ASTM F1292-22

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
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.
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Designation: F1292 − 18 F1292 − 22 An American National Standard
Standard Specification for
Impact Attenuation of Surfacing Materials Within the Use
Zone of Playground Equipment
This standard is issued under the fixed designation F1292; 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.
ε NOTE—Corrected 4.3.1 editorially in June 2020.
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. Severe head injuries are the most frequently implicated cause of death in
playground equipment-related falls. Use of appropriate impact-attenuating surfacing materials in the
use zone of playground equipment can reduce the risk of fall-related injury. In particular, it is believed
that the risk of life-threatening head injuries is reduced when appropriate surfacing materials are
installed.
This specification specifies impact attenuation performance requirements for playground surfaces
and surfacing materials and provides a means of determining impact attenuation performance using a
test method that simulates the impact of a child’s head with the surface. 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 specification 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. Its use will give designers, manufacturers, installers, 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.
This specification determines the critical fall height for the surface material or surfacing system at
each of three temperatures.
1. Scope
1.1 This specification establishes minimum performance requirements for the impact attenuation of playground surfacing
materials installed within the use zone of playground equipment.
This specification 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 Dec. 1, 2018Dec. 1, 2022. Published February 2019December 2022. Originally approved in 1991. Last previous edition approved in 20172018
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as F1292 – 17a.F1292 – 18 . DOI: 10.1520/F1292-18E01.10.1520/F1292-22.
U.S. CPSC Special Study. Injuries and Deaths Associated with Children’s Playground Equipment, April 2001. U.S. Consumer Product Safety Commission, Washington,
DC.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F1292 − 22
1.2 This specification is specific to surfacing used in conjunction with playground equipment, such as that described in
Specifications F1148, F1487, F1918, CSAZ614 (Canada), and SS457 (Singapore).
1.3 This specification establishes an impact attenuation performance criterion for playground surfacing materials; expressed as a
critical fall height.
1.4 This specification establishes procedures for determining the critical fall height of playground surfacing materials under
laboratory conditions. The laboratory test is mandatory for surfaces to conform to the requirements of this specification.
1.5 The laboratory test required by this specification addresses the performance of dry surfacing materials.
1.6 This specification also provides optional procedures to determine the critical fall height under wet or frozen test conditions,
or both.
1.7 The critical fall height of a playground surfacing material determined under laboratory conditions does not account for
important factors that have the potential to influence the actual performance of installed surfacing materials. Factors that are known
to affect surfacing material performance include but are not limited to aging, moisture, maintenance, exposure to temperature
extremes (for example, freezing), exposure to ultraviolet light, contamination with other materials, compaction, loss of thickness,
shrinkage, submersion in water, and so forth.
1.8 The impact attenuation specification and test methods established in this specification are specific to the risk of head injury.
There is only limited evidence that conformance with the requirements of this specification reduces the risk of other kinds of
serious injury (for example, long bone fractures).
NOTE 1—The relative risk of fatality and of different degrees of head injury may be estimated using the information in Appendix X1, which shows the
relationships between the Head Injury Criterion (HIC) scores of an impact and the probability of head injury.
1.9 This specification 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 specification
will reduce the risk of serious injury and death from falls, adherence to this specification will not prevent all injuries and deaths.
1.10 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.
1.11 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.
1.12 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
F1487 Consumer Safety Performance Specification for Playground Equipment for Public Use
F1918 Safety Performance Specification for Soft Contained Play Equipment
F2075 Specification for Engineered Wood Fiber for Use as a Playground Safety Surface Under and Around Playground
Equipment
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.
F1292 − 22
F3313 Test Method for Determining Impact Attenuation of Playground Surfaces Within the Use Zone of Playground Equipment
as Tested in the Field
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 ISO Document:
ISO/TR 20183 Sports and other recreational facilities and equipment – Injury and safety definitions and thresholds – Guidelines
for their inclusion in standards
3. Terminology
3.1 Definitions of Terms Related to Playground Installations:
3.1.1 critical fall height (CFH)—a measure of the impact attenuation performance of a playground surface or surfacing materials;
defined as the highest theoretical drop height from which a surface meets the impact attenuation performance criterion specified
by this specification. 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—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—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, CSAZ614, and SS457.
3.1.4 playground equipment—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—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—a free-standing structure with one or more components and their supporting members.
3.1.7 public use playground equipment—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—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—materials used to cover the surface of the playground use zone.
3.1.9.1 loose-fill surface—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—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—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—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.
Available from U.S. Government Printing Office, Superintendent of Documents, 732 N. Capitol St., NW, Washington, DC 20401-0001, http://
www.access.gpo.gov.Available from Society of Automotive Engineers (SAE), 400 Commonwealth Dr., Warrendale, PA 15096-0001.
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
F1292 − 22
3.2 Definitions of Terms Related to Impact Testing:
–2 –2
3.2.1 acceleration—the rate of change of velocity with time, expressed in units of m s (ft s ).
3.2.2 drop height—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—common notation for accelerations expressed in units of standard gravity, where 1 g = 1 standard gravity.
3.2.4 g-max—the maximum acceleration of a missile during an impact, expressed in g units.
3.2.5 head injury criterion (HIC)—a specific integral of the acceleration-time history of an impact, used to determine relative risk
of head injury. See Appendix X1.
3.2.6 HIC interval—the time interval within the acceleration-time history of an impact over which the HIC integral is evaluated.
3.2.7 impact—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—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—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—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—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—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—point on the surface of an installed playground surface that is selected as the target of an impact test.
3.2.11 impact velocity—the velocity (V ) of a falling body (for example, a missile) at the instant of impact.
3.2.12 missile—a rigid object of specified mass having a hemispherical surface of specified radius; used to impart an impact to
a surface.
3.2.13 performance criterion—limiting values of one or more impact test results used to specify minimum impact attenuation
performance.
3.2.14 qualified personnel—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.
3.2.15 reference drop height—a specification of the theoretical drop height of an impact test.
3.2.16 reference MEP pad—a modular elastomer programmer pad with consistent and known impact attenuation properties that
is used to verify proper functioning of the impact test equipment.
3.2.17 reference temperature—a specification of the temperature conditioning of a surfacing materials on which an impact test is
performed.
F1292 − 22
3.2.18 sample test point—point on the surface of a sample selected as the target of an impact test.
3.2.19 standard gravity—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 ).
3.2.19.1 Discussion—
Accelerations may be expressed in units of standard gravity.
3.2.20 theoretical drop height—the drop height (h) that, under standard conditions, would result in an impact velocity equal to a
missile’s measured impact velocity (V ).
3.2.20.1 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 surface performance.
4.2 Performance Criterion—The performance criterion used to determine conformance with the requirements of this specification
shall be: a g-max score not exceeding 200 g and a HIC score not exceeding 1000.
4.3 Critical Fall Height:
4.3.1 The critical fall height of the playground surface shall have been determined in accordance with the requirements of Section
15 of this specification, using reference temperatures of 25, 72, and 120°F (–4, 23, and 49°C), surface performance parameters,
and the performance criterion.
NOTE 2—The specified temperatures span the range experienced by most playgrounds. If higher or lower surface material temperatures prevail when the
playground is used, additional tests at higher or lower temperatures may be specified.
NOTE 3—Wet/Frozen Test—The specifier may require that surfacing materials be tested to determine critical fall height under wet or frozen surface
conditions, or both. Procedures for wet/frozen conditioning are described in Annex A1.
4.3.2 The laboratory test used to determine critical fall height shall have been conducted on surfacing material samples identical
in design, materials, components, thickness, and manufacture as the installed playground surface.
4.3.3 The laboratory test used to determine critical fall height of materials specified for use in a playground shall have been
conducted no more than five years prior to the date of installation of the playground surface.
4.3.4 Test Method F3313 is a test method for conducting g-max and HIC testing on an installed playground surface to ensure
quality control of surfaces as they are installed.
5. Summary of Test Method
5.1 Critical Fall Height Test—The impact attenuation of surfacing materials is measured using an impact test in which a missile
is dropped onto the playground surface from a predetermined drop height. The acceleration of the missile during the impact is
measured using an accelerometer and associated data recording equipment. The acceleration time history is analyzed to determine
g-max and HIC scores. For each playground surface sample at each reference temperature and drop height, scores from the second
and third of three consecutive drops are averaged to give average scores. No modification of the playground surface sample shall
be permitted between the three impacts.
5.2 The critical fall height of surfacing materials is determined by impact testing representative samples at a range of drop heights.
The surfacing material is tested at temperatures of 25, 72, and 120°F (–4, 23, and 49°C). The critical fall height is determined as
the highest theoretical drop height from which the surface performance parameters meet the performance criterion.
F1292 − 22
6. Significance and Use
6.1 The purpose of this specification is to establish minimum impact attenuation requirements for playground surfacing materials
in order to reduce the risk of severe head injury from falls.
6.2 This specification provides a uniform means of quantifying the impact attenuation performance of playground surfacing
materials and is appropriately used to compare the relative performance of different playground surfacing materials.
6.3 This specification is to be used as a reference for specifying the impact attenuation performance of playground surfacing
materials.
6.4 In combination with data relating impact test scores to head injury, the information generated by application of this
specification is suitable to estimate the relative risk of a severe head injury due to a fall.
7. Equipment Operator Qualifications
7.1 Impact tests shall be conducted by qualified personnel.
8. Test Apparatus
8.1 Temperature Measuring Device—The 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. (2.5 cm).
8.2 Impact Test System—A device or system for performing an impact test in which an instrumented missile is dropped onto a
playground surface or surfacing material.
8.2.1 Missile—The test will be conducted using Missile E as specified in Test Method F355.
8.2.2 Guided Impact Tests—It is acceptable to rigidly attach a supporting assembly (for example, a handle or ball arm) to the
missile as a means of 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).
8.2.2.1 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 or during its contact with the surface being tested; other than necessary impedance caused by friction in the
guidance mechanism.
8.2.3 Support Structure for Free-Fall Impact Tests—For free-fall impact tests, a support structure (for example, a tripod) shall be
used to ensure repeatable drop height and location. The support structure shall be sufficiently rigid to support the weight of the
missile without visible deformation. The support structure shall be erected in a manner that does not impede the trajectory of the
missile during its fall or during its contact with the surface being tested.
8.2.4 Drop Height Control Mechanism—The guidance mechanism of 8.2.2.1 or the support structure of 8.2.3 shall incorporate a
means of repeatedly positioning the missile at a predetermined drop height.
8.2.5 Release Mechanism—A manual or electronically operated quick-release mechanism shall be provided as a means of
initiating a drop of the missile. The operation of the release mechanism shall not influence the fall trajectory of the missile
following release.
9. Calculations
9.1 Theoretical Drop Height:
F1292 − 22
9.1.1 The theoretical drop height, h, shall be calculated from a measurement of impact velocity, v, using the formula h = v ⁄ 2g,
where g is the acceleration due to gravity.
9.1.2 Alternatively, in a free-fall test, one method to calculate the theoretical drop height, h, is by a measurement of fall time, t,
using the formula h = ⁄2g t .
9.1.3 Resultant Acceleration—If a triaxial accelerometer is used, the resultant acceleration at each point in the time history of the
2 2 2
impact shall be calculated as A 5=A 1A 1A where A is the resultant acceleration and A ,A , and A are the accelerations
R x y z R x y z
recorded by accelerometers aligned with the X,Y, and Z missile axes.
9.2 g-max—The g-max of score is determined as the maximum value of acceleration recorded during an impact. If a triaxial
accelerometer is used, g-max shall be determined as the maximum value of the resultant acceleration.
9.3 Average g-max—Determine the average g-max score by averaging the g-max score of the second and third of a series of three
impact tests.
9.4 Determination of Missile Angle—In a free-fall impact test, the angle of the missile at the onset of impact and at the instant
of maximum acceleration shall be calculated. For the purposes of this calculation, the onset of impact shall be the data sample at
which the resultant acceleration first meets or exceeds a threshold value of 5 g. The angle shall be calculated from the component
accelerations. The cosine of the missile angle shall be calculated as:
A
z
cos θ 5
~ !
headform
A
R
9.5 Head Injury Criterion —The HIC score of an impact shall be computed as follows:
9.5.1 In the acceleration-time history of the impact, locate the time point T at a point immediately preceding the onset of the
impact and the time point T at a point immediately following the cessation of the impact.
9.5.2 For each time interval (t , t ) for which t ≥ T , t > t and t ≤ T evaluate and record the trial HIC integral:
1 2 1 0 2 1 2 1
2.5
1 t
Trial HIC~t , t !5 ~t 2 t ! a dt
F * G
1 2 2 1 t
t5t
~t 2 t !
2 1
where:
a = acceleration at time t, defined as the resultant acceleration if a triaxial accelerometer is used.
t
9.5.3 For each time interval (t , t ) calculate and record the trial HIC interval, t − t .
1 2 2 1
9.5.4 The HIC score for an impact is determined as the maximum value of all the Trial HIC (t , t ) scores.
1 2
9.5.5 The numerical procedures used to calculate HIC shall provide results that are within 61 % of the true value.
10. Instrumentation Check
10.1 Check the proper operation of the test apparatus by performing a series of impact tests on a reference MEP pad immediately
prior to the start of testing and within 24 h of completion of the tests.
10.2 The reference MEP pad shall be provided by the equipment manufacturer or by another agency capable of ensuring
reproducible reference pads and shall have been assigned a reference drop height and a nominal g-max score.
10.3 Perform three impact tests on the reference MEP pad from the reference drop height with an interval of 1.5 6 0.5 min
between impacts.
Chou, C., and Nyquist, G., “Analytical Studies of the Head Injury Criterion,” SAE Paper No. 740082, Society of Automotive Engineers, 1974.
F1292 − 22
10.4 Determine the average g-max score by averaging the g-max scores from the second and third drops.
10.5 Compare the average g-max score to the nominal g-max score provided with the reference MEP pad.
10.6 If the difference between the recorded g-max score and the nominal g-max score exceeds either the manufacturer’s specified
tolerance or 5 % of the nominal g-max score, the equipment does not conform to the requirements of this specification and shall
not be used.
11. Impact Test Procedure
11.1 Data Recording:
11.1.1 Determine the test point of the conditioned sample.
11.1.1.1 If the sample has nonuniform properties (due to uneven thickness, seams, fasteners, or other factors) the sample test point
shall be the point on the surface of the specimen expected to show the least favorable impact attenuation properties that lies within
an area no closer than 3.0 in. (75 mm) to the edge of the sample.
11.1.1.2 Procedure for Determining Least Favorable Impact Location:
(1) Least favorable impact location shall be determined using the average of the last two of three impacts, from impacts
performed at 23°C, at all applicable locations.
(2) Once the average is calculated, divide the g value by 200, and divide the HIC value by 1000. The resulting calculations
are percentages of the maximum allowable value for both g and HIC.
(3) Determine the highest percentage of maximum allowable value, either g’s or HIC, for all locations tested. This calculated
highest percentage of the maximum allowable value(s), shall be considered the least favorable impact location.
(4) Subsequent to determining the least favorable impact location remaining temperature testing (–6°C and 49°C) shall be
performed at the determined least favorable impact location only.
(5) Exemptions to 11.1.1.1—Poured-in-place (for example, SBR with EPDM, TPV or turf top cap) and bonded safety surfaces
are exempt from least favorable impact location. Laboratory testing has been provided demonstrating that the maximum values
obtained among locations for these types of surface are minimal/insignificant.
11.1.1.3 If the sample has uniform properties, the sample test point shall be the center of the sample’s top surface.
11.1.2 Mount the sample to be tested on a flat, rigid anvil or floor beneath the impact test system.
11.1.3 Align the sample test point with the point of impact of the missile and fix the sample to the anvil or floor using an
appropriate means that does not alter the sample’s impact attenuation properties (for example, with double-sided adhesive tape).
NOTE 4—Tests with unitary surface samples show that the variability of g-max and HIC scores is increased by a factor of four or more if the sample is
not fixed to the underlying surface.
11.1.4 Before the first drop in any series, elevate the missile to the reference drop height. For subsequent drops in a series, the
missile shall be elevated to the same point, notwithstanding the formation of cavities of other elevation changes in the surface being
tested.
11.1.5 Before the first drop in any series, measure and record the drop height.
11.1.6 Release the missile and record the outputs of the acceleration measuring system and the drop height measuring system. If
the trajectory of the missile prior to and during impact is impeded by any fixtures, human intervention, or other means, data from
the trial shall be discarded.
11.1.7 Record the depth of any cavity in the surface formed by the impact.
NOTE 5—The depth is conveniently determined by measuring the distance between the lowest point of the elevated missile and the surface under test.
The cavity depth is the difference between this measurement and the originally measured drop height.
F1292 − 22
11.2 Data Check:
11.2.1 Examine the acceleration display. The recorded acceleration pulse shall conform to the following requirements:
11.2.1.1 The acceleration pulse shall consist of a single primary impact event.
11.2.1.2 Prior to the onset of impact, the recorded acceleration value needs to be 0 6 2 g.
11.2.1.3 The acceleration waveform needs to descend from its maximum value to a stable value of 0 6 2 g without overshooting
the zero baseline by more than 2 g.
NOTE 5—Excessive overshoot of the acceleration signal after an impact is indicative of transducer or signal processing error. Overshoot is frequently
symptomatic of inadequate low frequency response in the accelerometer data channel(s).
11.2.2 If the recorded acceleration pulse does not conform to the specifications of 11.2, the test shall be restarted using a freshly
conditioned specimen.
11.3 Data Analysis:
11.3.1 Calculate and record the g-max and HIC scores.
11.3.2 Calculate and record the theoretical drop height. If the calculated theoretical drop height differs from the measured drop
height by more than 63 in (676 mm) or by more than 62.5 % of the measured drop height, data from the trial shall be discarded.
NOTE 6—A difference between theoretical drop height and actual drop height that is greater than the specified margin may indicate an error in
measurement of impact velocity, an error in the measurement of fall time, or that the fall of the missile was retarded by excessive friction in the guidance
mechanism.
11.3.3 If a free-fall impact test is used, calculate the missile angle at the onset of impact and at the instant of maximum resultant
acceleration, in accordance with 9.4. If the calculated missile angle at either point exceeds 10° (that is, the cosine of the missile
angle is less than 0.966), data from the trial shall be 20°, data from the trial shall be reviewed for anomalies and if there is an
anomaly, the data shall be discarded.
CRITICAL FALL HEIGHT TEST
(Laboratory Test)
12. Temperature Conditioning
12.1 The critical fall height of a playground surface or surfacing material shall be determined under laboratory conditions by
performing a series of impact tests at reference temperatures of 25, 72, and 120 6 2°F (–4, 23, and 49 6 1°C).
12.2 Temperature Conditioning:
12.2.1 Samples shall be preconditioned at 50 6 10 % relative humidity and 72 6 5°F (23 6 3°C) for a minimum of 24 h prior
to beginning testing.
12.2.2 For testing at each reference temperature, three samples shall be conditioned at the reference temperature 62°F (61°C)
for a minimum of 8 h. Testing of a sample must be started within 1 min and all tests must be completed within 7 min of the sample’s
removal from the conditioning environment. If the testing is not started or completed within the specified interval, the sample mu
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