ASTM F2508-16e1

Standard Practice for Validation, Calibration, and Certification of Walkway Tribometers Using Reference Surfaces

SIGNIFICANCE AND USE
5.1 To be meaningful, walkway tribometer results must correlate the slip characteristics of a surface or contaminant, or both, to the actual propensity for human slips. To achieve this goal, walkway tribometer models must be validated against a standard with relevance to human ambulation.  
5.2 This practice prescribes a series of reference surfaces with known relative slip potential ranging from very high to low (as defined by laboratory conditions only) upon which walkway tribometer models can be validated. The relative slip potential of each reference surface was established from human subject walking trials.3  
5.3 The following should be considered in applying the validation and calibration obtained by this practice:  
5.3.1 The scientific study upon which the validation process is based was conducted with a select population of young adults (mean age 26 years) who were free from gait deviations while walking in a straight path on a level surface with a mean walking velocity of 2.18 m/s. This walking velocity is faster than the average walking velocity for the general population which includes a much wider age range with greater variability; thus, the study sample population of pedestrians and conditions is not representative of the larger general population of pedestrians.  
5.3.2 All subjects walked in Oxford-style shoes whose soles were constructed of smooth styrene butadiene rubber (SBR) with 75A Shore hardness. The shoe style and sole material is not representative of all combinations available in the marketplace.  
5.3.3 The reference surfaces defined in this practice are not representative of all walkway surfaces. The outcome of the validation practice reflects performance on the type of reference surfaces and surface conditions defined in this practice only. Validation and calibration of a walkway tribometer as defined by this practice does not imply validation and calibration under all combinations of test foot materials and walkway surfaces.  
5...
SCOPE
1.1 This practice is intended to establish the procedures for validation, calibration, and certification of walkway tribometers.  
1.2 This practice provides a walkway tribometer supplier with a procedure and suite of reference surfaces to validate his walkway tribometer by properly ranking and differentiating the surfaces.  
1.3 This practice provides the user of a walkway tribometer with a procedure and suite of reference surfaces to test calibration of his instrument.  
1.4 This practice provides a procedure through which an entity may certify a walkway tribometer model, signifying that the walkway tribometer model has a completed and documented validation and interlaboratory study.  
1.5 This practice describes the necessary materials, specifications, and the cleaning process for reference materials, as well as the requirements for the validation of a supplier’s walkway tribometer and calibration of a user’s walkway tribometer.  
1.6 This practice applies to walkway tribometers without reference to the nature of the scale of the readings produced by them. The scale used in the reports of validation and calibration must be the same, and are to be those of the instrument or defined for the instrument.  
1.7 The values stated in SI units are to be regarded as standard. The values given in parentheses are 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 T...

General Information

• Status: Published
• Publication Date: 30-Jun-2016
• ICS: 17.040.20 - Properties of surfaces
• ICS: 93.080.10 - Road construction
• Technical Committee: F13 - Pedestrian/Walkway Safety and Footwear
• Drafting Committee: F13.10 - Traction

Relations

• Replaces: ASTM F2508-16 - Standard Practice for Validation, Calibration, and Certification of Walkway Tribometers Using Reference Surfaces
• Effective Date: 01-Jul-2016
• Refers: ASTM F1646-16 - Standard Terminology Relating to Walkway Safety and Footwear
• Effective Date: 15-May-2016
• 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 F1646-13 - Standard Terminology Relating to Safety and Traction for Footwear
• Effective Date: 01-Jan-2013
• Refers: ASTM F1646-12 - Standard Terminology Relating to Safety and Traction for Footwear
• Effective Date: 01-Jul-2012
• 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 E691-08 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-Oct-2008
• Refers: ASTM D3244-07a - Standard Practice for Utilization of Test Data to Determine Conformance with Specifications
• Effective Date: 01-Nov-2007
• Refers: ASTM D3244-07 - Standard Practice for Utilization of Test Data to Determine Conformance with Specifications
• Effective Date: 01-Jul-2007
• 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 F1646-05e1 - Standard Terminology Relating to Safety and Traction for Footwear
• Effective Date: 01-Mar-2005
• Refers: ASTM F1646-05 - Standard Terminology Relating to Safety and Traction for Footwear
• Effective Date: 01-Mar-2005
• Refers: ASTM F1646-03e1 - Standard Terminology Relating to Safety and Traction for Footwear
• Effective Date: 10-Aug-2003
• Refers: ASTM F1646-03 - Standard Terminology Relating to Safety and Traction for Footwear
• Effective Date: 10-Aug-2003
• Refers: ASTM D3244-97(2002) - Standard Practice for Utilization of Test Data to Determine Conformance with Specifications
• Effective Date: 10-Dec-2002

Overview

ASTM F2508-16e1 is the internationally recognized standard defining the practice for validation, calibration, and certification of walkway tribometers using reference surfaces. Developed by ASTM International, this standard ensures consistent and meaningful measurement of walkway surface slip characteristics by setting out clear procedures for evaluating and maintaining tribometer performance. Correctly applying this practice enables both manufacturers and users to verify the reliability of walkway tribometer readings, directly supporting pedestrian safety by correlating instrumented slip resistance assessments to actual human ambulation.

Key Topics

• Validation: Establishes procedures to confirm that walkway tribometer models rank and differentiate reference surfaces according to slip resistance, as observed in controlled human walking trials.
• Calibration: Outlines processes for routine confirmation that a tribometer/test foot combination yields results consistent with reference data, ensuring ongoing measurement accuracy.
• Certification: Details the process by which an entity certifies a walkway tribometer model following documented validation and interlaboratory study, helping suppliers assert compliance with recognized standards.
• Reference Surfaces: Specifies a series of materials with predefined slip characteristics, established from human subject trials, to serve as benchmarks for tribometer testing.
• Reporting and Reproducibility: Requires comprehensive documentation of validation and calibration procedures, equipment, test conditions, and results to facilitate reproducible outcomes.

Applications

The practical application of ASTM F2508-16e1 spans various industries and sectors where walkway safety is crucial:

• Tribometer Manufacturers: Provides clear guidance for validating new tribometer models, certifying performance before market entry, and supporting product claims regarding slip measurement capability.
• Facility Safety Audits: Enables safety professionals and building owners to calibrate their tribometers, ensuring ongoing accuracy when conducting walkway slip risk assessments in facilities such as commercial buildings, transportation terminals, and public spaces.
• Legal and Insurance Investigations: Facilitates objective, standardized evaluation of walkway surface conditions in slip-and-fall incident investigations, supporting expert testimony and risk assessments.
• Research and Standardization: Offers a reproducible methodology for academic and industrial research into slip resistance, supporting advancements in footwear, floor surface materials, and safety standards.
• Quality Assurance: Assists maintenance teams and facility managers in monitoring high-traffic areas’ flooring to mitigate slip hazards proactively.

Related Standards

Professionals referencing ASTM F2508-16e1 should be aware of these additional standards that complement or inform its use:

• ASTM D1349: Practice for Rubber-Standard Conditions for Testing, informing preparation of test foot materials.
• ASTM D3244: Practice for Utilization of Test Data to Determine Conformance with Specifications.
• ASTM E691: Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method-essential for certification procedures.
• ASTM F1646: Terminology Relating to Walkway Safety and Footwear, providing standardized definitions relevant to tribometer testing.
• ISO and CEN Standards: While ASTM F2508 is widely used in North America, practitioners engaged in global operations may also cross-reference related international standards on slip resistance measurement.

By adhering to ASTM F2508-16e1, organizations can ensure that walkway safety assessments using tribometers are reliable, reproducible, and scientifically relevant, driving better risk management and compliance with legal and occupational safety requirements.

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.
´1
Designation:F2508 −16 An American National Standard
Standard Practice for
Validation, Calibration, and Certification of Walkway
Tribometers Using Reference Surfaces
This standard is issued under the fixed designation F2508; 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—Editorially corrected footnote 4 in August 2017.
1. Scope priate safety, health and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
1.1 This practice is intended to establish the procedures for
1.9 This international standard was developed in accor-
validation, calibration, and certification of walkway tribom-
dance with internationally recognized principles on standard-
eters.
ization established in the Decision on Principles for the
1.2 This practice provides a walkway tribometer supplier
Development of International Standards, Guides and Recom-
with a procedure and suite of reference surfaces to validate his
mendations issued by the World Trade Organization Technical
walkwaytribometerbyproperlyrankinganddifferentiatingthe
Barriers to Trade (TBT) Committee.
surfaces.
2. Referenced Documents
1.3 This practice provides the user of a walkway tribometer
2.1 ASTM Standards:
with a procedure and suite of reference surfaces to test
D1349 Practice for Rubber—Standard Conditions for Test-
calibration of his instrument.
ing
1.4 This practice provides a procedure through which an
D3244 Practice for Utilization of Test Data to Determine
entity may certify a walkway tribometer model, signifying that
Conformance with Specifications
the walkway tribometer model has a completed and docu-
E691 Practice for Conducting an Interlaboratory Study to
mented validation and interlaboratory study.
Determine the Precision of a Test Method
1.5 This practice describes the necessary materials, F1646 Terminology Relating to Walkway Safety and Foot-
wear
specifications,andthecleaningprocessforreferencematerials,
as well as the requirements for the validation of a supplier’s
3. Terminology
walkway tribometer and calibration of a user’s walkway
3.1 Fortermsusedinthispracticenotidentifiedherein,refer
tribometer.
to Terminology F1646.
1.6 This practice applies to walkway tribometers without
3.2 Definitions:
reference to the nature of the scale of the readings produced by
3.2.1 paired t-test, n—a test of statistical significance based
them.Thescaleusedinthereportsofvalidationandcalibration
on the use of student’s t-distribution and used to compare two
must be the same, and are to be those of the instrument or
sample means (see Annex A2).
defined for the instrument.
3.2.2 supplier, n—any individual, agent, company,
1.7 The values stated in SI units are to be regarded as
manufacturer, or organization responsible for the walkway
standard. The values given in parentheses are for information
tribometer prior to receipt by the user. D3244
only and are not considered standard.
3.2.3 test foot, n—shoe bottom material or surrogate
1.8 This standard does not purport to address all of the
mounted on the walkway tribometer that comes into contact
safety concerns, if any, associated with its use. It is the
with the surface being tested.
responsibility of the user of this standard to establish appro-
3.2.4 walkway tribometer, n—any apparatus used to mea-
sure the frictional forces acting at an interface between a
walkway surface and shoe material.
This practice is under the jurisdiction ofASTM Committee F13 on Pedestrian/
Walkway Safety and Footwear and is the direct responsibility of Subcommittee
F13.10 on Traction. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved July 1, 2016. Published July 2016. Originally approved contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
in 2011. Last previous edition approved in 2015 as F2508 – 15. DOI: 10.1520/ Standards volume information, refer to the standard’s Document Summary page on
F2508-16E01. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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F2508−16
3.2.4.1 Discussion—A judgement of the adequacy of these 4.5 Calibration for a specific walkway tribometer requires a
frictional forces acting on a walkway surface/shoe surface series of 16 tests on each of the reference surfaces from this
interface is the basis for an assessment of slip properties
practice. A specific walkway tribometer is considered within
relative to human locomotion. calibration if the bias of the mean test values for each surface
falls within the 95 % confidence interval for the walkway
3.3 Definitions of Terms Specific to This Standard:
tribometer model as established by the validation tests (as
3.3.1 calibration, n—the set of operations that establishes,
defined in 9.1, Eq 4).
under specified conditions, the relationship between the values
obtained by a walkway tribometer and the corresponding
5. Significance and Use
supplier reference values.
3.3.2 certification test method, n—aspecifictestmethodthat 5.1 To be meaningful, walkway tribometer results must
is used for all walkway tribometer operational tasks in this
correlate the slip characteristics of a surface or contaminant, or
practice performed as part of a certification. both, to the actual propensity for human slips. To achieve this
goal, walkway tribometer models must be validated against a
3.3.3 laboratory, n—a combination of one individual,
standard with relevance to human ambulation.
uniquely identifiable walkway tribometer, one individual,
uniquely identifiable test foot, and one operator, none of which
5.2 This practice prescribes a series of reference surfaces
(or whom) may be reused for the same purpose in the
with known relative slip potential ranging from very high to
interlaboratory study being conducted.
low (as defined by laboratory conditions only) upon which
3.3.4 reference surfaces (RS’s), n—specifiedmaterials,iden-
walkway tribometer models can be validated. The relative slip
tified in Section 7, that have an experimentally demonstrated
potentialofeachreferencesurfacewasestablishedfromhuman
slip properties for a select population of pedestrians and serve
subject walking trials.
as references for walkway tribometer measurements.
5.3 The following should be considered in applying the
3.3.5 validation, n—the set of operations that establishes,
validation and calibration obtained by this practice:
under specified conditions, the proper ranking and differentia-
5.3.1 The scientific study upon which the validation process
tion of reference surfaces by a walkway tribometer.
is based was conducted with a select population of young
adults (mean age 26 years) who were free from gait deviations
4. Summary of Practice
while walking in a straight path on a level surface with a mean
4.1 This practice establishes a procedure to: (1) validate
walking velocity of 2.18 m/s. This walking velocity is faster
walkway tribometer models against a human gait-based refer-
than the average walking velocity for the general population
ence system, (2) calibrate each individual walkway tribometers
which includes a much wider age range with greater variabil-
of a validated model against published suppliers’ reference
ity; thus, the study sample population of pedestrians and
values (as defined in 9.1, Eq 4), and (3) certify that the
conditionsisnotrepresentativeofthelargergeneralpopulation
tribometer model has completed a documented validation and
of pedestrians.
interlaboratory study.
5.3.2 All subjects walked in Oxford-style shoes whose soles
4.2 This practice provides for validation and calibration of
were constructed of smooth styrene butadiene rubber (SBR)
walkway tribometers as a means of verifying their relationship
with 75A Shore hardness. The shoe style and sole material is
to reference surfaces and verifying a particular device contin-
not representative of all combinations available in the market-
ues to produce consistent results. Certification, if conducted,
place.
formally documents the methods, data, and results of a
5.3.3 The reference surfaces defined in this practice are not
validation and interlaboratory study.
representative of all walkway surfaces. The outcome of the
validation practice reflects performance on the type of refer-
4.3 The method of ranking walkway surface slip properties
using a limited population of ambulating human subjects is ence surfaces and surface conditions defined in this practice
only. Validation and calibration of a walkway tribometer as
supported by a peer-reviewed study.
defined by this practice does not imply validation and calibra-
4.4 Validation consists of a series of 24 tests on each
tion under all combinations of test foot materials and walkway
reference surface from this practice. A walkway tribometer
surfaces.
model is considered valid if it ranks the four reference surfaces
5.3.4 The validation and calibration procedure defined by
from this practice in the proper order with statistically signifi-
this practice is not intended to establish a “safe threshold”
cant differentiation between results obtained for each surface.
value for any walkway surface.
Validation is intended to be accomplished for each walkway
tribometer model when it is initially introduced and is to be
6. Apparatus
accomplished by or on behalf of the supplier and made
available to each user.
6.1 The walkway tribometer shall be free of defects and
operational throughout its range. Refer to the walkway tribom-
eter instruction manual to ensure proper operation and instru-
Powers, C. M., Blanchette, M. G., Brault, J. R., Flynn, J., and Siegmund, G. P.,
ment condition before the validation and calibration process.
“Validation of Walkway Tribometers: Establishing a Reference Standard,” Journal
of Forensic Sciences, Vol. 55, No. 2, March 2010, pp. 366–370. 6.2 Test Foot Designation and Condition:
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F2508−16
6.2.1 The supplier must provide test foot material, reference surface for a minimum of 10 s. Reapply the cleaning
dimension, storage, and service life specifications. The speci- solution and repeat the minimum 10-s scrubbing two times.
fications shall be sufficient to permit procurement of an
8.2.1.4 Rinse the surface thoroughly with distilled water,
exemplar test foot.
ensuring that no visible suds or soap residues remain.
6.2.2 Auniquely numbered test foot, meeting the supplier’s
8.2.1.5 Prepare an ethanol solution containing equal parts
material and dimensional specifications shall be provided with
denatured ethanol in distilled water.
the walkway tribometer being tested.
8.2.1.6 Dip a clean soft-bristled nylon brush, different from
6.2.2.1 The calibration results shall apply only to the walk-
thatusedin8.2.1.3,intheethanolsolutionandgentlyscrubthe
way tribometer/test foot combination tested.
reference surface for 10 s.
6.2.3 Prepare the test foot as prescribed by the walkway
8.2.1.7 Dry the reference surface with dry and oil-free
tribometer supplier or by a fully documented procedure in-
compressed air or air dry if compressed air is not available.
cluded in the validation or calibration report.
Any visible contamination remaining after this step will
disqualify the reference surface for use.
7. Reference Surfaces (RS’s)
8.2.1.8 Ensure that handling of the reference surface does
7.1 Reference Surfaces:
not introduce contaminants to the surfaces, including exposing
7.1.1 RS A—Polished black granite whose surface beneath
the surfaces to contact of human skin.
the test foot is covered with a continuous film of 0.04 % by
8.2.1.9 The cleaning procedure should be performed before
volume solution of Triton X-100 (nonionic surfactant) in
each testing session.
distilled water (that is, 200 µL of Triton X-100 per 500 mL of
distilled water). 8.3 Reference Surface Mounting—Mount the reference sur-
7.1.2 RS B—Porcelain whose surface beneath the test foot is
face onto a flat and rigid substrate that prevents movement of
covered with a continuous film of distilled water. the reference surface parallel to the test plane of the walkway
7.1
...