ASTM F3189-20

Standard Test Method for Measuring Force Reduction, Vertical Deformation, and Energy Restitution of Synthetic Turf Systems Using the Advanced Artificial Athlete

SIGNIFICANCE AND USE
5.1 The dynamic interaction between the athlete and the synthetic turf surface affects the comfort and the performance of the athlete. Interaction with a surface that has low amounts of deformation and shock absorption allows the player to run fast and turn quickly, but has the potential to cause discomfort and damage to the lower extremity joints. Synthetic turf surfaces having high deformation have lower energy restitution. Less of the energy exerted by the athlete returns from the surface, possibly increasing the fatigue for the performing athlete.
SCOPE
1.1 This test method specifies a method for measuring force reduction, vertical deformation, and energy restitution of synthetic turf surfaces.  
1.2 This method is used to characterize properties of synthetic turf systems including the turf fabric, infill material, and shock pad (if applicable).  
1.3 It can be used for characterizing synthetic turf systems in laboratory environment or in the field.  
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.5 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.  
1.6 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.

General Information

• Status: Published
• Publication Date: 31-Oct-2020
• ICS: 97.220.10 - Sports facilities
• Technical Committee: F08 - Sports Equipment, Playing Surfaces, and Facilities
• Drafting Committee: F08.65 - Artificial Turf Surfaces and Systems

Relations

• Refers: ASTM E177-14 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-May-2014
• Refers: ASTM E691-13 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-May-2013
• Refers: ASTM E177-13 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-May-2013
• Refers: ASTM E691-11 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-Nov-2011
• Refers: ASTM E177-10 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-Oct-2010
• Refers: ASTM E691-08 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-Oct-2008
• Refers: ASTM E177-08 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-Oct-2008
• Refers: ASTM E177-06b - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 15-Nov-2006
• Refers: ASTM E177-06a - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-Nov-2006
• Refers: ASTM E691-05 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-Nov-2005
• Refers: ASTM E177-04e1 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-Nov-2004
• Refers: ASTM E177-04 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-Nov-2004
• Refers: ASTM E177-06 - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 01-Nov-2004
• Refers: ASTM E177-90a(2002) - Standard Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• Effective Date: 10-Jan-2002
• Refers: ASTM E691-99 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 10-May-1999

Overview

ASTM F3189-20 is the Standard Test Method for Measuring Force Reduction, Vertical Deformation, and Energy Restitution of Synthetic Turf Systems Using the Advanced Artificial Athlete. Developed and maintained by ASTM International, this test method provides critical procedures for evaluating performance characteristics of synthetic turf surfaces, including turf fabric, infill materials, and shock pads. The standard applies to both laboratory and field settings and is recognized by international sports governing bodies.

This method addresses athlete-surface interaction by measuring:

• Force reduction (impact absorption)
• Vertical deformation (surface flexibility)
• Energy restitution (energy return to the athlete)

These properties influence player comfort, safety, and athletic performance. The intent is to ensure that synthetic turf systems meet required standards for playability and athlete welfare.

Key Topics

• Force Reduction: Evaluates the surface's ability to absorb impact, reducing the risk of injury to athletes by minimizing the force transferred to joints and limbs.
• Vertical Deformation: Measures the extent to which the surface deforms under load, indicating cushioning and shock absorption. Proper deformation is vital for player safety and performance.
• Energy Restitution: Assesses how much energy is returned by the turf surface after impact. Higher restitution can enable faster, more dynamic athlete movement, while lower restitution may increase fatigue.
• Advanced Artificial Athlete: The specified test apparatus uses a falling mass simulating an athlete’s impact, gathering precise data for all three properties.
• Laboratory and Field Applicability: The method provides guidance for controlled lab testing as well as in situ field assessments, making it versatile for manufacturers, facility managers, and sports organizations.

Applications

ASTM F3189-20 is widely used by:

• Manufacturers: To design and optimize synthetic turf products for compliance with international performance and safety benchmarks.
• Third-party testing labs: To provide consistent and objective assessment of new or installed surfaces.
• Sports facility managers and specifiers: To evaluate and maintain fields, ensuring ongoing player safety and satisfaction.
• Sports governing bodies: Organizations such as FIFA, World Rugby, and FIH reference similar methods for certifying tournament-quality pitches.

The test outcomes inform decisions about material selection, installation practices, and periodic field maintenance. By providing standardized data, the method supports procurement, quality assurance, and certification processes.

Related Standards

ASTM F3189-20 is frequently referenced alongside a range of related national and international standards, including:

• ASTM E177: Practice for Use of the Terms Precision and Bias in ASTM Test Methods
• ASTM E691: Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• FIFA Quality Programme for Football Turf: Handbook of Requirements
• World Rugby Regulation 22: Performance Standards for Synthetic Turf Pitches
• FIH Handbook: Performance and Construction for Synthetic Turf Hockey Pitches

Adoption and use of ASTM F3189-20 help ensure synthetic turf systems are tested and maintained to recognized international requirements, supporting safe, high-performance sports environments.

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Keywords: ASTM F3189-20, synthetic turf testing, force reduction, vertical deformation, energy restitution, artificial turf performance, sports field safety, international standards, advanced artificial athlete, athlete-surface interaction

Standards Content (Sample)

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.
Designation:F3189 −20 An American National Standard
Standard Test Method for
Measuring Force Reduction, Vertical Deformation, and
Energy Restitution of Synthetic Turf Systems Using the
Advanced Artificial Athlete
This standard is issued under the fixed designation F3189; 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.
1. Scope 3. Terminology
1.1 This test method specifies a method for measuring force
3.1 Definitions of Terms Specific to This Standard:
reduction, vertical deformation, and energy restitution of syn-
3.1.1 energy restitution (ER), n—a measure of the energy
thetic turf surfaces.
returned by the synthetic turf surface after the impact force has
been applied.
1.2 This method is used to characterize properties of syn-
thetic turf systems including the turf fabric, infill material, and
3.1.2 energy restitution coeffıcient, n—the ratio of the dy-
shock pad (if applicable).
namic load energy applied to the surface to the energy returned
1.3 It can be used for characterizing synthetic turf systems by the surface.
in laboratory environment or in the field.
3.1.3 force reduction (FR), n—the ability of a synthetic turf
1.4 The values stated in SI units are to be regarded as
sports surface to reduce the impact force of a mass falling onto
standard. No other units of measurement are included in this that surface.
standard.
3.1.3.1 Discussion—The reduction in impact force for this
test method is expressed as a percentage reduction when
1.5 This standard does not purport to address all of the
compared to a reference force of 6760 N. The reference force
safety concerns, if any, associated with its use. It is the
is the theoretical maximum impact force that occurs when the
responsibility of the user of this standard to establish appro-
test is performed on a rigid surface (concrete).
priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
3.1.4 synthetic turf system, n—all components of the syn-
1.6 This international standard was developed in accor-
thetic turf surface and subsurface that have the potential to
dance with internationally recognized principles on standard-
influence the dynamic properties of the surface.
ization established in the Decision on Principles for the
3.1.4.1 Discussion—These include any shock pads or dy-
Development of International Standards, Guides and Recom-
namic base constructions installed as part of the synthetic turf
mendations issued by the World Trade Organization Technical
system.
Barriers to Trade (TBT) Committee.
3.1.5 vertical deformation (Def), n—a measure of the dis-
2. Referenced Documents
tance a test foot penetrates into the surface when a standard
impact force is applied.
2.1 ASTM Standards:
E177 Practice for Use of the Terms Precision and Bias in
3.2 Symbols:
ASTM Test Methods
3.2.1 A—acceleration in m/s .
E691 Practice for Conducting an Interlaboratory Study to
3.2.2 Def—deformation in millimeters.
Determine the Precision of a Test Method
3.2.3 E—energy in Joules.
3.2.4 ER—energy restitution.
This test method is under the jurisdiction of ASTM Committee F08 on Sports
Equipment, Playing Surfaces, and Facilities and is the direct responsibility of
3.2.5 F—force in Newtons.
Subcommittee F08.65 on Artificial Turf Surfaces and Systems.
Current edition approved Nov. 1, 2020. Published December 2020. Originally
3.2.6 FR—force reduction in %.
approved in 2017. Last previous edition approved in 2017 as F3189 – 17. DOI:
10.1520/F3189-20.
3.2.7 g—acceleration due to gravity.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
3.2.8 R—coefficient of restitution.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. 3.2.9 t—time in seconds.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F3189−20
4. Summary of Test Method 6.1.1 Laboratory tests shall be conducted on samples of the
complete turf system. The test sample shall have nominal
4.1 Amass with a spring attached is allowed to fall onto the
dimensions of 1 m by 1 m. The turf samples shall be prepared
test surface. The acceleration of the mass is recorded from the
in accordance with the manufacturers stated method.
moment of release until after its impact with the turf surface.
6.1.2 Characteristics of the Laboratory Floor—The labora-
Force Reduction is the percentage reduction in the measured
tory floor shall be concrete with a minimum thickness of 100
maximum force (Fmax) relative to the reference force (Fmax).
mm.
4.2 Deformation is calculated by double integration of the
6.1.3 Conditioning and Test Temperature—The test piece
record of acceleration versus time. Energy restitution is calcu-
shall be conditioned at laboratory temperature (23 6 2°C) for
lated from the force versus deformation curve.
24 6 0.5 h.
6.2 Field Test Conditions—Testing in the field shall be
5. Significance and Use
performed at ambient temperature and humidity which shall be
5.1 The dynamic interaction between the athlete and the
recorded and reported.
synthetic turf surface affects the comfort and the performance
of the athlete. Interaction with a surface that has low amounts
7. Test Apparatus
of deformation and shock absorption allows the player to run
7.1 TheprincipleofthetestapparatusisshowninFig.1and
fast and turn quickly, but has the potential to cause discomfort
consists of the following essential components specified in 7.2
and damage to the lower extremity joints. Synthetic turf
– 7.7.
surfaces having high deformation have lower energy restitu-
tion. Less of the energy exerted by the athlete returns from the
7.2 Fallingmass(3),incorporatingahelicalmetalspring(5)
surface, possibly increasing the fatigue for the performing and steel foot (6) and fitted with an accelerometer (4), having
athlete.
a total mass of 20.0 6 0.1 kg.
7.3 Helical steel spring (5), whose characteristic is linear
6. Test Conditions
(measured with maximum increments of 1000 N) with a spring
6.1 Laboratory Test Conditions: rate of 2000 6 60 N/mm over the range of 0.1 to 7.5 kN. The
Keys:
1 guide for the falling mass
2 electric magnet
3 falling mass
4 accelerometer
5 spring
6 test foot
FIG. 1Test Apparatus
F3189−20
axis of the spring shall be vertical and shall be directly below 7.7 Means of supporting the mass (2) that allows the falling
the center of gravity of the falling mass. The spring shall have heighttobesetwithanuncertaintyofnogreaterthan0.25mm.
three coaxial coils that shall be rigidly fixed together at their
7.8 Meansofconditioningandrecordingthesignalfromthe
ends. The mass of the spring shall be 0.80 6 0.05 kg.
acceleration sensing device and a means of displaying the
7.4 Steel test foot (6) having a lower side rounded to a recorded signal (see Fig. 2).
radius of 500 6 50 mm; an edge radius of 1 mm; a diameter of 7.8.1 Sampling rate minimum: 9600 Hz;
70 6 1 mm and a minimum thickness of 10 mm. The mass of 7.8.2 ElectronicA-Dconverterwitharesolutiongiving1bit
the test foot shall be 400 6 50 g. equal to a maximum 0.005 g acceleration;
7.8.3 Signal from the acceleration sensing device shall be
7.5 Test frame with minimum of three adjustable supporting
filtered with a 2nd order low-pass Butterworth filter with a
feet, no less than 250 mm from the point of application of the
cut-off frequency of 600 Hz.
load. The design of the supporting feet shall insure the weight
of the test apparatus is equally distributed on all of the feet. 7.9 Means of calculating the speed and displacement of the
7.5.1 The pressure (with the mass) on each foot shall be falling weight during the course of impact by integration and
<0.020 N/mm and the pressure (without the mass) on each double integration of the acceleration signal. To be verified in
foot shall be >0.003 N/mm . accordance with 8.4 and 8.5.
7.5.2 The complete system will have a mass of ≤50 kg.
8. Verification of Impact Speed
7.6 A piezo-resistive accelerometer (4) with the following
characteristics: 8.1 General—The verification is carried out to ensure the
(1) measuring range: 6 50 g; correct impact speed (or energy, because the mass is fixed) and
(2) 3 dB upper frequency response: ≥ 1 kHz; the correct functioning of the apparatus. The checking proce-
(3) linearity error<2%. dure shall consist of three steps and shall be carried out on a
7.6.1 The accelerometer shall be firmly attached to avoid stable and rigid floor (no significant deflection under a 5
natural filtering and the generation of spurious signals. kg/cm pressure) as follows:
FIG. 2Example of Falling Mass Acceleration Versus Time Curve
where:
T0 = time when the mass starts to fall.
T1 = time when the test foot makes initial contact with the surface (determined on the Velocity/time curve – Vmax*)
T2 = time (determined on the Velocity/time curve – Vmin*) corresponding to the maximum velocity when the mass rebounds
after the impact.
NOTE 1—Vmin can be a minimum or maximum value depending on the sensor’s direction.
F3189−20
8.1.1 Laboratory Testing—At least once on any day on 10.3.1 Calculate the maximum force (F ) at the impact
max
which testing is undertaken or following dismantling and with the following formula:
re-assembly of the test apparatus, prior to carrying out any
F 5 m 3 A 1 g (1)
~ !
max max
measurements
where:
8.1.2 Site Testing—Following re-assembly of the test
F = peak force, expressed in Newtons (N);
apparatus, prior to carrying out any measurements.
max
–2
A = peak acceleration during the impact (ms );
max
8.2 Setuptheapparatustoensureafreedropthatisnomore
m = calibrated mass of the falling weight (kg); and
–2
than 61° from the vertical.Adjust the height of the lower face
g = the acceleration due to gravity (ms ).
of the steel test foot so it is 55.00 6 0.25 mm above the rigid
10.3.2 Calculate the Force Reduction (FR) with the follow-
floor. Drop the weight on the rigid floor and record the
ing formula:
acceleration of the falling weight unti
...

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.
Designation: F3189 − 17 F3189 − 20 An American National Standard
Standard Test Method for
Measuring Force Reduction, Vertical Deformation, and
Energy Restitution of Synthetic Turf Systems Using the
Advanced Artificial Athlete
This standard is issued under the fixed designation F3189; 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.
1. Scope
1.1 This test method specifies a method for measuring force reduction, vertical deformation, and energy restitution of synthetic
turf surfaces.
1.2 This method is used to characterize properties of synthetic turf systems including the turf fabric, infill material, and shock pad
(if applicable).
1.3 It can be used for characterizing synthetic turf systems in laboratory environment or in the field.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 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.
1.6 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:
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
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 energy restitution (ER), n—a measure of the energy returned by the synthetic turf surface after the impact force has been
applied.
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
F08.65 on Artificial Turf Surfaces and Systems.
Current edition approved Jan. 1, 2017Nov. 1, 2020. Published February 2017December 2020. Originally approved in 2017. Last previous edition approved in 2017 as
F3189 – 17. DOI: 10.1520/F3189-17.10.1520/F3189-20.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F3189 − 20
3.1.2 energy restitution coeffıcient, n—the ratio of the dynamic load energy applied to the surface to the energy returned by the
surface.
3.1.3 force reduction (FR), n—the ability of a synthetic turf sports surface to reduce the impact force of a mass falling onto that
surface.
3.1.3.1 Discussion—
The reduction in impact force for this test method is expressed as a percentage reduction when compared to a reference force of
6760 N. The reference force is the theoretical maximum impact force that occurs when the test is performed on a rigid surface
(concrete).
3.1.4 synthetic turf system, n—all components of the synthetic turf surface and subsurface that have the potential to influence the
dynamic properties of the surface.
3.1.4.1 Discussion—
These include any shock pads or dynamic base constructions installed as part of the synthetic turf system.
3.1.5 vertical deformation (Def), n—a measure of the distance a test foot penetrates into the surface when a standard impact force
is applied.
3.2 Symbols:
3.2.1 A—acceleration in m/s .
3.2.2 Def—deformation in millimeters.
3.2.3 E—energy in Joules.
3.2.4 ER—energy restitution.
3.2.5 F—force in Newtons.
3.2.6 FR—force reduction in %.
3.2.7 g—acceleration due to gravity.
3.2.8 R—coefficient of restitution.
3.2.9 t—time in seconds.
4. Summary of Test Method
4.1 A mass with a spring attached is allowed to fall onto the test surface. The acceleration of the mass is recorded from the moment
of release until after its impact with the turf surface. Force Reduction is the percentage reduction in the measured maximum force
(Fmax) relative to the reference force (Fmax).
4.2 Deformation is calculated by double integration of the record of acceleration versus time. Energy restitution is calculated from
the force versus deformation curve.
5. Significance and Use
5.1 The dynamic interaction between the athlete and the synthetic turf surface affects the comfort and the performance of the
athlete. Interaction with a surface that has low amounts of deformation and shock absorption allows the player to run fast and turn
quickly, but has the potential to cause discomfort and damage to the lower extremity joints. Synthetic turf surfaces having high
deformation have lower energy restitution. Less of the energy exerted by the athlete returns from the surface, possibly increasing
the fatigue for the performing athlete.
F3189 − 20
6. Test Conditions
6.1 Laboratory Test Conditions:
6.1.1 Laboratory tests shall be conducted on samples of the complete turf system. The test sample shall have nominal dimensions
of 1 m by 1 m. The turf samples shall be prepared in accordance with the manufacturers stated method.
6.1.2 Characteristics of the Laboratory Floor—The laboratory floor shall be concrete with a minimum thickness of 100 mm.
6.1.3 Conditioning and Test Temperature—The test piece shall be conditioned at laboratory temperature (23 6 2°C) for 24 6 0.5
h.
6.2 Field Test Conditions—Testing in the field shall be performed at ambient temperature and humidity which shall be recorded
and reported.
7. Test Apparatus
7.1 The principle of the test apparatus is shown in Fig. 1 and consists of the following essential components specified in 6.27.2
– 6.77.7.
7.2 Falling mass (3), incorporating a helical metal spring (5) and steel foot (6) and fitted with an accelerometer (4), having a total
mass of 20.0 6 0.1 kg.
7.3 Helical steel spring (5), whose characteristic is linear (measured with maximum increments of 1000 N) with a spring rate of
Keys:
1 guide for the falling mass
2 electric magnet
3 falling mass
4 accelerometer
5 spring
6 test foot
FIG. 1 Test Apparatus
F3189 − 20
2000 6 60 N/mm over the range of 0.1 to 7.5 kN. The axis of the spring shall be vertical and shall be directly below the center
of gravity of the falling mass. The spring shall have three coaxial coils that shall be rigidly fixed together at their ends. The mass
of the spring shall be 0.80 6 0.05 kg.
7.4 Steel test foot (6) having a lower side rounded to a radius of 500 6 50 mm; an edge radius of 1 mm; a diameter of 70 6 1
mm and a minimum thickness of 10 mm. The mass of the test foot shall be 400 6 50 g.
7.5 Test frame with minimum of three adjustable supporting feet, no less than 250 mm from the point of application of the load.
The design of the supporting feet shall insure the weight of the test apparatus is equally distributed on all of the feet.
7.5.1 The pressure (with the mass) on each foot shall be <0.020 N/mm and the pressure (without the mass) on each foot shall
be >0.003 N/mm .
7.5.2 The complete system will have a mass of ≤50 kg.
7.6 A piezo-resistive accelerometer (4) with the following characteristics:
(1) measuring range: 6 50 g;
(2) 3 dB upper frequency response: ≥ 1 kHz;
(3) linearity error < 2 %.
7.6.1 The accelerometer shall be firmly attached to avoid natural filtering and the generation of spurious signals.
7.7 Means of supporting the mass (2) that allows the falling height to be set with an uncertainty of no greater than 0.25 mm.
7.8 Means of conditioning and recording the signal from the acceleration sensing device and a means of displaying the recorded
signal (see Fig. 2).
7.8.1 Sampling rate minimum: 9600 Hz;
7.8.2 Electronic A-D converter with a resolution giving 1 bit equal to a maximum 0.005 g acceleration;
7.8.3 Signal from the acceleration sensing device shall be filtered with a 2nd order low-pass Butterworth filter with a cut-off
frequency of 600 Hz.
7.9 Means of calculating the speed and displacement of the falling weight during the course of impact by integration and double
integration of the acceleration signal. To be verified in accordance with 7.48.4 and 7.58.5.
8. Verification of Impact Speed
8.1 General—The verification is carried out to ensure the correct impact speed (or energy, because the mass is fixed) and the
correct functioning of the apparatus. The checking procedure shall consist of three steps and shall be carried out on a stable and
rigid floor (no significant deflection under a 5 kg/cm pressure) as follows:
8.1.1 Laboratory Testing—At least once on any day on which testing is undertaken or following dismantling and re-assembly of
the test apparatus, prior to carrying out any measurements
8.1.2 Site Testing—Following re-assembly of the test apparatus, prior to carrying out any measurements.
8.2 Set up the apparatus to ensure a free drop that is no more than 61° from the vertical. Adjust the height of the lower face of
the steel test foot so it is 55.00 6 0.25 mm above the rigid floor. Drop the weight on the rigid floor and record the acceleration
of the falling weight until the end of the impact.
8.3 Repeat 7.18.1 twice, giving a total of 3 impacts.
8.4 For each impact calculate, by integration from T0 to T1 of the acceleration signal, the initial impact velocity. Calculate the
F3189 − 20
FIG. 2 Example of Falling Mass Acceleration Versus Time Curve
where:
T0 = time when the mass starts to fall.
T1 = time when the test foot makes initial contact with the surface (determined on the Velocity/time curve – Vmax*)
T2 = time (determined on the Velocity/time curve – Vmin*) corresponding to the maximum velocity when the mass rebounds
after the impact.
NOTE 1—Vmin can be a minimum or maximum value depending on the sensor’s direction.
mean impact velocity of the three recordings. The mean impact velocity shall be in the range of 1.02 m/s and 1.04 m/s. If the initial
impact velocity is outside the specified range, the te
...