ASTM F3313-20

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Designation: F3313 − 19 F3313 − 20
Standard Test Method for
Determining Impact Attenuation of Playground Surfaces
Within the Use Zone of Playground Equipment as Tested in
the Field
This standard is issued under the fixed designation F3313; 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
Surveys by the United States Consumer Product Safety Commission (CPSC) and others have
shown that falls from playground equipment onto the underlying surface are a significant cause of
injuries to children. While entanglement is the leading cause of deaths in playground, severe head
injuries are the most frequently implicated cause of death in playground equipment-related falls. Falls
are 79 % of playground injuries. Use of appropriate impact-attenuating surfacing materials in the use
zone of playground equipment can reduce the severity of fall-related injuries. In particular, there is
evidence from automotive industry research testing that lowering impact values reduces head injury
severity. Lower impact values also reduced the severity of all injuries when appropriate surfacing
materials are installed based on reasonable foreseeable use of the play structures associated with the
surface.
This test method provides a means of determining impact attenuation performance of a playground
using a test method that simulates the impact of a child’s head with the playground surfaces. The test
method quantifies impact in terms of g-max and Head Injury Criterion (HIC) scores. G-max is the
measure of the maximum acceleration (shock) produced by an impact. The Head Injury Criterion or
HIC score is an empirical measure of impact severity based on published research describing the
relationship between the magnitude and duration of impact accelerations and the risk of head trauma.
The purpose of this test method is to reduce the frequency and severity of fall-related head injuries
to children by establishing a uniform and reliable means of comparing and specifying the impact
attenuation of playground surfaces. Although the focus is on head injury, lower values for impact
attenuation should lower the severity of other impact related injuries. Its use will give designers,
manufacturers, installers, specifiers, prospective purchasers, owners, and operators of playgrounds a
means of objectively assessing the performance of surfacing materials under and around playground
equipment and hence of evaluating the associated injury risk.
1. Scope
1.1 This test method provides a means of determining impact attenuation performance of a playground using a test method that
simulates the impact of a child’s head with the playground surfaces.
This test method is under the jurisdiction of ASTM Committee F08 on Sports Equipment, Playing Surfaces, and Facilities and is the direct responsibility of Subcommittee
F08.63 on Playground Surfacing Systems.
Current edition approved Sept. 1, 2019Oct. 1, 2020. Published September 2019November 2020. Originally approved in 2018. Last previous edition approved in 20182019
as F3313 – 18.F3313 – 19. DOI: 10.1520/F3313-19.10.1520/F3313-20.
U.S. CPSC Special Study. Injuries and Deaths Associated with Children’s Playground Equipment, April 2001. US Consumer Product Safety Commission, Washington
DC.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F3313 − 20
1.2 This test method is specific to surfacing materials used in conjunction with playground equipment, such as that described in
Specifications F1148, F1487, F1918, CSA Z614 (Canada), and SS457 (Singapore).
1.3 This test method establishes procedures for determining the impact attenuation value of playground surfaces as tested in the
field and for comparison with the test performed under laboratory conditions in Specification F1292 and contract and warranty
requirements. This test method does not establish the critical fall height for an installed playground surface.
1.4 The field test required by this test method addresses the performance of playground surfaces as they are found in the field
during a time when play by children 2-12 is anticipated.
1.5 The impact attenuation test method and test methods established in this test method are specific to the risk of head injury. There
is evidence that lowering impact attenuation values can reduce the risk of other kinds of serious injury (for example, long bone
fractures).
1.6 This test method relates only to the impact attenuation properties of playground surfacing materials and does not address other
factors that contribute to fall-related injuries. While it is believed that conformance with the requirements of this test method will
reduce the risk of severe injury and death from falls, adherence to this test method will not prevent all injuries and deaths.
1.7 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical
conversions to SI units that are provided for information only and are not considered standard.
1.8 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, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.9 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 Standards:
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
F355 Test Method for Impact Attenuation of Playing Surface Systems, Other Protective Sport Systems, and Materials Used for
Athletics, Recreation and Play
F1148 Consumer Safety Performance Specification for Home Playground Equipment
F1292 Specification for Impact Attenuation of Surfacing Materials Within the Use Zone of Playground Equipment
F1487 Consumer Safety Performance Specification for Playground Equipment for Public Use
F1918 Safety Performance Specification for Soft Contained Play Equipment
2.2 Federal Documents:
U.S. Consumer Product Safety Commission, Publication 325 Handbook for Public Playground Safety
U.S. Consumer Product Safety Commission Special Study: Injuries and Deaths Associated with Children’s Playground
Equipment. April 2002
U.S. Department of Justice – 2010 Standard for Accessible Design
2.3 Other Documents:
CSA Z614 Children’s Playspaces and Equipment
ISO TC83 Technical Report on and Thresholds to the Used in Standards
SS457 Specification for Playground Equipment for Public Use
3. Terminology
3.1 Definitions of Terms Related to Playgrounds:
3.1.1 critical fall height (CFH), n—a measure of the impact attenuation performance of a playground surface or surfacing
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volume information, refer to the standard’s Document Summary page on the ASTM website.
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materials; defined as the highest theoretical drop height from which a surface meets the impact attenuation performance criterion
specified by this test method. The critical fall height approximates the maximum fall height from which a life-threatening head
injury would not be expected to occur.
3.1.2 designated play surface, n—any elevated surface for standing, walking, sitting, or climbing, or a flat surface larger than 2.0
in. (51 mm) wide by 2.0 in. (51 mm) long having less than 30° angle from horizontal.
3.1.3 fall height, n—the vertical distance between a designated play surface and the playground surface beneath it.
3.1.3.1 Discussion—
Fall heights for specific types of play structure are defined in Specifications F1148, F1487, F1918, CSA Z614, and SS457.
3.1.4 playground equipment, n—any fixed physical structure installed in a designated play area that is accessible to children for
activities such as climbing, swinging, sliding, rocking, spinning, crawling, creeping, or combinations thereof.
3.1.5 playground surface, n—a manufactured or natural material used to cover the ground below playground equipment, including
foundations, substrates, and any compliant surfacing materials intended to attenuate impact.
3.1.6 play structure, n—a free-standing structure with one or more components and their supporting members.
3.1.7 public use playground equipment, n—a play structure anchored to the ground or not intended to be moved, for use in play
areas of schools, parks, child-care facilities, institutions, multiple-family dwellings, private resorts and recreation developments,
restaurants, and other areas of public use.
3.1.8 specifier, n—person or entity responsible for specifying the performance requirements of a playground surface. (For example
an architect, or the prospective purchaser, owner, or operator of a playground.)
3.1.9 surfacing materials, n—materials used to cover the surface of the playground use zone.
3.1.9.1 loose-fill surface, n—a compliant top layer of small, independently, movable components; for example, wood fiber, bark
mulch, wood chips, shredded foam, shredded rubber, sand, gravel, and so forth.
3.1.9.2 aggregate surface, n—a loose fill surface in which the compliant top layer is made of particulate materials (for example,
sand, gravel, crushed marble, slag, cinders, calcined materials).
3.1.9.3 unitary surface, n—a compliant top layer of one or more material components bound together to form a continuous
surface; for example, urethane and rubber composites, molded foam, molded rubber mats.
3.1.10 use zone, n—the area beneath and immediately adjacent to a play structure or playground equipment that is designated for
unrestricted circulation around the equipment and on whose surface it is predicted that a user would land when falling from or
exiting the equipment.
3.2 Definitions of Terms Related to Impact Testing:
-2 -2
3.2.1 acceleration, n—the rate of change of velocity with time, expressed in units of ft s (m s ).
3.2.2 drop height, n—height from which the missile is dropped during an impact test, measured as the vertical distance between
the lowest point of the elevated missile and surface under test.
3.2.3 g, n—common notation for accelerations expressed in units of standard gravity, where 1 g = 1 standard gravity.
3.2.4 g-max, n—the maximum acceleration of a missile during an impact, expressed in g units.
3.2.5 head injury criterion (HIC), n—a specific integral of the acceleration-time history of an impact, used to determine relative
risk of head injury.
3.2.6 HIC interval, n—the time interval within the acceleration-time history of an impact over which the HIC integral is evaluated.
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3.2.7 impact, n—contact caused by a moving object (for example, an impact test missile) striking another object (for example, a
surface) and during which one or both bodies are subject to high accelerations.
3.2.8 impact attenuation, n—property of a playground surface that, through localized deformation or displacement, absorbs the
energy of an impact in a way that reduces the magnitudes of peak impact force and peak acceleration.
3.2.9 impact test, n—a procedure in which the impact attenuation of a playground surface or surfacing materials is determined by
measuring the acceleration of a missile dropped onto the surface.
3.2.9.1 free-fall impact test, n—an impact test in which the trajectory of the missile is not restrained by rails, wires, or
mechanisms or structures of any type.
3.2.9.2 guided impact test, n—an impact test in which the trajectory of the missile is restrained by rails, wires, or other
mechanism or structure.
3.2.9.3 impact test results, n—one or more measured or calculated values from one or more impact tests used to define the
impact attenuation of a playground surface or surfacing materials.
3.2.10 impact test site, n—point on the surface of an installed playground surface that is selected as the target of an impact test.
3.2.11 impact velocity, n—the velocity (V ) of a falling body (for example, a missile) at the instant of impact.
3.2.12 missile, n—a rigid object of specified mass having a hemispherical surface of specified radius; used to impart an impact
to a surface.
3.2.13 qualified personnel, n—those with current knowledge, training, skill, education and experience who have successfully
demonstrated the ability to solve or resolve problems relating to the subject matter and work through the application of professional
judgement.
3.2.14 reference pad, n—an elastomeric pad with consistent and known impact attenuation properties that is used to verify proper
functioning of the impact test equipment.
3.2.15 standard gravity, n—the nominal value of the acceleration due to gravity at sea level having an international standard value
-2 -2
of exactly 9.806 65 m s (approximately 32.174 ft s ).
3.2.15.1 Discussion—
Accelerations may be expressed in units of standard gravity.
3.2.16 surface test point, n—point on the playground surface selected as the target of an impact test.
3.2.17 theoretical drop height, n—the drop height (h) that, under standard conditions, would result in an impact velocity equal to
a missile’s measured impact velocity (V ).
3.2.17.1 Discussion—
The standard conditions assume that friction and air resistance do not affect the acceleration of the missile and that the acceleration
due to gravity is equal to the standard value of g at sea level. In a free-fall impact test, the actual drop height will approximate
the theoretical drop height. In a guided impact test, the theoretical drop height will be less than the actual drop height, due to the
effects of friction in the guidance mechanism.
4. Performance Requirements
4.1 Surface Performance Parameters—The average g-max and average Head Injury Criterion (HIC) scores calculated from the
last two of a series of three impact tests shall be used as measures of playground surface performance.
4.2 Performance Measure—The linear acceleration in g for each drop is recorded and reported as is the HIC calculated, recorded
and reported. The value for each test location is the average of the last 2 of three drops.
4.3 Performance of Installed Playground Surfaces:
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4.3.1 When an installed playground surface is tested in accordance with the requirements of Sections 10 – 14, the surface
performance parameters at every tested location in the use zone shall meet the performance criteria of Specification F1292. The
drop height shall be the greater of (1) the height specified by the owner/operator prior to purchase, or (2) the equipment fall height,
as defined in the applicable equipment specification(s).
NOTE 1—When an installed playground surface is tested in accordance with this section, if the impact test scores at any tested location in the use zone
of a play structure do not meet the performance criterion, the entity requesting tests shall be informed that the surface is not in compliance with existing
performance standards.
4.3.2 More Stringent Test Methods—The specifier is permitted to specify additional impact attenuation performance requirements,
providing that such additional performance requirements are more stringent than the performance requirements of this test method.
5. Summary of Test Method
5.1 Installed Surface Performance Test—To test whether a playground surface installed within the use zone of a play structure
meets the performance criterion of Specification F1292, an impact test is performed in accordance with Sections 10 – 14 using a
theoretical drop height equal to or greater than the equipment fall height of the structure as specified by the owner/operator. The
test is performed under ambient conditions and the results reported.
6. Significance and Use
6.1 The purpose of this test method is to establish impact attenuation for the installed playground surface at the time of testing.
6.2 This test method provides a uniform means of quantifying the impact attenuation performance of installed playground
surfaces.
6.3 This test method is to be used as a reference for specifying the impact attenuation performance of an installed playground
surface.
6.4 This test method provides a uniform means of comparing the impact attenuation performance of installed playground surfaces
with the performance requirements of this test method and with other performance requirements expressed in terms of drop height.
Consequently, the test method is appropriately used to determine the actual impact attenuation performance of installed playground
surfaces under ambient conditions of use.
6.5 In combination with data relating impact test scores to head injury, the information generated by application of this test method
is suitable to estimate the relative risk of a severe head injury due to a fall.
6.6 Performance of this test does not satisfy the requirements to certify surfaces to the specification Specification F1292.
7. Equipment Operator Qualifications
7.1 Impact tests shall be conducted by qualified personnel.
8. Test Apparatus
8.1 Temperature Measuring Device—A thermometer, digital temperature gage, or other sensor used to measure surface
temperature shall have a functional range of at least from 20 to +130°F (-7 to +54°C), a resolution of 1.0°F (0.6°C), and an
accuracy of 61.0°F (0.6°C). The temperature sensor shall be capable of penetrating the playground surface to a depth of at least
1 in. (25 mm).
8.2 Impact Test System—A device or system as described as missile E in Test Method F355. Missile E is used for performing an
impact test in which it is dropped onto a playground surface from a drop height as determined in 4.3.1. Missile E suspended in
a fixed location for free fall testing and ensure consistency of the drop height, velocity measurement and impact location.
8.2.1 It is acceptable to rigidly attach a supporting assembly (for example, a handle or ball arm) to the missile as a means of
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connecting it to an external guidance system. The total mass of the drop assembly, which is the combined mass of the missile,
accelerometer, and supporting assembly shall be 10.1 6 0.05 lb (4.6 6 0.02 kg). The mass of the supporting assembly alone shall
not exceed 3.0 lb (1.4 kg ).
8.2.2 Guidance Mechanism for Guided Impact Tests—For guided impact tests, it is acceptable for the missile to be connected to
low-friction guides (such as monorail, dual rails, or guide wires) using a follower or other mechanism in order to constrain the fall
trajectory of the missile to a vertically downward path. The guidance system must allow the missile to be leveled prior to a drop
and must maintain the missile in a level (65°) attitude during the drop. The guidance mechanism shall be constructed in a manner
that does not impede the trajectory of the missile during its fall
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