【AS澳大利亚标准】AS 2512.5.1-2008 Methods of testing protective helmets Method 5.1 Determination of strength of retention system—Static strength.doc

accessed by university of south australia on 06 mar 2008as/nzs 2512.5.1:20081 as/nzs 2512.5.1:2008australian/new zealand standardtmmethods of testing protective helmetsmethod 5.1: determination of strength of retention systemstatic strengthprefacethis standard was prepared by the joint standards australia/standards new zealand committee cs-097, testing of helmets and visors, to supersede as/nzs 2512.5.1:1998, methods of testing protective helmets, method 5.1: determination of strength of retention systemstatic strength.the objective of this revision is to refine the testing procedure.method1 scopethis standard sets out a method for determining the static strength of the retention system of a protective helmet. the method applies to each individual component of a system in which the components can be independently fastened without securing the complete assembly.2 referenced documentsthe following document is referred to in this standard: as/nzs2512methods of testing protective helmets2512.1method 1: definitions and headforms2512.2method 2: general requirements for the conditioning and preparation of test specimens and laboratory conditions3 definitionsfor the purpose of this standard, the definitions given in as/nzs 2512.1 apply.4 principlewith the helmet positioned on a fixed headform, a static tensile force is applied to the retention system. the elongation of the retention system is then measured.note: the value obtained for the elongation of the retention system is not intended to include any reading due to the compression of any impact-attenuating material (e.g. the crushable liner) or due to the elongation caused by the helmet rotating on the headform.copyrightas/nzs 2512.5.1:2008accessed by university of south australia on 06 mar 2008the standard is downloaded from standard sharing5 apparatusthe apparatus shall include a loading device with a chin stirrup which consists of(a) two parallel, freely rotating rollers each having a diameter of 12.7 1.0 mm, which are separated 75.0 1.5 mm centre-to-centre; and(b) a test headform of the dimensions and design specified in as/nzs 2512.1. typical apparatus is shown in figure 1.helmet test headform stand for test retention syste mloading device s cale weight (or oil pressure may be used) figure 1 typical apparatus for retention system test6 procedurethe procedure shall be as follows:(a) condition and prepare the helmet(s) in accordance with as/nzs 2512.2. (b)ensure the laboratory conditions are as specified in as/nzs 2512.2.(c) position the helmet on the headform in accordance with as/nzs 2512.2 and do up the retaining strap to leave approximately 30 mm of webbing through the buckle.note: where a securing buckle lies at a corner of the loading device and such position is likely to cause failure of the test, it is permissible to re-position the buckle away from the corner.(d) gradually apply an increasing load to the retention system of the magnitude and duration specified in the product standard. the force shall be applied normally to the basic plane of the test headform and symmetrical with respect to the mid-sagittal plane.(e) gradually apply an additional test load to the retention system of the magnitude specified in the product standard, and then maintain this load for the duration specified in the product standard. the force shall be applied normally to the basic plane of the mid-sagittal plane.note: the application of the preliminary and additional load is intended to be gradual such that each load does not induce a jolt or shock on the retention system.(f) measure the increase in deflection of the loading device.copyrightaccessed by university of south australia on 06 mar 20083 as/nzs 2512.5.1:20087 test reportthe test report shall include the following: (a)identity of helmet under test.(b) details of the headform.(c) whether or not the retention system consists of components which can be independently fastened without securing the complete assembly.(d) elongation caused by the test load.(e) whether or not the retention system separated from its points of attachment either to the helmet or to other components.(f) reference to this australian/new zealand standard, i.e. as/nzs 2512.5.1.as/nzs 2512.5.1:2008this australian/new zealand standard was prepared by joint technical committee cs-097, testing of helmets and visors. it was approved on behalf of the council of standards australia on 5 july 2007 and on behalf of the council of standards new zealand on26 october 2007 and published on 5 february 2008.the following are represented on committee cs-097: brain foundationcertification interests (australia)consumers federation of australiaiea national panelbiomechanics of injuryland transport safety authority new zealandnational association of testing authorities australianational injury surveillancenew zealand employers and manufacturers associationnew zealand helmet testing interestsroads and traffic authority of nswtestsafe australiathe university of new south waleskeeping standards up-to-datestandards are living documents which reflect progress in science, technology and systems. to maintain their currency, all standards areperiodically reviewed, and new editions are published. between editions, amendments may be issued. standards may also be withdrawn. itis important that readers assure themselves they are using a current standard, which should include any amendments which may have beenpublished since the standard was purchased.detailed information about joint australian/new zealand standards can be found by visiting the standards web shop at .au or standards new zealand web site at www.standards.co.nz and looking up the relevant standard in the on-line catalogue.alternatively, both organizations publish an annual printed catalogue with full details of all current standards. for more frequent listings or notification of revisions, amendments and withdrawals, standards australia and standards new zealand offer a number of update options. for information about these services, users should contact their respective national standards organization.we also welcome suggestions for the improvement in our standards, and especially encourage readers to notify us immediately of any apparent inaccuracies or ambiguities. please address your comments to the chief executive of either standards australia international or standards new zealand at the address shown on the back cover.originated as part of as 2512.51981. previous edition as/nzs 2512.5.1:1998. seco