CEN/TR 16148:2011

SLOVENSKI STANDARD
01-junij-2011
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Head and neck impact, burn and noise injury criteria - A Guide for CEN helmet standards
committees
Kriterien für Verletzungen durch Einwirkung auf Kopf und Hals, Verbrennungen und
Lärmverletzungen - Leitfaden für Arbeitsgruppen, die europäische Helmnormen
erarbeiten
Ta slovenski standard je istoveten z: CEN/TR 16148:2011
ICS:
01.120 Standardizacija. Splošna Standardization. General
pravila rules
13.340.20 Varovalna oprema za glavo Head protective equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL REPORT
CEN/TR 16148
RAPPORT TECHNIQUE
TECHNISCHER BERICHT
March 2011
ICS 13.340.20
English Version
Head and neck impact, burn and noise injury criteria - A Guide
for CEN helmet standards committees
Critères relatifs au traumatisme cervico-facial et aux lésions Kriterien für Verletzungen durch Einwirkung auf Kopf und
dues aux brûlures et au bruit - Guide destiné aux comités Hals, Verbrennungen und Lärmverletzungen - Leitfaden für
des normes sur les casques de protection du CEN Arbeitsgruppen, die europäische Helmnormen erarbeiten

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 16148:2011: E
worldwide for CEN national Members.

Contents Page
Foreword .3
Introduction .4
1 Abbreviated injury scale, AIS .5
2 Peak linear acceleration (A.3.1 & A.4) .9
3 Head injury criterion HIC (A.4) .9
4 Rotational motion (A.2.6, A.3.2 & A.4.3) . 10
4.1 Peak Rotational Acceleration . 10
4.2 Tangential force at the helmet surface . 10
5 Skull crushing and penetration force (A.2.2 & A.3.3) . 11
5.1 Crushing force . 11
5.2 Penetration force . 11
6 Neck injury . 11
7 Noise (Appendix section A5.0) . 12
8 Heat: burns and fatigue (A.6) . 12
8.1 Burns . 12
8.2 Heat fatigue . 13
9 References . 14
Annex A Biomechanics of head injury from impact, noise and heat . 15
A.1 General . 15
A.2 Head injuries . 16
A.3 Head injury mechanisms . 24
A.4 Head injury criteria . 29
A.5 Noise . 31
A.6 Heat: burns and fatigue . 35
A.7 Conclusions . 41
Bibliography . 42

Foreword
This document (CEN/TR 16148:2011) 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.
Introduction
Members of helmet Standards committees frequently need to define limits for test procedures. Such limits
relate to test values that indicate the potential for injury and yet it is often difficult for members to know the
type and severity of injury that is represented by a given test value. Over the years, criteria have been
developed for different body regions and usually these have been derived from a combination of accident and
casualty data, and tests on cadavers, cadaver body parts, animals and human volunteers. However, such
criteria are often used by the automotive industry as pass/fail values without a clear understanding of human
tolerance to injurious forces. This sometimes leads to the mistaken belief that any value below the stated limit
implies uninjured and all values above imply a serious or fatal injury.
This misconception gives very little freedom to choose values that are different from the often inappropriate
automotive value. This is particularly true for head injury criteria for which values for a helmeted head may be
different to those for the unhelmeted head. Many accidents to wearers of helmets, which cover a wide range
of activities from horse riding to downhill skiing, result in a closed head injury. This is when the brain is
damaged without any skull or external tissue damage. Conversely, head injuries in automotive accidents are
much more frequently open head injuries with skull fracture and soft tissue lesions.
Other misconceptions arise because of the failure to understand that human response to a given dose or
injurious parameter varies across a range of the population. The dose response curve tends to be "S"
(sigmoid) shaped such that as the magnitude of the injurious parameter increases so does the percent of the
population that sustains an injury of a given severity. Thus, a family of "S" curves can be generated for a
range of injury severity such as AIS and a measurement or criterion such as HIC, the Head Injury Criterion.
Unfortunately, the data for such an analysis is generally difficult to obtain because measurements generated
by test apparatus do not relate directly to injury severity because a headform for example does not respond in
an impact like a human head. Hence, it is necessary to find a relationship between these test measurements
and injury severity.
This paper is designed to provide information to convenors that will help in choosing test limits in relation to a
particular injury type and severity. It is worth noting that accident investigators use a scale known as the
Abbreviated Injury Scale, AIS (AAAM). This was developed (in the USA) so that injury severity could be
recorded in databases regardless of the body region and type of injury thus avoiding lengthy medical terms
that were unfamiliar and difficult to interpret. This paper begins by reviewing the AIS scale and its application
to head and neck injuries and burn injuries. Thereafter, each measurement type is reviewed and the severity
of injury for given values is identified where possible. A section on burn injuries and fatigue related to heat
exposure has been included to assist with Standards for equipment to protect firefighters. The Appendix
describes the skin structure and the category and consequence of burn injuries.
Premature deafness because of high noise levels and the converse problem of over attenuation of auditory
warnings was also considered. Suggested levels have been included with details of test methods in Annex A.
1 Abbreviated injury scale, AIS
This is a scale that extends from 0 to 6 where 0 is uninjured and 6 is unsurviveable. Each level can be applied
to any body region according to a coding manual developed by the Association for the Advancement of
Automotive Medicine (AAAM). Tables 1 and 2 give the scale and injury severity and an indication of the head
and neck injuries that would be classified at each level. Table 3 gives similar information for burn injuries by
degree, surface area and region of the body.

Table 1 — AIS scale with head injury severity
AIS 0 AIS 1 AIS 2 AIS 3 AIS 4 AIS 5 AIS 6
uninjured minor slight moderate serious severe unsurviveable
Scalp
superficial abrasions, contusions, lacerations X
major laceration or minor blood loss  X
blood loss >20% or total scalp loss  X

Intracranial vessels (arteries)

laceration   X X
Cranial nerves
contusion, laceration, loss of function  X

Brain
swelling, contusions, haemorrhage  X
haematoma, large >15cc contusion   X
massive >30cc contusions, diffuse axonal injury, large haematoma   X
crush, penetrating injury    X

Loss of consciousness
< 1 hour  X
1 - 6 hours or < 1 hour with neurological deficit  X
6 – 24 hours, or 1-6 hours with neurological deficit   X
> 24 hours, or 6-24 hours with neurological deficit   X

Skull Fracture
simple  X
compound  X
complex, open, loss of brain tissue   X
Table 2 — AIS scale with neck injury severity
AIS 0 AIS 1 AIS 2 AIS 3 AIS 4 AIS 5 AIS 6 unsurviveable
uninjured minor slight moderate serious severe
Whole area
Skin
superficial abrasions, contusions, lacerations X
major laceration or minor blood loss  X
blood loss >20%  X
Decapitation    X
Vessels (arteries)
carotid, jugular and vertebral laceration minor  X
carotid jugular and vertebral laceration major  X

Nerves
vagus injury X
phrenic injury  X
Spine
hyoid fracture  X
cord contusion   X
incomplete cord syndrome   X
complete cord syndrome or laceration C-4 or below   X
complete cord syndrome or laceration C-3 or above   X
disc injury without nerve root damage  X
disc injury with nerve root damage  X

Table 3 — AIS scale with burn injury severity
AIS 0 AIS 1 AIS2 AIS 3 AIS 4 AIS 5 AIS 6
uninjured minor slight moderate serious severe unsurviveable
1st degree
unspecified X
2nd degree
< 10% TBS (Total Body Surface) X

3rd degree
< 10% TBS  X
< 10% TBS with face, hand or genitalia  X
involvement
2nd or 3rd degree
10% to 19% TBS  X
10% to 19% TBS with face, hand or  X
genitalia involvement
20% to 29% TBS   X
20% to 29% TBS with face, hand or   X
genitalia involvement
30% to 39% TBS   X
30% to 39% TBS with face, hand or   X
genitalia involvement
40% to 89% TBS   X
≥ 90%    X
TBS = Total Body Surface
2 Peak linear acceleration (A.3.1 & A.4)
This is the most frequently used parameter in helmet testing and is derived usually from a tri-axial
accelerometer mounted in the headform unless the headform is rigidly supported and then the source is a
single axis accelerometer. In both types, the helmet is mounted onto the headform and then the apparatus
allowed to fall unimpeded onto a rigid anvil.
Table 4 is a scale published by Newman (1980) and is supported by research that is more recent.
Table 4 — Peak acceleration and typical AIS Equivalent
Peak Acceleration AIS
< 50 g AIS 0
50 g – 100 g AIS 1
100 g – 150 g AIS 2
150 g – 200 g AIS 3
200 g – 250 g AIS 4
...