ASTM F1446-20

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it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: F1446 − 15b F1446 − 20 An American National Standard
Standard Test Methods for
Equipment and Procedures Used in Evaluating the
Performance Characteristics of Protective Headgear
This standard is issued under the fixed designation F1446; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
INTRODUCTION
These test methods specify equipment and procedures used for testing protective headgear.
Individual ASTM performance standards (standard specifications) will use these procedures and
equipment. Test conditions, pass-fail criteria, and other performance requirements will be specified in
the individual performance standards, tailored to the needs of a particular activity (for example,
bicycling, skateboarding, skiing, etc.).
These test methods were developed using resources in medical, scientific, mechanical engineering,
human factors, and biomechanical fields. However, it is recognized that it is not possible to write a
protective headgear performance standard that will result in headgear that can protect against injury
or death in all accidents. It is also recognized that serious injury or death can result from both low-
and high-energy impacts, even when protective headgear is worn.
These test methods incorporate aspects of other recognized headgear performance standards. They
draw from work done by others where appropriate for these test methods. These standards are
referenced within this standard test method. It should be noted that these test methods specify
laboratory tests of completed headgear to measure its ability to reduce head acceleration during use
and other selected parameters.
1. Scope
1.1 These test methods cover laboratory equipment, procedures, and basic requirements pertinent to testing protective headgear.
Deviations or additions, or both, to these test methods will be specified, as required, in individual ASTM performance standards.
1.2 Requirements—The protective headgear is to be tested under specified environmental conditions for the following:
1.2.1 Impact attenuation (the limiting of head acceleration) of the protective headgear, and
1.2.2 Strength and stability of the retention system and its attachment to the protective headgear.
1.2.3 Special tests for particular protective headgear uses will be specified in the individual performance standards to be used in
conjunction with these test methods.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
These test methods are under the jurisdiction of ASTM Committee F08 on Sports Equipment, Playing Surfaces, and Facilities and are the direct responsibility of
Subcommittee F08.53 on Headgear and Helmets.
Current edition approved Nov. 1, 2015Oct. 1, 2020. Published January 2016November 2020. Originally approved in 1993. Last previous edition approved in 2015 as
F1446 – 15a.F1446 – 15b. DOI: 10.1520/F1446-15B.10.1520/F1446-20.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F1446 − 20
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standard:
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
F2220 Specification for Headforms
2.2 Federal Motor Vehicle Safety Standard:
218 S7.1.8 Motorcycle Helmets
2.3 SAE Standard:
SAE J211 Recommended Practice for Instrumentation for Impact Tests—Requirements for Channel Class 1000
3. Reference Table
3.1 For references to these test methods, the standard terms for reference are listed in bold type in Table 1 with the items to
consider for each method. For conditions and anvils, use the standard term listed in Table 1. Referring to section numbers in these
test methods is not the recommended method for reference.
4. Terminology
4.1 Definitions:
4.1.1 basic plane, n—an anatomical plane (Frankfort Horizontal Plane) that includes the superior rim of the external auditory
meatus (upper edge of the external openings of the ear) and the inferior margin of the orbit (the lowest point of the floor of the
eye socket).
4.1.1.1 Discussion—
The headforms are marked with the basic plane (see Figs. 1 and 2).
4.1.2 coronal plane, n—an anatomical plane perpendicular to both the basic and midsagittal planes and passing through the
superior rims of the right and left auditory meatuses.
4.1.2.1 Discussion—
The transverse plane corresponds to the coronal plane (see Figs. 1 and 2).
TABLE 1 Table for Reference
Terms for Reference Section Items to Consider for Each Method
Chin Bar Rigidity 12.9 Types defined: impact velocity, nominal drop height
Conditioning Environments 10 Types defined: ambient, low temperature, high temperature, water
immersion
Configuration 12.2 Standard requirement defined
Dynamic Retention Test 12.7.1 Types defined: mass of drop weight, drop height, extension pass/fail
criteria
Headforms 7.1 Headforms to be used in all tests in Test Methods F1446
Impact Anvil 7.3.1 Types defined: flat, hemispherical, cylindrical, triangular hazard, curb-
stone
Impact Attenuation Test 12.8 Types defined: number of impact sites, impact velocity and theoretical
drop height, and maximum peak g value
Internal Projections 12.5.1 Standard requirement defined
Labeling 12.4 Standard labeling requirements defined
Materials 12.3 Standard requirement defined
Peripheral Vision 12.6.1 Standard method of pass/fail for horizontal vision defined
Reference Marking 12.1 Standard method of marking defined, define test lines
Reporting 13 Standard report format defined
Roll-Off Test (Helmet Stability Test) 12.7.2 Types defined: mass of drop weight, drop height, standard method of
pass/fail defined
Samples for Testing 8 Criteria to be considered in selecting number of samples
Selecting the Correct Headform 7.1.1 Method defined
Test Schedule 11 Standard test schedule defined
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from National Highway Traffic Safety Administration (NHTSA), 400 7th St., NW, Washington, DC 20590.
Available from Society of Automotive Engineers (SAE), 400 Commonwealth Dr., Warrendale, PA 15096-0001.
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FIG. 1 Anatomical Planes
FIG. 2 Test Headform—Basic, Reference, and Midsagittal Planes
4.1.3 field of vision, n—angle of vision as measured on the reference headform (upward, downward, and peripheral).
4.1.4 headform size selection, n—helmets shall be tested on the appropriate test headform size(s), as determined by the testing
laboratory. Helmets shall be tested on the largest and smallest size test headforms on which they fit. When multiple headform sizes
are required, each test set of helmets will include at least one extent of coverage, vision test, retention test, and impact test on each
specified headform size. “Fit” means that it is not physically difficult to put the helmet on the larger headform and that the helmet’s
comfort or fit-foam is partially compressed on the smaller headform. For helmets equipped with adjustable fit systems, the
headform sizes are determined by the fit at the smallest and largest limits of the adjustment.
4.1.5 helmet, n—a protective device worn on the head in an effort to reduce or minimize injury to that portion of the head that
is within an area above the test line (as defined in the individual performance standards).
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4.1.5.1 Discussion—
A helmet of a given size is further defined as a combination of structure(s) making up the primary energy-absorption structure
covering part of the wearer’s head. Each structural size is made up of a specific size energy-absorbing structure that may include
an outer or inner hard shell, or both.
4.1.6 helmet position index (HPI), n—the vertical distance from the brow of the helmet to the basic plane, when the helmet is
placed on a reference headform. The manufacturer shall specify the size of the headform and the vertical distance.
4.1.7 helmet type, n—a category of helmets which do not differ in basic construction components such as shell, energy-absorbing
layer(s), retention system, or any other component that is tested.
4.1.7.1 Discussion—
Difference in size alone does not constitute a different helmet type.
4.1.8 midsagittal plane, n—an anatomical plane perpendicular to the basic plane and containing the midpoint of the line
connecting the notches of the right and left inferior orbital ridges and the midpoint of the line connecting the superior rims of the
right and left external auditory meatus.
4.1.8.1 Discussion—
The longitudinal plane corresponds to the midsagittal plane (see Figs. 1 and 2).
4.1.9 modular elastomer programmer (MEP), n—a cylindrical-shaped pad used as the impact surface for the spherical impactor.
4.1.10 preload ballast, n—a “bean-bag” filled with shot placed on the helmet to secure its position on the headform. The weight
of the preload ballast shall be 5.0 6 0.1 kg unless otherwise specified in the individual performance specification.
4.1.11 projection, n—any part of a helmet, internal or external, that extends beyond the faired surface and is likely to cause injury.
4.1.12 protective headgear, n—see helmet.
4.1.13 reference headforms, n—measuring headforms contoured in the same configuration as the test headforms sizes A, C, E, J,
M, and O, as defined in Specification F2220.
4.1.13.1 Discussion—
The reference headforms should include surface markings corresponding to the basic, coronal, midsagittal, and reference planes
(see Figs. 1 and 2).
4.1.14 reference plane, n—a plane marked on the headforms at a specified distance above and parallel to the basic plane (see Fig.
3).
4.1.15 retention system, n—the complete assembly that secures the helmet, in a stable position, on the wearer’s head.
4.1.16 shield, n—optional equipment used in place of goggles to protect the eyes.
4.1.17 size, n—a combination of structure(s) making up the primary energy-absorption structure covering part of the wearer’s
head.
4.1.17.1 Discussion—
Each structural size is made up of a specific size energy-absorbing structure that may include an outer or inner hard shell, or both.
4.1.18 spherical impactor, n—a device made of low resonance material (for example, magnesium), aluminum alloy, or stainless
steel that couples mechanically with the ball arm connector of the drop assembly in place of the impact test headform. When
mounted, the device presents a spherically machined impact face with a radius of 73 mm on its bottom surface. All radii from the
center of the curvature of the impact face to its outer edge shall from angles of no less than 40° with the downward vertical axis.
The center of curvature shall be within 5 mm of the vertical axis drawn through the center of the ball arm. The mass and center
of gravity of the drop assembly including the impactor shall meet the same requirements as those specified for the drop assembly
incorporated with the test headforms (see 7.3.2), using the 5 6 0.1 kg drop mass.
4.1.19 test area, n—the area of the helmet on or above a specified test line, subject to impact or penetration testing.
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Headform X, mm Y, mm Z, mm
Label
F2220-A 24.0 89.7 11.1
F2220-C 25.0 91.2 11.5
F2220-E 26.0 96.0 11.9
F2220-J 27.5 102.5 12.7
F2220-M 29.0 107.0 13.3
F2220-O 30.0 110.0 13.7
FIG. 3 Location of Reference Line
4.1.20 test headforms, n—test headforms that correspond to the physical dimensions defined in Specification F2220 as sizes A,
C, E, J, M, and O. The weight of the drop assembly including the headform shall be 5.0 6 0.10 kg unless a variable mass drop
assembly configuration is specified. If a variable mass configuration is specified, then the weight of the drop assembly shall comply
with the weight specifications presented in Table 2. The test headforms may include surface markings corresponding to the basic,
coronal, midsagittal, and reference planes (see Fig. Fig. 2).
TABLE 2 Test Headforms and Mass Specifications for Variable
Mass Drop Assembly Configuration
Headform Label Drop Assembly Mass
F2220-A 3.1 ± 0.10 kg
F2220-C 3.6 ± 0.10 kg
F2220-E 4.1 ± 0.12 kg
F2220-J 4.7 ± 0.14 kg
F2220-M 5.6 ± 0.16 kg
F2220-O 6.1 ± 0.18 kg
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4.1.21 test line, n—a line drawn on the helmet as specified in the individual performance standards.
4.1.22 visor (peak), n—optional equipment for protection against sun or glare, and sometimes used as a rock or dirt deflector.
5. Significance and Use
5.1 The purpose of these test methods is to provide reliable and repeatable tests for the evaluation of various types of protective
headgear. Use of these test methods in conjunction with the specific individual performance standards is intended to reduce the
likelihood of serious injury and death resulting from impacts to the head sustained by individuals participating in sports, recreation,
and other leisure activities in which protective headgear is worn.
6. Certification
6.1 These test methods permit self-certification. It is recommended that each manufacturer employ an independent test laboratory
at least annually to test each model and size of protective headgear.
7. Apparatus
7.1 Test Headforms:
7.1.1 General—These test methods specify six headform sizes as identified in Specification F2220 (A, C, E, J, M, and O) for
performing reference measurements, impact, roll-off, dynamic retention, penetration, and other tests required by the individual
performance specification standards.
7.1.2 Impact Headforms—These headforms shall be made of K1A magnesium material and shall conform to the external
dimension requirements of each particular headform size, as specified in Specification F2220.
7.1.3 Other Headforms—These headforms should be made of material of sufficient strength and stiffness to maintain their
geometry during testing. They shall conform to the external dimension requirements of each particular headform size, as specified
in Specification F2220. Full-chin headforms will be used as necessary.
7.2 Retention System—The test apparatus for the roll-off and dynamic retention testing are shown in Fig. 4 and Fig. 5, respectively.
The mass of the drop weight and drop height are specified in the individual performance specification standards.
7.2.1 Roll-Off Test Apparatus—The test apparatus shall be used to apply a shock load to a helmet secured to the headform by its
own retention system. The geometry of the test headform shall comply with the dimension of the full chin reference headforms.
The headform shall be secured in a test fixture with its vertical axis pointing downward at 45° to the direction of gravity (see Fig.
4). The test fixture shall permit rotation of the headform about its vertical axis and include a means to lock the headform in the
face-up and face-down positions. The cable and hook shall be a flexible strap or cable and attaching hook which connect the guide
rod to the upper edge of the helmet. The flexible strap or cable shall be of material having an elongation of no more than 18 mm/m
when loaded with 1000 N. The guide rod and drop weight are similar to those in the dynamic retention strength test minus the
simulated mandible. This equipment shall allow a drop weight to slide in a guided free fall to impact a rigid stop. No pad shall
be used between the drop weight and the rigid stop. The mass of the roll-off test apparatus, excluding the drop weight, shall be
1.0 -0.0 +0.2 kg.
7.2.2 Dynamic Retention Test Apparatus—The retention system test equipment shall allow a drop weight to slide in a guided free
fall to impact a rigid stop (see Fig. 5). No pad shall be used between the drop weight and the rigid stop. The guide rod and drop
weight shall consist of a simulated mandible, guide rod with rigid stop, drop weight and electronic position measuring system(s).
The entire dynamic test apparatus, including the drop weight shall hang loosely restrained from non-vertical movement on the
retention system. The mass of the dynamic test apparatus, excluding the drop weight, shall be 7 6 0.1 kg.
7.2.2.1 Electronic Position Measuring System—A device to measure the dynamic and residual displacement of the moving parts
of the test fixture. Such devices shall have a minimum sampling rate of 1000 Hz.
7.2.2.2 Simulated Mandible Fixture—This fixture shall consist of two metal bars that spin freely, each with a diameter of 12.5 6
0.5 mm, that have a center distance of 76.0 6 1 mm.
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FIG. 4 Typical Apparatus for Roll-off (Stability) Test
7.3 Impact Attenuation—The impact attenuation test apparatus shall allow determination of the impact attenuation characteristics
of helmet (see Fig. 6).
7.3.1 Impact Anvils—The selection of anvils to be used for testing any given type of helmet is noted in the individual performance
standards. The construction specifications for several types of anvils are given in Figs. 7-11. Other anvils may be specified
(including construction specifications) in individual performance standards. All of the anvils, with the exception of the modular
elastomer programmer (MEP) specified in these test methods, are constructed of steel and shall be solid (that is, without internal
cavities).
7.3.1.1 Modular Elastomer Programmer (MEP)—The MEP is 152 mm in diameter and 25 mm thick. It is affixed to the top surface
of a flat, 6.35-mm thick aluminum plate. The durometer hardness of the MEP is 60 6 2 Shore A.
7.3.1.2 Flat Anvil—The flat anvil shall have a flat surface of a minimum 125-mm diameter circle and shall be at least 24 mm thick
(see Fig. 7).
7.3.1.3 Hemispherical Anvil—The hemispherical anvil shall have a spherical surface with a radius of 48 6 1 mm. The spherical
surface shall constitute one half of the surface of a sphere (see Fig. 8).
7.3.1.4 Cylindrical Anvil—The cylindrical anvil shall be one half of a cylinder with a diameter of 75 6 1 mm and a minimum
length of 200 mm (see Fig. 9).
7.3.1.5 Triangular Hazard Anvil—The triangular hazard anvil shall have a 90° 6 0.5° striking edge with a 0.5- to 1.5-mm radius.
The height shall be not less than 50 mm and the length not less than 200 mm (see Fig. 10).
7.3.1.6 Curbstone Anvil—The curbstone anvil shall have two faces making an angle of 105° 6 0.5° and meeting along a striking
edge with a radius of 15 mm 6 0.5 mm. The height shall be not less than 50 mm and the length not less than 200 mm (see Fig.
11).
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FIG. 5 Typical Apparatus for Testing Strength and Extension of Retention System
7.3.2 Impact Test Apparatus—The geometry of the test headform shall comply with the dimension of the Specification F2220
reference headforms. The headform should be secured in a test fixture to allow for impact of the helmet at any location above the
test line. The weight of the drop assembly (which is the combined weight of the instrumented test headform and supporting
assembly, exclusive of the test helmet) for the drop test shall be 5 6 0.1 kg unless a variable mass drop assembly configuration
is specified. The weight of the supporting assembly cannot exceed 1.1 kg. The weight of the support assembly is the weight of the
drop assembly minus the weight of the headform, ball arm, ball clamp, ball clamp bolts, and accelerometer. The center of gravity
of the headform shall be at the center of the mounting ball. The center of gravity of the combined test headform and supporting
assembly must meet FMVSS 218 S7.1.8 with any type of guide system (see Appendix X1). The helmet and headform are dropped
in a guided free fall, using a wire or rail guided apparatus (see Fig. 6), onto an anvil fixed to a rigid base.
7.3.3 Accelerometer—Acceleration is measured by a uniaxial accelerometer, which is capable of withstanding a shock of at least
9810 m/s (1000 g) in the headform. The uniaxial accelerometer is mounted at the center of gravity of the test headform with the
sensitive axis aligned within 5° of vertical. The acceleration data channel and filtering shall comply with SAE Recommended
Practice J211. A low-pass filter (either analog or digital) with a 4-pole Butterworth transfer function and a corner frequency of 1000
Hz meets this requirement.
7.4 Chin Bar Rigidity Test Apparatus—The apparatus shall consist of a striker that shall be guided. An example is shown in Fig.
12. The striking surface shall be flat, steel, and have a diameter greater than 112 mm. The total mass of the striker and guide arm
shall be 5 6 0.2 kg. There shall be a means to securely mount a helmet as shown in Fig. 12. A toggle clamp can be modified to
firmly position the helmet by clamping against the inside rear of the helmet. A linear transducer shall be fixed against the inside
of the helmet’s chin bar to measure deflection. A means of measuring the velocity of the striker in its last 60 mm of fall shall be
fitted.
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FIG. 6 Typical Apparatus for Impact Test
FIG. 7 Flat Anvil
8. Samples for Testing
8.1 Conditions and Attachments—Helmets shall be tested complete, in the condition as offered for sale. They must pass all tests
with or without any included attachments.
8.2 Number of Samples—A test normally requires samples of each shell/liner size combination. The number of test samples is
defined in the individual performance standards.
9. Calibrat
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