UGANDA STANDARD  
  US 774
First Edition
2008-09-08
 
 
Reference numbe r
US 774: 2008
 © UNBS 2008 
  
Specification for protective helmets for motor cycle users 
 US 774: 2008 
ii © UNBS 2008 – All rights reserved
 Compliance with this standard does not, of itself confer immunity from legal obligations 
A Uganda Standard does not purport to include all necessary provisions of a contract. Users are 
responsible for its correct application  
© UNBS 2008  
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilised in any 
form or by any means, electronic or mechanical, in cluding photocopying and microfilm, without prior written 
permission from UNBS. 
Requests for permission to reproduce this document should be addressed to 
The Executive Director 
Uganda National Bureau of Standards 
P.O. Box 6329 
Kampala  
Uganda 
Tel: 256 414 505 995 
Fax: 256 414 286 123 
E-mail: unbs@infocom.co.ug
Web: www.unbs.go.ug  US 774:2008 
© UNBS 2008 – All rights reserved  iii
 Contents Page 
1 Scope ......................................................................................................................................................1  
2 Terms and definitions ...........................................................................................................................1  
3 Types ......................................................................................................................................................2  
4 Sizes and tolerances .............................................................................................................................6  
5 Components, materials and construction ..........................................................................................7  
5.1 Components ...........................................................................................................................................7  
5.1.1 General ...................................................................................................................................................7  
5.1.2 Chinstrap/retention system ..................................................................................................................7  
5.1.3 Shell ........................................................................................................................................................7  
5.1.4 Shock-absorbing liner ...........................................................................................................................7  
5.2 Materials .................................................................................................................................................7  
5.3 Construction ..........................................................................................................................................8  
6 Requirements .........................................................................................................................................8  
6.1 Shock absorption ..................................................................................................................................8  
6.2 Penetration resistance ..........................................................................................................................9  
6.3 Rigidity ...................................................................................................................................................9  
6.4 Strength of chinstrap and fastening device .......................................................................................9  
6.4.1 Resistance to deformation ...................................................................................................................9  
6.4.2 Resistance of chinstrap and fastening device to detachment from shell .......................................9  
6.5 Flexibility of peak ..................................................................................................................................9  
7 Marking and labelling ............................................................................................................................9  
8 Sampling and criteria for conformity ................................................................................................10  
8.1 Lot............................................................................................................................... ..........................10  
8.2 Sampling ............................................................................................................................... ...............10  
8.2.1 General ............................................................................................................................... ..................10  
8.2.2 Sampling and acceptance for tests on sizes, components, materials and construction ............10  
8.2.3 Sampling and acceptance for test on requirements ........................................................................10  
8.3 Criteria for conformity .........................................................................................................................11  
9 Testing ............................................................................................................................... ...................11  
9.1 Conditioning for testing ......................................................................................................................11  
9.1.1 Pre-conditioning ............................................................................................................................... ...11 
9.1.2 Low temperature conditioning ...........................................................................................................11  
9.1.3 High temperature conditioning ..........................................................................................................11  
9.1.4 Wet conditioning ............................................................................................................................... ..11 
9.2 Impact management test ....................................................................................................................12  
9.2.1 Apparatus ............................................................................................................................... ..............12  
9.2.2 Test definitions ............................................................................................................................... .....12  
9.2.3 Test impacts ............................................................................................................................... ..........13  
9.2.4 Impact test interpretation ...................................................................................................................13  
9.3 Penetration test ............................................................................................................................... ....14  
9.3.1 Apparatus and principle .....................................................................................................................14  
9.3.2 Procedure ............................................................................................................................... ..............14  
9.4 Rigidity test ............................................................................................................................... ...........14  
9.4.1 Apparatus ............................................................................................................................... ..............14  
9.4.2 Procedure ............................................................................................................................... ..............14  
9.5 Test for strength of retention systems with chin straps .................................................................15  
9.5.1 General ............................................................................................................................... ..................15  
9.5.2 Apparatus ............................................................................................................................... ..............15  US 774: 2008 
iv © UNBS 2008 – All rights reserved
 9.5.3 Procedure for resistance to deformation ......................................................................................... 15  
9.6 Face shield penetration test .............................................................................................................. 16  
9.7 Peripheral vision test ......................................................................................................................... 17  
9.8 Test of flexibility of peak .................................................................................................................... 19  
Annex A (normative)   Headforms .................................................................................................................. 21  
Annex B (normative)  Reference headforms (shape, dimensions above reference plane) ..................... 23  
Annex C (normative)  Helmet size testing with respect to headforms ....................................................... 28  
 US 774:2008 
© UNBS 2008 – All rights reserved  v
 Foreword 
Uganda National Bureau of Standards (UNBS) is a parastatal under the Ministry  of Tourism, Trade and 
Industry established under Cap 327, of the Laws of Uganda.  UNBS is mandated to co-ordinate the 
elaboration of standards and is  
(a) a member of International Organisation for Standardisation (ISO) and  
(b) a contact point for the WHO/FAO Codex A limentarius Commission on Food Standards, and  
(c) the National Enquiry Point on TBT/SPS Agr eements of the World Trade Organisation (WTO). 
The work of preparing Uganda Standards is carried out through Technical Committees. A Technical 
Committee is established to deliberate on standards in a gi ven field or area and consists of representatives of 
consumers, traders, academician s, manufacturers, governme nt and other stakeholders. 
Draft Uganda Standards adopted by the Technical Committ ee are widely circulated to stakeholders and the 
general public for comments. The committee reviews the comments before recommending the draft standards 
for approval and declaration as Uganda Standards by the National Standards Council.  
Committee membership 
The following organisations were represented on the Technical Committee for Transport and Communication 
standards, UNBS/TC 8, in the development of this standard: 
• Arrive Alive Uganda 
• Chevron Uganda Ltd 
• Kyambogo University 
• Makerere University 
• Ministry of Finance , planning and Economic Development 
• Ministry of Works and Transport 
• Shell Uganda Ltd 
• Total Uganda Ltd 
• Uganda National Bureau of Standards (UNBS) US 774: 2008 
vi © UNBS 2008 – All rights reserved
 Introduction 
Road traffic injuries are a major problem and a leading cause of death and injury around the world. Each year 
nearly 1.2 million people die as a result of road crashes,  and millions more are injured or disabled. In many 
low-income and middle-income countries, where motorcycles and bicycles are an increasingly common 
means of transport, users of two-wheelers make up a la rge proportion of those injured or killed on the roads. 
Motor cycle and bicycle riders are at an increased risk of  being involved in a crash. This is because they often 
share the traffic space with fast-moving cars, buses and trucks, and also because they are less visible. In addition, their lack of physical protection makes them particularly vulnerable to being injured if they are 
involved in a collision. Injuries to the head and neck are t he main cause of death, severe injury and disability 
among users of motorcycles and bicycles.  
Globally, there is an upward trend in the number and use of  motor cycles and bicycles, both for transport and 
recreational purposes. Indeed, most of the growth in the number of vehicles on t he world’s roads comes from 
an increasing use of motorized two-wheelers. UGANDA STANDARD US 774: 2008
 
 
1                 © UNBS 2008 – All rights reserved 
 Specification for protective helmets for motor cycle users 
1 Scope 
This Uganda Standard specifies types, sizes and tolerances, components, materials and construction,
requirements, marking and labelling, sampling and criteria for conformity and testing for protective
helmets for motor cycle users (riders and passengers). 
This standard is applicable only to protective helmets for users of general motor bicycles and certain motor 
cars, which shall be referred to hereinafter as "helme ts"; it does not cover helmets for vehicle users in 
competitive events. 
2 Terms and definitions 
For the purpose of this standard, the fo llowing terms and definitions shall apply. 
2.1  
protective helmet 
helmet primarily intended to protect the upper part of the wearer's head against a blow. Some helmets may 
include additional protection features. 
2.2  
half type protective helmet 
helmet having a shell to protect the upper part of the wearer's head 
2.3 
headform 
three dimensional approximation of part, or all, of  the human head, excluding facial features and pinnae 
2.4  
jet type protective helmet 
helmet having a shell to protect the upper part of the we arer's head, the occipital and jaws areas of the wearer 
2.5   
full-face type protective helmet 
helmet having a shell to protect the upper part of the head, the occipital and chin areas of the wearer 
2.6  
shell 
hard material that provides the outer form of the helmet, covering the shock absorbing liner and other 
components US 774: 2008 
2 © UNBS 2008 – All rights reserved
 2.7  
shock-absorbing liner 
lining material provided inside the helmet to mitigate the effects of a blow on the head 
2.8 
chinstrap  
strap which passes under or round the wearer's chin to retain the helmet in a position that can be adjusted to 
tighten or loosen as appropriate 
2.9  
cushioning 
lining material provided to improve wearing comfort 
2.10  
ear flap 
part of the helmet designed to cover the wearer's ear  
2.11   
rim 
part covering the edge of the helmet 
2.12  
peak 
permanent or detachable extensi on of the shell above the eyes 
2.13  
windshield 
part protecting eyes against wind 
2.14 
ventilation holes  
holes made in the shell to permit circulation of air inside the helmet 
2.15  
hearing holes  
holes designed to permit hearing 
2.16 
goggles strap holder 
device on the shell for holding the goggles strap 
2.17 
visor 
transparent protective screen extending over the eyes and covering all or part of the face 
2.18 
labelling  
marking of the helmet with the largest and smallest  appropriate head circumferences in centimetres 
3 Types 
Protective helmets shall be divided into 3 types:  
a) half type protective helmet (see Figure 1) 
b) jet type protective helmet (see Figure 2)  
c) full-face type protective helmet (see Figure 3)  US 774:2008 
© UNBS 2008 – All rights reserved  3
  
 
 
 
 
 
Figure 1 — Half type protective helmet 
 
 
 
 
 
 
 
 US 774: 2008 
4 © UNBS 2008 – All rights reserved
  
 
 
 
 
 
 
 
Figure 2 — Jet type protective helmet 
 
 
 
 
 
 US 774:2008 
© UNBS 2008 – All rights reserved  5
  
 
 
 
 
 
Figure 3 — Full face type protective helmet 
Key 
1. Shell  
2. Shock-absorbing liner 
3. Chinstrap 
4. Cushioning 
5. Ear flaps 
6. Rim (if any) 
7. Peak (if any) 
8. Windshield (if any) 
9. Goggles strap holder (if any) 
 US 774: 2008 
6 © UNBS 2008 – All rights reserved
 4 Sizes and tolerances 
Helmets are of generally of 8 sizes,  
• Extra Extra Small (XXS),  
• Extra Small (XS),  
• Small (S),  
• Medium (M),  
• Large (L)  
• Extra Large (XL),  
• Extra Extra Large (XXL) and  
• Extra Extra Extra large (XXXL).  
The suggested specification for these sizes is as show n Table 1 below. They shall ensure a close fit when 
mounted to head forms of the same code letter. 
Table 1 — Sizes of helmets 
Description Sizes Head circumference, 
mm 
Extra Extra Small XXS 510 - 520 
Extra Small XS 530 - 540 
Small S 550 - 560 
Medium M 570 - 580 
Large L 590 - 600 
Extra Large XL 610 - 620 
Extra Extra Large XXL 630 - 640 
Extra Extra Extra Large XXXL 650 - 660 
 
 
 
 
 
 
 
 
 US 774:2008 
© UNBS 2008 – All rights reserved  7
 Dimensions of head forms shall comply with Table 2 and Annex A.  
Compliance is checked by visual inspection and measurement. 
Table 2 — Sizes of headforms 
Symbols Size, 
mm Drop Mass, 
kg 
A 500 3.1 ± 0.10 
C 520 3.6 ± 0.11 
E 540 4.1 ±  0.12 
J 570 4.7 ± 0.14 
M 600 5.6 ± 0.16 
O 620 6.1± 0.18 
 
5 Components, materials and construction 
5.1 Components 
5.1.1 General 
General components of helmets shall comply with Figure s 1 - 3. Any devices fitted to the helmet, in particular 
the metallic part of rigid materials, protruding from the inside surface of the shell, shall be such that it is 
unlikely to cause any injury to the wearer in the event of an accident.  
5.1.2 Chinstrap/retention system 
The chinstrap fitted to the helmet shall not be less than 20 mm wide.  Fabric chinstrap, if used shall not be 
secured to the shell by bolt or by rivet.  Quick rele ase buckles, if used, shall not be able to be released 
accidentally. 
The chinstrap and fastening devices shall be securely fixed to the shell. 
Compliance is checked by visual inspection and measurement. 
5.1.3 Shell 
The shell shall be of uniform strength and shall no t be specially reinforced at any particular point. 
5.1.4 Shock-absorbing liner 
The shock-absorbing liner shall closely fit the inner curv ature of the shell and be capable of absorbing impact 
energy. 
Compliance is checked by visual inspection and test using 9.2. 
5.2 Materials 
The materials used in the manufacture of helmets shall be of  durable quality, that is, their characteristics shall 
not undergo appreciable alteration under influence of ageing or of the circumstances of use to which the US 774: 2008 
8 © UNBS 2008 – All rights reserved
 helmet is normally subjected, i.e. exposure to sun, rain , cold, dust, vibrations, skin , sweat or cosmetics for skin 
or hair.  
Chinstrap and fastening devices shall not be made of  materials that would be hazardous to the skin. 
Compliance is checked by visual inspection. 
5.3 Construction 
5.3.1  The assembled helmet shall have a smooth external and internal surface without reinforcing ridges. 
There shall be no external projections or concavity greater than 3 mm from the outer surface of the shell 
except a fastening device for peak or windshiel d which shall not project more than 7 mm.  
The above requirement does not apply to the co ncavity of the hearing hole and ventilation hole. 
Measurement of protrusion of the fa stening device for peak or windshield t hat is easily detachable shall be 
made with the peak or windshield removed. 
Measurement of protrusion of the fast ening device for peak or windshield that is not easily detachable shall be 
made without removing the peak or windshield. 
5.3.2  The fastening device fitted to the shell shall be protected to prevent abrasion with the wearer's head. 
5.3.3  Rivet heads shall not project more than 2 mm abov e the outer surface of the helmet and shall be free 
from sharp edges, offering no laceration or puncture hazard. 
5.3.4 An assembled helmet shall have a mass not exceeding 2 kg.  
5.3.5  The jet type helmet and the full-face type helmet shall provide for ventilation by holes permitting air to 
flow over the head top. 
5.3.6  An assembled helmet with ear-covering feature shall be provided with hearing holes. Compliance is 
checked by visual inspection. 
5.3.7  Face shield, if any, shall be made of transparent and colourless material and shall resist penetration 
by small particles.. 
5.3.8  Metallic screws and sharp metalli c rivets shall not be used. Co mpliance is chec ked by visual 
inspection and measurement. 
5.3.9  The helmet shall provide peripheral visual cl earance as measured using a reference headform 
appropriate to the size of the helmet. This peripheral visi on includes a horizontal clearance of at least 210°, an 
upward clearance of at least 7° and a downward clearance of at least 30°. However, this downward clearance 
makes specific allowance for breath def lectors. These clearances are described  in terms of planes fixed in the 
reference headforms. 
Compliance is checked by visual inspection and measurement. 
6 Requirements 
6.1 Shock absorption 
When the helmets are submitted to the low and high temp erature and moist conditions as described in clause 
9.2.3 and tested as prescribed either in clause 9.2.3.2 or clause 9.2.3.3 the follo wing requirements shall be 
adhered to:  
a) the force transmitted shall not exceed 20 kN; or US 774:2008 
© UNBS 2008 – All rights reserved  9
 b) the maximum acceleration of the head form shall not exceed 
2/000 2s mmg 
where  
m is the mass, in kilograms, of the head form plus helmet; and 
2g is acceleration of gravity expressed in m/s . 
The shell of the helmet shall not show any penetration cracks. 
6.2 Penetration resistance 
When tested in accordance with 9.3, the distance bet ween the point of the spike and the headform shall at no 
time be less than 5 mm. 
6.3 Rigidity 
When tested in accordance with 9.4 at an initial load of 30 N which shall be increased to 630 N, the difference 
of the distance between two metal plates measured at  both load applications shall not exceed 40 mm. After 
decreasing the load to 30 N, the difference of the distance between the two plates in relation to the initial load 
shall not exceed 15 mm. 
6.4 Strength of chinstrap and fastening device 
6.4.1 Resistance to deformation 
When tested in accordance with 9.5.3, the extension under specified load of chinstrap and fastening device 
shall not exceed 25 mm. 
6.4.2 Resistance of chinstrap and fastening device to detachment from shell 
When tested in accordance with 9.5.2 the chinstrap, t he fastening device and its attachment shall not break or 
tear away. 
6.5 Flexibility of peak 
If a peak is provided, when tested in accordance with 9.8 the deflection of the peak shall be not less than 6 mm and not more than 32 mm. 
7 Marking and labelling 
7.1 Each helmet shall be legibly and permanently marked on the inside in such a way that the following 
information is accessible to the user: 
a) type and code letter of the helmet; 
b) mass in grams or kilograms, to the nearest 50 g; 
c) size of the helmet in millimetres; 
d) month and year of manufacture or lot identification; US 774: 2008 
10 © UNBS 2008 – All rights reserved
 e) name of manufacturer or fact ory or registered trade-mark; and 
f) country of origin. 
In case foreign language is used, the meaning shall correspond to that in English specified above. 
7.2 Any person who manufactures products complying with this standard may use the Quality Mark in 
connection with his products only after having received a license from UNBS. 
8 Sampling and criteria for conformity 
8.1 Lot  
A lot comprises helmets of the same type and code letter made from the same materials under the same 
process which are manufactured or delivered or purchased at the same period of time. 
8.2 Sampling 
8.2.1 General 
Sampling and acceptance shall comply with the sa mpling plan or other technically equivalent plan. 
8.2.2 Sampling and acceptance for tests on siz es, components, materials and construction  
8.2.2.1  Samples shall be drawn at random from the same lot as given in Table 3. 
8.2.2.2  Provided the number of the samples failing to comply with each of the requirements of clauses 4 
and 5 does not exceed the acceptance number given in Tabl e 3, that lot shall be deemed to comply with the 
requirements. 
8.2.3 Sampling and acceptance for test on requirements 
8.2.3.1  Samples shall be drawn at random from those which conformed to the requirements on sizes, 
components, materials and construction in accordance with Table 3, and divided into portions as follows: 
a) 1/6 of the sample size shall be tested for p enetration resistance, then subjected to the tests on 
strength of chinstrap and fastening dev ice and flexibility of peak respectively; 
b) 1/2 of the sample size shall be tested for shock absorption; and 
c) 1/3 of the sample size shall be tested for rigidity (number of tests along the longitudinal and those 
along transverse axes being equal.) 
8.2.3.2  Provided all the samples meet all requirements of Cl ause 6, that lot shall be deemed to comply with 
the requirements. 
 
 
 
 
 US 774:2008 
© UNBS 2008 – All rights reserved  11
 Table 3 — Sampling plan for tests on sizes, components, materials and construction and other 
requirements (8.2.1 and 8.2.2.1) 
Tests on sizes, components, 
materials and construction Test on other 
requirements 
Lot size units 
Sample size 
units Acceptance 
number Sample size units 
Up to 500 20 2 7 
501 up to 1200 32 3 12 
1201 up to 3200 50 5 18 
3201 up to 10000 80 7 24 
 
8.3 Criteria for conformity 
Provided the samples meet all the requirements of 8.2.2.2 and 8.2.3.2, that lot of helmets shall be deemed to 
comply with the standard. 
9 Testing 
9.1 Conditioning for testing 
9.1.1 Pre-conditioning 
All helmets shall be pre-conditioned for at least six hour s at a temperature of 25 °C ± 5 °C and a relative 
humidity of 65 % ± 5% before applying the followi ng individual conditioning treatment and testing. 
9.1.2 Low temperature conditioning 
The helmet shall be placed in a refrigerator at a temperature of -10 °C ± 2 °C for not less than 4 h and not 
more than 24 h. 
9.1.3 High temperature conditioning 
The helmet shall be placed in an oven at a temperatur e of 50 °C ± 2 °C for not less than 4 h and not more 
than 24 h.  
Refrigerator and oven shall be sufficiently large to ensur e that the helmets do not touch one another or the 
sides. In any event the total volume shall be not less than 0.13 m3. The oven shall be fitted with a fan to 
provide effective air circulation. The relative humidity of  the air in the oven shall be controlled at approximately 
65 % ± 5 % by means of a saturated solution of sodium dichromate or by other equivalent method. 
9.1.4 Wet conditioning 
After removal of any protective covering from the outs ide of the shell, the helmet shall be sprayed externally 
with water at 25 °C ± 5 °C at the rate of 1 dm3 /min for not less than 4 h and not more than 24h. US 774: 2008 
12 © UNBS 2008 – All rights reserved
 9.2 Impact management test 
9.2.1 Apparatus 
9.2.1.1 The smallest of the headforms appropriate for the helmet sample,  which shall be of rigid, low 
resonance metal such as magnesium alloy and shall conf orm to the ‘A’, ‘E’, ‘J’, ‘M’ or ‘O’ geometries 
9.2.1.2 Ball-arm/collar assembly  which is fitted to a socket machined into the base of the headform. 
The ball/socket configuration shall be such that the geom etrical centre of the ball is located on the central 
vertical axis of the head form 12.7 mm above the refe rence plane. The ball-arm/collar assembly shall also 
include a unixial accelerometer fixed firmly into the ball. 
9.2.1.3  Headform support assembly rigidly attached to the ball-arm.   This support assembly shall be 
such that it and consequently the headform may be gui ded in a vertical drop. The weight of the support 
assembly shall not exceed 25% of the combined weights of the headform,  ballarm, collar and accelerometer. 
The total mass of the headform/support assembly shall be 5.0 kg ±.1 kg.  
9.2.1.4  Guidance system such that the headform/support assembly is guided in a vertical drop onto a 
test anvil. This guidance system may consist of two or more wires or one or more rails. The headform/support 
- guidance system - test anvil alignment shall be such that: 
a) the drop trajectory shall be a strai ght line within 3° of vertical and with in 5° of the sensitive axis of the 
uniaxial accelerometer. 
b) the line parallel to the drop trajectory and passing through the centre of the h eadform ball-socket shall 
pass within 5 mm of the centre of the test anvil,  within 10 mm of the centre of gravity of the 
headform/support assembly, and within 5 mm of the s ensitive element of the uniaxial accelerometer. 
9.2.1.5 Rigid anvil mount  consisting of a solid mass of at least 135 kg.  The upper surface of the anvil 
mount shall consist of a steel plate with a minimum thickness of 12 mm and a minimum surface area of 0.10 
m2. 
9.2.1.6 Three test anvils: flat, hemispherical and edge  
9.2.1.6.1 The flat anvil shall have a minimum surface area of 0.0127 m2,for example 127 mm diameter 
face. When fixed in position on the anvil mount, the surf ace shall be perpendicular to the headform trajectory. 
9.2.1.6.2  The hemispherical anvil shall have a 48 mm ± 0.5 mm radius. 
9.2.1.6.3  The edge anvil shall have a striking face 6.3 mm wi de by at least 180 mm long with a depth of at 
least 35 mm. When in position, the striking face shall be perpendicular to the headform trajectory. 
9.2.1.7 Uniaxial accelerometer. The acceleration data channel shall comply with SAE recommended 
practice J 211 requirements for channel class 1000 with  the exception that the frequency response need not 
include the range from dc to 10 hz which may not be obtainable using certain types of transducers. 
9.2.1.8 Velocity measurement device  which will yield the velocity of the headform/support assembly 
within the last 40 mm of travel before impact. The velo city measurements shall be accurate to within ±1%. 
9.2.2 Test definitions 
9.2.2.1 The impact site refers to the portion of the helmet struck during an impact test. It is defined as the 
point where a line passing through the centre of the headform ball and the centre of the anvil intersects the 
outer surface of the helmet at the inst ant the helmet first touches the anvil. 
9.2.2.2 The impact energy is the kinetic energy of t he headform/support assembly at the instant of 
impact. It is defined as the mass of the headform/s upport assembly times the square of the velocity 
measurement times one half. The mass of the helmet is ignored in this calculation. US 774:2008 
© UNBS 2008 – All rights reserved  13
 9.2.2.3 There are two levels of test.  The first is the st andard level used to identify those helmets which 
definitely meet this standard and which are applied to sa mples submitted for certification testing and to those 
acquired for the random sample test (RST) program. The second is the deviation level which is applied to 
samples acquired for second round RST procedures, that is: testing of sa mples of currently certified models 
for which previous samples have obtained failing results in RST testing. 
9.2.3 Test impacts 
9.2.3.1 Test impact sites shall be on or above the test line. Rivets, vents and any other helmet feature 
within this region shall be valid test sites. Each impact site will be subjected to a group of one or two impacts 
according to the anvil selected for that site.  The impact si te for the first impact within a group is the target for 
the successive impacts in the same group. However, if an impact group is sited closer than 120 mm to any 
previous impact group, that later impact shall be declared invalid.  There is no restriction regarding test anvil 
selection. The impact energies for each te st impact are in 9.2.3.2 to 9.2. 3.4 
9.2.3.2 There shall be two impacts at each site tested a gainst the flat anvil.  For the first impact, the 
impact energy shall be 150 J for all standard level testing and 140 J for all deviation level testing. For the second impact, the impact energy shall be 110 J for all standard level testing and 105 J for all deviation level testing. Given an ideal frictionless mechanical test fa cility, the standard impact energies represent 3.0+ meter 
drops of a 5 kg headform and supporting assembly. 
9.2.3.3 There shall be two impacts at each site tested  against the hemispherical anvil. For the first 
impact, the impact energy shall be 150 J for all standard level testing and 140 J for all deviation level testing. For the second impact, the impact energy shall be 110 J for all standard level testing and 105 J for all 
deviation level testing. Given an ideal frictionless mechanical test facility, t he standard impact energies 
represent 3.0+ meter drops of a 5 kg headform and supporting assembly. 
9.2.3.4 There shall be one impact at each site tested  against the edge anvil. For each impact against the 
edge anvil, the impact energy shall be 150 J for all st andard level testing and 140 J for all deviation level 
testing. Given an ideal frictionless mechanical test facility, this standar d impact energy represents a 3.0 + 
metre drop of a 5 kg headform and supporting assembly. 
9.2.3.5 If the impact energy for any test impact exceeds the energy specified by more than 3 %, that 
impact shall be declared invalid. 
NOTE The impacts described above are based on specific energies and not pre scribed drop heights. To attain the 
proper energy for an impact, it is likely that the drop height will need to be adjust ed to compensate for frictions inherent in  
most mechanical helmet testing systems. Height adjustments for these frictions shou ld not account for mo re than 10 % of 
the total drop height. Also, the 3 % margin allowed for impac t energy reflects the uncertainties expected even for well 
maintained drop equipment. It is expected that drop heights will  always be selected to produce,  as closely as possible, the 
precise impact energy called out in the standards. 
9.2.4 Impact test interpretation 
The peak acceleration of the headform shall not exceed 290 G’s for any valid certification impact nor 300 G’s 
for any other valid test impact.  The helmet’s protective structures shall not break apart throughout the testing. 
If the UNBS technical personnel conclude that fracture of  the helmet shell, impact liner, retention system or 
other components could reasonably imply an undue laceration  hazard either from the impact surface or from 
the helmet itself, the sample shall be considered to have failed. A flip-up configuration tested with the chin bar closure locked at the outset of a valid impact and which releases inadvertently as a result of the impact will also be deemed to have failed.  If, in certification testing, a sample is found to meet all the test criteria but any 
two of the impacts were at less than 97% of the impact energy specified, the testing for that sample shall be 
declared inconclusive and shall be repeated. Similarly, if there are two instances where an impact falls beyond 10 mm from the first impacts in its group, the testing for the sample shall be declared inconclusive and must 
be repeated. 
Finally, if an invalid impact produces a peak accelerati on exceeding the test criterion, the testing for the 
sample shall be declared inconclusive and must be r epeated.  The impact test procedures leave considerable 
latitude to the helmet tester regarding site and anvil sele ction. It is expected that the tester will orchestrate US 774: 2008 
14 © UNBS 2008 – All rights reserved
 each standard test series in order to investigate potential  weaknesses and to exercise each likely failure mode 
and will conduct deviation level testing to exerci se the failure modes identified previously. 
9.3 Penetration test 
9.3.1 Apparatus and principle 
A conical spike shall be placed on the shell at the point to be tested. The weight shall fall on to the top of the 
spike, and the depth of penetration of the spike shall be measured by a suitable non-inertial device such as a 
photo-electric cell. 
The penetration test striker shall have a mass of 3 kg ± 50 g. The striker shall fall through a height of 3 000 
mm ± 15 mm.  The point of the striker shall be a cone with an included angle of 60° ± 0,5° and an altitude of 
38 mm ± 0,38 mm. The striking tip shall have a hardness of 60 Rockwell (scale C ± 3 points) and a radius of 
0.5 mm ± 0.01 mm.  The test striker may be directed at any site on or above the test line but the penetration 
test site shall be at least 75 mm removed from the centre  of any impact test site or any other penetration test 
site. At the test technician’s discretions, samples may be tested at more than one site on the shell. 
For all penetration tests performed, t he test striker shall not penetrate to achieve even momentary contact with 
the test headform. 
Any helmet with ventilation ducts on the s hell shall be exempt from penetration test. 
9.3.2 Procedure 
9.3.2.1 The helmet is conditioned in the manner that gave th e worst result in the shock absorption test as 
in 9.2.3 and then tested in accordance with clause 9. 3.2.2 within 1 min of the time of removal from the 
conditioning atmosphere, the helmet being placed firmly on the appropriate headform in accordance with 
Annex A as in actual use. 
9.3.2.2  The spike is placed on the shell at the test po int which should be above line AA (see Figure 11). 
The striker is allowed to fall on to the top of the spik e through a distance of 1 metre measured from the top of 
the spike to the underside of the striker. 
9.3.2.3  The minimum distance remaining between t he point of the spike and the headform shall be 
measured. 
9.4 Rigidity test 
9.4.1 Apparatus 
Two metal plates for loading 
9.4.2 Procedure 
9.4.2.1  Samples are subjected to pre-conditioning as in 9.1.1 with number of tests along the longitudinal 
and those along transverse axes being equal. 
Each helmet is placed between two parallel plates. 
9.4.2.2  Apply an initial load of 30 N to the shell. After 2 min the distance between the plates is measured. 
9.4.2.3  Increase the load to 630 N by increments of 100 N every 2 min. Maintain the load of 630 N for 2 
minutes, then measure the distance between the plates. 
9.4.2.4  The load is then reduced to 30 N and maintained for 5 min and the distance between the plates is 
re-measured. US 774:2008 
© UNBS 2008 – All rights reserved  15
 9.5 Test for strength of retention systems with chin straps 
9.5.1 General 
A downward shock load is applied twice to the chin st raps on a helmet. Dynamic and static extensions and 
slippage of the strap are observed.  
9.5.2 Apparatus 
A suitable apparatus is shown in Figure 4. 
A support is provided for base of the brim of the helmet under test and additional support is provided for a 
headform.  
NOTE For this test the headform is used only for pos itioning purposes and is not required to withstand any 
substantial loading. It may, therefore be ma de of material other than metal or wood.  
Below the approximate chin strap position a guide bar is mounted in guides which maintain it in position while 
permitting substantially frictionless vertical movement. T he upper end of the bar carries two parallel horizontal 
rollers capable of free rotation, each 12.5 mm ± 0.5 mm in  diameter and at 76.0 ± 0.5 mm centres separation. 
This arrangement is considered to approximate to the bone structure of a human lower jaw. 
Means are provided for measuring both the maximum dy namic vertical extension and the static residual 
vertical extension of any chain strap looped under the roller. This may be achieved by attaching to the guide 
bar a displacement transducer and a pointer indicating against a fixed vertical scale.  
Any anvil having a horizontal upper surface cushioned by a pad of foam 10 ± 2 mm thick is rigidly mounted on 
the guide bar. 
NOTE Polyethylene foam with a bulk density of 40 kg/m3  hasbeen found suitable. 
A drop weight of mass 10 kg can be slid up the bar and dropped onto the anvil in substantially frictionless 
fall through a distance of at least 750 mm. 0.25
0+
−
The total mass of the guide bar and all its attachments excluding the drop weight is  kg. 7.00
0.25+
−
9.5.3 Procedure for resistance to deformation 
Place the helmet with its base resting on the helmet support and adjust the headform to steady the helmet in 
such a position that when the fastened chin strap is pulled vertically downw ards it lies in the same vertical 
plane as  the guide bar. With the drop weight in its ra ised position, the chin strap is fastened under the rollers 
so that the chin strap supports the weight of the guide bar and anvil, and the buckle is not in contact with the 
roller. It is recommended that the rollers should be approximately 130 mm below the headform reference line. 
Read or set to zero the static extension measuring dev ice and mark the position of the buckle on the chin 
strap. Allow the drop weight to fall on to the anvil through a height of 750 mm ± 5 mm, including the thickness 
of the foam pad. Read the peak dynamic extension and while the drop weight rests on the anvil re-read, or 
read and set to zero, the static extension measuring device. 
NOTE Extension includes any slippage of the buckle. 
Without disturbing the helmet or ch in strap, raise the drop weight and repeat the impact. Read the peak 
dynamic extension and, while the drop  weight rests on the anvil, note t he static extension. Re-mark the 
position of the buckle on the chin strap.  US 774: 2008 
16 © UNBS 2008 – All rights reserved
 Record the peak dynamic extension an d static extension for each impact separately and the total slippage of 
the buckle. 
 
 
 
Figure 4 — Apparatus for testing retention system strength 
9.6 Face shield penetration test 
If a face shield is provided with a full face helmet, this face shield shall be tested for penetration resistance in 
the following manner: 
The face shield shall be tested on the appropriate helm et, correctly deployed across the facial opening and 
under laboratory ambient conditions.  A soft lead pellet weighing 1 g ± 0.1 g with a diameter of 5.5 mm ± 0.1 
mm and travelling at a velocity of 500 km ± 20 km per hour  shall strike the face shield normal to the surface. 
The face shield shall be tested in at least three different locations: the centre line and 80 ± 5 mm to either side 
of the centre line. The pellet shall not penetrate to the interior of the helmet. US 774:2008 
© UNBS 2008 – All rights reserved  17
 9.7 Peripheral vision test  
The clearance for peripheral vision will be checked by placing the helmet on each appropriate ISO headform, 
positioning it according to the opposite helmet positioning index and holding it in place with a force of 50 N. 
The clearance shall include the following so lid angles to the front of the headform: 
a) the upward visual clearance; 
b) the lateral visual clearance; and 
c) the downward visual cl earance except for the breat h deflector allowance. 
The upward visual clearance is the solid angle boun ded by the reference plane of the headform and a second 
plane tilted 7° up from the reference plane. This second plane intersects the reference plane at two points on  
the front surface of the headform that  are 31 mm to the right and left of the longitudinal plane as shown in 
Figure 5. 
 
 
 
Figure 5 — Upward visual clearance 
 
The lateral visual clearance, as shown in Figure 6, is the solid angle bounded by the reference plane, the S 4 
plane and two more planes that are perpendicular to the reference plane and that contain the reference point 
on the front of the headform. One of these two planes forms an angle of 105° with the longitudinal plane and 
lies to the left of the headform. 
 
 
 
 
 
 
 
 
 
 
 US 774: 2008 
18 © UNBS 2008 – All rights reserved
  
 
Figure 6 — Lateral vision clearance 
The other forms the same angle to the right of the headform.  The downward visual clearance is the solid 
angle bounded by the basic plane of the headform and a second plane tilted 30° down from the basic plane 
that intersects it at two points on the front surface of  the headform that are 31 mm to the right and left of the 
longitudinal plane as shown in Figure 7. However, intrusions into this downward clearance are permitted so 
long as the intrusions are within the breath deflector allowance.   
 
 
 
Figure 7 — Downward visual clearance 
 
 US 774:2008 
© UNBS 2008 – All rights reserved  19
  
 
 
Figure 8 — Breath deflective allowance 
 
The breath deflector allowance is shown in Figure 8. It in cludes the region that is within 31 mm to the right and 
left of the longitudinal plane and that lies below the two planes that form 45° angles with the longitudinal plane 
and that intersect it at the level of the S  plane. 4
9.8 Test of flexibility of peak 
The sample which passed the test for the fastening device and chinstrap strength shall be mounted on an 
appropriate headform (Annex A) with a mass of 12 kg applied to the top of the helmet to hold it firmly in place. 
A mass of 1 kg shall be then freely suspended for 2 minutes  from a point within 12.5 mm of the centre of the 
front edge of the peak. The deflecti on of the peak shall be measured. 
 
 
Figure 9 — Test for flexibility of peak 
 US 774: 2008 
20 © UNBS 2008 – All rights reserved
  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Figure 10 — Test for resistance to deformation 
 US 774:2008 
© UNBS 2008 – All rights reserved  21
 Annex A 
(normative)  
 
Headforms 
 
Figure 9 — Headform  
 
The extent of protection corresponds to that region of the head for which protection is sought. This region is 
defined according to the geometry of five refe rence headforms: ‘A’, ‘E’, ‘J’, ‘M’ and ‘O’. 
There are a number of planes fixed in the geometry of  these headforms as shown in Figure 11. This 
description of the extent of protecti on uses the definitions of the basic plane, the longitudinal plane, the 
transverse plane and the reference plane.  The longitudinal plane is perpendicular to the basic plane and is 
the plane of symmetry dividing the right  half of the headform from the left. The transverse or coronal plane is 
perpendicular to both the longitudinal and basic planes. It corresponds to the anatomical plane that contains 
the two auditory measures and divides the front from the rear portions of the head. The reference plane is 
parallel to the basic plane and lies above it at a distance  determined by the size of the headform: 24 mm, 26 
mm, 27.5 mm, 29 mm and 30 mm for the ‘A’ through ‘O’ headforms respectively. 
These four planes are all well known entities. The remaining planes, however, have been defined purely for the purposes of this standard. The S
0 plane is parallel to the basic plane and lies above it at a distance 
determined by the size of the headform, 46,8 mm, 50,0 mm, 53,0 mm,  55,2 mm and 57,2 mm for the ‘A’ 
through ‘O’ headforms respectively. 
The S 3 plane is parallel to the S0 plane and the basic plane and lies between them at a distance of 26.1 mm, 
28.2 mm, 30 mm, 31.5 mm and 32.2 mm below the S 0 plane for the ‘A’ through ‘O’ headforms respectively. 
The S 4 plane is also parallel to the S 0 plane and lies below it at a distan ce of 52,2 mm, 56,4 mm, 60,0 mm, 
63,0 mm and 64,5 mm for the ‘A’ through ‘O’ headforms respec tively.  The rear plane divides the rear third of 
the head from the front two thirds. It is parallel to the tr ansverse plane and lies at a given distance behind the 
point where the reference plane and longitudinal planes in tersect with the front surface of the headform. The US 774: 2008 
22 © UNBS 2008 – All rights reserved
 distance from this point, hereafter called the reference point, is determined by the size of the headform: 128.6 
mm, 139.0 mm, 148.4 mm, 155.8 mm and 161.5 mm for t he ‘A’ through ‘O’ headforms respectively. 
The fore plane is also parallel to the transverse pl ane. It lies behind the reference point at a distance 
determined by the size of the headform, 39.0 mm, 42.2 mm, 45.2 mm,  47.4 mm and 49.2 mm for the ‘A’ 
through ‘O’ headforms respectively.  The extent of protection provided by the helmet shall include the entire 
region above the S 0 plane and forward of the fore plane, the entire region above the S 3 plane and between the 
fore and rear planes and the entire region above the S 4 plane and behind the rear plane (see Figure 12 and 
Table 4). 
 
 
Figure 12 — Extent of protection 
 
Table 4 — Extent of protection 
Dimensions in millimetres 
Head form a b c d e 
A 39,0 128,6 26,1 46,8 52,2 
E 42,2 139,0 28,2 50,0 56,4 
J 45,2 148,4 30,0 53,0 60,0 
M 47,4 155,8 31,5 55,2 63,0 
O 49,2 161,5 32,2 57,2 64,5 
 
 US 774:2008 
© UNBS 2008 – All rights reserved  23
 Annex B 
(normative) 
 
Reference headforms (shape, dime nsions above reference plane) 
 
Figure 13 — Headform 
Dimensions of upper part of headforms (to be used in conjunction with Figure 12 and Table 4) US 774: 2008 
24 © UNBS 2008 – All rights reserved
 Table B.1  — Headform A 
Dimensions in millimetres  
Height above 
reference line Front 
0º  
15º  
30º  
45º  
60º  
75º  
90º  
105º  
120º  
135º  
150º  
165º Rear 
180º 
0 88.1 86.4 83.1 75.4 69.9 66.8 66.5 69.3 73.4 78.8 84.1 87.6 88.1 
12.7 86.9 85.3 83.1 75.4 69.9 66.8 66.5 69.3 73.4 78.8 84.1 86.1 86.1 
25.4 84.6 83.6 82.3 75.4 69.9 66.8 66.5 69.3 73.4 78.8 84.1 86.1 86.1 
38.1 80.8 80.3 79.5 72.9 67.6 65.3 65.0 67.6 71.6 76.5 81.3 82.8 82.8 
50.8 74.7 74.4 74.0 68.1 63.2 61.0 60.7 63.2 66.8 71.6 73.7 76.7 76.7 
63.5 64.8 64.8 64.8 59.9 55.6 53.3 53.1 55.4 59.2 63.5 67.7 67.7 67.7 
76.2 45.7 45.7 45.5 43.4 41.4 40.4 40.4 42.4 46.2 50.5 54.6 54.6 54.6 
82.6 31.0 31.2 31.2 31.0 30.0 29.7 30.2 32.5 36.1 40.4 43.9 44.5 44.5 
Dimension Y: 89.7 mm – Head circumference:  500 mm 
 
Table B.2 — Headform C 
Dimensions in millimetres 
 
 
 Height above 
reference line Front 
0°  
15°  
30°  
45°  
60°  
75°  
90°  
105°  
120°  
135°  
150°  
165° Rear 
180° 
0 91.2 89.7 86.1 78.7 72.6 69.9 69.6 72.4 76.7 82.0 87.4 90.4 91.2 
12.7 89.9 88.6 86.1 78.7 72.6 69.9 69.6 72.4 76.7 82.0 87.4 90.4 91.2 
25.4 87.6 87.1 85.3 78.7 72.6 69.9 69.6 72.4 76.7 82.0 87.4 89.2 89.9 
38.1 84.6 83.8 82.3 76.5 70.6 68.1 68.1 70.6 74.7 79.8 84.3 85..6 86.4 
50.8 78.5 78.2 77.5 72.4 66.5 64.3 64.3 66.5 70.4 75.4 79.5 80.3 80.8 
63.5 69.3 69.1 69.1 64.5 59.4 57.2 57.4 59.7 63.5 68.3 71.9 71.9 71.9 
76.2 52.3 52.3 52.3 49.3 46.2 45.2 45.7 48.0 51.6 56.1 59.4 59.7 59.9 
82.6 39.9 39.9 39.9 38.1 37.1 36.6 36.8 38.6 41.9 46.2 50.5 51.1 51.3 
88.9 20..6 20.6 20.6 21.3 22.1 22.9 23.9 25.4 28.2 31.8 34.3 34.5 34.5 
Dimension Y: 92.7 mm – Head circumference: 540 mm US 774:2008 
© UNBS 2008 – All rights reserved  25
 Table B.3 —- ISO Headform E 
Dimensions in millimetres  
Height 
above 
reference 
line 0° 
Front 15° 30° 45° 60° 75° 90° 105° 120° 135° 150° 165°180o
Rear 
0 
94.5 93.0 89.7 82.0 76.2 73.2 72.9 75.7 79.8 84.8 90.7 93.7 94.5 
12.7 93.2 91.9 89.7 82.0 76.2 73.2 72.9 75.7 79.8 84.8 90.7 93.7 94.5 
25.4 91.2 90.7 88.9 82.0 76.2 73.2 72.9 75.7 79.8 84.8 90.7 92.7 93.0 
38.1 87.6 87.9 85.9 80.0 74.7 71.6 71.4 74.2 77.7 82.6 88.6 89.2 89.2 
50.8 82.0 82.3 81.0 75.4 70.4 67.8 67.6 70.4 73.9 79.0 83.8 84.3 84.3 
63.5 73.4 73.7 73.4 68.6 64.0 61.5 61.2 63.5 67.1 71.9 76.5 76.5 76.5 
76.2 57.7 57.9 58.2 55.9 52.6 50.5 50.3 52.1 55.1 59.7 64.5 64.8 64.8 
82.6 46.5 46.5 46.5 45.2 43.2 42.4 42.9 44.5 47.5 52.3 56.4 56.6 56.6 
88.9 30.5 30.5 30.7 31.0 31.2 31.2 31.8 33.8 36.8 40.4 43.9 44.2 44.2 
Dimension:  Y:  96 mm – Head Circumference:  540 mm 
 
Table B.4 — Headform G 
Dimensions in millimetres 
Front  Height 
above 
reference 
line 0° 15° 30° 45° 60° 75° 90° 105° 120° 135° 150° 165° Rear 
180° 
0 97.5 95.8 93.0 85.1 79.5 76.2 75.9 78.5 83.1 88.4 94.0 97.0 97.5 
12.7 96.3 95.3 92.7 85.1 79.5 76.2 75.9 78.5 83.1 88.4 94.0 97.0 97.5 
25.4 93.7 92.7 91.4 85.1 79.5 76.2 75.9 78.5 83.1 88.4 94.0 95.8 96.3 
38.1 90.4 89.7 88.9 83.3 77.7 75.2 74.9 77.0 81.3 86.6 91.7 92.7 93.0 
50.8 86.1 85.6 84.6 79.0 73.7 71.1 70.9 73.2 78.0 82.8 87.1 87.9 88.1 
63.5 77.5 77.2 76.5 72.1 67.3 64.5 64.3 66.5 70.9 75.9 79.0 79.8 80.0 
76.2 63.8 63.8 64.0 61.2 57.4 53.3 54.9 56.9 61.5 66.5 68.8 69.1 69.1 
88.9 39.6 39.6 39.6 39.1 38.4 37.8 38.4 40.4 44.2 49.8 52.8 53.8 53.8 
95.3 20.6 20.6 20.6 21.3 22.4 23.4 23.9 25.4 28.7 33.5 37.8 39.1 39.1 
Dimension:  Y:  96 mm – Head Circumference:  560 mm US 774: 2008 
26 © UNBS 2008 – All rights reserved
 Table B.5 —ISO Headform J 
Dimensions in millimetres  
Height 
above 
reference  
line 0° 
Front 15° 30° 45° 60° 75° 90° 105° 120° 135° 150° 165° 180o
Rear 
0 100.8 98.8 96.5 88.1 82.0 79.5 79.2 82.0 85.9 91.7 96.8 100.1 100.8 
12.7 99.6 98.0 95.8 88.1 82.0 79.5 79.2 82.0 85.9 91.7 96.8 100.1 100.8 
25.4 96.8 95.8 94.5 88.1 82.0 79.5 79.2 82.0 85.9 91.7 96.8 98.3 98.8 
38.1 93.7 92.7 91.9 86.1 80.0 77.2 77.7 80.0 83.8 89.4 94.5 95.8 96.0 
50.8 89.2 88.6 87.9 82.0 76.2 73.9 74.4 77.0 80.5 85.9 90.4 90.9 90.9 
63.5 81.5 80.8 81.0 75.9 70.6 68.1 68.3 71.1 74.4 79.5 83..8 84.1 84.1 
76.2 69.3 69.1 69.3 65.3 61.2 58.9 59.2 61.7 65.0 69.3 73.2 73.4 73.4 
88.9 47.2 47.5 48.0 46.2 44.5 43.7 44.2 46.2 50.0 54.1 58.2 58.4 58.4 
95.3 32.8 32.8 33.3 32.5 32.0 32.3 33.0 35.1 38.1 42.2 46.5 47.3 47.2 
Dimension:  Y:  102.4 mm – Head Circumference:  570 mm 
 
Table B.6 — Headform K 
Dimensions in millimetres  
 
Front  Height above 
reference  line 0° 15° 30° 45° 60° 75° 90° 105° 120° 135° 150° 165° Rear
180°
0 102.4 101.1 97.0 89.7 84.1 81.3 80.8 83.3 87.9 92.7 98.3 101.6 102.4
12.7 101.1 100.1 97.0 89.7 84.1 81.3 80.8 83.3 87.9 92. 7 98.3 101.6 102.4
25.4 98.8 98.3 96.3 89.7 84.1 81.3 80.8 83.3 87.9 92.7 98.3 99.8 100.6
38.1 95.5 95.3 93.7 87.4 82.0 79.5 79.5 81.5 85.9 90.4 95.5 97.0 97.7
50.8 90.9 90.4 89.7 83.6 78.5 76.2 76.2 78.5 83.1 87.4 91.9 92.5 93.2
63.5 83.1 82.8 82.0 77.2 72.1 69.9 70.4 72.4 76.7 80.8 84.6 85.1 85.6
76.2 71.1 71.1 71.4 68.1 63.8 61.2 61.2 63.0 67.1 71.6 74.9 75.2 75.2
88.9 51.8 51.0 51.8 50.8 48.5 46.7 47.2 49.3 52.1 56.9 60.7 60.7 60.7
95.3 37.6 37.3 37.3 37.3 36.8 36.6 37.1 38.9 42.2 47.0 51.1 51.8 51.3
101.6 18.3 17.8 17.8 18.0 18.5 19.3 20.1 21.8 24.9 29.0 33.8 36.1 36.6
Dimension:  Y:  102.4 mm – Head Circumference:  580 mm US 774:2008 
© UNBS 2008 – All rights reserved  27
 Table B.7 — ISO Headform M 
Dimensions in millimetres  
Height 
above 
reference  
line 0° 15° 30° 45° 60° 75° 90° 105° 120° 135° 150° 165° 180o
Rear 
0 105.7 103.9 100.6 92.7 86.9 84.1 83.8 86.4 90.7 96.0 102.1 105.7 105.7 
12.7 104.4 103.4 100.3 92.7 86.9 84.1 83.8 86.4 90.7 96.0 102.1 105.7 105.7 
25.4 102.1 101.6 99.8 92.7 86.9 84.1 83.8 86.4 90.7 96.0 102.1 104.4 104.4 
38.1 99.3 98.8 97.8 90.9 85.3 82.6 82.3 84.6 88.9 94.0 99.8 100.8 101.1 
50.8 95.0 94.7 93.5 86.9 81.3 79.0 78.7 81.0 85.3 90.4 96.0 96.5 96.3 
63.5 87.1 86.9 86.9 80.8 75.4 73.2 73.2 75.4 79.5 84.8 89.4 89.7 89.4 
76.2 75.9 76.2 76.2 71.6 67.1 64.8 64.8 66.5 70.6 75.4 80.0 80.0 79.8 
88.9 58.2 58.2 58.2 56.6 54.6 52.3 52.3 53.8 56.9 61.7 66.8 67.1 66.8 
95.3 45.5 45.7 46.0 46.0 44.5 43.4 43.2 44.5 47.2 52.1 57.7 58.2 57.9 
101.6 26.4 26.2 26.7 27.7 28.7 29.5 30.0 31.2 34.0 38.6 42.7 43.2 42.7 
Dimension:  Y:  107.2  mm – Head Circumference:  600 mm 
 
Table B.8 —ISO Headform O 
Dimensions in millimetres  
Height above 
reference  line 0° 15° 30° 45° 60° 75° 90° 105° 120° 135° 150° 165° 180o
Rear 
0 108.7 107.4 103.4 95.8 90.4 87.6 87.1 90.2 94.2 99.8 105.4 107.4 108.7 
12.7 107.7 106.4 103.4 95.8 90.4 87.6 87.1 90.2 94.2 99.8 105.4 107.4 108.7 
25.4 105.2 104.4 102.9 95.8 90.4 87.6 87.1 90.2 94.2 99.8 105.4 106.7 106.9 
38.1 102.4 102.1 101.1 94.2 88.9 86.1 85.9 88.9 93.0 98.6 103.4 104.1 104.1 
50.8 97.8 97.5 96.5 90.2 58.1 82.3 82.6 85.3 89.9 94.7 99.6 100.3 100.3 
63.5 91.2 91.2 90.4 84..3 97.2 76.7 77.0 79.8 83.8 88.4 93.0 93.2 93.2 
76.2 81.0 81.3 80.8 76.2 71.6 69.3 69.6 71.9 75.7 80.5 84.6 84.6 84.6 
88.9 64.5 64.5 64.5 61.5 58.4 57.2 57.7 60.2 63.5 68.1 71.9 71.4 71.9 
95.3 54.1 53.8 54.1 52.6 50.3 49.0 49.5 51.6 55.4 60.5 64.3 64.0 64..0 
101.6 37.6 37.6 38.1 38.4 38.1 37.8 38.4 40.4 43.4 48.0 51.3 51.3 51.1 
Dimension:  Y:  110.2 mm – Head Circumference:  620 mm US 774: 2008 
28 © UNBS 2008 – All rights reserved
 Annex C 
(normative) 
 
Helmet size testing with  respect to headforms 
The table below shows the heads considered appropriate to head size ranges (in centimetres).  If a helmet‘s 
specified size range falls into one of the light gray ce lls along the table’s principal diagonal, only a single head 
form is deemed appropriate and only five samples fitted to the largest intended size are necessary, or else the 
manufacturer or marketer must provide two additional  samples fitted to the smallest intended head size. 
Table 13 — Test Head forms  
Test Head Forms as Determined by size (Head Circumference in mm) 
Largest Size Specified 
  500 - 520 - 530 540 - 560 570 - 590 600 - 610 ≥ 620 
<520 A A - C A - E A - J A - M A - O 
520 - 530   C C- E C - J C - M C - O 
540 - 560     E E - J E - M E - O 
570 - 590       J J - M J - O 
600 - 610         M M - O Smallest Size Specified 
≥ 620           O 
 
 US 774:2008 
© UNBS 2008 – All rights reserved  29
 Certification marking 
Products that conform to Uganda standards may be  marked with Uganda National Bureau of Standards 
(UNBS) Certification Mark shown in the figure below.  
The use of the UNBS Certification Mark is gove rned by the Standards Act, and the Regulations made 
thereunder. This mark can be used only by those licens ed under the certification mark scheme operated by 
the Uganda National Bureau of Standards and in co njunction with the relevant Uganda Standard. The 
presence of this mark on a product or in relation to a product is an assurance that the goods comply with the 
requirements of that standard under a system of supervision, control and  testing in accordance with the 
certification mark scheme of the Uganda National  Bureau of Standards. UNBS marked products are 
continually checked by UNBS for conformity to that standard.  
Further particulars of the terms and conditions of  licensing may be obtained from the Director, Uganda 
National Bureau of Standards.  
 
`US 774: 2008 
 
ICS nn.nnn.nn 
Price based on 36 pages 
© UNBS 2008– All rights reserved