Voices of Safety International (VOSI)

  Home    Slip
& Fall
Standards
   SCOF
Testing
   Public
Safety
   Public
Health
   Environmental
Issues
   Forensic
Engineers
   Contacts
& Links
   VOSI
Members
 

VOSI Research Report RR9-V41
Evaluation of VOSI & ASTM
Task Group Friction Test Sensors

Click Here for Printable Version

 

Forensic Engineers - VOSI Research Report RR9-V41

"EVALUATION OF VOSI & ASTM TASK GROUP FRICTION TEST SENSORS"

REFERENCES:

  1. VOSI V41.21, "Universal Specification/Test Method for Slip Resistant Walkways, in the Field & Laboratory, as Measured by a Drag Type Friction Tester".
  2. "Board of Directors Task Group on Slip Resistance"; Report to ASTM F13 committee members from Dave Fleisher, 12/22/00
  3. "Interview with the Chairman of the 2001 ASTM Board of Directors - Donald E. Marlowe"; ASTM "Standardization News", January 2001
  4. "ASTM Lights the Way for Tissue Engineered Medical Products Standards" by Grace Lee Picciolo, PhD & David L. Stocum; ASTM "Standardization News", January 2001

Ref. 1 specifies that both leather and Monarch EVA sensors are used dry and Monarch EVA wet (distilled water) when measuring walkway slip resistance regardless of flooring material or coatings.

Ref. 2 specifies leather, Neolite and Toplift TPU (Thermoplastic polyurethane) as surrogate footwear materials for testing walkways.

The purpose of the 1/19/2001 research was to test both VOSI test materials, rubber and leather, and compare them with the ASTM task group test materials. Using the Technical Products Co. Model 80 Floor & Footwear Friction Tester and the ASTM C1028 calibration ceramic tile, wet and dry testing was performed on all elastomers, while only dry testing was performed on the leather.

A 4" x 4" x 1/4" thick sample of "Toplift TPU" ,the same sample used for ASTM testing which was supplied to Wen Chung of Liberty Mutual Insurance Co., was obtained from Dave Kincman, owner of Styletek, manufacturer of the "Toplift TPU".

The measured Shore D hardness of the three samples received was 56-62. The samples are patterned on one side and smooth on the other side. Three plugs, 7/16" diameter were cut for the Model 80 (smooth side out). All samples were sanded with 400-grit wet/dry paper before dry testing and were not re-sanded for wet test. The Monarch EVA values were corrected to "standard rubber" dry and wet values marked on the back of the Technical Products Co. primary standard #7 ceramic tile. Separate 10 lb. Model 80 test blocks were used to contain each of the four materials tested, with the following results:

Table 1.

SCOF DRY/C1028 Tile

SCOF WET/C1028 Tile

Sensor Material

Avg.

+

-

S.D.

Avg.

+

-

S.D.

Neolite

0.62

0.02

0.04

0.021

0.05

0.02

0.02

0.014

Monarch EVA (uncorrected)

0.44

0.02

0.00

0.007

0.36

0.01

0.02

0.011

Monarch EVA (corrected)

0.50

0.02

0.00

0.007

0.35

0.01

0.02

0.011

Leather

0.27

0.01

0.02

0.011

Can't wet test leather

TPU, before sanding

0.25

0.01

0.01

0.007

-

-

-

-

TPU, after sanding

0.26

0.01

0.01

0.007

0.33

0.01

0.02

0.011

Test Conditions:

67oF, 50% relative humidity. Gage Correction Factor and Humidity Correction Factor = 1.00

Ref. 3 states: "Donald E. Marlowe is the director of the Office of Science & Technology at the Center for Devices & Radiological Health of the Food & Drug Administration (FDA)" .

Mr. Marlowe's comment on the following interviewer's question: "The National Technology Transfer Act of 1995 requires that all federal agencies utilize private sector standards. How has FDA responded to the NTTAA since its implementation?" was "...our whole program relating to standards, dating back to the late 1970s, has been based on the premise of using consensus standards to describe how devices should perform." Mr. Marlowe also states: "The Tech Transfer Act enabled us to strengthen the message we were trying to convey to the medical device manufacturers about the inherent benefits of developing PERFORMANCE standards through the consensus process."

The word "performance" is emphasized because all of the present ASTM "standards" for measuring slip resistance of flooring and footwear are actually test methods for using specific test instruments for measuring both the SCOF of flooring materials and coatings or measuring both the SCOF and DCOF of footwear materials.

VOSI is the only NIST recognized private sector standards development organization that has approved performance based consensus standards for measuring the SCOF of both walkway materials and coatings (ref. 1) and footwear (VOSI V41,22). (see www.voicesofsafety.com ..."About VOSI" and "Slip & Fall Standards").

The only performance based ASTM test method for measuring the SCOF of polishes is ASTM D2047. This test method uses a leather sensor and the non-portable James Machine. The typical substrate for testing polishes is "Official Vinyl Composition Tile" (OVCT).

Ref. 4 states: "Uniformity in regulatory review and approvals will be improved and expedited, as the opportunity for standards recognition by the FDA and self certification by the manufacturer are provided" (D. E. Marlowe, et al., 1998 "FDA Recognition of Consensus Standards in the Pre-market Notification Program", Biomedical Instrumentation & Technology, Hanley & Belfus, Inc. pp. 301-304).

VOSI requires that operators of drag type SCOF testers be certified in order that test results be accurate.

Conclusions:

  1. Neither Neolite nor Toplift TPU represents rubber footwear soling materials, whereas Monarch EVA was selected because it represents an average rubber footwear soling material.

  2. All sensor material s used for measuring the SCOF of flooring or coatings have variable properties due to lot and sanding variations. Since SCOF involves the properties of both the sensor and floor or coating, the sensor must be standardized in order that the floor or coating is the only variable.

  3. Donald Marlowe, Chairman of the ASTM Board of Directors and Slip Resistance Task Group Chairman should review the performance based VOSI standards and reference these documents in all ASTM test methods for measuring SCOF or DCOF.

  4. See www.voicesofsafety.com ...read "About VOSI" ...Click on "Slip & Fall Standards" and "Public Safety"

  5. Research should not be performed in a vacuum. All pertinent documents should be reviewed in order not to waste time on useless research.

Donald C. Meserlian, P.E.
VOSI Chairman & ASTM Member F 13, D21C21F6 etc.

Voices of Safety International (VOSI) - 1998 - 2017
Contact: webmaster@voicesofsafety.com
Created: 2001-01-20 Last Updated: 2001-04-03