Standards Update

COF – Major Changes to North American Criteria

Thin Tile - Overview and Specification Challenges

Bill Griese

Standards Development and Green Initiative Manager

bgriese@tileusa.com

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

ksimpson@tileusa.com

Claudio Bizzaglia

cb@tileusa.com

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

bgriese@tileusa.com

864-646-8453