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Standards Update
COF – Major Changes to North American Criteria
Thin Tile - Overview and Specification Challenges
Bill Griese
Standards Development and Green Initiative Manager
North America is switching from Static
COF with ASTM C1028 method to
Dynamic COF with BOT 3000
• ANSI A137.1 has always specified ASTM C1028 for • ANSI A137.1 has always specified ASTM C1028 for coefficient of friction test results
• There has never been a requirement in ANSI or any other governing body (i.e. OSHA, ADA, etc.)
• ADA used to have a 0.6 COF recommendation in an old Access Board document that was removed because it did not specify a test method or condition (wet or dry)
• However, many projects have long required 0.6 SCOF measured by ASTM C1028.
• Variables that can affect results (testing requires experienced skilled technician)
– Pulling motion
– Sanding pressure– Sanding pressure
• Availability of Neolite rubber material
• Stiction
– Affects measurement of polished and highly smooth surfaces
• No standardized reference value
May occur when measuring wet static COF of • May occur when measuring wet static COF of polished or very smooth surfaces
• Like two wet pieces of glass sticking together• Like two wet pieces of glass sticking together
• Possible to generate higher COF results which may give a false expectation of slip resistance
• No standard value exists: This causes a risk that
the manufacturer might be held responsible for
“failure to warn” or “strict liability” (to provide a
safe product) when a slip occurs in the absence of
Most commercial projects blindly require tile that
safe product) when a slip occurs in the absence of
a defined standard.
• Most commercial projects blindly require tile that
meets or exceeds ASTM C1028 SCOF value of 0.6
without regard for stiction effect.
For tiles expected to be walked on
when wet, …ANSI A137.1 now
specifies 0.42 DCOF measured with
the BOT 3000 per the procedure in the the BOT 3000 per the procedure in the
A137.1 standard
• Definitions help differentiate between the two
methods
– How they are measured
– How the results differ– How the results differ
• The definitions clearly state that SCOF is
higher than DCOF on most surfaces
• Definitions point to effects from contaminants
Dynamic Coefficient of Friction (DCOF): Sometimes called kinetic
coefficient of friction. This is the ratio of the force necessary to keep a
surface already in motion sliding over another divided by the weight
(or normal force) of an object. This force is a materials property of
the two surfaces. DCOF is usually less than SCOF for the same
materials. Contaminants such as dirt, water, soap, oil, or grease can
change this value.change this value.
Static Coefficient of Friction (SCOF): This is the ratio of the force
necessary for a surface to begin sliding over another divided by the
weight (or normal force) of an object This force is a materials
property of the two surfaces. SCOF is usually higher than DCOF for
the same materials. Contaminants such as dirt, water, soap, oil, or
grease can change this value.
• Dynamic testing is done in many other • Dynamic testing is done in many other countries
• Generally more repeatable predictor of slip resistance
• DCOF is a more suitable test of polished and highly smooth surfaces
• DCOF measures COF when sensor is already in motion, which better simulates human ambulation at the time of a slip.
Why the BOT 3000?
• Measures wet and dry, static and dynamic coefficient
of friction
• Easy to use with little possibility of human error
• Self-propelled device
• Uses various sensor
materials
• Extensive research done at the University of
Wuppertal in Germany
– Studied various devices, sensor materials, and wetting
agentsagents
• Extensive research done at the University of
Wuppertal in Germany
– The BOT 3000 had a good correlation to the German Ramp
(considered by many as the “Gold Standard”) and GMG
100 (current device specified by the German Worker’s 100 (current device specified by the German Worker’s
Compensation Board)
• BOT 3000 and German Ramp (r2=0.879)
• BOT 3000 and GMG 100 (r2=0.926)
Note: r2 of 1.00 is ideal
• TCNA has conducted multiple studies over
the past 5-6 years to find the most
repeatable and reproducible method
– Static vs. Dynamic COF
– DI water vs. SLS water (slightly soapy water
used in German research)
– BOT 3000 vs. C1028
– BOT 3000 vs. British Pendulum
– Designed a specialized sanding device for BOT
3000 sensors to eliminate variation from
sanding
BOT 3000 testing method
(ANSI A137.1 Section 9.6)
• Dynamic COF (DCOF) testing with 0.05% SLS water
• SBR Sensor resurfaced with sanding device after each set of four measurements
TCNA Sanding Device
• Radius matches radius of BOT 3000 sensor
• Provides consistent pressure on sensor
• Sensor is resurfaced every 4 measurements
SensorSensor400 Grit 400 Grit
SandpaperSandpaper
BOT 3000 testing method (ANSI A137.1
Section 9.6)
• Four measurements on
• Test at least 3 representative tiles (additional samples
required if more than 3 texture variations exist)
• Four measurements on
each tile
• Average of each piece of
tile reported separately
Test Method Precision
• Measurement Consistency:
– Device consistency (solid state electronics)
– Consistency of the sensor materials (well-
documented SBR material made to DIN documented SBR material made to DIN
specification)
– Sensor preparation (TCNA sanding device)
– Only remaining variability is the variability of the
tile surface!
Video Demonstration 1
Video Demonstration 2
Video Demonstration 3
There is a DCOF Threshold
Value included in ANSI
A137.1 – 2012
0.42 for level interior
spaces expected to be spaces expected to be
walked upon when wet.
Note: Minimum threshold value is found in the
specification tables for mosaic tile, quarry tile, pressed
floor tile, and porcelain tiles, as well as, section
6.2.2.1.10 of ANSI A137.1-2012.
“Because many variables affect the risk of a slip
occurring, the COF shall not be the only factor in
determining the appropriateness of a tile for a
particular application.”
Multiple factors that affect the possibility of a slip
occurring on a tile surface are listed.
“The specifier shall determine tiles appropriate for
specific project conditions, considering by way of
example, but not in limitation, type of use, traffic,
expected contaminants, expected maintenance, expected contaminants, expected maintenance,
expected wear, and manufacturers’ guidelines and
recommendations.“
Footnote: The COF of installed tiles can change over time as a result of wear
and surface contaminants. In addition to regular cleaning, deep cleaning and
traction-enhancing maintenance may be needed periodically to maintain
DCOF values.
“The presence on installed tiles of water
(including standing water as can exist on
floors which are not properly sloped for
drainage or on exterior tiles immediately drainage or on exterior tiles immediately
after a rain storm or on which snow is
melting), oil, grease, and any other
elements which reduce traction, creates
slippery conditions where the risk of a
slip or fall cannot be completely
eliminated.”
Also in Section 6.2.2.1.10…
extra caution in product selection, use, and maintenance.
“Tile installations with exposure to such elements require
extra caution in product selection, use, and maintenance.
The risk of a slip can be diminished but not eliminated in
these installations by installing tiles with a these installations by installing tiles with a
structured/textured surface, mosaic tiles, or certain
extruded unglazed quarry tiles. The The specifierspecifier shall follow shall follow
manufacturers’ guidelines and recommendations for manufacturers’ guidelines and recommendations for
these productsthese products.”
“When tested using SLS solution as per the procedure in section 9.6.1, tiles with a wet DCOF of less than 0.42, (including by way of example, but not in limitation, polished tiles), shall only be installed when the surface will be kept dry when walked upon and proper safety procedures will be applied when cleaning the tiles.”applied when cleaning the tiles.”
– 0.42 value stems from the research done at the University of Wuppertal over ten years to establish threshold values in DIN 51131 used by the German Workers used by the German Workers Compensation Board.
– Various human subjects walked on force plates to determine actual force requirements to reduce accidents.
• University of Wuppertal researchers determined threshold in two ways:
– Accident Statistics: Required DCOF - threshold determined to be 0.36
– Hazard Awareness: Required DCOF when hazard – Hazard Awareness: Required DCOF when hazard awareness is elevated… threshold determined to be 0.35
• The German researchers conducted a validation study with additional human subjects and based on their perception of slipperiness and to incorporate additional safety criteria, the value was set at 0.42.perception of slipperiness and to incorporate additional safety criteria, the value was set at 0.42.
– TCNA Comparison of over 300 tile surfaces: 0.6 SCOF correlated with 0.38 DCOF (w/SLS).
A137.1 specifies 0.42 to follow German Research and include additional measure of safety over
A137.1 specifies 0.42 to follow German Research and include additional measure of safety over
current level
• With no standard value there is a risk that the • With no standard value there is a risk that the manufacturer might be held responsible for “failure to warn” or “strict liability” (to provide a safe product) when a slip occurs in the absence of a defined standard.
• Reference to old SCOF method will remain available when specifiers still ask for 0.60- Most commercial projects blindly require tile that
meets or exceeds ASTM C1028 SCOF value of 0.6 without regard for stiction effect.
• TCNA Handbook insert• TCNA Handbook insert
• Information on our website
• Seminar at Coverings• Seminar at Coverings
• TCNA press breakfast at Coverings
• TCNA Press Release
• Articles in Industry Magazines
• Online banner ads
• Testing products!• Testing products!
• Educating!– Adding information to websites
– Link to TCNA’s information
• Educating clients about the change• Educating clients about the change
• Educating the architectural community about the change– Using connections (AIA, CSI, etc.)
– National architectural publications
– Local chapter newsletters
• Press releases to reinforce TCNA general press release
Questions on COF?
Helpful Contacts:
Katelyn Simpson
Claudio Bizzaglia
Now . . .
A Brief Discussion on “Thin” Tile
“Thin” Tile
• Generally, any tile 5.5 mm thick or less
• Options for reinforced or non-reinforced backingnon-reinforced backing
• Several Different Types (based on type of manufacture), including . . .
– “Lamina” Technology
– “Continua”-Fed Presses
– Traditional Dust Pressed
Thin Tile
Advantages• Environmental
– Reduced material used in production
– Reduced energy for production/square foot
– Reduced energy for transport/square foottransport/square foot
• New interior design options – Tile over tile
– Large panels available
– Potential “bending” applications with unique reinforced products
Thin Tile
Concerns
• Material Properties
– Generally, weaker than thicker
tiles
– Lower breaking strength
– Lower impact resistance– Lower impact resistance
– More prone to failure from
improper coverage
– More prone to edge-chipping
from lippage
Thin Tile
Concerns
• No product standards established
– Definitions for different types of products and quality specifications for each type
– Strength and flexibility– Strength and flexibility
– Water absorption
– Bonding ability, especially reinforced products
– Reinforcement quality
– Sizing and planarity
– Mechanical behavior of reinforced tiles are very different from non-reinforced tiles
Thin Tile
Concerns
• Lack of guidance on proper
installation
– No industry standards or guidelines
– No way to specify suitable products
(lack of product standards)(lack of product standards)
– A very different experience with
different techniques
Thin Tile
Things being considered . . .
• Full coverage is essential . . . experimentation of new techniques with unique trowels
Thin Tile
Things being considered . . .
• Even with 100% coverage, are thin tiles strong enough? – So far, observed failures tend to be compressive in nature
Thin Tile
Things being considered . . . • Can the bending ability of some reinforced
products introduce new methodologies for wood construction?
• Do different types of thin tiles (i.e. lamina vs. dust-pressed) need to be specified for different applications?different applications?
• Are all lamina products created equal? Are all continua products created equal? Are all pressed products created equal? – A product standard is very much needed
before we will know which products to specify.
What’s Next for Thin Tile?
• Product standards being developed
internationally (ISO TC 189
Committee on Ceramic Tile)
• North American installation • North American installation
guidelines likely to be developed
based on research at TCNA
• Perhaps, improved products and
installation quality and greater
North American market acceptance
Thank You!
• Questions/Discussion?
Bill Griese
Standards Development and Green Initiative Manager
864-646-8453