Safety standards for police body armour

146 Pages·2010·3.78 MB·English

by  Anthony Bleetman

Safety Standards for Police Body Armour
by
Anthony Bleetman FRCSEd FFAEM DipIMC RCSEd

A thesis submitted to the Institute of Occupational Health,
Faculty of Medicine of The University of Birmingham for the
Degree of
DOCTOR OF PHILOSOPHY

November 2000
University of Birmingham Research Archive

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Table of Contents

PART 1: INTRODUCTION
Introduction 4
Appearance 5
Risk Assessments 5
PART 2: HISTORY OF ARMOUR - AN OVERVIEW
Introduction 9
Armour 9
Leather armour 10
Fabric armour 10
Mail armour 13
Rigid plate armour 16
Design, decoration and symbolism 18
Modern armour 19
PART 3: THE EVOLUTION OF ARMOUR
Introduction 21
The American Experience 22
PART 4: THE CASE FOR THE ISSUE OF BODY ARMOUR
TO UK POLICE: THE THREAT OF VIOLENCE
Background 25
Introduction 25
Assaults on police 25
The Epidemiology of Assault 28
The threat to police 28
Anatomical sites of injury for police victims of assault 30
Location of assault 30
Civilian assaults 32
Injury patterns in civilian assault 36
The Weapon Threat 38

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PART 5: THE PHYSICAL PROPERTIES OF MODERN BODY ARMOUR
Introduction 44
Materials 44
Stab resistant armour materials 45
Modern knife-resistant systems 46
Standards 47
Knife resistance 50
Knife resistance testing: current test procedures 53
Accepting and Applying Standards 54
Testing Issues 56
Ballistic testing 57
Knife testing 58
The assailant and method of delivery 58
The weapon 58
PART 6: INJURY POTENTIAL
Introduction 62
Arrested Ballistic Blunt Trauma 62
Penetrating Knife Injury 63
The force required to cause a stab wound 64
Injury Scoring Systems 68
Quantifying Injury and Predicting Outcome after Injury 68
TRISS methodology 68
Red Cross classification 70
The new injury severity score (NISS) 70
Injuries Caused by Stabbing 71
Pneumothorax 73
Haemothorax 74
Aortic injury 75
Liver laceration 77
Splenic laceration 77
Cardiac lacerations 78
Kidney 79
Bowel injury 80
Stomach 80
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Mesentery 80
Oesophagus 80
Major blood vessels and nerve groups 81
Spinal cord injury 82
Other organs 82
Injuries from Arrested Ballistic Trauma 83
Body Coverage 84
PART 7: AN ASSESSMENT OF THE VULNERABILITY OF REGIONS OF
THE HUMAN BODY TOWARDS STAB ATTACKS
Introduction 86
Methods 86
Anatomical Demarcation Lines 87
Results 92
Severity of stab wounds 105
Regional Scoring 107
Other Observations from this Study 112
PART 8: SAFETY STANDARDS FOR STAB-RESISTANT BODY
ARMOUR: A COMPUTER TOMOGRAPHIC ASSESSMENT OF
ORGAN TO SKIN DISTANCES
Introduction 114
Methods 115
Results 115
Discussion 119
Conclusion 120
PART 9: CRITERIA FOR ZONING - THE POTENTIAL ROLE IN BODY
ARMOUR DEVELOPMENT
Introduction 123
Anatomical Landmarks 123
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PART 10: PLOTTING THE REGIONAL PROTECTION REQUIREMENTS OF
THE HUMAN BODY
Introduction 128
Determining the Anti-Stab Standards 130

Plotting the Knife Protection Requirements of the Body 131
Zoning Boundaries 135
Non-Penetrating (arrested) Ballistic Trauma 136
PART 11: APPROACHING THE FINAL PRODUCT
Ergonomic Considerations 139
Male/Female Differences 140
Mass Production 141
The Way Ahead 142
Summary 143

References 145
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Table of Figures

Figure 1: 18th Century Indian quilted coat 11
Figure 2: Coconut husk armour from the Gilbert Islands 12
Figure 3: American soldiers were issued soft armour in the Vietnam War 13
Figure 4: A chain mail coat with outer plate armour 14
Figure 5: Combination plate and mail armour 15
Figure 6: Two examples of Japanese lamellar armour 17
Figure 7: An example of Japanese large plate armour 18
Figure 8: Location of assaults on police officers 30
Figure 9: The type of police activity at the time of assault 30
Figure 10: A bullet arrested by body armour 44
Figure 11: Indentation into clay after the bullet is arrested by the armour 47
Figure 12: PSDB test rig 49
Figure 13: Blade penetration through armour into clay 50
Figure 14: Drop tower at Cranfield University 51
Figure 15: Accelerating mechanism for a test blade on the drop tower 52
Figure 16: Diaphragmatic excursion with the breathing cycle 67
Figure 17: Multiple stab wounds to the chest 71
Figure 18: A minority of chest stabbings are to the back 72
Figure 19: An open chest stab wound 74
Figure 20: Emergency thoracotomy following a penetrating stab wound 75
Figure 21: The aorta (A,B,C) 76
Figure 22: Extrusion of viscera through a stab wound in the left flank 77
Figure 23: The internal thoracic organs 78
Figure 24: The heart and lungs 79
Figure 25: The brachiocephalic vein (B) 81
Figure 26: Common handgun ammunition 83
Figure 27: Anterior view with anatomical regions 88
Figure 28: Right lateral view with anatomical regions 89
Figure 29: Left lateral view with anatomical regions 90
Figure 30: Posterior view with anatomical regions 91
Figure 31: Minor wounds – anterior 93
Figure 32: Minor wounds – right side 94
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Figure 33: Minor wounds – left side 95
Figure 34: Minor wounds – posterior 96
Figure 35: Major wounds – anterior 97
Figure 36: Major wounds – right side 98
Figure 37: Major wounds – left side 99
Figure 38: Major wounds – posterior 100
Figure 39: Devastating wounds – anterior 101
Figure 40: Devastating wounds – right side 102
Figure 41: Devastating wounds – left side 103
Figure 42: Devastating wounds – posterior 104
Figure 43: Regional wound scores – anterior 108
Figure 44: Regional wound scores – right side 109
Figure 45: Regional wound scores – left side 110
Figure 46: Regional wound scores – posterior 111
Figure 47: The range of minimum organ to skin distances
for both male and female subjects 117
Figure 48: The minimum and median skin to organ distances 118
Figure 49: Anatomical landmarks (anterior) 124
Figure 50: Anatomical landmarks (posterior) 125
Figure 51: Armour protection zones (anterior) 132
Figure 52: Armour protection zones (posterior) 133
Figure 53: Armour protection zones (lateral) 134
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List of Tables
Table 1: Annual assaults on police officers 25
Table 2: Anatomical sites of ‘serious injuries’ 29
Table 3: Mode of assault in Lewisham 35
Table 4: Distribution of injuries in blunt assault in assault victims in Bristol 37
Table 5: Anatomical sites of injury in assaults on police officers 38
Table 6: Weapons used in assaults on patients in Lewisham 39
Table 7: Assault weapons by locus of incident 39
Table 8: Weapons confiscated by Norfolk Constabulary 40
Table 9: Weapons used in assaults on police officers 41
Table 10: NIJ ballistic testing 48
Table 11: Severity of wounds 105
Table 12: Distribution of wounds by region and severity 106
Table 13: Distribution of wounds by region and severity in percent 116
Table 14: Minimum skin to organ distances 117
Table 15: Range of skin to organ distances (mm)
for both male and female subjects 119
Table 16: The position of the organs by surface anatomy 126
Table 17: Regional risk assessment for stab injury 129
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Abstract
Assaults on the Police continue to increase. Of particular concern is the threat of injury
from edged weapons. Shootings remain rare. The Home Office has embarked on a
program to provide all police officers with suitable body armour.
Body armour has been on general issue to police officers in America for over twenty years
and has a superb record in saving lives from shootings. Little is known about its ability to
prevent serious stab wounds from knives, as this is a much less common threat in the
American policing environment. Therefore the specification for armour for police use in
this country must be set to provide protection against the threats in the UK policing
environment.
Current knife-resistance standards are based on animal experimentation and have not been
examined by any other model. To understand the protective requirements of armour, it is
necessary to understand the weapon threat, the assailant’s method of delivery, and the
vulnerability of the target.
The biophysics of human stabbing (the assailant’s method of delivery), is the subject of
ongoing investigation, and is outwith the scope of this thesis.
In this thesis, the history and development of body armour is reviewed. An overview of
the materials and properties of modern armour is presented. To understand the threat, the
epidemiology of assaults on police officers and civilians is described.
To determine the ideal protective qualities of body armour for issue to the police, two
studies are presented.
The first is a retrospective cohort study of 500 civilian victims of penetrating injury. The
frequency of wounding, and the severity of wounding by body region is plotted on
anatomical charts. This will demonstrate the vulnerability, and hence the protection
requirements of each body area to penetrating injury.
No previous study has measured the depth of the internal organs from the skin. A CT
study is presented. It describes the accessibility of the internal organs to the passage of a
blade by measuring the shortest distances from the skin.
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