NBSIR 76-1005

A Comparison of Two Testers in

Evaluating the Slip-Resistance

of Bathtub and Shower Base

Surfaces

Robert J. Brungraber

Theresa J R. Raper

Center for Building Technology

Institute for Applied Technology

National Bureau of Standards

Washington, D.C. 20234

Issued October 1 977

The research reported herein was supported by the

Consumer Product Safety Commission

U.S. DEPARTMENT OF COMMERCE

NATIONAL BUREAU OF STANDARDS

NBSIR 76-1005

A COMPARISON OF TWO TESTERS IN

EVALUATING THE SLIP-RESISTANCE

OF BATHTUB AND SHOWER BASE

SURFACES

Robert J. Brungraber

Theresa J.R. Raper

Center for Building Technology

Institute for Applied Technology

National Bureau of Standards

Washington, D.C. 20234

Issued October 1977

The research reported herein was supported by the

Consumer Product Safety Commission

U.S. DEPARTMENT OF COMMERCE, Juanita M. Kreps, Secretary

Dr. Sidney Harman, Under Secretary

Jordan J. Baruch, Assistant Secretary for Science and Technology

NATIONAL BUREAU OF STANDARDS, Ernest Ambler. Acting Director

TABLE OF CONTENTS

Page

ABSTRACT 1

1. INTRODUCTION 2

2. TEST PROGRAM 2

2.1 Testers 3

2.1.1 NBS-Brungraber Tester 3

2.1.2 Kollsman Tester 3

2.2 Sensors 6

2.3 Sample Materials 7

2.4 Soap Solution 8

2.5 Experimental Schedule 10

2.6 Laboratory Procedure 11

3. RESULTS 12

4. DISCUSSION 16

4.1 Discussion of Data 16

4.2 Discussion of the Two Testers 20

4.3 Checklist for Evaluation of a Tester

for Determining the Slip-Resistance of

Bathtub and Shower Base Surfaces 22

5. CONCLUSIONS 22

6. RECOMMENDATIONS 24

7. SI CONVERSION UNITS 25

Appendix A. Program Proposal 26

Appendix B. Program Proposal - Revised 27

Appendix C. Program Revision 28

Appendix D. Instructions for Operation of the NBS-Brungraber

Portable Slip-Resistance Tester 30

Appendix E. The Kollsman Test for Bathtub Slip-Resistance 36

Appendix F. Kollsman Apparatus - Operating Procedure 41

Appendix G. Procedure for Testing 47

Appendix H. Results of Test Program - Raw Data Tabulations .... 48

A COMPARISON OF TWO TESTERS IN EVALUATING THE

SLIP-RESISTANCE OF BATHTUB AND SHOWER BASE SURFACES

Robert J. Brungraber and Theresa J. R. Raper

ABSTRACT

The report describes a program of tests planned by ASTM

Committee F15.03 on Safety Standards for Bathtub and Shower

Structures, and conducted at the National Bureau of Standards

for the purpose of comparing the NBS-Brungraber and the Kollsman

tester with respect to their effectiveness in evaluating the slipresistance of bathtub and shower base surfaces. This program

represents a contribution by the National Bureau of Standards to

the efforts of the American Society for Testing and Materials and

the Consumer Product Safety Commission in developing safety

standards for bathrooms and bathroom fixtures. Both testers employ

the same material (drumheads of "slunk") to simulate human skin,

and the report concludes that both testers will satisfactorily

discriminate between different bathroom surfaces on the basis of

slip-resistance. The conclusion may be made that the NBS-Brungraber

tester is considerably more convenient to use.

Key words: Kollsman tester; NBS-Brungraber tester; safety of

bathrooms; slip-resistance of bathtub and shower base surfaces;

slip-resistance testers.

I
1. INTRODUCTION

The Building Safety Section has been conducting an extensive study

of the slip-resistance of walkway surfaces. A significant contribution

of this study has been the design of a new portable tester, the NBSBrungraber tester, for evaluating the slip-resistance of in situ floor

surfaces. This tester was intended for the evaluation of surfaces that

are usually used by people with shod feet and thus the sensor facing

elements selected were typical of materials used for shoe-sole surfaces.

The interest of The American Society for Testing and Materials (ASTM)

Committee F15.03, with the support of the Consumer Product Safety

Commission, in the slip-resistance of bathtub and shower base surfaces

provided the Building Safety Section with an opportunity to apply the

new tester to another class of surfaces. For this application it has

been necessary to select a new sensor facing material that might

simulate the sole of a bare human foot.

As requested by ASTM Task Committee F15.03.01 and the Consumer

Product Safety Commission, the Building Safety Section performed a

series of tests to assist ASTM F15.03.01 in selecting a suitable

tester for evaluating the slip-resistance of bathtub and shower base

surfaces. The task as specified in the minutes of the ASTM F15.03.01

(Appendix A) meeting of June 5-6, 1975, and then later revised by

ASTM F15.03.01 (Appendix B) on July 16, 1975, and by the investigators,

(Appendix C) August 8, 1975, -was to conduct a series of tests on five

representative bathtub or shower base surfaces using the NBS-Brungraber

tester and the Kollsman tester.

2. TEST PROGRAM

The test program was organized to execute the task as specified

and modified.

2
2.1 Testers

2.1.1 The NBS-Brungraber Tester

This tester, shown in figure 1, was designed to measure the static

coefficient of friction between a representative walkway surface and a

piece of shoe soling or heel material. For the program of the present

report the sensor shoe of the tester was modified for use with a

material intended to simulate human skin and be representative of a

bare foot. Appendix D contains a description of this tester with an

illustration and operating instructions. The tester, as designed, is

able to employ one, two, or three 5-pound circular weights so that

the vertical or normal force can be varied between the limits of

approximately 8 pounds and 18 pounds. For the tests of the present

report two weights were used so that the total vertical force,

including the weights of both struts and the shoe sensor assembly, was

13.32 pounds.

2.1.2 Kollsman Tester

This tester, shown in figure 2, has been described by its inventor

and his representative as a mechanical analog that represents the

action of a person slipping in a bathtub or shower. A report describing

the design of this tester is attached as appendix E, and the instructions

for the use of the tester are attached as appendix F. These instructions

reflect modifications made, under the supervision of Kollsman, during

the first half day of testing. Significant modifications include:

a) number of measurements in a series of tests and the total

number of tests (though not consistently described in the

appended document),

b) increasing the screw adjustment on the sensor pad from two

turns, as was required by the original instructions, to

three and one half turns.
I

i

Figure 1. NBS-Brungraber Tester

4
Figure 2. Kollsman Tester

5
The Kollsman tester can be operated in three separate modes -

static, static/dynamic, and dynamic. However, in accordance with the

specified test program, the Kollsman tester was to be evaluated in

only two modes. As instructed by Mr. Kollsman and his representative,

the static mode was eliminated from the test program. For the program

of the present report the Kollsman tester was operated with the weight

in the position intended to develop a normal force of 25 pounds; however,

the magnitude of this force was not checked.

2.2 Sensors

Based on the experience of Mr. Kollsman and that of the Building

Safety Section in evaluating the slip-resistance of swimming pool decks,

a material thought to be suitable for simulating the bare skin on the

sole of a human foot was selected. The material selected was a

natural drumhead known as "slunk," which is made from the hide of an

unborn calf. The particular skin selected was one intended for the

lower or snare side of a snare drum. This skin was measured with a micrometer caliper and found to have an average thickness of 0.008

inch + 0.002 inch. This skin was selected since, based on orior

qualitative studies by Mr. Kollsman, it had been found to be the least

susceptible to swelling and stretching under tension when soaked in

warm water or soap solution.'

Subsequent investigations have shown that the frictional properties

of slunk vary from sample to sample and that, contrary to expectations,

the frictional properties vary as the skin is used for testing or

simply soaked in pure or soapy water. When evaluating the slipresistance of relatively rough surfaces, such as surfaces used for

swimming pool decks, the slunk surface could be observed sloughing

off, indicating that the material was being affected by use. However,

such sloughing off was not observed on the surfaces tested for the program described in the present report. In appendix C the slunk is

incorrectly identified as kip.

6
A 3-inch wide strip of skin was cut to fit the sensor of the NBSBrungraber tester and a 5-inch diameter circle was cut to fit the

sensor of the Kollsman tester. After soaking in distilled water at

100° + 10°F for at least 15 minutes, the skin specimens were attached

to the proper sensors and returned to the water bath for at least 15

minutes before starting the slip-resistance measurements. For both

testers, the skin was backed by a 3/16-inch thick layer of closed

cell neoprene sponge. Contrary to the instructions of item D(l) of

appendix B, it was found that only 15 minutes of soaking was needed

to make the skins sufficiently pliable to permit their installation

on the sensor of either tester.

For the Kollsman tester, the sensor was a 3 1/2-inch diameter

circle and for the NBS-Brungraber tester, the sensor was a 3-inch

square. This results in a contact area of 9.6 square inches for the

Kollsman tester and 9 square inches for the NBS-Brungraber tester. A

single skin was used to provide the sensor covers for both testers and a single cover was used on each instrument throughout the entire test program.

2.3 Sample Materials

As specified in appendix B, the materials to be tested were:

porcelained cast iron - smooth; porcelained cast iron - textured,

with a sand blasted surface; textured, gel-coated fiberglass-reinforced

plastic (FRP) having a pebble grained surface; dot-pattern appliques

applied to smooth, porcelained cast iron; and flower-pattern appliques

applied to smooth, porcelained cast iron. However, the cast iron

specimens were replaced by similarly finished porcelain-enameled

steel specimens, because of the ready availability of the latter.

Two specimens of each material were provided: one 12 x 30 inches

for use with the NBS-Brungraber tester, and one 6 x 12 to 13 inches for

use in the Kollsman tester. The porcelain-enameled steel specimens

were supplied by the Porcelain Enamel Institute. In order to insure

that these specimens would remain flat throughout the test procedure,

7
they were bonded with an epoxy adhesive to 1/4 inch thick cementasbestos board, which was backed with light-gage, sheet aluminum.

The FRP material, a textured shower base, was used as supplied by the

manufacturer. The dot-pattern appliques were supplied and installed

by the developer. The flower-pattern appliques were supplied by the

manufacturer and installed at the National Bureau of Standards (MBS)

according to the manufacturer's instructions. The two patterns of the

applique treatments are illustrated at full size in figure 3. The dotpattern appliques were made of a sheet vinyl having a smooth surface

and the flower pattern appliques were made of a synthetic rubber

sheet material having a pebble-grained surface. Both types of appliques

were attached with pressure sensitive adhesive which had been applied

by the manufacturer.

All specimens were prepared for testing by conditioning them in

distilled water at 100° + 10°F for at least 15 minutes. Conditioning

was conducted in a covered, insulated and temperature-controlled

galvanized steel tank. The sensors, with slunk attached, for both

testers were also kept in the water bath except when they were being

used in a test.

2.4 Soap Solution

The soap solution was a mixture, by weight, of 90% distilled

water and 10% soap flakes, as specified by the ASTM Committee (per

appendix B). The soap flakes, a mild white laundry type, were intended to

be representative of pure white bath-type soap as would meet ASTM D499-69

(Reapproved 1974) "Standard Specification for White Floating Toilet

Soap." The soap solution was kept in plastic wash bottles, and

maintained at 100° + 5°F on a temperature-controlled hot plate, except

when the solution was being applied to the sensors or the surface

of the specimens. It was found necessary to maintain this temperature

in order to prevent precipitation of the soap and formation of a gel.

The use of a closed plastic wash bottle was to prevent evaporation

of the mixing water so that the soap concentration would be the same

for all of the specimens tested.

8
FIGURE S. CONFIGURATION OF APPLIQUE TREATMENTS

Dot-Pattern Applique
2.5 Fxperimental Schedule

The order for testing, determined as described in "Procedure for

Testing," appendix G, was:

1) Textured porcelain-enamel on steel

a) Kol Isman-static/dynamic mode

b) NBS-Brungraber

c) Kol Isman-dynamic mode

2) Smooth porcelain-enamel on steel

a) Kol Isman-dynamic mode

b) NBS-Brungraber

c) Kol lsman-static/dynamic mode

3) Flower-pattern appliques on smooth, porcelain-enameled steel

a) Kol lsman-static/dynamic mode

b) NBS-Brungraber

c) Kol 1 sman-dynamic mode

4) Dot-pattern appliques on smooth, porcelain-enameled steel

a) Kol Isman-dynamic mode

b) NBS-Brungraber

c) Kol lsman-static/dynamic mode

5) Textured, gel-coated, fiberglass reinforced plastic (FRP)

a) Kol lsman-static/dynamic mode

b) NBS-Brungraber

c) Kol Isman-dynamic mode

This alternating of the test order from material to material was adopted

to help eliminate unnecessary bias from the testing procedure. The

sequence of using the Kollsman tester in two modes and the NBS-Brungraber

tester in one mode on each of the five materials was repeated three times

so that a total of 15 observations was to be made for each mode of each

tester on each material. A complete sequence of tests took approximately

three hours. In order to meet or exceed the requirement of ten replicates

specified in item B of appendix B, a total of 15 observations or replicates

was made by going through the order of testing three complete times, making

five observations or replicates at each stage of each test.

10
2.6 Laboratory Procedure

Prior to testing, the sensors (with the slunk) and specimens were

immersed in distilled water at 100° + 10°F for at least 15 minutes to

bring them up to temperature. This was judged to be an adequate

immersion period since no apparent signs of gelation of the soap

solution occurred during any of the tests. For all materials, tests

began with one of the two modes of the Kollsman tester. A specimen

and sensor were removed from the bath and placed in the Kollsman tester.

The screw adjustment was made, as described in appendix F. The specimen

and sensor were returned to the bath for at least 15 seconds to restore

them to a satisfactory lathering temperature. The specimen and sensor

were then replaced in the tester, soap solution applied to both sensor

and specimen, and either a static/dynamic or a dynamic test performed.

The same type of test was repeated without any additional soaping or

soaking for a total of five observations. That is, at each increment

of weight on the support rod, five distinct repeat operations of the

tester were performed. Thus five distinct readings were made for each

increment of the Kollsman test, however many increments might be

required to achieve a full travel of 6.5 inches, indicating attainment

of uncontrolled slip. Upon completion of the first Kollsman test

sequence, the specimen and sensor were then returned to the bath to

soak while the specimen and sensor for the NBS-Brungraber tester were

removed from the bath and soap applied. Five measurements with the

NBS-Brungraber tester were then performed without any additional soaping

or soaking. The specimen and sensor were returned to the bath while

the Kollsman specimen and sensor were reinstalled and the alternate

type of Kollsman test performed. All specimens and sensors were

thoroughly rinsed in warm tap water before they were returned to the

bath of distilled water.

The test program was conducted at ambient conditions in a laboratory in which the temperature and relative humidity were controlled

by the central heating and ventilating system of NBS. The temperature

and relative humidity were continuously monitored by a device capable

of measuring to within + 2°F and + 2% relative humidity (rh). During

11
this test program the atmospheric conditions ranged between a low of

72°F with 58% rh and a high of 75°F with 66% rh. Since all tests were

conducted using a soap solution and specimens which were preheated to

100° + 10°F, the atmospheric conditions in the laboratory were not

considered to be critical.

3. RESULTS OF TESTS

A summary of the test results is presented in tables 1 and 2.

Both tables include means and standard deviations for use in later

statistical analysis. These calculations are only made for continuous

variables, the static coefficient of friction for the NBS-Brungraber

tester and the displacement of the carriage (in inches) for the Kollsman

tester. (The raw data is included in this report as appendix H.)

Table 1, for the NBS-Brungraber tester, presents the average

static coefficient of friction (X) and the standard deviation (s) for

the five observations in each replicate as well as overall, a total

of 15 or 20 observations The overall mean and deviations from the

overall mean are used in calculating the 95 percent confidence interval.

This interval would be expected to bracket the true mean (of the

population) 95 percent of the time. The upper and lower confidence

limits, X and X, , are shown in table 1.

upper lower

The Kollsman tester measures the displacement of the carriage for

discrete test loads and uses the attainment of a displacement of 6 1/2

inches as an indication of the onset of uncontrolled slip. The displaceAt the conclusion of the first day of testing, during which the two

enameled surfaces (smooth and textured) and the flower-pattern appliques

were tested, it was found necessary to change the technique for

adjusting the Kollsman tester (see section 2.1.2). For this reason,

the original data taken with the Kollsman tester was discarded and the

test program reinitiated. However, the data for the NBS-Brungraber

tester was satisfactory and retained for analysis; four replicates,

20 observations, are reported.

12
ment values for respective test loads are given in table 2, showing

the average and standard deviation for the five observations in each

replicate as well as overall, for a total of 15 observations. In the

cases where all five observations in a replicate were greater than

6 1/2 inches, a notation to this effect was made, in table 2, in the

column. In cases where some, but not all, of the observations were greater

than 6 1/2 inches no average is reported and the letters "N.A." are

entered in the columns where mean and standard deviations are normally

reported. For the purpose of analysis, the averages and standard

deviations are reported to two decimal places though the displacement had

been determined and recorded to the nearest 1/16-inch. In many cases

using the Kollsman tester, the carriage would move rapidly a certain

distance, slow down distinctly and then creep on, sometimes to the end of

travel, approximately 6 13/16 inches. Whenever there was a temporary

halt, so that the displacment could be read at the point, this value was

recorded. Otherwise the result, greater than 6 1/2 (>6.5) inches, was

entered. This indicates that there is a need for some interpretation of

the performance of the Kollsman tester. No instructions for such an

interpretation were supplied with the tester.

It is noted that the load, as applied for the Kollsman tester, is

a discrete rather than a continuous variable and that the goal of the

test is attaining a limiting value (see 3.14, 4.23, and 5.23 of appendix

F). It is also noted that the standard deviation of the displacement

data tends to increase as the load increases, which can be seen in

table 2. 3.

Kollsman and his representative have reported that a technique has been

developed for analyzing data from the Kollsman tester that involves

plotting the value of the applied test load versus the resulting

displacement. However, this technique was not reported to the NBS

investigators. Depending upon the criteria used to indicate uncontrolled slip, this technique could be used to establish slipresistance as a continuous variable. However, in view of the dilemma

of continuous versus discrete data and the variability of the displacement measurements, the application of this technique did not appear to

be justified.

13
Table 1. NBS-BRUNGRABER TESTER RESULTS _ STATIC COEFFICIENT

OF FRICTION AS AN INDICATOR OF SLIP RESISTANCE*

Test Surface Test Data

Identification

Static

Coefficient

of Friction

95% Confidence

Limits

X s X X lower upper

Smooth

Porcelain-Enamel

on Steel

Rep #1

Rep #2

Rep #3

Rep #4

.07

.07

.08

.09

.004

.006

.006

.008

Overall .08 .008 .074 .082

Textured Rep #1 .11 .013

Porcelain-Enamel

#f (\\ . ;TM , on Steel Rep #4 .14 .008

' Overall .13 .018 .120 .136

Textured Rep #1 .13 .013

Gel -Coated Rep #2 .13 .018

Fi berglass Rep #3 .13 .016

Reinforced

Plastic Overal

1

.13 .015 .121 .137

Dot-Pattern Appliques Rep #1 .23 .021 on Smooth Rep #2 .19 .016

Porcelain- Rep #3 .20 .013

Enameled

Steel Overall .20 .023 .191 .217

Flower-Pattern Rep #1 .22 .023

Appliques on Rep #2 .22 .011

Smooth Rep #3 .23 .019

Porcelain- Rep #4 .22 .019

fnameled

Steel Overal

1

.22 .018 .212 .228

*There are 5 observations in each replication; 15 or 20 observations for each material.

14
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15
4. DISCUSSION

4.1 Discussion of Data

The discussion of the results focuses on the ability of the two

testers to discriminate between different test materials. For the

NBS-Brungraber tester, a statistical g-test was selected.^ This

technique is used to show whether the test procedure can detect

differences among the materials. The data from the Kollsman tester

were not suitable for the application of this technique.

The average results from the NBS-Brungraber tester are plotted

in figure 4, along with the 95 percent confidence interval. In this

figure, the data is reported for the materials in the order of increasing

slip-resistance: smooth porcelain-enamel, textured porcelain-enamel,

gel -coated FRP (textured), dot-pattern appliques, and flower-pattern

appl iques.

The results of a g-test, indicating statistical differences between

test materials, are provided in table 3. Fifteen measurements were used

in the calculations for all materials; 5 observations were selected

randomly to be discarded for materials having 20 measurements. The

results of the g-test ( a = 0.05) indicate that, with respect to slipresistance, the two manufactured, textured surfaces are not significantly

different; and that the two applique treatments are also not different.

Figure 4 also illustrates the similarity of these types of materials.

The g-test demonstrates that the NBS-Brungraber tester can discriminate,

on the basis of slip-resistance, between smooth and textured surfaces

and between manufactured, textured surfaces and applique treatments.

In figure 5, the data from the Kollsman tester are plotted in the

same order as in figure 4. For the Kollsman tester, load at which slip

Natrella, M. G. Experimental Statistics, National Bureau of Standards

Handbook 91, 1963

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becomes uncontrolled, which is related to dynamic friction, is used as

an indicator of slip-resistance. The Kollsman tester produces a rankorder different from the NBS-Brungraber tester only in its assessment

of the dot-pattern applique. The dot-pattern applique required about

three times the test load required by any other material to attain

uncontrolled slip. It should be noted that both operating modes of the

Kollsman tester result in the same rank-order. The Kollsman tester also

showed that the two manufactured, textured surfaces had approximately the

same slip-resistance characteristics.

4.2 Discussion of the Two Testers

A review of the results shown for the most slippery surface, the

smooth porcelain-enamel, on steel, reveal that, for low values of coefficient of friction, the NBS-Brungraber tester yields relatively high

results. The reported value of coefficient of friction, 0.08, would

indicate that slip would not occur on an inclined surface until the

angle of inclination had exceeded 4°. Such an angle of inclination is

greater than reported, but unpublished, research observations made by

other members of ASTM Committee F15.03. This indicates that in order to

achieve acceptable accuracy for small values of coefficient of friction

such as those that occur on soapy bathroom surfaces, the NBS-Brungraber

tester. must be calibrated against a reliable standard. Such a standard

has been developed by obtaining a low friction, ball-bearing shoe for

the NBS-Brungraber tester and then simulating variable friction forces

by using standard weights to apply a known lateral force to the shoe. The

ratio of simulated friction force to the known normal force developed

by the Brungraber tester results in a reliable standard for static

coefficient of friction.

There are three fundamental differences in the operation of the

NBS-Brungraber tester and the Kollsman tester:

20
1. The NBS-Brungraber tester makes a direct measurement of a fundamental

property of the foot-floor interaction, the static coefficient of

friction. The Kollsman tester is a mechanical analog that compares

the performance of different bathroom surfaces in a way that involves

the dynamic coefficient of friction. In fact, if you define dynamic

coefficient of friction as the ratio of lateral force to normal

force when uncontrolled slip occurs, the Kollsman tester can be

used to approximate the value of the dynamic coefficient of friction.

2. The NBS-Brungraber tester employs the movement of a trigger to

establish when slip has occured or when the static coefficient of

friction has been reached. Although there is no statement to this

effect in the instructions supplied with the Kollsman tester, it

appears that uncontrolled slip is considered to have occurred and

the dynamic coefficient of friction exceeded when the carriage goes

to the end of its travel, greater than 6 1/2 inches.

3. The NBS-Brungraber tester employs a variably inclined strut to

apply a continuously increasing lateral force. The tangent of the

angle of this strut at the beginning of slip is the static coefficient

of friction. Thus, the static coefficient of friction as measured

by the NBS-Brungraber tester is a continuous variable that can be

recorded to any calibrated degree of precision. In view of the

variability of conditions likely to be met in the field, the scale

of the Brungraber tester is graduated in divisions of 0.05 units of

coefficient of friction so values can be conveniently interpolated

to the nearest 0.01 units. The Kollsman tester employs a lateral

activating force that is increased in units of approximately 300

gms or 0.67 lbs so that, considering that the normal force is

approximately 25 lbs, the ratio of horizontal to vertical force

can be determined. However, in view of the fact that the carriage

is not known to be moving at a constant velocity, there is no

assurance that such a ratio would be the dynamic coefficient of

friction.

21
4.3 Checklist for Evaluation of a Tester for Determining

Slip-Resistance of Bathtub and Shower Base Surfaces

Based on a study of a variety of slip-resistance testers and the

general problem of slip-resistance of walkway and bath surfaces, a checklist suitable for evaluating such testers, has been devised. This

checklist, presented as table 4, is used to compare the two testers in

question.

5. CONCLUSIONS

The test program and subsequent data analysis affords the following

conclusions concerning the NBS-Brungraber and Kollsman testers:

1. With one exception, the dot-pattern applique, both testers rank the

materials in the same order according to slip-resistance.

2. Both the dynamic and static/dynamic modes of the Kollsman tester

rank the materials in the same order.

3. Both testers are sufficiently sensitive to discriminate between the

various materials on the basis of slip-resistance.

4. The NBS-Brungraber tester is considered easier to use than the

Kollsman tester in that it requires less time to conduct a test

and less continual clean-up and maintenance.

5. The NBS-Brungraber tester directly measures static coefficient of

friction, a fundamental property related to the slip resistance of

walking surfaces. The Kollsman tester demonstrates the relative

slip-resistance of surface materials in a dynamic situation but

does not currently measure a fundamental property related directly

to slip-resistance.

22
TABLE 4

CHECKLIST FOR EVALUATION OF

A TESTER FOR DETERMINING

SLIP-RESISTANCE OF BATHTUB AND SHOWER BASE SURFACES

NBS-Brungraber Tester Kollsman Tester

The tester measures a .fundamental,

interpretable property, eg. , coefficient of friction

yes not directly

The tester is capable of using an actual tub or shower base as a sample

yes no

The tester is capable of discriminating between different surfaces

yes yes

The tester is easily

transportable

yes yes

The tester is

convenient to use

The tester is a permanent assembly having

only two easily re- movable parts

The tester is an assembly consisting

of numerous easily

separable parts

The tester is easily adjusted

and serviced

yes yes

The tester employs a sensing

surface that acceptably

resembles human skin

yes yes

The vital parts of the tester

(bearings and operating surfaces) are free from contamination by

water or soap solution

yes no

The data is capable of being

readily treated statistically

yes no

The tester is capable of considering

both static and dynamic effects

Static only Dynamic (as evaluated)

Static (with the introduction of additional

techniques)

The time for conducting a test

is relatively brief

Less than five

minutes (regardless of the material tested)

Five minutes to 30

min. (depending upon

the material being

tested, smooth materials

take the least time)

The tester measures in SI units yes

(nondimensional

no

parameter 3 (could be so modified)

The tester is available and

at a reasonable cost

Two samples of the tester

are presently available

and a third is being

made. Additional ex- amples could be delivered within eight

weeks of order at an estimated cost of $3,000

A pilot model of

this tester is

presently available;

cost and delivery

information for

finished examples is

not known

The operating procedure is

available and capable of

being followed by a representative technician

yes

The operating procedure

is available but in need

of refinement

23
6. RECOMMENDATIONS

Based on the present study, the following items are recommended for

further study:

1. Representative levels of soap concentration occurring in bathing

situations should be determined. It may be found that lower concentrations of soap could and should be used. This might make the

test conditions less slippery so that any tester could more readily

discriminate between different surfaces. It might also lessen the

tendency for the soap solution to precipitate out and gel as the

temperature is lowered and thus permit tests to be conducted more

nearly at room temperature. These determinations should probably

concentrate on soaps meeting ASTM D499-69 specifications, since

these are currently the most popular bath soaps.

2. The need for distilled water for soaking specimens and for making

the soap solution should be evaluated. If deionized water or water of

controlled hardness would be satisfactory, this would considerably

reduce the cost of any test program.

3. The need for including dynamic effects should be studied by evaluating actual accident situations.

4. Other ways of including dynamic effects, that would meet more of

the criteria of the checklist, should be sought.

5. The quest for a suitable material to use as a sensor to simulate

human skin should be continued. For the present, slunk is recommended;

but with the knowledge that it has shortcomings and is, therefore,

not the ideal material for this purpose.

24
7. SI CONVERSION UNITS

In view of present accepted practice in this technological area,

primarily U.S. customary units of measurement have been used in this

report. It should be noted that the U.S. is a signatory to the General

Conference on Weights and Measures' which gave official status to the

International System of Units (SI) in 1960. Readers interested in

making use of the coherent- system of SI units will find conversion

factors in ASTM Standard Metric Practice Guide, ASTM Designation E380-72

(Available from American Society for Testing and Materials, 1916 Race

Street, Philadelphia, Pennsylvania 19103). Conversion factors for units

used in this paper are:

Length:

1 in = 2.54 cm

1 ft = 30.480 cm

Area:

1 sq in = 6.451 sq cm

Weight:

1 lb = 453.00 g

Temperature:

°C = 5/9 (Temperature °F - 32)

25
APPENDIX A

PROGRAM PROPOSAL

Task Group #1 on Slip Resistance wishes to propose the following program to

the CPSC. This program is to evaluate the Brungraber and Kollsman Slip Resistance

Testers

Work to be performed at NBS (Building Safety Section, Center for Building

Technology) with the following guide lines:

A. Program to be set up statistically by NBS to provide test values

at a 95% confidence level.

B. Test Condition wet at standard laboratory atmosphere (72°F - 60% R.H.)

using the following two test solutions:

(1) Distilled water

(2) 10% soap solution (by weight) using distilled water and soap

defined in ANSI Spec. Z124 on Plastic Bath Tubs.

C. Skin used in both the testing machines to be of the same material (anima]

skin - goat, cowhide, etc.) but should be 0.015 to 0.020 inches thick

and transluscent . Smooth side of skin to be contact surface.

D. Test surfaces to be supplied to NBS by manufacturers. The following

surfaces to be used:

(1

(2

(3

(4

(5

(6

(7

(8

(9

(10

(11

(12

Porcelain Steel - Smooth & Textured - Peerless Pottery

Porcelain Cast Iron - Smooth & Textured - American Standard

Post Coated SMC - Smooth - Owens Corning Fiberglas

SMC (uncoated) - Smooth & Textured - OCF

Gel Coated FRP - Smooth - Snyder Industries

Gel Coated FRP - Textured - Universal Rundle

Acrylic - Smooth - Powers Fiat

Acrylic - Textured - Powers Fiat

Kollsman Applique - Al Shaines

3M Applique - Al Shaines

Rubber Maid Applique - Al Shaines

Porcelain Steel - Smooth - Verson Home Products

Panel size 12" x 30" to be shipped as soon as feasible after acceptance of

Program. Applique to be applied by NBS to smooth Porcelain Steel Panel.

Final selection of test machine will be made by Task Group after reviewing

test results. Additional tests on selected surfaces may be made after reviewing

data and at the discretion of the Task Group, if further clarification is required.

In order to meet the time table set up by Task Group #1, the results from this

program must be available for the July 16th meeting.

Task Group #1

W. C. Krieger

Vice Chairman

26
APPENDIX B

PROGRAM PROPOSAL - Revised 7/16/75

The original proposal, reported in the June 1975 meeting minutes, was revised

after being reviewed by NBS and Task Group 1. The revised proposal will have two

phases — Phase I - Evaluation of the Brungraber and Kollsman Slip Resistance Testers

and Phase II - Material Evaluation using the results from Phase I.

Phase I to be performed at NBS (Building Safety Section, Center for Building

Technology) will be conducted along the following guidelines:

A. Program to be set up statistically by NBS to provide test results at

a 95% confidence level.

B. Ten replicates per test will be used in all tests.

C. Test will be conducted at ambient temperature and humidity.

D. Skin used on all tests to be same. . NBS to make selections.

(1) Skin to be soaked in distilled water for 24 hours prior to use.

(2) Same amount of soap to be used in all tests.

(3) Soap to be applied to wet skin rubbed in for 5 to 15 seconds.

(4) Test surface to be wet with soap solution and then rinsed off

with distilled water before test. (Rinsed or left on at

discretion of NBS)

E. Soap Solution to be used - 10% (by weight) Ivory Flakes and Distilled

water stored in plastic tub or container to prevent contact with air,

maintained at 100°F.

F. Test surfaces to be supplied by manufacturers are as follows:

(1) Porcelain Cast Iron - Smooth 3 pes. (2' x 3

1 ) Eljer Plumb ingware

(2) Porcelain Cast Iron - Textured 1 pc. (2

1 x 3') Eljer Plumbingware

(3) Gel Coated FRP - Textured 1 pc. (2' x 3') Universal Rundle

(4) Kollsman dot-patterned applique applied to smooth

cast iron Kollsman

(5) Rubbermaid flower-patterned applique applied to

smooth cast iron Rubbermaid

Total Number of specimens needed for Kollsman tester in the 6" x 13" size

are as follows: three (3) smooth porcelain cast iron, one (1) textured

porcelain cast iron, and one (1) gel coated FRP.

G. Address for Shipping Address for Mail:

Dr. R. J. Brungraber

National Bureau of Standards

Quince Orchard Road

Gaithersburg, Maryland 20760

Dr. R. J. Brungraber

Room B362

Building 226

Washington, D.C. 20234

27
i

I UNITED STATES DEPARTMENT OF COMMERCE j National Diircou of Standards

Washington. D C. 20234

APPENDIX C

August 8, 1975

MEMORANDUM TO: Members of Committee F15.03

FROM: R. J. Brungraber, Building Safety Section

*

R.E.: Program Proposal - Revised 7/16/75 \J

The tests are currently being conducted with some necessary modification

in test procedure that should be noted. These will be noted with

reference to the above referenced proposal.

A. Although the specifications that the test results be at a 95% confidence level is incomplete without also stating a desired band-width

or data tolerance, sufficient replications are being made so that S, the

standard deviation of the sample, can be expected to be an unbiased

estimator of at least 95% of the standard deviation of the population.

B. Based on preliminary tests conducted with both testers, it was

found that good repeatability could ht achieved by making rive repeat

tests on a given sample without removing it from the tester or resoaping

it. Thus the procedure was changed to:

1) Soak the sample and skin covered sensor in distilled

water at 100 + 10°F for 15 seconds or more.

2) Place the sample in the carriage of the Kollsman

tester or on the floor for the Brungraber tester

and install the skin covered sensor on the

appropriate tester.

3) Apply the 10% soap solution at 100 + 10F to both the

sensor and the sample.

4) Conduct five repeat tests as quickly as possible

generally in a few seconds.

5) Wash soap from the specimen and return it to the

water bath until all tests have been completed on

the other four specimens and then repeat steps one

through four two or more times. This provides

three replications, fifteen observations.

28
2

C. This being monitored and recorded to ± 2*F and 2% R.H.

D. The skin selected was identified as kip, suitable for the "transparent snare side of a snare drum. A sensor covering for each of the

testers was cut from the same skin and used throughout the test

program.

1) It was found that soaking in distilled water at 100 ± 10°F

for at least 15 minutes was sufficient to soften the skins.

4) Upon removal from the water bath both the skin covered

sensor and the speciir.cn had the soap solution applied

and rubbed in for 5 to 15 seconds. After each series

of five tests, the skin and specimen were both rinsed

or wiped free of scap and returned to soak in the water

(warm) bath until the next series of five tests.

E. The soap solution was stored in a plastic wash bottle at 100 + 10°F,

F. At the time of writing of this memo, August 8, 1975, the cast iron

specimens had not yet been received so that substitute steel specimens,

both smooth and textured, were used.

A complete description of the test procedure will be included in the

test report.

29
APPENDIX D

INSTRUCTIONS FOR THE OPERATION OF THE NBS-BRUNGRABER PORTABLE SLIP-RESISTANCE

TESTER

Description of Components (Referring to Figure 3)

A. Main frame

B. Travel bars

C. Carriage

D. Linear splined shaft

E. Articulated shaft

F. Recording shaft with magnet

G. Recorder clamp

H. Trigger

I. Sensor shoe, with magnetic strip for retention of sensor facing clip, Q

J . Weight

K. Handle

L. Retainer plate

M. Control springs

N. Shock absorber

0. Attraction plate for magnet

P. Adjustable stop for shock absorber

Q. Sensor facing clip (not shown)

R. Initial position stop (not shown)

Principal of Operation

The NBS-Brungraber portable slip-resistance tester is designed to measure the

static coefficient of friction between a representative sample of shoe

sole material, such as leather, and a flooring surface; under true field

conditions. It does this by applying a predetermined vertical force,

(the weights, J) through a vertical splined shaft, D, and an articulated

shaft, E, to the sensor shoe, I.

At the start of a test the carriage, C, is brought forward to a stop

position such that the articulated shaft is not vertical but set at a

slight angle towards the back of the tester (approximately equivalent to

a tangent or coefficient of friction of 0.1). This establishes an

unbalanced lateral force against the carriage. At the instant that the

handle, K, is released and the vertical load is applied, the carriage

begins to move back along the travel bars, B, inducing an increasing

lateral load on the shoe as the angle between the articulated shaft and

the vertical increases. The tangent of this angle at the moment that

slip occurs is the static coefficient of friction. This angle is measured

by the recording shaft, F, which is magnetized and drawn along by attachment of the attraction plate, O, as the carriage moves backwards. When

slip occurs, the shoe sole, I, hits the trigger, H, so that the recorder

30

clamp, G, grips the recording shaft, F, retaining the shaft in its

position at the time of slip. The value of coefficient of friction

(tangent of the angle of the articulated shaft with the vertical) is

read at the front end of a short piece of transparent tubing protruding

from the front of the recorder clamp from a graduated scale imprinted

along the length of the recorder shaft.

The motion of the carriage is controlled by the springs, M, and the shock

absorber, 0, which contacts an adjustable stop, P, attached to the main

support frame, A. The retaining plate, L, helps to keep the shoe in

position while the tester is being lifted and moved to a new test location.

Preparation for a Test

In order to obtain consistent results with any slip-resistant tester, it is

essential that the sensor facing be maintained in a consistent condition.

This is done on the Brungraber tester by unclipping the sensor facing

clip, Q, from the shoe, I, so that the facing surface can be stroked

four times in each of two perpendicular directions against a sheet of

400 grit sandpaper held against a flat, uniform surface. This must be

done at least before each series of tests for a given floor surface and

a given test condition. In the event that lack of repeatability demonstates that the facing is picking up wax, dirt or other extraneous

material from the surface being evaluated, it may be necessary to resurface

or recondition the shoe facing more frequently.

The floor surface should be in a condition representative of the service

conditions to be evaluated; waxed or bare, buffed or unbuffed, wet or

dry, dirty or clean, etc. An area large enough to permit at least three

independent tests must be selected such that the service conditions are

uniform over the entire area. The NBS-Brungraber tester is a sensitive

instrument and inconsistency or nonrepeatability of results demonstrates

that either the floor surface being tested is not uniform or else the

sensor facing is picking up extraneous material.

If a wet floor surface is to be tested, the sensor facing should be

soaked in water before the test to simulate the likely condition of the

shoe sole or heel on a wet and rainy day.

Operation of the Tester

Before starting a series of tests the tester should be checked for free

and proper movement of all of the parts and proper adjustment of the

trigger, H. In the event the tester appears to have been knocked out of

adjustment, refer to the section of service and adjustment.

With the sensor facing properly conditioned and in place, the entire

tester is lifted by means of the handle so that the weight is lifted,

and the shoe lifted, releasing the trigger, permitting the carriage and

the recorder shaft to return to the initial position. Care should

be taken not to force the carriage forward before the shoe is lifted clear

32
of the floor permitting the release of the trigger, as this will cause

the forced movement of the recorder shaft through the clamped recorder

clamp, causing excessive wear of the recorder clamp and recorder shaft.

A convenient way to assure the release of the trigger is to push the shoe

back to its starting position with one hand while lifting the tester by

the handle with the other hand. With the tester suspended from the hand,

it is gently placed on the floor surface to be evaluated and the handle

immediately released. The tester is self-activating and as soon as the

carriage comes to rest against the shock absorber, the reading can be

made on the recorder shaft at the front of the recorder clamp. The

recorder shaft is graduated in divisions of 0.05 units of coefficient of

friction* and thus the reading can easily be interpolated to the nearest

0.01 unit of coefficient of friction. The procedure may now be repeated

for the next test.

*Note: Coefficient of friction just as the tangent of an angle is a ratio

and. thus, strictly speaking, has no units or dimension.

Service and Adjustments

The Brungraber tester is a fairly simple and rugged device and should

require very little maintenance; however, the following information may

be of help:

1) The proper vertical and rotational alignment of the splined and

articulated shafts is essential to the correct operation of the

tester. This alignment can be checked by visually noting the

orientation of the sensor shoe with respect to the hole in the base

plate. There is supposed to be a modest amount of free rotational

play of the splined and articulated shafts and when the sensor shoe

is in the center of the travel permitted by this play it should

also be in the center of the lateral dimension of the hole in the

base plate and the front and rear edges respectively, of the hole

in the base plate. If this is not the case, first check for possible

bending of the articulated shaft, which is unlikely unless the

tester has been severely abused.

If there is misalignment that is not caused by bending of the

shafts and other parts, this can be corrected by rotating the

splined linear ball bushing with respect to the carriage in which

it is supported. This can be done by first loosening the four

Allen set screws, one in each face of the carriage.

2) The trigger, H, lifts the recorder clamp, G, by means of an adjustable

screw in the upper portion of the trigger. There are four light

coil springs controlling the motion of the recorder clamp so that

the "free" motion of the trigger meets a slight resistance. When

the shoe is in the initial or rearward position this "free" travel

of the trigger should be in the range of 1/16 in to 1/8 in. In

33
the event these limits are exceeded, the amount of free travel can

be controlled by the previously mentioned adjustment screw. A

convenient way of determining the free travel of the trigger is to

observe the resulting free travel of the recorder clamp.

3) The recorder shaft should be lubricated with silicone spray and

checked for free movement after prolonged storage (1 week or more).

From time to time there may be enough dirt accumulation on the

recorder shaft as to make it difficult to read the graduations. In

this event the shaft should be wiped with a clean cloth or napkin

and relubricated.

4) It may be necessary to adjust the shock absorber so that the carriage

is free to travel its full stroke while at the same time it does

not induce a shock at the end of its travel. This adjustment is

effected by turning the screw in the end of the shock absorber with

either a screw driver or a small wrench.

5) When carrying the tester for a considerable distance, it may be

found desirable to remove the handle and weights so that they can

be carried in one hand and the rest of the tester in the other.

Another convenient and satisfactory way to carry the tester is to

first pick up the tester by the handle, thus fully withdrawing the

splined shaft, and then grasping the splined shaft just below the

weights. This suspends the tester so that it clears the floor with

the arm in a fully extended and thus more comfortable position.

34
ADDENDUM

TO THE OPERATING PROCEDURE

FOR THE NBS-BRUNGRABER SLIP-RESISTANCE TESTER

Modification of the Tester to

Accommodate the Simulated

Human Skin

In order to attach the piece of "slunk" to the NBS-Brungraber tester, a sligh

modified clip-shoe combination must be fitted. The clip has full width upturned portions at the front and the rear rather than the trigger-tripper

at the front and the two hooks at the rear, that the standard clip has.

The up-turned portion at the rear accommodates a brass retainer that holds

one end of the skin to the clip. The other end of the skin is brought down

over the closed-cell neoprene sponge, that has been glued to the bottom of

the clip, and up over the up-turned portion of the front of the clip. The

leather is then retained at the front by a heavier brass clip-angle, secured

with two small machine screws. The brass clip-angle also incorporates a

trigger-tripper similar to that which is part of the standard clip.

In order to accommodate the modified clip, a slightly modified shoe must

also be fitted. The major modification is that the magnetic strip extends only

to within 3/8 in of the front of the shoe, leaving space to accommodate the heavv

brass clip-angle on the front of the clip. After the skin is properly installed

on the clip and the modified shoe installed on the tester, the clip should be

fitted to the shoe and the trigger adjusted to provide 1/16 - 1/8 in of free

travel before the clutch is activated.

. 35
APPENDIX E

THE KOLLSMAN TEST FOR BATHTUB SLIP-RESISTANCE

The Kollsman test for evaluating the slip-resistance of various bathtub

materials is essentially a mechanical analog of the human forces and movements under the conditions in which slipping occurs in a bathtub.

Slipping and the concomitant loss of balance and falling usually occur

when a) the surface of either the bottom of the foot or the bathtub is

soapy or oily and b) the bather is in the process of moving his foot from

one position to another. This can occur when he is either moving the foot

forward in a standing position or when he is to stand up from a sitting

position. In the act of making either of these movements, the bottom of

his foot comes into contact with a soapy, oily film on the surface of the

bathtub.

During the initial stages of these movements very little force or weight

is applied to the moving foot, almost all of the body weight being taken

up by the other foot (in the standing position) or by the other parts of

the body (in the sitting position)

.

The weight on the moving or adjusting foot is never applied vertically

down, but at some angle to the normal, giving it a horizontal as well as

a vertical component.

There is a very little resistance to the horizontal component since the

coefficient of friction between the bottom of the foot and the soapy film

is very low. The foot will therefore slip at an accelerated rate unless

the vertical force can be applied in such a way as to break through the

film and bring the foot into contact with the bathtub material itself

with which it often has a much higher coefficient of friction, or until the

film of soapy liquid has been squeezed thin enough to produce viscous drag.

It is estimated that a man or woman will put about 15% of his or her body

weight on the moving foot. For an average man weighing 180 pounds this is

26 pounds and for an average woman weighing 113 pounds this is 17 pounds.

If the angle the foot or leg makes with the normal in moving from one position to another is as little as 10°, then the vertical force applied by

the average man would be 25 pounds and the horizontal force 7.33 pounds.

In the case of a woman the vertical force would be 15 pounds and the horizontal force 7.33 pounds. If the angle is greater than 10° as it normally

is, the horizontal force would be proportionately greater.

It is further estimated that if the bather starts to slip, his or her foot

will move across the bathtub surface at about 2 feet per second.

The effectiveness of a bathing surface in preventing slipping can best be

determined by simulating the human slipping action and this in turn can be

done by applying the forces, angles and velocities cited above to a soapy

or oily bathtub surface.

36
The Kollsman Test Equipment does just this. It applies a vertical force to

a 2 3/4-in diameter x 3/16-in thick soft neonrene closed cell SDonee covered

with an animal skin which has about the same texture and hydrophilic properties

as human skin. At some fixed but controlled period of time preceding the

application of the vertical force, the bathtub surface is moved forward by

the application of a horizontal force, the relationship between the two

forces being such as to define the angle of the "moving" foot and the forces

themselves defining the weight applied. The forward velocity of the "moving"

foot is controlled by the horizontal force applied to the bathtub surface

before the "foot" makes contact with it.

The effectiveness of the surface in preventing slipping is determined by

the distance the surface moves before it is stopped by the application of

the vertical force.

The Kollsman Test Equipment is shown diagramatically in the attached figure.

The equipment is made up of a base (25), a post (26) on which a beam (27)

is pivoted at point (28) . The beam carries a pad (29) which is 3 inches

in diameter and is made up of a neoprene rubber sponge covered with beef

skin epidermis 0.01 - 0.04-in thick when dry. The pad is mounted on the beam

by means of spindle (30) and nut (31) so that its height can be adjusted.

The beam is mounted above a carriage (32) which can move horizontally along

the base by means of rollers (33) . The carriage supports and carries a piece of the bathtub surface to be tested (34) which rests against the rear

shoulder (35) of the carriage. The carriage has a cord (36) attached to it

which passes over a pulley (37) having a weight carrier (38) attached to its

other end. The carrier is loaded with stackable disc type weights (39), thereby

producing a predetermined pull on the carriage.

The beam carries a weight (46) which serves to place a load on the pad (29)

.

The beam is raised slightly so that the pad is positioned above the test

piece 1/8 - 1/4 in by means of a cam (41) which is operated by a lever (45).

The cam and lever arrangement are so constructed that they can operate in

either one of two ways:

1. The cord (36) can be released and the beam dropped simultaneously.

This would represent a condition in which a person slips from a

stationary or static condition. While this is not a normal case,

it is possible.

2. The cord (36) can be released before the beam drops. Since the

velocity the carriage attains before the pad drops is a function

of the distance it travels, the velocity can be controlled by

controlling the distance the carriage is permitted to move before

the beam is released. If, for example, the carriage moves one

inch, it will attain a velocity of about 2 feet per second. This

system more nearly represents the conditions most conducive to

slipping in a bathing area.

37
Thus this equipment permits the control of :

1. the vertical force applied to the 'foot'

2. the angle which the foot makes with the normal (the relative

vertical and horizontal forces)

3. the horizontal force applied

4. the horizontal velocity of the moving 'foot'

5. the condition of the surface to be tested - soapy, oily, dry, etc.

This equipment, essentially as described, was used to test a number of

bathtub surfaces under the following test conditions:

1. the surfaces of both the pad (29) and the surface to be tested (34)

were thoroughly wet with an Ivory Liquid Soap solution consisting

of one part soap solution and six parts water

2. the pad had a diameter of 3 inches, slightly larger than the heel

of the average foot

3. the pad material was beef skin epidermis 0.01 - 0.04-in thick

when dry

4. the tests were conducted at room temperature

5. two vertical weights (46) were used, 25 pounds and 15 pounds

6. the pad was always suspended 1/8 - 1/4 in above the test surface

7. the horizontal force (weight on the cord) was 7-1/3 pounds

8. tests were conducted with the carriage released and the weight

dropped simultaneously (static) and with the weight dropped after

the carriage had moved one inch and had achieved a velocity of 2

feet per second.

The attached table gives the results for nine different surfaces, each

tested under these four conditions.

38
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COw<

CO

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39
NOTE: The model of the Kollsman

tester supplied for evaluation

differed from this figure in three

respects:

(1) The pulley-weight assembly

is at the opposite end of

the tester.

(2) The trigger arrangement is

more complex than that

illustrated.

(3) Only a single weight (46)

was supplied, but it could

be placed at two different

locations on beam (27) so

that the resultant force on

the pad (29) would be either

15 or 25 pounds.

40
APPENDIX F

Kollsman Apparatus

Operating Instructions

Introduction

The Kollsman Apparatus tests the slip-resistance of bathtub surfaces under

three different conditions:

1. Static in which the full vertical force is applied to the foot

with no horizontal force for a period of time long enough to

squeeze out the soapy film beneath the film and then a horizontal

force slowly applied until slippage occurs. This would be the

condition of a person standing in a bathtub or shower and leaning

over.

2. Static /Dynamic in which the full horizontal force is applied

simultaneously with the full vertical force. This condition

would exist if a person took a deliberate step forward or perhaps

in arising from a sitting position.

3. Dynamic in which the full horizontal force is applied at a given

velocity before any vertical force is applied. This condition

would exist if a person gingerly stepped into a bathtub or moved

from one place to another within the tub.

To limit the extent of the test series and to avoid involvement in a development program for either tester, ASTM Committee F15.03 requested

that the Kollsman tester be evaluated in only two of its three possible

modes of operation, the choice to be Mr. Kollsman's. Mr. Kollsman

selected the Static/Dynamic and the Dynamic modes as the ones to be

evaluated.

Operating Procedure

See last page for test procedure amendments.

1.0 Equipment Preparation

1.1 Set the equipment on a table so that the pulley end overhangs

the table 3 inches.

1.2 Level the equipment using a spirit level on the base.

1.3 Check the bearings on the 4 wheels and lubricate if necessary.

Check the bearing on the release roller on the top of the

carriage and lubricate if necessary. Clean the surfaces of

all the wheels of any dirt or soap accumulation.

1.4 Condition all skins to be used by placing them in distilled water

at 100° + 10°F for approximately 15 minutes before using.

1.5 Place the neoprene sponge pad on the 3 1/2" diameter circular

plate and place a conditioned skin on the pad.

41
Draw the skin retaining ring over the skin so that it draws

the skin snugly against the neoprene pad so that there is a

minimum of air trapped between the skin and the neoprene sponge

and so that there is very little skin pinched in the ring opening.

Draw the ring down so that its 'bottom' edge is about even with

the bottom edge of the 3 1/2" circular plate.

Place the foot (skin, sponge rubber pad and plate) on the threaded

rod which passes through the support plate and lock it in place with

the threaded pin provided.

Wipe the skin with a soft wet cloth or a sponge substantially

free of soap.

Weigh and number each of the weights. There is one 150 gm wt.;

subsequent weights, a 36 gm weight and eleven weights of about 300 gms,

each, are supported by a T ring support.

2.0 Sample Preparation

2.1 Wash sample with soap and water. Rinse with clean water.

2.2 Immerse sample in warm distilled water at 100 + 10°F for at least 5

minutes and keep it in the water until it is ready to be tested.

2.3 Fold back the support plate and place the sample on the bed of

the carriage.

2.4 Fold the support plate back to its operating position and move

the carriage so that the foot is just above the sample.

2.5 Release the foot lock-nut on the top side of the support plate

and lower the foot by rotating the knurled knob until the skin

touches the top surface of the sample. Rotate the knob an additional 3 1/2 complete turns clockwise so that the foot will press

down onto the sample.

3.0 Static Measurements

(Note: The measurements described in this section were not made as part

of the test procedure discussed in this report.)

3.1 Apply the 100 gm weight.

3.2 Place the sample to be tested in distilled water maintained at

100 + 10°F for 15 seconds or more.

3.3 Place the sample on the carriage.

3.4 Wet the skin with distilled water-at 100 + 10°F.

3.5 Sponge the sample surface with the standard soap solution

maintained at 100 + 10°F.

I

1.6

1.7

1.8

1.9

42
3.6 Move the carriage to the right until the pointer on the carriage

is even with the 0 mark on the guage on the base. The release

lever should be in the forward position and slide lock pushed back.

Hold the carriage in this position.

3.7 Fold the support plate so that the foot comes to rest on the

sample. Continue to hold the carriage at the 0 position.

3.8 Place the vertical weight at the 25 pound position. Hold for

2 seconds.

3.9 Release the carriage.

3.10 Record the distance traveled by the carriage before it comes to

a stop, describe its travel, e.g. 3 inches quickly, 3 1/2 inches

very slowly.

3.11 Remove the vertical weight and fold back the support plate. Wipe

the soap off the skin with warm distilled water. Wash the sample

by placing it in warm water (100 + 10°F)

.

3.12 Repeat steps 3.2 through 3.11 nine more times. If the distance

traveled is less than 6 1/2 inches 8 of the 10 times go on to

step 3.13. If the distance traveled is equal to or greater than

6 1/2 inches 8 of the 10 times go on to step 4.0.

3.13 Add a second weight to the support rod and repeat steps 3.2

through 3.11 ten times.

3.14 Continue this procedure until either all eleven weights have

been added or the distance traveled by the carriage is equal to or

greater than 6 1/2 inches for 8 or more times in the 10 tests.

4.0 Static/Dynamic Measurements

4.1 Place the 150 gm weight on the hook provided.

4.2 Place the sample to be tested in distilled water maintained at 100 + 10°F

for 15 seconds or more.

4.3 Place the sample on the carriage.

4.4 Sponge the skin with a 10% soap solution at 100 + 10° F.

4.5 Sponge the sample surface with the standard 10% soap solution

maintained at 100 + 10°F.

4.6 Move the carriage to the right until the second hole in the rod

at the end of the carriage passes through the end plate. Lock

the carriage in this position by pushing the metal dowel attached

to the metal slide through the second hole.

4.7 Fold over the support plate until it comes to rest on the release

roller on the carriage.

43

I
4.8 Place the vertical weight at the 25 pound position.

4.9 Release the carriage by rotating the release lever 90°.

4.10 Record the distance traveled.

4.11 Without lifting the support plate or removing the 25 pound

weight repeat steps 4.6, 4.9 and 4.10 four more times for

a total of 5 tests.

4.12 Remove the vertical weight and fold back the support plate.

Wipe the soap off the skin with water. Wash the sample thoroughly

with water and place it in warm water at 100 + 10°F.

4.13 Repeat steps 4.2 through 4.12 four more times. This will give

a total of 25 tests at the 150 gm weight. If the distance traveled

is less than 6 1/2 inches for 20 of the 25 tests go on to step

4.14. If the distance traveled is equal to or greater than 6 1/2

inches 20 of the 25 times, go on to step 5.0.

4.14 Remove the 150 gm weight. Place the 201 gm weight on the T ring

support and place the T ring support on the hook provided.

4.15 Repeat steps 4.2 through 4.12.

4.16 Repeat steps 4.2 through 4.12 four more times with the 201 gm

weight. This will give a total of 25 tests with the 201 gm

weight. If the distance traveled is less than 6 1/2 inches for

20 of the 25 tests go on to step 4.17. If the distance traveled

is equal to or greater than 6 1/2 inches for 20 of the 25 tests,

go on to 5.0. »

4.17 Remove the 201 gm weight. Place one of the eleven 300 gm weights

on the T ring support and place the T ring support on the hook

provided.

4.18 Repeat steps 4.2 through 4.12.

4.19 Repeat steps 4.2 through 4.12 four more times with the 300 gm

weight. This will give a total of 25 tests with the 300 gm weight.

If the distance traveled is less than 6 1/2 inches for 20 of the

25 tests go on to step 4.20. If the distance traveled Is equal

to or greater than 6 1/2 inches for 20 of the 25 tests go on to 5.0.

4.20 Add a second 300 gm weight to the T ring support for a total of

600 gms.

4.21 Repeat steps 4.2 through 4.12.

4.22 Repeat steps 4.2 through 4.12 four more times.

44
4.23 Continue this procedure of adding 300 gm weights to the T ring

support and carrying out 25 tests with each weight in the manner

described until either all 11 weights have been added or the

distance traveled by the carriage is equal to or greater than

6 1/2 inches for 20 of the 25 tests at a given weight.

Dynamic Measurements

Note: The preparation and introduction of specimens for the dynamic

tests is to be the same as for the static/dynamic tests.

5.1 Place the 150 gm weight on the hook provided.

5.2 Place the sample to be tested in distilled water maintained at

100 + 10°F for 15 seconds or more.

5.3 Sponge the sample on the carriage with the standard 10% soap

solution heated to 100°F + 10°F.

5.4 Wet the skin with water.

5.5 Sponge the skin surface with the standard 10% soap solution

maintained at 100 + 10°F.

5.6 Move the carriage to the right until the fourth hole in the rod

at the end of the carriage passes through the end plate. Lock

the carriage in this position by pushing the metal dowel attached

to the metal slide through the fourth hole.

5.7 Fold over the support plate until it comes to rest on the release

roller on the carriage.

5.8 Place the vertical weight at the 25 pound position.

5.9 Release the carriage by rotating the release lever 90°.

5.10 Record the distance traveled.

5.11 Without lifting the support plate, or removing the 25 pound

weight, repeat steps 5.6, 5.9 and 5.10 four more times for a total of 5 tests.

5.12 Remove the vertical weight and fold back the support plate. Wipe

the soap off the skin with water. Wash the sample thoroughly

with water and place it in warm water at 100 + 10°F.

5.13 Repeat steps 5.2 through 5.12 four more times. This will give a total of 25 tests at the 150 gm weight. If the distance traveled

is less than 6 1/2 inches for 20 of the 25 tests go on to step

5.14. If the distance traveled is equal to or greater than 6 1/2

inches for 20 of the 25 tests, the test is completed.

45
5.14 Remove the 150 gm weight, Place the 201 gm weight on the T ring

support and place the T ring support on the hook provided.

5.15 Repeat steps 5.2 through 5.12.

5.16 Repeat steps 5.2 through 5.12 four more times with the 201 gm weight

This will give a total of 25 tests with the 201 gm weight. If the

distance traveled is less than 6 1/2 inches for 20 of the 25 tests

go on to step 5.17. If the distance traveled is equal to or

greater than 6 1/2 inches for 20 of the 25 tests, the test is

completed.

5.17 Remove the 201 gm weight. Place one of the eleven 300 gm weights

on the T ring support and place the T ring support on the hook

provided.

5.18 Repeat steps 5.2 through 5.12.

5.19 Repeat steps 5.3 through 5.12 four more times with the 300 gm weight.

This will give a total of 25 tests with the 300 gm weights. If the

distance traveled is less than 6 1/2 inches for 20 of the 25 tests,

go on to step 5.20. If the distance traveled is equal to or

greater than 6 1/2 inches for 20 of the 25 tests, the test is complete.

5.20 Add a second 300 gm weight to the T ring support for a total of

600 gms.

5.21 Repeat steps 5.2 through 5.12

5.22 Repeat steps 5.3 through 5.12 four more times.

5.23 Continue this procedure adding 300 gm weights to the T ring support

and carrying out 25 tests with each weight in the manner described

until either all 11 weights have been added or the distance traveled

by the carriage is equal to or greater than 6 1/2 inches for 20 of the

25 tests at a given weight.

46
APPENDIX G

Procedure for Testing (August 5)

Laboratory Notes

1. The order in which materials were to be tested was obtained by a

blind drawing of lots, labeled for the four samples, by an independent person. The following order was established: (1) abrasive,

(2) smooth, (3) Rubbermaid appliques, (4) Kollsman dot appliques,

the slip-resistant fiberglass tub surface had not arrived at the time

of the drawing (4:30 p.m.).

2. In order to provide the most nearly similar conditions during replications for all materials, it was decided to undertake the first

series of tests for all materials, then the second for all; then a

third. Should the fiberglass tub arrive, it can be placed fifth in

the rotational sequence; if it does not arrive, it will be tested sepa

rately, still alternating from Kollsman to Brungraber tester. (Only

three replications, instead of the original five, will be conducted fo

each of the materials.)

3. The samples will be tested first in one mode of the Kollsman tester;

then the other mode of the Kollsman tester. Five sequential replications will take place on a sample for the Kollsman tester; then

five with the Brungraber tester, moving down the length of the sample

enough to be similar to the operation over a length of material made

by the Kollsman device. Alternating between devices will also enable

the reheating of the samples for the Kollsman tester between static/

dynamic and dynamic measurements.

(August 6 Note: The fiberglass sample has arrived and will be placed

fifth in the rotational sequence.)

47
APPENDIX H. RESULTS OF TEST PROGRAM - RAW DATA TABULATIONS

48
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49
DATA OBSERVED WITH KOLLSMAN TESTER

STATIC/DYNAMIC MODE OF OPERATION

(Entries are the Displacement of the Carriage, in Inches)

REPLICATE TEST OBSERVATION LATERAL DRIVING FORCE IN GRAMS

MATERIAL NUMBER CONDITIONS NUMBER 150 237 340 648 952

75°F 1 1 4 7A6* >6 1/2

66%rh 2 3/4 4 7/16 >6 1/2

OlllWVJ Oil 3 13/16 5 >6 1/2

4 1 5 1/4 >6 1/2

Porcelain Enamel 5 5/8 6 1/4 >6 1/2

2 1 2 9A6 >6 1/2

on Steel

62$rh 2

3

2 3/8

2

>6 1/2

>6 1/2

4 2 1/8 >6 1/2

5 2 1/2 >6 1/2

74°F 1 2 1/4* 6 1/2 >6 1/2

62%rh 2 2 1/2* 4* >6 1/2

3 2 1/2* 5 3/8* >6 1/2

4 2 1/2* 3 3/4* >6 1/2

5 2 3A* 5 1/4 >6 1/2

IX 75°F 1 7/16 7/8 1 5/8 5 7A6 1/ 1- 66%rh 2 7/16 13/16 l 5/8 5

1 /?

-Textured 3 3/8 13/16 l 13A6 6

4 3/8 3/4 2 1/4 5 3A6 >6 1/2

5 3/8 11/16 2 1/2 5 3/8 >6 1/2

Porcplain Enamel

2 72°F 1 3/16 3/8 1 1/4 5 V8* >6 1/2

62#rh 2 3/16 7/16 1 7A6 5 1/4 >6 1/2 on Steel 3 3/16 7A6 1 1/2 5 5/8 >6 1/2

1/4 7A6 1 9A6 5 5/8 >6 1/2

5 3/16 3/8 1 9A6 6 >6 1/2

3 74°F 1 1/4 7/8 7/8 >6 1/2 >6 1/2

62#rh 2 1/4 15A6 1 >6 1/2 >6 1/2

3 5A6 7/8 1 1/4 >6 1/2 >6 1/2

5A6 13A6 1 3/8 >6 1/2 >6 1/2

5 5/16 13A6 1 11/16 >6 1/2 * u

"1X 72°F 1 3/8 1 1/8 1 5/8 5* -* u

Textured

62#rh 2

—

-Jf 3/8w 3/8

1 1/8

1

2 9/16

2 5/16

5*

5*

u 1/ <-

-L/ £

Gel-Coated 4 7/16 1 2 3/8 5* >6 1/2

Fiberglass 5 V2 1 1/16 2 1/2 5* >6 1/2

Reinforced 2 74°F 1 5A6 7/8 3* >6 1/2

Plastic 62#rh 2 5/16 1 3/4* 3* >6 1/2

3 3/8 2* 3 3/8* >6 1/2

4 3/8 2 3 1/2 >6 1/2

5 5/16 2 3 1/2 >6 1/2

3 72°F 1 5/16 1 1/16 2 5/8* >6 1/2

58$rh 2 5/16 1 1/2* 2 7/8* >6 1/2

3 5/16 1 1/2* 2 7/8* >6 1/2

4 1/4 1 5/8* 2 7/8 >6 1/2

5 5/16 1 5/8 2 7/8 >6 1/2

* The skin creeps along after the noted displacement, where it stops temporarily.

50
DATA OBSERVED WITH KOLLSMAN TESTER

STATIC/DYNAMIC MODE OP OPERATION

(Entries are the Displacement of the Carriage, in Inches)

(Continuation)

1 1 iL'om TEol UbobnVA1 1UJM LATERAL DRIVING FORCE _LJNJ unAFlo

MATERIAL NUMBER CONDITIONS NUMBER 150 237 340 648 952

Dot-Pattern

Appliques

on Smooth

1 75°F

66%rh

1

2

3

H

5

1/8

1/8

3/16

3/16

3/16

3/16

3/16

3/16

1/4

3/16

5/16

5/16

1/4

1/4

1/4

7/16

5/8

7/16

1/2

7/16

3/4

13/16

11/16

3/4

11/16

PorcelainEnameled

Steel**

2 74°F

62%rh

1

2

3

u

5

1/16

1/16

1/16

1/16

1/8

1/8

1/8

1/8

1/8

1/8

1/8

1/8

1/8

1/8

5/16

5/16

5/16

0/10

3/8

3/8

3/8

3/8

1 /l c f/lo

7/16

IB'

3 74°F

62#rh

*k

2

3

4

5

1/8

1/8

1/8

1/8

1/8

1/8

1/8

1/8

1/8

1/8

1/4

3/16

3/16

3/16

3/16

3/8

3/8

3/8

3/8

3/8

5/8

5/8

5/8*

5/8*

5/8*

Flower Pattern

Appliques

on Smooth

PorcelainEnameled

Steel*

75°P 1 1/8 V8 1/4 5 1/2*

66#rh 2 1/8 3/16 1/4 5 1/2

3 1/8 3/16 1/4 >6 1/2

4 1/8 3/16 1/4 >6 1/2

5 1/8 3/16 1/4 >6 1/2

74°P 1 V8 1/8 3/16 3 1/16*

62#rh 2 1/8 1/8 3/16 >6 1/2

3 1/16 1/8 3/16 >6 1/2

4 1/16 1/8 3/16 >6 1/2

5 1/16 1/8 3/16 >6 1/2

74°P 1 1/16 1/8 5A6 1* >6 1/2

62$rh 2 1/16 1/8 3/8 2* >6 1/2

3 1/16 1/8 3/8 3* >6 1/2

4 1/16 1/8 3/8 2* >6 1/2

5 1/8 3/16 5/16 4 1/4 >6 1/2

The skin creeps along after the noted displacement, where it stops temporarily.

See Extension Sheet of Lateral Driving Force for Dot-PatternAppliques.

51
DATA OBSERVED WITH KOLLSMAN TESTER

STATIC/DYNAMIC MODE OP OPERATION

(Entries are the Displacement of the Carriage, in Inches)

(Extension Sheet for Dot Pattern

LATERAL DRIVING FORCE IN GRAMS

1249 J- c—~ J 1563 1876 2187 2488 2801 L_ WW J_ 3115 3425

1 1 1/2 1 3/8* 2 3/8* 3 5/8* 3 7/8* 6 1/8*

1 1 5/8* 2 3/16* 2 7/16* 3 5/8* 4 1/2* 6 1/8*

1 1/16* 1 11/16* 2* 2 3/4* 3 1/2* 4 3/4* >6 1/2

1 1/8* 1 3/4* 2t— 11/16* 1.1/ -UW 4* 5J 1/8* _L/ U >6 1/2*

1 1/8* 1 3/4* 2 1/8* 2 15/16 3 1/2* 4 5/8* >6 1/2

5/8 1 3/16* 1 1/2* 2 5/16* 3 1/2* 4 3/4*

3/4 1 3/8 1 7/8* 2 15/16* 5 1/2* 6 1/2*

7/8 1 9/16* 2 1/16 3 1/8* 6* >6 1/2

3/4 1 5/8 2 3/16* 3 1/4* 6 1/4* >6 1/2

7/8 1 3/4* 2 1/4 3 3/8* 6 1/2* >6 1/2

7/8* 1 1/8* 1 7/16* 2 1/2* 3 1/2* >6 1/2

7/8* 1 1/4* 1 15/16* 2 7/8* 4 1/2* >6 1/2

1* 1 1/4* 1 7/8* 3* 5 1/8* >6 1/2

1* 1 5/16* 2* 3 1/4* 4 3A* >6 1/2

1* 1 5/16* 2* 3 3/8* 5 1/8* >6 1/2

I

!

52
DATA OBSERVED WITH KOLLSMAN TESTER

DYNAMIC MODE OF OPERATION

(Entries are the Displacement of the Carriage, in Inches)

REPLICATE TEST OBSERVATION LATERAL DRIVING FORCE IN CRAMS

MATERIAL NUMBER CONDITIONS NUMBER 150 237 340 648 952

1 75°F 1 5 >fi -*U iX//?c. 66$rh 2 u 3/V8<-> >f,U 1X//?C

3 6U 1/4 X/ *T >fi 1 /?

Smooth 4 5 7/8 >6 1/2

5 6 1/8 >6 1/2

Porcelain Enamel 2 72°P 1 P -V o >fiU X/1 /?£1 62$rh 2 ^ R/fi >6U 1X//?£

3 ^ S/8 >fi 1 /p

on Steel 4 5 3/4 >6 1/2

5 6 >6 1/2

74°F 1 U X/ £1 62#rh 2

3

>fi * U 1X//p

4 >6 1/2

5 >6 1/2

i 75°F 1 £ X^/ XD 3 -lO/XO U >6 1/2

• f f rrl i 66$rh 2 3 xx/ xo U X/ XD >6 1/2

3 3 j/4 6U 1X//lxu >6 1/2

Textured 4 3 3/8 3 9/16 6 1/16 >6 1/2

5 3 7/16 3 9/16 6 1/16 >6 1/2

Procelain Enamel 2 72°P 1 P 7/8 C I/I) 5 X/H J 0/0 >6 1/2

62%vh 2 ? 7/fi R 1 /P ^ x/£ P J/ H >6 1/2

3

P 7/fi R 1 /P 5 >6 1/2

on Steel 4 2 7/8 5 1/2 6 1/8 >6 1/2

5 2 13/16 5 1/2

' 6 1/8 >6 1/2

3 74°F 1 9 1/2 >6 1/2

62#rh 2 j 3/^ ii 3/8 > O 1X//p

3

4 3/8 3/ o >fiU 1X//P<i 4 3 3/4 4 1/2 >6 1/2

5 3 3/4 4 1/4 >6 1/2

1 72°F 1 J x/ xu ^ n /i f\ i /h*

Textured 62#rh 2 9 1 /I (\ J X/XO J j/4 u

3

9 3/1 6 J J/ xu 9 7/8 J I/O >fi 1 /P

uel-uoated i

,

4 3 1/8 3 13/16 >6 1/2

Fiberglass 5 3 1/16 3 15/16 6*

Reinforced 2 74°F 1

"5 Q /I £s j y/-Lo 3 -L/ -LD 9 i /p >6 1/2

Plastic

** j-v ~4 62%vh 2 9 7/1 0 ( / XO 9 3/8 j 3/ o 9 1^/1^* >6 1/2

3

"5 7/1 ^ J f /ID 9 3/8 J j/ o 4* >6 1/2

4 9 7/1

6

3 3/8 3 7/8* >6 1/2

5 3 3/8 3 7/16 4 1/8* >6 1/2

3 72°P 1 4 3/16 5 1/4 6* >6 1/2

58#rh 2 4 1/8 5 1/8 6* >6 1/2

• 3 4 1/2 5 3/4 6 1/8* >6 1/2

4 4 3/8 5 3/4 6 1/4* >6 1/2

5 4 1/4 6 6 1/4 >6 1/2

*The skin creeps along after the noted displacement, vnere it stops temporarily.

53
DATA OBSERVED WITH KOLLSMAN TESTER

DYNAMIC MODE OP OPERATION

(Entries are the Displacement of the Carriage, in Inches)

(Continuation)

REPLICATE TEST OBSERVATION LATERAL DRIVING FORCE IN GRAMS

MATT7DT AT lNUivinr' l nr, nftTnTrpTf~)MQ UUlMUlllUJMo JNUI'Mln IpU 237 340 648 9Dd

-<1 ft) p 1

"3 /h J/4 7/8 3/4 1 1/4 1 ( Dot-Pattern DD/orn 7/o O f]\ 3/4 1 1/4 1 1

3 3/4 7/8 7/8 1 3/8 1 1

Appliques 4 3/4 7/8 3/4 1 3/8 1 1

on Smooth 7/8 3/4 1 3/8 d

Od 1 5/8 5/8 1 3/16 1 1

Enameled D^/orn o 1/

£

3/4 11/16 1 1/4 1 1

oJ -L/ <^ 3/4 11/16 1 1/4 1 1

Steel** 4 7/16 3/4 11/16 1 3/16 1 3, 5 7/16 3/4 5/8 1 3/16 1 1.

3 74°F 1 3/4 11/16 7/8 1 7/16 21

62#rh 2 3/4 3/4 1 1 9/16 2 3/

3 3/4 3/4 1 1 9/16 2 3/

4 3/4 3/4 1 1 1/2 2 7/

5 13/16 11/16 15/16 1 1/2 2 7/

Flower Pattern

Appliques

on Smooth

PorcelainEnameled

Steel*

1 75°F 1 1 1/4 1 7/16 2 1/4 >6 1/2

66$rh 2 1 1/4 1 5/8 2 5/16 >6 1/2

3 1 5A6 1 5/8 2 5A6 >6 1/2

4 1 5/16 1 5/8 2 3/8 >6 1/2

5 1 5/16 1 5/8 2 3/8 >6 1/2

2 74 °F 1 1 1/16 1 5/16 1 13/16 5 1/8 >6 1 62#rh 2 1 3/16 1 5/16 2 5 3/16 >6 1 3 1 1/8 1 3/8 1 15/16 6 1/2 >6 ] 4 1 3/16 1 7/16 2 >6 1/2 >6 ] 5 1 3/16 1 3/8 2 1/8 >6 1/2 >6 l!

3 74°F 1 1 3/16 1 3/8 2 4 3/4* >6 ] 62%vh 2 1 5/16 1 9/16 2 1/8 5* >6 3 3 1 3/16 1 5/8 2 1/4 5* >6 3 4 1 1/8 1 5/8 2 1/4 5 1/4* >6 3 5 1 1/8 1 5/8 2 1/4 5 1/2 >6:

*The skin creeps along after the noted displacement, where it stops temporarily.

**See Extension Sheet of Lateral Driving Force for Dot-Pattern Applique's

.

54
DATA OBSERVED WITH KOLLSMAN TESTER

DYNAMIC MODE OP OPERATION

(Entries are the Displacement of the Carriage, in Inches)

(Extension Sheet for Dot- Pattern Appliques)

LATERAL DRIVING FORCE IN GRAMS

1249 1563 1876 2187 2488 2801 3115 3425

1 3/4 ~ v: 2 1/2 3 1/2 4 5/8 4 7/8 >6 1/2

2 1/8 2 5/8 3 7/8 5 1/4 5 3/4 >6 1/2

C. I/O 2 5/0 o i /Q 3 r/o 5 1/4 r0 >D 1/2

2 2 5/8 3 3/4 5 1/8 6 >6 1/2

2 1/16 2 15/16 3 7/8 5 1/4 5 7/8 >6 1/2

2 2 3/4 4 1/8 4 1/2 6 1/4

2 1/8 3 3/16 5 5 1/8 >6 1/2

2 1/4 3 1/4 4 7/8 5 1/2 >6 1/2

2 3/8 3 1/2 4 7/8 5 3/4 >6 1/2

2 3/8 3 1/2 5 1/4 5 3/4 >6 1/2

2 7/16 4 1/8* 5 3/8* >6 1/2

2 7/8 4 1/2* >6 1/2 >6 1/2

3 4 5/8 >6 1/2 >6 1/2

2 15/16 4 7/8 >6 1/2 >6 1/2

2 15/16 4 13/16* >6 1/2 >6 1/2

I

I

I

55
NBS-1 14A (REV. 7-73)

U.S. DEPT. OF COMM.

BIBLIOGRAPHIC DATA

SHEET

1. PUBLIC A 'HON OK REPORT NO.

NBSIR 76-1005

2. Gov't Accession

No.

3. Rec ipient's Accession No.

4. TITLE AND SUBTITUi

A Comparison of Two Testers in Evaluating the

Slip-Resistance of Bathtub and Shower Base Surfaces

5. Publication Date

October 1977

6. Performing Organization ( ode

7. AUTHOR(S)

Robert J. Brunaraber and Theresa J.R. Raper

8. Performing Organ. Report No.

9. PER FORMING ORGANIZATION NAME AND ADDRESS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

10. Project /Task/Work Unit No. 4610374

1 1. Contract/Grant No.

12. Sponsoring Organization Name and Complete Address (Street, City, State, ZIP)

Same as above

13. Type of Report & Period

Covered

Interim

14. Sponsoring Agency Code

15. SUPPLEMENTARY NOTES

16. ABSTRACT (A 200-word or less factual summary oi most significant information. If document includes a significant

bibliography or literature survey, mention it here.)

The report describes a program of tests planned by ASTM Committee F15.03 on Safety Standards for Bathtub and Shower Structures, and conducted at the

National Bureau of Standards for the purpose of comparing the NBS-Brungraber

and the Kollsman tester with respect to their effectiveness in evaluating

the slip-resistance of bathtub and shower base surfaces. This program

represents a contribution by the National Bureau of Standards to the efforts

of the American Society for Testing and Materials and the Consumer Product

Safety Commission in developing safety standards for bathrooms and bathroom

fixtures. Both testers employ the same material (drumheads of "slunk") to

simulate human skin, and the report concludes that both testers will satisfactorily discriminate between different bathroom surfaces on the basis

of slip-resistance. The conclusion may be made that the NBS-Brungraber tester

is considerably more convenient to use.

:

17. KEY WORDS (six to twelve entries; alphabetical order; capitalize only the first letter of the first key word unless a proper name; separated by semicolons) Ko I i sman tester; NBS-Brungraber tester; safety of

bathrooms; slip-resistance of bathtub and shower base surfaces; slip-resistance

testers.

18. AVAILABILITY |3P Unlimited 19. SECURITY CLASS

(THIS REPORT)

21. NO. OF PAGES

I For Official Distribution. Do Not Release to NTIS

UNCLASSIFIED 5*3

Order From Sup. of Doc, U.S. Government Printing

Washington. D.C. 20402. SD Cat. No. C13

Office 20. SECURITY CLASS

(THIS PAGE)

22. Price

\~X\ Order From National Technical Information Service

Springfield, Virginia 22151

(NTIS)

UNCLASSIFIED $4.50

USCOMM-DC 29042-P