n tern ati o n al Org an i z ati o n fo r S tan d ard i z ati o n