Note to users: This electronic document is not subject to copyright. You may copy it, but 

you are requested not to disseminate altered copies. 

Technology Assessment Program 

NIJ Standard for Ballistic Helmets 

Supersedes NILECJ-STD-0106.00 dated September 1975 

A Voluntary National Standard Promulgated by the 

National Institute of Justice

December 1981 

U.S. DEPARTMENT OF JUSTICE 

National Institute of Justice

JAMES L. UNDERWOOD Acting Director
ACKNOWLEDGMENTS 

This standard was formulated by the Law Enforcement Standards Laboratory of the National 

Bureau of Standards under the direction of Ralph A. Gorden Jr., Manager, Protective Equipment 

Program, and Lawrence K. Eliason, Chief of LESL. The technical research was Performed by 

Nicholas J. Calvano of the NBS Center for Consumer Product Technology. The standard has 

been reviewed and approved by the Technology Assessment Program Advisory Council and 

adopted by the International Association of Chiefs of Police (IACP) as an IACP Standard. 

For sale by the Superintendent of Documents, U.S. Government Printing Office, 

Washington, DC 20402 

FOREWORD 

This document. NIJ Standard-0106.01, Ballistic Helmets. is an equipment standard developed by

the Law Enforcement Standards Laboratory of the National Bureau of Standards. It is produced 

as part of the Technology Assessment Program of the National Institute of Justice. A brief 

description of the program appears on the inside front cover. 

This standard is a technical document that specifies performance and other requirements 

equipment must meet to conform to the needs of criminal justice agencies for high quality 

service. Purchasers can use the test methods described in this report to determine firsthand 

whether a particular piece of equipment meets the standards, or they may have the tests 

conducted on their behalf by a qualified testing laboratory. Procurement officials may also refer 

to this standard in their purchasing documents and require that equipment offered for purchase 

meet the requirements. with compliance guaranteed by the vendor or attested to by an 

independent laboratory. 

Because this NIJ standard is designed as a procurement aid. it is necessarily highly technical. For 

those who seek general guidance about the capabilities of ballistic helmets, user guides also are 

published. The guides explain in non-technical language how to select equipment capable of the 

performance required by an agency. 

NIJ standards are subjected to continuing review. Technical comments and recommended 

revisions are welcome. Please send suggestions to the Program Manager for Standards, National 

Institute of Justice, U.S. Department of Justice, Washington, DC 20531. 

Before citing this or any other NIJ standard in a contract document, users should verify that the 

most recent edition of the standard is used. Write to: Chief, Law Enforcement Standards 

Laboratory, National Bureau of Standards. Washington, DC 20234. 

Lester D. Shubin 

Program Manager for Standards 

National Institute of Justice 

ii
TABLE OF CONTENTS 

ACKNOWLEDGMENTS .............................................................................................................. ii

FOREWORD.................................................................................................................................. ii 

TABLE OF CONTENTS...............................................................................................................iii 

1. PURPOSE AND SCOPE............................................................................................................ 1

2. CLASSIFICATION.................................................................................................................... 1 

2.1 Type I (22 LR-38 Special).................................................................................................... 1 

2.2 Type II-A (Lower Velocity 357 Magnum-9 mm)................................................................. 1 

2.3 Type II (Higher Velocity 357 Magnum-9 mm).................................................................... 1 

2.4 Special Type.......................................................................................................................... 2 

3. DEFINITIONS............................................................................................................................ 2 

3.1 Angle of Incidence................................................................................................................ 2 

3.2 Basic Plane............................................................................................................................ 2 

3.3 Coronal Plane........................................................................................................................ 2 

3.4 Fair Hit.................................................................................................................................. 2 

3.5 Full Metal Jacketed Bullet (FMJ) ......................................................................................... 2 

3.6 Jacketed Soft Point (JSP)...................................................................................................... 2 

3.7 Lead Bullet............................................................................................................................ 2 

3.8 Mid-sagittal Plane ................................................................................................................. 2 

3.9 Penetration ............................................................................................................................ 2 

3.10 Reference Plane .................................................................................................................. 3 

3.11 Witness Plate....................................................................................................................... 3 

4. REQUIREMENTS...................................................................................................................... 3 

4.1 Sampling for Test.................................................................................................................. 3 

4.2 Test Sequence ....................................................................................................................... 3 

4.3 Projections............................................................................................................................. 3 

4.4 Openings............................................................................................................................... 3 

4.5 Workmanship........................................................................................................................ 4 

4.6 Labeling ................................................................................................................................ 5 

4.7 Ballistic Penetration.............................................................................................................. 5 

4.8 Ballistic Impact Attenuation ................................................................................................. 5 

5. TEST METHODS....................................................................................................................... 5 

5.1 Test Equipment ..................................................................................................................... 5 

5.1.1 Type I Test Weapons and Ammunition......................................................................... 5 

5.1.2 Type II-A Test Weapons and Ammunition ................................................................... 6 

5.1.3 Type II Test Weapons and Ammunition 5.1.3.1 Higher Velocity 357 Magnum ......... 7 

5.1.4 Chronograph .................................................................................................................. 7 

5.1.5 Penetration Test Headforms........................................................................................... 7 

5.1.6 Impact Test Headform ................................................................................................... 7 

5.1.7 Witness Plate.................................................................................................................. 7 

5.1.8 Acceleration Measurement System................................................................................ 7 

5.2 Ballistic Penetration Test.................................................................................................... 11 

5.3 Ballistic Impact Attenuation Test ....................................................................................... 11 

APPENDIX A-REFERENCES .................................................................................................... 13 

 

iii
NIJ STANDARD 0106.01 FOR BALLISTIC HELMETS

1. PURPOSE AND SCOPE 

The purpose of this standard is to establish performance requirements and methods of test for 

helmets intended to protect the wearer against gunfire. Requirements for face shields are not 

included in this standard. The standard is a revision of NILECJ-STD-0106.00, dated September 

1975. 

This revision redefines the classification system, and establishes threat levels and test rounds that 

are consistent with companion NIJ standards for ballistic protective equipment and materials 

[l,4]*. 

2. CLASSIFICATION 

Ballistic helmets covered by this standard are classified into three types, by level of performance. 

The ballistic threat posed by a bullet depends, among other things on its composition, shape, 

caliber, mass, and impact velocity. Because of the wide variety of cartridges available in a given 

caliber and because of the existence of hand loads, helmets that will defeat a standard test round 

may not defeat other loadings in the same caliber. For example, a helmet that prevents 

penetration by a 357 Magnum test round may or may not defeat a 357 Magnum round with 

higher velocity. Similarly, for identical striking velocities, non-deforming or armor piercing 

rounds pose a significantly greater penetration threat than an equivalent lead core round of the 

same caliber. The test ammunition specified in this standard represent common threats to the law 

enforcement community. 

2.1 Type I (22 LR-38 Special) 

This helmet protects against the standard test rounds as defined in paragraph 5.1.1. It also 

provides protection against lesser threats such as 12 gauge No. 4 lead shot and most handgun 

rounds in calibers 25 and 32. 

2.2 Type II-A (Lower Velocity 357 Magnum-9 mm) 

This helmet protects against the standard test rounds as defined in paragraph 5.1.2. It also 

provides protection against lesser threats such as 12 gauge 00 buckshot, 45 Auto., 22 caliber 

Long Rifle High Velocity (rifle), High Velocity 38 Special and some other factory loads in 

caliber 357 Magnum and 9 mm, as well as the threats mentioned in paragraph 2.1. 

2.3 Type II (Higher Velocity 357 Magnum-9 mm) 

This helmet protects against the standard test rounds as defined in paragraph 5.1.3. It also 

provides protection against lesser threats such as 12 gauge 00 buckshot, 45 Auto., 22 caliber 

Long Rifle High Velocity (rifle), High Velocity 38 Special and most other factory loads in 

caliber 357 Magnum and 9 mm, as well as the threats mentioned in paragraph 2.1. 

1
2.4 Special Type 

A purchaser having a special requirement for a level of protection other than one of the above 

standards should specify the exact test rounds to be used, and indicate that this standard shall 

govern in all other respects. 

3. DEFINITIONS 

3.1 Angle of Incidence 

The angle between the line of flight of a bullet and the perpendicular to the plane tangent to the 

point of impact. See figure 1. 

3.2 Basic Plane 

The plane through the centers of the external ear openings and the lower edges of the eye 

sockets. See figure 2. 

3.3 Coronal Plane 

The plane, perpendicular to the basic and mid-sagittal planes, which passes through the centers 

of the external ear openings. See figure 2. 

3.4 Fair Hit 

A hit that impacts the helmet at an angle of incidence no greater than 5°, and is at least 5 cm (2 

in) from a prior hit or the edge of the helmet. A bullet that impacts too close to the edge or a 

prior hit and/or is of too high a velocity, but does not penetrate, shall be considered a fair hit for 

the determination of penetration. 

3.5 Full Metal Jacketed Bullet (FMJ) 

A bullet made of lead completely covered, except for the base, with copper alloy (approximately 

90 copper-10 zinc). 

3.6 Jacketed Soft Point (JSP) 

A bullet made of lead completely covered, except for the point, with copper alloy (approximately 

90 copper-10 zinc). 

3.7 Lead Bullet 

A bullet made of lead alloyed with hardening agents. 

3.8 Mid-sagittal Plane 

The plane, perpendicular to the basic and coronal planes, which symmetrically bisects the head. 

See figure 2. 

3.9 Penetration 

Perforation of a witness plate by any part of the test specimen or test bullet, as determined by the 

passage of light when the witness plate is held up to a 60-W light bulb. 

2
3.10 Reference Plane 

The plane 60±1 mm (2.36±0.04 in) above and parallel to the basic plane. See figure 2. 

3.11 Witness Plate 

A thin sheet of aluminum whose perforation serves as a means of determining penetration. 

4. REQUIREMENTS 

4.1 Sampling for Test 

Three helmets, size 7 l/4 and selected at random, shall constitute a test sample. 

4.2 Test Sequence 

The helmets shall be examined to determine compliance with the requirements of paragraphs 4.3 

through 4.6, and shall then be tested for compliance with the requirements of paragraphs 4.7 and 

4.8 in that sequence. 

4.3 Projections 

The helmets shall have no rigid projections that protrude from the inside shell surface. 

4.4 Openings 

The helmets shall have no slits, holes, or other openings. 

3
 

4.5 Workmanship 

The helmets shall be free from dents, blisters, cracks, crazing, chipped or sharp corners and other 

evidences of inferior workmanship. 

4
4.6 Labeling 

Each helmet shall be permanently and legibly labeled so that the label can be easily read without 

removing padding or any other permanent part, and shall include the following information: 

a. name, designation, or logo of the manufacturer 

b. type of helmet, according to section 2 of this standard 

c. size 

d. month and year of manufacture 

e. lot number 

4.7 Ballistic Penetration 

Two helmets shall be tested for resistance to ballistic penetration in accordance with paragraph 

5.2. Penetration by any fair hit shall constitute failure. The detailed ballistic performance 

requirements are summarized in table 1. 

4.8 Ballistic Impact Attenuation 

One helmet shall be tested for ballistic impact attenuation in accordance with paragraph 5.3. No 

measured peak acceleration shall exceed 400 gn , (400 times the acceleration due to gravity). 

5. TEST METHODS 

5.1 Test Equipment 

It should be noted that hand-loaded ammunition may be required to achieve some of the bullet 

velocities required in the following paragraphs. 

5.1.1 Type I Test Weapons and Ammunition 

5.1.1.1 22 LR 

The test weapon may be a 22 caliber handgun or test barrel. The use of a handgun with a 15 to 

16.5 cm (6 to 6.5 in) barrel is suggested. Test bullets shall be 22 Long Rifle High Velocity lead, 

with nominal masses of 2.6 g (40 gr) and measured velocities of 320±12 m (1050±40 ft) per 

second. 

5.1.1.2 38 Special 

The test weapon may be a 38 Special handgun or test barrel. The use of a handgun with a 15 to 

16.5 cm (6 to 6.5 in) barrel is suggested. Test bullets shall be 38 Special round-nose lead, with 

nominal masses of 10.2 g (158 gr) and measured velocities of 259±15 m (850±50 ft) per second. 

TABLE 1. Test summary 

Test variables Performance requirements 

Helmet 

type 

Test 

ammunition 

Nominal 

bullet 

mass 

Suggested 

barrel 

length 

Required 

bullet 

velocity 

Required 

fair hits per

helmet part 

Permitted 

penetrations 

I 22 LRHV 2.6 g 15 to 16.5 320±12 4 0 

5
TABLE 1. Test summary 

Test variables Performance requirements 

Lead 50 gr cm 

6 to 6.5 in 

m/s 

1050±40 

ft/s 

38 Special 

RN Lead 

10.2 g 

158 gr 

15 to 16.5 

cm 

6 to 6.5 in 

259±15 

m/s 

850±50 ft/s

4 0 

357 Magnum 

JSP 

10.2 g 

158 gr 

10 to 12 cm

4 to 4.75 in 

381±15 

m/s 

1250±50 

ft/s 

II-A 4 0 

9 mm 

FMJ 

8.0 g 

124 gr 

10 to 12 cm

4 to 4.75 in 

332±15 

m/s 

1090±50 

ft/s 

4 0 

357 Magnum 

JSP 

10.2 g 

158 gr 

15 to 16.5 

cm 

6 to 6.5 in 

425±15 

m/s 

1395±50 

ft/s 

II 4 0 

9 mm 

FMJ 

8.0 g 

124 gr 

10 to 12 cm

4 to 4.75 in 

358±15 

m/s 

1175±50 

ft/s 

4 0 

Abbreviations: 

FMJ—Full Metal Jacketed 

JSP—Jacketed Soft Point 

LRHV—Long Rifle High Velocity 

RN—Round Nose 

5.1.2 Type II-A Test Weapons and Ammunition 

5.1.2.1 Lower Velocity 357 Magnum 

The test weapon may be a 357 Magnum handgun or test barrel. The use of a handgun with a 10 

to 12 cm (4 to 4.75 in) barrel is suggested. Test bullets shall be 357 Magnum jacketed soft point, 

with nominal masses of 10.2 g (158 gr) and measured velocities of 381±15 m (1250±50 ft) per 

second. 

5.1.2.2 Lower Velocity 9 mm 

The test weapon may be a 9 mm handgun or test barrel. The use of a handgun with 10 to 12 cm

(4 to 4.75 in) barrel is suggested. Test bullets shall be 9 mm full metal jacketed, with nominal 

masses of 8.0 g (124 gr) and measured velocities of 332±15 m (1090±50 ft) per second. 

6
5.1.3 Type II Test Weapons and Ammunition 

5.1.3.1 Higher Velocity 357 Magnum 

The test weapon may be a 357 Magnum handgun or test barrel. The use of a handgun with a 15 

to 16.5 cm (6 to 6.5 in) barrel is suggested. Test bullets shall be 357 M g a num jacketed soft 

point, with nominal masses of 10.2 g (158 gr) and measured velocities of 425±15 m (1395±50 ft) 

per second. 

5.1.3.2 Higher Velocity 9 mm 

The-test weapon may be a 9 mm handgun or test barrel. The use of a handgun with a 10 to 12 cm

(4 to 4.75 in) barrel is suggested. Test bullets shall be 9 mm full metal jacketed, with nominal 

masses of 8.0 g (124 gr) and measured velocities of 358±15 m (1175±50 ft) per second. 

5.1.4 Chronograph 

The chronograph shall have a precision of 1 μs and an accuracy of 2 μs. Its triggering devices 

shall be of either the photoelectric or conductive screen types. 

5.1.5 Penetration Test Headforms 

Each penetration test headform shall be size 7 l/4 and shall have the dimensions shown in figure 

3. The sagittal penetration type shall be so modified that it can rigidly hold a witness plate in the 

coronal Plane as shown in figure 4. Conversely, the coronal penetration type shall be able to hold 

a witness plate in the sagittal plane. as shown in figure 4. 

5.1.6 Impact Test Headform 

The impact test headform shall be size 7 l/4. shall have the dimensions given in figure 3, and 

shall exhibit no resonance frequencies below 3000 Hz: it may be made of any suitable material. 

such as magnesium alloy K-1A. A test headform found to be suitable can be obtained from

United States Testing Laboratories, Inc., 1415 Park Avenue, Hoboken, NJ 07030. 

The impact headform shall be rigidly mounted on a base (see fig. 5) which is free to move In the 

direction of motion of the test bullet. The total mass of the instrumented headform and base 

assembly shall be 5.0±0.5 kg (11 ± 1.1 lb) and the static force, parallel to the direction of motion, 

required to initiate motion of the assembly shall not exceed 9 N (2 lbf). 

5.1.7 Witness Plate 

The witness plates shall be 0.5 mm (0.020 in) thick and shall be made of type 2024-T3 or 2024-

T4 aluminum alloy. 

5.1.8 Acceleration Measurement System 

The accelerometer should be able to withstand shocks up to 2000 gn . The acceleration data 

channel, including all instrumentation which may alter the frequency content of the test data and 

all recording and analysis procedures, shall comply with SAE Recommended Practice J211b 

requirements for channel class 1000 [5]. 

7

9

5.2 Ballistic Penetration Test 

Set up the test equipment as shown in figure 6. Firmly clamp the appropriate test weapon, with 

the barrel horizontal. in such a manner that the alignment of the weapon is not altered when it is 

discharged. Use the test weapon and ammunition combination in accordance with paragraphs 

5.1.1.1 through 5.1.3.2 as appropriate for the threat level classification of the helmet as rated by 

the manufacturer in accordance with section 2. 

Position a sheet of cardboard 5 m (16 ft) from the muzzle of the test weapon and fire a pre-test 

round through the cardboard to determine the line of flight and the point of impact of the bullet. 

Place the triggering devices 2 and 3 m (6.6 and 9.8 ft), respectively, from the muzzle of the test 

weapon and arrange them so that they define planes perpendicular to the line of flight of the 

bullet. Measure the distance between them with an accuracy of 1 mm (0.04 in). 

Insert a witness plate in the sagittal penetration test headform. place the helmet under test on the 

headform and secure it by its chin strap or by other means which will not interfere with the test. 

Place the helmeted headform in back of the sheet of cardboard, with the desired point of impact 

touching the bullet hole made by the test round. and then remove the cardboard. 

Fire one round at the front of the helmet, hitting it at a point no more than 9 cm (3.5 in) above the 

basic plane and no more than 5 cm (2 in) from the mid-sagittal plane. Record the time of flight of 

the bullet between the two triggering screens, as determined by the chronograph, and calculate 

the bullet velocity. Then fire a round at the back of the helmet, impacting it within the area 

diametrically opposite the front impact area. Examine the helmet and witness plate to determine 

whether penetration occurred when a bullet traveling at an acceptable speed made a fair hit 

within the required area. 

If no penetration occurred, place the helmet on the coronal penetration test headform and shoot it 

once on each side. at a point no more than 5 cm (2 in) above the basic plane and no more than 

7.5 cm (3.0 in) from the coronal plane. 

If no penetration occurs, repeat the above test on a second helmet, which has been 

preconditioned by immersion for 2 to 4 h in water at 25±5°C (77±9°F). 

5.3 Ballistic Impact Attenuation Test 

Set up the test equipment as shown in figure 6 and locate the line of fire and point of impact of 

the bullet as described in paragraph 5.2. Use the test weapon and ammunition combination in 

accordance with paragraphs 5.1.1.1 through 5.1.3.2 as appropriate for the threat level 

classification of the helmet as rated by the manufacturer in accordance with section 2. 

Mount the accelerometer at the center of mass of the impact test headform in such a manner that 

it can be easily repositioned for all impacts: a universal ball-and-socket mount has been found to 

be suitable. Position the helmet squarely on the headform and secure it by its chin strap or other 

means which will not interfere with the test. Position the instrumented test headform-base 

assembly in the line of fire so that the sensitive axis of the accelerometer and the line of fire are 

colinear within 5°. 

11
Allow all electronic equipment to warm up for 30 min or until stability is achieved, whichever 

time is greater, prior to testing, and perform the tests at an ambient temperature of 20-28°C (68-

82 °F) and a relative humidity of 30 to 70%. Shoot four test rounds at the helmet, one at each of 

the four sites as described in paragraph 5.2, and measure the velocity of each fair hit and the 

headform acceleration which it produces. 

12
APPENDIX A-REFERENCES 

1. NILECJ-STD-0101.01, "The Ballistic Resistance of Body Armor," National Institute of 

Justice, U.S. Department of Justice. Washington, DC 20531 (Dec. 1978). 

2. NIJ Standard-0104.01, "Riot Helmets," National Institute of Justice, U.S. Department of 

Justice, Washington, DC 20531 (Aug. 1980). 

3. NILECJ-STD-0105.00, "Crash Helmets," National Institute of Justice, U.S. Department 

of Justice, Washington, DC 20531 (June 1975). 

4. NIJ Standard-0108.00, "Ballistic Resistant Protective Materials." (In preparation). 

5. SAE Recommended Practice J211b, Society of Automotive Engineers, Inc., Two 

Pennsylvania Plaza, New York, NY. 

* United States Government Printing Office:1982--361-233/6344 

13