1、Designation: F1952 15 An American National StandardStandard Specification forHelmets Used for Downhill Mountain Bicycle Racing1This standard is issued under the fixed designation F1952; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisio
2、n, 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 specification covers performance requirements forhelmets used by downhill mountain bicycle riders.
3、 Studieshave shown higher risk to the head and face for this sport ascompared to recreational street riding; hence, this specificationrequires greater impact protection and provides performancecriteria for chin bars on full-face helmets, but does not requirefull-face helmets. This specification reco
4、gnizes the desirabilityof lightweight construction and ventilation; however, it is aperformance specification and is not intended to restrict design.1.2 All testing and requirements of this specification shallbe in accordance with Test Methods F1446, except where notedherein.1.3 Partial utilization
5、of this standard is prohibited. Anystatement of compliance with this specification must be acertification that the product meets all of the requirements ofthis specification in its entirety. A product that fails to meet anyone of the requirements of this specification is considered tohave failed thi
6、s standard, and should not be sold with anyindication that it meets parts of this standard.1.4 Headgear designed to comply with this and otherstandards may proclaim uses as certified by the manufacturer.1.5 The values stated in SI units are to be regarded asstandard. No other units of measurement ar
7、e included in thisstandard.1.6 The following safety caveat applies to the chemical,mechanical, or physical, or a combination thereof, test methodsdescribed herein and is meant specifically for those performingthe tests (in an effort to provide them with notice to take theappropriate precautions when
8、 conducting the tests): This stan-dard does not purport to address all of the safety concerns, ifany, associated with its use. It is the responsibility of the userof this standard to establish appropriate safety and healthpractices and determine the applicability of regulatory limita-tions prior to
9、use.2. Referenced Documents2.1 ASTM Standards:2F1446 Test Methods for Equipment and Procedures Used inEvaluating the Performance Characteristics of ProtectiveHeadgear3. Labels and Warnings3.1 Shall meet the requirements of Test Methods F1446.3.2 Shall have the words “For downhill mountain bicyclerac
10、ing.”4. Marking the Test Line4.1 The test line is shown in Fig. 1 and shall be marked inaccordance with Test Methods F1446.5. Conditioning and Number of Samples5.1 Conditioning of the samples to be tested shall be inaccordance with the section entitled “Conditioning Environ-ments” in Test Methods F1
11、446.5.2 For helmets with a chin bar, five sample helmets arerequired for each shell-liner size combination.5.3 For helmets without a chin bar, four sample helmets arerequired for each shell-liner size combination.6. Retention System Testing6.1 Retention system tests shall be performed before impactt
12、esting.6.2 The ambient helmet shall be subjected to the positionalstability (roll-off) test in accordance with Test Methods F1446using a 4-kg drop mass from a height of 0.6 m.6.3 The hot, cold, and wet helmets shall be subjected to thedynamic strength retention test in accordance with Test Meth-ods
13、F1446 using a 4-kg drop mass from a height of 0.6 m.6.4 The retention system shall remain intact without elon-gating more than 30 mm.1This specification is under the jurisdiction of ASTM Committee F08 on SportsEquipment, Playing Surfaces, and Facilities and is the direct responsibility ofSubcommitte
14、e F08.53 on Headgear and Helmets.Current edition approved May 15, 2015. Published June 2015. Originallyapproved in 1999. Last previous edition approved in 2010 as F1952 10. DOI:10.1520/F1952-15.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at s
15、erviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States17. Impact Sites and Projections7.1 Impact sites are d
16、escribed in Test Methods F1446.7.2 ProjectionsAny unfaired projection extending morethan 7 mm from the helmets outer surface shall break away orcollapse when impacted with forces equivalent to those pro-duced by applicable impact-attenuation tests described inSection 9.HEADFORM DIMENSIONSIZE X L/2 Y
17、 R S T UA 24.0 88.0 89.7 47.5 23.0 142.0 84.0C 25.0 91.0 92.7 48.0 23.5 146.5 86.0E 26.0 94.5 96.0 49.0 24.0 151.0 88.0J 27.5 101.0 102.5 50.5 25.0 160.0 92.0M 29.0 106.0 107.0 52.0 27.0 166.0 96.0O 30.0 108.5 110.0 53.0 27.0 170.0 97.0FIG. 1 Marking the Test LineF1952 1527.2.1 There shall be no fix
18、ture on the helmets inner surfaceprojecting more than 2 mm into the helmet interior exceptoccipital stabilizers and foam fit pads.8. Impacting Schedule8.1 All impacting shall be performed in accordance withTest Methods F1446, using the variable mass drop assemblyconfiguration.8.2 Helmets shall be im
19、pacted with the anvils centered on orabove the test line described in Fig. 1.8.3 The test anvils can be oriented in any horizontal,centered position.8.4 For full face helmets with a chin bar, a fifth ambienthelmet shall be tested in accordance with Section 10.9. Impact Testing9.1 Retention system te
20、sting shall be completed prior toimpact testing.9.2 The helmet can be impacted such that the theoreticalcenter of impact described in Test Methods F1446 is anywhereon or above the test line with the curbstone anvil in anyhorizontal orientation.9.3 Anvils to be used are the flat, hemispherical, andcu
21、rbstone anvils in Test Methods F1446.9.4 The helmet shall be dropped onto the flat anvil toachieve an impact velocity of 6.2 m/s 6 3 % (corresponding toa theoretical drop height of 2.0 m).9.5 The helmet shall be dropped onto the hemispherical andcurbstone anvils to achieve an impact velocity of 5.6
22、m/s 63 % (corresponding to a theoretical drop height of 1.6 m).9.6 Each helmet shall be given two flat anvil impacts andone each hemispherical and curbstone anvil impact in anysequence.9.7 The theorretical center of each impact site shall beseparated from the theoretical center of other impact sites
23、 by aminimum of 120 mm.9.8 The peak acceleration of each impact shall not exceed300 g.10. Chin Bar Rigidity Test10.1 The chin bar rigidity test applies to helmets with a chinbar only.10.2 If a chin bar is present, it shall be tested in accordancewith the procedures in Test Methods F1446, Chin Bar Ri
24、gidityTest, with an impact velocity of 2.8 m/s 6 5 % (correspondingto a theoretical drop height of 0.4 m), using a fifth ambientsample that has not been subjected to any other impact testing.The maximum deflection of the chin bar shall not exceed60 mm.11. Keywords11.1 bicycle; downhill; helmets; mou
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