1、BS 8479:2008Textiles Method for determination of propensity of fabrics to snagging Rotating chamber methodICS 59.080.01NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBRITISH STANDARDPublishing and copyright informationThe BSI copyright notice displayed in this document indicat
2、es when the document was last issued. BSI 2008ISBN 978 0 580 56168 9The following BSI references relate to the work on this standard:Committee reference TCI/24Draft for comment 07/30142621 DCPublication historyFirst published November 2008Amendments issued since publicationAmd. no. Date Text affecte
3、dBS 8479:2008 BSI 2008 iBS 8479:2008ContentsForeword iiIntroduction 11 Scope 12 Normative references 13 Terms and definitions 14 Principle 25 Apparatus 26 Preparation of test specimen tubes 57 Pre-treatment of fabric 78 Conditioning of fabric 79 Preparation of test specimens 710 Procedure 811 Assess
4、ment 812 Test report 10AnnexesAnnex A (informative) Example of the location of test specimens on a length of fabric supplied for test 12Annex B (informative) Recommendations for periodic cleaning, and for verification, of the test chamber 13Bibliography 14List of figuresFigure 1 Test chamber 4Figure
5、 2 Covering of test specimen tubes with felt 6Figure A.1 Example of the location of test specimens 12List of tablesTable 1 Grading system 9Table 2 Classification system for surface defects 9Summary of pagesThis document comprises a front cover, an inside front cover, pages i and ii, pages 1 to 14, a
6、n inside back cover and a back cover.BS 8479:2008ii BSI 2008ForewordPublishing informationThis British Standard is published by BSI and came into effect on 3 2008. It was prepared by Technical Committee TCI/24, Physical testing of textiles. A list of organizations represented on this committee can b
7、e obtained on request to its secretary.Information about this documentThis standard gives a method of test which uses a rotating chamber containing snagging pins to measure the propensity of fabric test samples to snagging. Another procedure for this test which uses external snagging pins attached t
8、o a “mace” is under development. It is envisaged that this procedure will be added to the standard in a future revision.Use of this documentIt has been assumed in the preparation of this British Standard that the execution of its provisions will be entrusted to appropriately qualified and experience
9、d people, for whose use it has been produced.Presentational conventionsThe provisions of this standard are presented in roman (i.e. upright) type. Its methods are expressed as a set of instructions, a description, or in sentences in which the principal auxiliary verb is “shall”.Commentary, explanati
10、on and general informative material is presented in smaller italic type, and does not constitute a normative element.Contractual and legal considerationsThis publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Complian
11、ce with a British Standard cannot confer immunity from legal obligations.0 November BSI 2008 1BS 8479:2008IntroductionSnagging is a phenomenon in which undesirable loops of varying sizes appear on the surface of a garment, usually as a result of the fabric catching on sharp points or objects. Fabric
12、s made of filament yarns, both textured and untextured, are most prone to snagging. However, certain fabrics made of spun staple yarns, and certain fabric structures e.g. satin and sateens, can also be prone to snagging. It is important to be able to measure the propensity of fabrics to snagging so
13、that fabrics with the lowest propensity to snagging can be selected for making garments.1 ScopeThis British Standard gives a method for determining the propensity of fabrics to snagging, and related surface defects. The standard is applicable to knitted and to woven fabrics.2 Normative referencesThe
14、 following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.BS 3870-1, Stitches and seams Part 1: Classification
15、and terminology of stitch typesBS EN ISO 139, Textiles Standard atmospheres for conditioning and testingBS EN ISO 12947-1, Textiles Determination of the abrasion resistance of fabrics by the Martindale method Part 1: Martindale abrasion testing apparatus3 Terms and definitionsFor the purposes of thi
16、s British Standard the following terms and definitions apply.3.1 snagundesirable loop on the surface of a woven or knitted fabricNOTE Snags can be of various sizes and are usually the result of the fabric catching on sharp points or objects.3.2 protrusionpartially formed snag3.3 filamentationfibrous
17、 or hairy appearance on the surface of a fabric due to broken yarn filaments3.4 pulled threadthread in a fabric that is tighter than the threads adjacent to itBS 8479:20082 BSI 20083.5 shinerthread that is more lustrous (and generally tighter) than the threads adjacent to itNOTE Shiners most commonl
18、y occur in fabrics made of continuous filament yarn. They often occur as a result of snagging, as this causes the yarn to be pulled.3.6 indentationconcave distortion of the surface of a fabric4 PrincipleSpecimens of the fabric under test are mounted on felt-covered polyurethane tubes and tumbled ran
19、domly in a test chamber rotating at a constant speed, the inside of which is fitted with rows of pointed pins. The specimens are then examined for the presence of snags and other surface defects.5 Apparatus5.1 Test chamber, the inner surface of which has a regular octagonal cross-section, closed at
20、one end and with an openable flap at the other (see Note), as illustrated in Figure 1, with an internal diameter between opposite parallel faces of (224.5 0.3) mm and a depth of (228.0 0.1) mm.NOTE The opening should be sufficiently large to permit access to the inside of the chamber for cleaning.Th
21、e inner surface shall be made of a non-absorbent material, such as stainless steel or polypropylene, that is known to be resistant to degradation by generally available cleaning materials. It shall not have any surface finish, such as paint or varnish, that might be abraded during the tests.The inne
22、r surface, including both ends, shall be smooth and free from defects.The chamber shall be fitted with, or to, a device which is able to rotate the chamber about its horizontal axis at a constant speed of (60 2) r/min.The chamber shall be fitted with four lines of inward pointing pins made of metal
23、with a minimum harness value of 58 Rockwell (C scale). Each pin shall have a nominal diameter of (1.0 0.1) mm. The top (1.5 0.1) mm of each pin shall be tapered to a sharp point. The point shall be free from hooks and burrs. Pins with rounded ends shall not be used. The lines of pins shall run paral
24、lel to the long axis of the chamber and shall be evenly spaced round the inner circumference of the chamber. The pins shall either be fitted to a series of bars which are recessed into the chamber wall, or be fixed directly into the chamber wall. The holes into which the pins are secured shall be bl
25、ind so that the pins cannot be forced down into the bar or the chamber wall during the test, thus altering their height. BSI 2008 3BS 8479:2008The length of each pin protruding into the chamber, i.e. the length from the tip of the pin to the point at the centre of the pin which is level with the sur
26、face of the bar or chamber wall see Figure 1c) shall be (5.0 0.3) mm. The pins shall be inclined at an angle of 60 0.5 to the wall of the chamber in the direction of rotation of the chamber. There shall be 20 pins in each line, spaced (10.0 0.5) mm apart.5.2 Temperature and humidity controlled room,
27、 in which the atmosphere conforms to the standard atmosphere specified in BS EN ISO 139.5.3 Four polyurethane tubes, (70 1) mm long, inside diameter (25 1) mm and wall thickness (3 0.5) mm see Figure 2a).5.4 Four pieces of woven wool felt, conforming to BS EN ISO 12947-1, each piece (70 0.5) mm (110
28、 0.5) mm.5.5 Double sided adhesive tape, with adhesion properties sufficient to hold the felt onto the tubes.5.6 Polyurethane or rubber based adhesive.5.7 Locking rings, for placing inside the ends of the polyurethane tubes to secure the test specimens during the test procedure, comprising lengths o
29、f natural black rubber strip, or similar material, of Shore hardness 50, (88.5 0.5) mm long, (25.0 0.5) mm wide and (2.5 0.5) mm thick. 5.8 Lockstitch sewing machine, capable of producing lockstitch type 301 as detailed in BS 3870-1, and fitted with a needle and polyester thread suitable for sewing
30、the fabric under test.NOTE A medium ballpoint needle (size Nm 90, designated in accordance with ISO 8239:1987) and 470 dtex polyester corespun thread (ticket number 75 or 80 as designated in accordance with BS 4134:1990) are recommended. A preliminary test should be carried out with a double layer o
31、f the fabric under test to determine whether this needle and thread can sew the fabric without causing damage or distortion. If damage or distortion occurs, different needles and threads should be tried until a suitable combination is found.5.9 Specimen template, comprising a flat piece of rigid mat
32、erial, e.g. acrylic sheet, (140 0.5) mm (140 0.5) mm, approximately 2 mm thick.5.10 Viewing cabinet, with a matt black surface, fitted with a light source comprising a white fluorescent tube or bulb arranged so as to give uniform illumination over the width of the test specimen and masked in such a
33、way that the observer does not look directly into the light when viewing the test specimen. The light source shall be positioned such that the light strikes the test specimen at an angle of between 5 and 15 to the plane of the test specimen.NOTE The colour temperature of the light source is not crit
34、ical.5.11 Assessment mask, comprising a flat piece of rigid material, e.g. PVC sheet, with a matt black surface, (140 0.5) mm (120 0.5) mm with an oblong aperture (110 0.5) mm (70 0.5) mm.5.12 Steel rule or gauge, for measuring the length of snags on the test specimens.BS 8479:20084 BSI 20085.13 Sti
35、ff brush, for cleaning fibrous debris off the pins.5.14 Vacuum cleaning device, for removing dust and debris from the inside of the chamber.Figure 1 Test chamberDimensions in millimetresKey1 Test chamber2 Pin bars3 Pins4 Device for rotating the test chambera) Sectional view of test chamber10.0 0.532
36、4212228.0 0.1224.5 0.3 BSI 2008 5BS 8479:20086 Preparation of test specimen tubesCut a piece of the double sided adhesive tape (5.5) long enough to wrap around one of the polyurethane tubes (5.3) to give a single layer over the whole surface, excluding the rounded edges at the ends of the tube. Cove
37、r the tube with the tape as shown in Figure 2b).Wrap a piece of felt (5.4) around the tube over the adhesive tape, with the shorter sides of the felt parallel to the long axis of the tube. Press the felt firmly onto the tube so that it sticks securely to the adhesive tape. Apply a layer of adhesive
38、(5.6) to each of the shorter sides of the felt, butt them together and hold them firmly in place until they are stuck see Figure 2c).Figure 1 Test chamber (continued)Key1 Pin bar2 Pinsb) Isometric view of a pin barLinear dimensions in millimetresKey1 Surface of pin bar2 Pin3 Pointed end of pin4 Flat
39、 end of pin fitted into blind hole in pin barc) Detailed view of a pin2112345.0 0.31.50.160 51.00.1BS 8479:20086 BSI 2008Repeat this procedure with the remaining three tubes.If reusing tubes that have been used previously, check the condition of the felt and the tubes before each test. If the felt h
40、as lifted away from the tube, if the join has parted, or if the felt is soiled or damaged, remove the felt and re-cover the tube with a new piece of felt. If the exposed ends of any of the tubes have cracked, discard them and use new tubes.Condition the felt covered tubes in the standard atmosphere
41、(see 5.2) for a minimum of 16 h, and keep them in the standard atmosphere until needed for the test.Figure 2 Covering of test specimen tubes with feltDimensions in millimetresa) Test specimen tubeKey1 Double sided adhesive tapeb) Test specimen tube covered with double sided adhesive tapeKey1 Felt2 S
42、hort ends of felt butted together and gluedc) Test specimen tube covered with felt25 13 0.570 1112 BSI 2008 7BS 8479:20087 Pre-treatment of fabricUnless otherwise agreed between the interested parties, the fabric shall be tested as received. If washing or cleaning of the fabric prior to testing is a
43、greed, this shall be carried out as agreed between the interested parties, and the details shall be recorded in the test report.8 Conditioning of fabricCondition the roll of fabric, swatch or sample length supplied for testing, in the standard atmosphere (see 5.2) for a minimum of 4 h prior to prepa
44、ration of the test specimens.9 Preparation of test specimens9.1 Using the specimen template (5.9) cut four test specimens (140 0.5) mm (140 0.5) mm from the roll, swatch or length of fabric submitted for testing, ensuring that where there are different length or width yarns in the fabric these are a
45、ll represented in each test specimen.9.2 If the fabric has a pattern, all areas of the pattern shall be included in the test specimens. If it is not possible to include all areas in the four test specimens specified in 9.1 then one or more additional sets of four test specimens shall be prepared in
46、accordance with 9.1.NOTE An example of positioning of test specimens on a length of fabric is given in Annex A.9.3 Fold each test specimen in half, with the upper or outer surface of the fabric to the inside. Fold two test specimens with the fold running parallel to the warp, or the length direction
47、, and the other two with the fold running parallel to the weft, or the width direction. Using the lockstitch sewing machine (5.8) sew a seam along the long raw edges of each test specimen to produce an open ended tube of fabric. NOTE It is important that the tube of fabric fits onto the test specime
48、n tube in such a way that the fabric is not so loose that it can wrinkle, or so tight that it distorts the test specimen tube. To ensure this, it is recommended that the seam is sewn 8 mm from the edge for woven fabrics and 9 mmto 10 mm from the edge for knitted fabrics. However, for some fabrics a
49、different seam position might be needed, depending on the fabric structure. It is recommended that some extra test specimens are used in a preliminary evaluation to determine the best position for the seam for the particular fabric being tested.9.4 Turn each test specimen so the outer or upper face of the fabric is on the outside.9.5 Fit each test specimen onto a test specimen tube by carefully sliding it, by hand, over the felt coveri
