SIST-TP CEN/TR 16149:2011
(Main)Guidance Document for drafting CEN/TC 158 Standards
Guidance Document for drafting CEN/TC 158 Standards
This document has been produced by the convenors of CEN/TC158 working groups. It is intended to serve as a guide, to be consulted when drafting new EN standards for head protection and when revising or amending existing ones.
Whilst implementation of its contents is not mandatory, working groups are urged not to make deviations from this guidance document without good cause.
This is a living document - omissions will be covered in later issues.
In this document, reference is made FprCEN/TR 16148, Head and neck impact, burn and noise injury criteria. This gives further guidance about the areas of the head which helmet standards should aim to protect, and about head and neck injuries.
The working group should assess the foreseeable risks against which the helmet should provide protection. Each of the helmet standards should provide for a helmet, which will offer optimum protection to the head against these foreseeable risks and should satisfy the Basic Health and Safety Requirements of EU Directive 89/686/EEC to the extent indicated in annex ZA of the helmet standard.
Helmet standards should indicate, in an informative annex, how the level of performance requirements specified relates to the severity of injury to be tolerated. Working groups should refer to FprCEN/TR 16148 when drafting this annex.
Reference is also made to EN 13087, Protective helmets, Test methods. This standard provides harmonized methods of test for many of the topics listed below. The various parts of EN 13087 are listed in the Bibliography.
Leitfaden für die Erarbeitung von Normen des CEN/TC 158
Üblicherweise enthält eine Helmnorm einen Abschnitt zu Anforderungen und einen Abschnitt zu Prüfungen.
1.1 Abschnitt zu Anforderungen
Es sollten immer mindestens die nachfolgend angegebenen Themengebiete angesprochen werden. Weitere Anforderungen, die hier nicht enthalten sind, sind vom Typ des Helms abhängig, für die die Norm geschrieben wird.
Die Auswahl der Leistungsanforderungen sollte auf dem Risiko für den Träger beruhen und seiner Fähigkeit, während des Helmtragens die auszuführenden Aufgaben zu erfüllen.
Es wird empfohlen, dass diese Kriterien in der Einleitung zur Helmnorm angegeben werden (und möglicherweise ebenfalls im Anwendungsbereich), damit die Risiken und Arbeitsaktivitäten, die die Norm umfassen soll, klargestellt sind. Es kann außerdem sinnvoll sein, den Verletzungsgrad anzugeben, der als tolerierbar betrachtet wird, wenn der Helm die Leistungsanforderungen erfüllt. Das muss vorsichtig formuliert werden – es darf weder der Eindruck entstehen, dass dadurch der Anwender von der Notwendigkeit befreit ist, seine eigene Risikobeurteilung vor der Auswahl/Verwendung eines Helms durchzuführen, noch sollte ausgeschlossen werden, dass der Helm wohlüberlegt außerhalb seines eigentlichen Anwendungsbereichs verwendet wird.
Die Stufe der Leistungsanforderung sollte auf dem Schweregrad der zu tolerierenden Verletzung beruhen. Für eine besondere Leitlinie zum entsprechenden Thema ist auf FprCEN/TR 16148 zu verweisen. Ist eine Leistungsanforderung vorhanden, muss auch ein entsprechendes Prüfverfahren vorliegen.
1.2 Abschnitt zu Prüfungen
Bevor eine Prüfung für eine besondere Anforderung festgelegt wird, ist zu überprüfen, ob ein entsprechender Teil von EN 13087 vorhanden ist. Ist das nicht der Fall oder wird EN 13087 von der Arbeitsgruppe nicht als geeignet empfunden, soll die Arbeitsgruppe ein Prüfverfahren erstellen und es in die Helmnorm aufnehmen.
Document directeur pour la rédaction des normes CEN/TC 158
En règle générale, une norme sur les casques de protection comprend un article relatif aux exigences et un article relatif aux essais.
1.1 Exigences
Il convient au minimum de toujours traiter les sujets énumérés ci-dessous. Les autres exigences, ne figurant pas dans le présent document, dépendent du type de casque auquel la norme est consacrée.
Il convient de décider du choix des exigences de performance en fonction du risque pour le porteur et de la capacité à réaliser les tâches à entreprendre en portant le casque.
Il est recommandé de spécifier ces critères dans l’introduction à la norme sur les casques de protection (et si possible également dans le Domaine d’application) afin de clarifier les risques et les activités entreprises que la norme est destinée à couvrir. Il peut également se révéler utile de spécifier le niveau de blessure considéré comme tolérable lorsque le casque satisfait à ses exigences de performance. Ceci doit être formulé avec soin – en effet il convient de ne pas suggérer de pouvoir remplacer la nécessité pour l’utilisateur de réaliser sa propre évaluation des risques avant de choisir/utiliser un casque, ni d’exclure l’utilisation prudente du casque en dehors de son domaine principal d’application.
Il convient de fonder le niveau des exigences de performance en fonction de la gravité des blessures tolérables. Se reporter au FprCEN/TR 16148 pour des recommandations spécifiques sur le sujet correspondant. L’existence d’une exigence de performance implique nécessairement une méthode d’essai correspondante.
1.2 Essais
Avant de spécifier un essai pour une exigence particulière, vérifier s’il n’existe pas une partie correspondante de l’EN 13087 applicable. Dans le cas contraire ou si la méthode de l’EN 13087 est considérée comme inappropriée par le WG (groupe de travail), il convient que le WG rédige une méthode d’essai et l’inclue dans la norme sur les casques de protection.
Navodilo za načrtovanje standardov CEN/TC 158
Ta dokument so izdelali sklicatelji CEN/TC158 delovnih skupin. Namenjen je uporabi kot vodilo, ki se upošteva pri pripravi novih standardov EN za varovanje glave in pri revidiranju in spreminjanju obstoječih.
Čeprav izvajanje njegove vsebine ni obvezno, so delovne skupine pozvane, da ne odstopajo od tega pisnega navodila brez dobrega razloga.
To je živ dokument - opustitve bodo zajete v poznejših izdajah.
V tem dokumentu je podano sklicevanje na FprCEN/TR 16148, Merila za določanje poškodbe glave in vratu, ki nastanejo zaradi udarca, opekline ali hrupa. To podaja nadaljnje vodilo o področjih glave, k varovanju katerih bi morali stremeti standardi o čeladah, in o poškodbah glave in vratu.
Delovna skupina mora oceniti predvidljiva tveganja, pred katerimi mora varovati čelada. Vsak izmed standardov o čeladah mora biti pripravljen za čelado, ki bo optimalno zaščitila glavo pred temi predvidljivimi tveganji, in izpolnjevati osnovne zdravstvene in varnostne zahteve evropske Direktive 89/686/EGS v obsegu, navedenem v dodatku standarda o čeladi ZA.
Standardi za čelade morajo v informativnemu dodatku navajati, kako se raven nekaterih zahtev po zmogljivosti nanaša na resnost poškodbe, ki se dopušča. Delovne skupine morajo pri pripravi tega dodatka upoštevati FprCEN/TR 16148.
Podano je tudi sklicevanje na EN 13087, Varovalne čelade, Preskusne metode. Ta standard določa usklajene metode preskušanja za številne teme, navedene v nadaljevanju. Različni deli EN 13087 so navedeni v bibliografiji.
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
SIST-TP CEN/TR 16149:2011
01-julij-2011
1DYRGLOR]DQDþUWRYDQMHVWDQGDUGRY&(17&
Guidance Document for drafting CEN/TC 158 Standards
Leitfaden für die Erarbeitung von Normen des CEN/TC 158
Document directeur pour la rédaction des normes CEN/TC 158
Ta slovenski standard je istoveten z: CEN/TR 16149:2011
ICS:
13.340.20 Varovalna oprema za glavo Head protective equipment
SIST-TP CEN/TR 16149:2011 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST-TP CEN/TR 16149:2011
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SIST-TP CEN/TR 16149:2011
TECHNICAL REPORT
CEN/TR 16149
RAPPORT TECHNIQUE
TECHNISCHER BERICHT
March 2011
ICS 13.340.20
English Version
Guidance Document for drafting CEN/TC 158 Standards
Document directeur pour la rédaction des normes CEN/TC Leitfaden für die Erarbeitung von Normen des CEN/TC 158
158
This Technical Report was approved by CEN on 27 December 2010. It has been drawn up by the Technical Committee CEN/TC 158.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2011 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 16149:2011: E
worldwide for CEN national Members.
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Contents Page
Foreword .4
Introduction .5
1 General .6
2 Type of injuries .6
3 Areas of coverage, areas to be protected and areas to be tested .6
4 Field of vision .7
5 Helmet sizes .8
6 Ventilation .8
7 Mass .8
8 Comfort .8
9 Skin irritation .9
10 Innocuousness of materials .9
11 Ignitability / Flame resistance .9
12 Corrosion .9
13 Combined and combination PPE and accessories .9
14 Compatibility with other headgear . 10
15 Compatibility with other PPE . 10
16 Shock absorption. 10
17 Rotational effects . 10
18 Penetration . 11
19 Crush and rigidity . 11
20 Retention system strength . 12
21 Retention system effectiveness . 12
22 Radiant heat . 13
23 Electrical and electrostatic properties . 13
24 Protection against molten metal . 14
25 Testing scheme . 14
26 Pre-conditioning . 15
27 Conditioning . 15
28 Pre-requisites for the testing . 15
29 Sizes of headforms . 15
30 Application of the uncertainty of measurement . 16
31 Marking and labelling . 16
32 Information to be supplied by the manufacturer for users . 17
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33 Life of helmet . 18
34 Terms and definitions . 18
35 Annex ZA of the PPE Directive . 19
Annex A (informative) Combined and combination PPE and accessories . 20
Annex B (informative) Application of uncertainty of measurement . 21
Bibliography . 23
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Foreword
This document (CEN/TR 16149:2011) has been prepared by Technical Committee CEN/TC 158 “Head
Protection”, the secretariat of which is held by BSI.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
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Introduction
This document has been produced by the convenors of CEN/TC158 working groups. It is intended to serve as
a guide, to be consulted when drafting new EN standards for head protection and when revising or amending
existing ones.
Whilst implementation of its contents is not mandatory, working groups are urged not to make deviations from
this guidance document without good cause.
This is a living document – omissions will be covered in later issues.
In this document, reference is made to CEN/TR 16148, Head and neck impact, burn and noise injury criteria
A Guide for CEN helmet standards committees. This gives further guidance about the areas of the head
which helmet standards should aim to protect, and about head and neck injuries.
The working group should assess the foreseeable risks against which the helmet should provide protection.
Each of the helmet standards should provide for a helmet, which will offer optimum protection to the head
against these foreseeable risks and should satisfy the Basic Health and Safety Requirements of EU Directive
89/686/EEC to the extent indicated in Annex ZA of the helmet standard.
Helmet standards should indicate, in an informative annex, how the level of performance requirements
specified relates to the severity of injury to be tolerated. Working groups should refer to CEN/TR 16148 when
drafting this annex.
Reference is also made to EN 13087 (all parts), Protective helmets Test methods. This standard provides
harmonized methods of test for many of the topics listed below. The various parts of EN 13087 are listed in
the Bibliography.
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1 General
Typically, a helmet standard will include a Requirements section and a Testing section.
1.1 Requirements section
The topics listed below should always be addressed, as a minimum. Other requirements, not included here,
will be dependent upon the type of helmet for which the standard is being written.
The choice of performance requirements should be based upon the risk to the wearer and the ability to
perform the tasks to be undertaken whilst wearing the helmet.
It is recommended that these criteria be stated in the introduction to the helmet standard (and possibly also in
the Scope) so that the risks and work activities that the standard intends to cover are made clear. It may also
be useful to state the injury level that is regarded as tolerable when the helmet meets its performance
requirements. This needs to be phrased with care – it should not suggest that it can replace the need for the
user to conduct their own risk assessment before choosing/using a helmet, nor should it exclude the helmet
from carefully considered use outside its primary field of use.
The level of performance requirement should be based upon the severity of injury to be tolerated. Refer to
CEN/TR 16148 for specific guidance on the relevant topic. If there is a performance requirement then there
must be a corresponding test method.
1.2 Testing section
Before specifying a test for a particular requirement, check to see if there is a relevant part of EN 13087. If
there is not, or if the EN 13087 method is not considered suitable by the WG, then the WG should write a test
method and include it in the helmet standard.
2 Type of injuries
This topic is covered in CEN/TR 16148.
3 Areas of coverage, areas to be protected and areas to be tested
The following three areas are variously mentioned in many helmet standards. For the purpose of this
document, they are defined and explained as follows.
1) ‘Area to be tested’ - the area /points on the helmet which will be subjected to a performance test (not
only a visual assessment). This area may include ventilation features.
2) ‘Area to be protected’ - the area/points on a head or headform for which protection is
intended/deemed to be provided by the helmet. This area should correspond to the parts of the head
that are intended to be protected from injury, as described at the end of this section.
The helmet standard should specify performance and, if necessary, constructional requirements for all areas
designated as areas to be protected. It is preferable for the ‘area to be protected’ to be entirely described by
the area to be tested, i.e. to be defined only by performance requirements.
However, if performance testing of some parts of the ‘area to be protected’ is deemed by the working group to
be too complex or difficult, then a constructional requirement may be used – e.g. specify a minimum thickness
of the shell or liner or both and that the shell or liner or both shall be of the same density and material as
within the test area. Such a constructional requirement should be carefully considered, and in particular the
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validity of the assumption, that a similar thickness of shell or liner or both at different points on the helmet will
afford similar impact performance at those different points, should be examined.
Therefore, the ‘area to be protected’ will include, but may extend beyond, the area to be tested by a
performance test, (1) above.
3) ‘Area of coverage’, ‘extent of coverage’ - the area/points on a head or headform which are intended
to be covered by the helmet; currently assessed visually in several helmet standards. These, and
similar, terms should not be used within helmet standards because they are not relevant to the
protective function of the helmet. They are subjective, cause confusion and lead to differences in
interpretation.
For each performance requirement (e.g. shock absorption, resistance to penetration, etc), the working group
should determine requirements for areas (1) and (2). These should be defined and assessed using the
appropriate test headform, specified in the helmet standard.
For example, EN 1078:1997 states specifically:
“4.4 Shock absorbing capacity
The helmet shall give protection to the forehead, rear, sides, temples and crown of the head.”
Standards should be no less descriptive than this example and should consider the need to be more
descriptive with reference to N551. For example, use of terms such as "temporal region", "parietal region" and
“occipital region" should be encouraged; if the Committee believes that this gives a more precise definition for
the purpose of protection. Furthermore, if one part of the head is deemed to be more vulnerable or more
susceptible to injury for a given dose (for example force, acceleration) then the committee should consider this
and prescribe different requirements for the different parts. For example it is known that an impact in the
temporal region is likely to be more in injurious than an equivalent impact to the occipital region. The
committee should be precise about the requirements for the area of protection if this is defined to be greater
than the test area. It is not sufficient simply to define an area of protection without defining the requirements
for that area.
As is noted in Clause 13 (and in sections W and X of Annex A), parts of the helmet (and accessories) may, or
may not, have a protective function. Where part of the helmet or an accessory is not designed to protect it
must not reduce the level of protection afforded by any other part of the helmet. In practice, this will often
mean that the helmet should be tested with the non-protective part of the helmet or accessory fitted.
4 Field of vision
There will generally be a need to define at least a minimum requirement for the field of vision, since there is a
balance between the protection from impact etc. and the risk of the field of vision being too small to be safe.
The working group should specify the requirements for field of vision that are relevant for the particular type of
helmet. In many types of helmet, requirements for field of vision may compromise both the area of the head to
be protected and the area of the helmet to be tested for shock absorption and/or penetration.
Examples of field of vision requirements in helmet Standards include:
Motorcycle helmets (UN ECE 22 05) – upward 7o from top of eyes, downward 45o from bottom of
eyes, horizontally +/-52.5o. This reflects the need to protect the forehead and the lack of need to
view very far upward to see the road, etc. The same requirement is used for snowmobile/bobsleigh
helmets (EN 13781:2001) for the same reasons.
Ice hockey helmets (EN ISO 10256:2003) - upward 35o from top of eyes, horizontally +/-45o. Here
there is a greater need for upward vision, while there is no chin-guard so downward vision has not
been specified.
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A useful reference for general fields of vision for different tasks is EN 894-2:1997, Safety of machinery
Ergonomics requirements for the design of displays and control actuators Part 2: Displays. Subclauses
4.1.1 and 4.1.2 define three zones of decreasing efficiency for visual signal detection and monitoring tasks;
recommended zone – a cone with 30o internal angle;
acceptable zone – between a cone with 30o and 60o internal angle; and
not suitable zone – outside a cone with 60o internal angle.
Of course, for many helmet applications peripheral vision outside the 60o cone is still needed (e.g. the
Standards above).
Requirements for field of vision should use the test method given in EN 13087-6.
5 Helmet sizes
Helmet standards should specify which requirements are to be satisfied for particular sizes, or for ranges of
helmet sizes, relevant to the population of intended wearers.
If ranges of sizes is preferred, it may be useful to refer in the standard to “helmet type”, i.e. “Category of
helmets, which does not differ in such essential respects as the materials or dimensions or construction of the
helmet, of the retention system or of the protective padding”.
6 Ventilation
Ventilation features should allow air movement between the inside and outside of the helmet.
Ventilation of any helmet has an important impact on comfort and wearability. However, at present, there is no
recognised test method for assessing ventilation performance. In many types of helmet, requirements for
ventilation may compromise both the extent of protection provided and the area of the helmet to be tested for
shock absorption and/or penetration. If ventilation features are provided and are positioned within the area of
the helmet to be tested for shock absorption and/or penetration, all such features should be subjected to these
tests. The definition of ventilation (and non-ventilation) holes and features needs to be carefully considered
and clearly worded so as to avoid ambiguities in interpretation.
7 Mass
The mass of the helmet should always be made available to the user. The working group should define how
and where this is done.
8 Comfort
It should be remembered that comfort is a very subjective assessment. However, it is a well-known fact that
the more comfortable a piece of personal protective equipment, the more likely the user is to wear it. Many
factors are involved – mass / position of the centre of gravity / stability of the helmet on the head / ventilation /
provision of a comfort band or sweatband, etc.
If provision is made for the fixing of accessories, such as ear-muffs, face-shields, etc, both the design and
positioning of the fixing point can affect the comfort of the total assembly.
Comfort is generally best assessed by practical performance tests. Such tests may be combined with tests for
compatibility (see Clauses 14 and 15). There are existing standards which specify requirements and test
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methods for the objective and subjective evaluation of the ergonomic and thermal effects on the human body
of personal protective equipment (PPE) ensembles, including gloves, footwear, clothing, helmets and
respiratory protective equipment (RPE), on wearers.
For example, BS 8469:2007, Personal protective equipment for firefighters Assessment of ergonomic
performance and compatibility Requirements and test methods has been developed for the PPE
ensembles used in structural firefighting.
Similarly, BS 7971-2:2003, Protective clothing and equipment for use in violent situations and in training - Part
2: Guidance on risk assessment and on the selection, use, cleaning and maintenance of protective clothing
and equipment also has some advice on user trials of PPE (Subclause 5.4).
These standards are also useful references for practical performance trials of compatibility (see Clauses 14
and 15).
9 Skin irritation
At present, there are no prescriptive requirements for skin irritation. Refer to EU Directives 67/548/EEC and
76/769/EEC. (See also Clause 10, Innocuousness of materials.)
10 Innocuousness of materials
A recommendation has been sent to all PPE Technical Committees to introduce a clause and an informative
annex on innocuousness, based on a model European Standard EN 340:2003, Protective clothing General
requirements. Further guidance is included in part C2 of Document PPE N122, CEN PPE Forum, Guide for
the drafting or the revision of EN standards on PPE.
11 Ignitability / Flame resistance
The underlying philosophy for requiring an ignitability test is that wearing a helmet should not increase the
user’s susceptibility to injury from flame. The test method is given in EN 13087-7. More severe ignitability test
methods are given in EN 13274-4, Respiratory protective devices Methods of test Part 4: Flame tests.
12 Corrosion
If metal parts are used in the helmet construction, the working group should consider whether the corrosion of
such parts during the lifetime of the helmet would adversely affect the protection afforded by the helmet or
adversely affect its innocuousness.
13 Combined and combination PPE and accessories
Other items of PPE and accessories are often attached to, or built into, protective helmets. This practice then
leads to the questions – “Does the helmet continue to satisfy the respective helmet standard, when such other
items are attached or built in?”; “If the other item is PPE, normally covered by its own standard, does the item
still satisfy its standard when attached to or built into the helmet?”
Following consideration of these questions within a CEN/BTS/4 ad hoc group a few years ago, the wording as
given in Annex A was recommended and this should be applied by all TC158 working groups.
As noted Annex A, parts of the helmet and accessories may, or may not, have a protective function. Where
part of the helmet or an accessory does not have a protective function, it must not reduce the level of
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protection offered by any other part of the helmet. In practice, this will often mean that performance tests
should be conducted with the non-protective part of the helmet or accessory fitted.
14 Compatibility with other headgear
The wearing of other PPE headgear (e.g. = goggles, respiratory protective device) at the same time as
helmets should be considered, such that the ensemble should be wearable, and the individual items should
continue to provide the same protection as when worn alone.
This item is not the same as (12) above and it is clearly difficult to give guidance on all eventualities. The
working group should consider possible implications and draft requirements accordingly. Refer also to Annex
A.
The compatibility of helmets with other PPE, whether this is solely headgear or covers other parts of the body,
is generally best assessed by practical performance tests. Such tests may be combined with tests for comfort
(see Clause 8). There are existing standards which specify requirements and test methods for the objective
and subjective evaluation of the compatibility of PPE ensembles. Examples of these standards are given in
Clause 8.
15 Compatibility with other PPE
The wearing of other PPE (e.g. – jacket, gloves) at the same time as helmets should be considered such that
the ensemble should be wearable, and the individual items should continue to provide the same protection as
when worn alone. The working group should consider possible implications and draft requirements
accordingly.
The compatibility of helmets with other PPE, whether this is solely headgear or covers other parts of the body,
is generally best assessed by practical performance tests. Such tests may be combined with tests for comfort
(see Clause 8). There are existing standards which specify requirements and test methods for the objective
and subjective evaluation of the compatibility of PPE ensembles. Examples of these standards are given in
Clause 8.
16 Shock absorption
Head protection should absorb energy and spread the impact force over the head.
The working group should consider likely accidents, likely injury types, likely wearer profiles, and the desirable
Abbreviated Injury Scale (AIS). The wearability of the helmet, the impact test site and impact angle, the striker
shape, and the need for single or multiple impacts, should also be considered.
Harmonised test methods are specified in EN 13087-2. Helmet standards should be consistent in specifying
these requirements – e.g. peak force, deceleration, HIC, GSI, etc.
17 Rotational effects
Head protection should limit the force and torque applied to the skull, brain and neck.
The working group should consider likely accidents, likely injury types, likely wearer profiles, and the desirable
Abbreviated Injury Scale (AIS).
TC158/WG11 is currently developing test methods to assess rotational effects. Until these are published
however, working groups should consider requirements for the geometry of the outer surface of the helmet,
which might reduce these effects.
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18 Penetration
Head protection should resist penetration and distribute the impact force over the head. In a penetration
incident there are two potential injury mechanisms. First, contact of the penetrating object with the head and,
second, shock to the head from the impact. So the penetration test method could consider both penetration
and shock absorption.
In existing standards the penetration test has not directly considered or measured the shock produced during
impact. This is because the impact energy used in the penetration test is lower than that used in the shock
absorption test (Clause 16). So, if a helmet passes the shock absorption test, then it has been assumed that it
will also “pass” for the shock produced in the penetration test.
The working group should consider whether this assumption is valid. The striker for the penetration test may
concentrate the impact force on a smaller area of the helmet than the striker for the shock absorption test. If
this is the case than the pressure applied to the impact area may be greater for the penetration test than for
the shock absorption test. The effect of this higher pressure on forces transmitted through the helmet to the
head, and the potential resulting levels of injury, will need to be considered. This transmission will be affected
by the nature of the helmet e.g. the stiffness of the shell, the softness of any liner, the contact between helmet
and head, etc. For standards where the shock absorption test using a falling headform and the penetration
test uses a falling striker the impact forces, etc, can still be calculated for each test and then compared. The
comparison is just more complicated than in the case where both shock and penetration tests use a falling
mass.
In summary, it is often a reasonable assumption that, if the impact energy in a penetration test method is less
than that used for a similar impact in the shock absorption test method, then there is likely to be no need to
consider shock absorption as a part of the penetration test. The working group should always consider
whether this assumption is valid.
The working group should consider likely accidents, likely injury types, likely wearer profiles, and the
acceptable level of injury (AIS). The wearability of the helmet, the impact test site and impact angle, the striker
shape and the need for single or multiple impacts should also be considered.
Harmonised test methods are specified in EN 13087-3. Helmet standards should be consistent in specifying
these requirements.
19 Crush and rigidity
When the head is supported on one side and a force from a moving object is applied to the opposite side then
skull fracture and brain injury can occur. Examples are: A horse rider falls to the ground and then the horse
falls on the rider's head; an industrial worker or fire-fighter can fall to the ground and an object falls on their
head.
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