ACTIVITY REPORT OF JIS STANDARDS DEVELOPMENTCOMMITTEE ABOUT THE TEST METHODS OF SLIP RESISTANCEOF PROTECTIVE FOOTWEAR AND OCCUPATIONAL FOOTWEAR
Kazuharu KasaiMidori Anzen Co.,Ltd. , 5-4-3 Hiroo, Shibuya, Tokyo 150-8455, JapanThe background that was decided to be established the test method about the slip
resistance performance of protective footwear and occupational footwear, as JIS
standards again. There is the following status. 1. Fall disaster is most frequent in thedifferent type casualties disaster generation state of the occupational accidents ofJapan and is accounting for about 20 % or more of the entire. 2. Senior workers
population of Japan has been increasing year by year, therefore fall disaster isbecoming likely to occur. 3. As the cause of the fall disaster, fall by the "stumbling"is also more frequently occurring in addition to the fall due to "slip". 4. Test method
for the "slip resistance" is defined in JIS T 8101and ISO 13287, but the test method
for the "stumbling" has not been established yet. 5. Fall due to "ice" and "powder"
are also occurring, but these test method also has not been established yet. Based on
the current status, the contribute to the reduction of fall accidents is the aim, and we
carried out that enact the JIS standards of slip resistance test method which isincluding the "stumbling", "ice" and "powder" in addition to the conventional slip,
as the first activity.

The fall by stumbling
First, we considered the test methods about the "stumbling". If we analysed the situation that occurs
the fall by stumbling before examining the test method for stumbling, there are two situations.
1) The case you have changed the direction suddenly or stop suddenly in the state that the friction
between the floor and the sole is large, or you have stopped suddenly to come running, theshoe sole did not slip on the floor surface, therefore the leg could not be follow to the changeof centre of gravity of the trunk, will tip over finally.
2) The floor has unevenness surface and if the height of the toe of shoe (toe spring) is low, the toe
is caught without being step over the unevenness floor by the method of walking, will tip over.
In order to be able to validate these two states quantitatively by the coefficient of friction
between the shoe and the floor, we decided to design the test apparatus for stumbling.
When we designed of the test apparatus for stumbling, the main purpose of the test is realization of
the form close to the actual walking posture.
Move the shoe or the floor to the horizontally direction, with the state that lift the heel of theshoe and add a constant load to the over part of the shoe contacting to the floor, we have considered
the measuring method of maximum static friction coefficient of when the shoe sole contact with thetest floor. (See figure below) From the situation that causes stumbling fall, we considered thefollowing three test methods can be carried out.

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1. Test floor mode without the step
1. In the test floor modmode without
the step, measure the maximum
mstatic friction between the shoesole and test floor.

2. Test floor mode with the step
2. In the test floor mode w
with thestep, measure the maximum staticfriction when the shoe sole hits thestep.㻌

3. Test floor mode with an angle
3. In the test floor mode with anangle, measure the maximum
maxim
staticfriction when the shoe ssole is incontact with the inclined ffloor. 㻌1 Three test modes for the stumbling test
Figure 1.
In the test method specified in ISO 13287, the test conditions are defined as below.
z Contact angle of the heel is 7 ± 0.5 °.
z The normal force of shoes size 25.0 or more is 500 ± 25N, Shoes size less than 25.0 is 400 ±20N.
z Tensile speed is 0.3 ± 0.03m / s.
From these conditions, selected conditions of the stumbling test are as below.
z The normal force (Normal load) should be 50N.
z The tensile speed of shoe should be 0.3 ± 0.03m / s.
z The angle of the wedge should be 7 °.
From these conditions, selected conditions of the stumbling test are as below.
z The normal force (Normal load) should be 50N
z The tensile speed of shoe should be 0.3±0.03m/s.
z The angle of the wedge should be 7°
And we selected condition that material, surface treatment and structure should be selectedfor making as small as possible the friction between the floor and the forefoot of shoes. We aremaking first apparatus of the stumbling test now, and doing preparation for collecting data.

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The above figure is first apparatus for stumbling test.
But we are trying to improve for making the load of 50N
on the forefoot of shoes, with the state which last wasinserted into shoes, in the actual test.

Figure 2. An example of the stumbling test

The slip on the powder
Next, we made study of the slip on the powder.
We have tested whether occurred difference in the perceived of the slip on the powder, by using
the shoes from A to E of a different dynamic friction coefficient in slip test of JIS standard.
Finally, we have found that there is no relation between dynamic friction coefficient difference
and the perceived of slip.

Figure 3. An example of the steel inclined plate  Figure 4. An example of the slip test on
the powder
The above figure is that walking repeatedly up and down, by using safety shoes, in the statethat is sprinkled powder on top of the stainless steel inclined plate, thereby confirmed the statusperceived of slip.
We prepared a three types of powder as A: Toyoura sand (standard sand in constructionmaterials), B: Baby powder (surface treated talc), C: Cake flour (flour fine particles). We tested
the difference between slip perceived by varying the angle of the stainless steel inclined plate.

  ABC

DEFigure 5. Sole design image of the test sample- 219 -

Table 1. Slip experience test results of different sample different angle different powder
Angle plate 10°
Angle plate 15°
ABCABCsampleToyoura
Baby
ToyouraBaby
Cake flour
Cake flour
sandpowder
sandpowder
A××ᇞ×××Bᇞᇞᇞᇞ×ᇞC‫۔‬‫۔‬ࠐࠐࠐ
ࠐD‫۔‬‫۔‬ࠐࠐᇞࠐ
E××××××
 signify the slip perceived. ‫ ڹ‬signify the slightly slip perceived.
ࠐ signify the few slip perceived. ‫ ۔‬signify not slip perceived.
We have prepared 5samples as different types of outsole material, shape and structure.
A: Protective footwear with dual-layer urethane sole. (Dynamic friction coefficient 0.25)
B: Protective footwear with single-layer rubber sole. (Dynamic friction coefficient 0.09)
C: Non-slip occupational footwear on the powder. (Dynamic friction coefficient 0.10 to 0.15)
D. Non-slip occupational footwear on the roof. (Dynamic friction coefficient 0.10 to 0.15)
E. Non-slip occupational footwear in the kitchen. (Dynamic friction coefficient 0.50)
Size is all 26.0.
From these test results, the following conclusions were derived.
1. In the perceived test of the slip on the powder, there is no correlation with the dynamicfriction coefficient, but there is the case that sole with the high dynamic coefficient is rather
more slipping. We considered that the ground contact area of the cleat design is affecting,and there is tendency that the sole with the large ground contact area is generally hard to slip.
However, in case on the powder, we guess that the phenomenon of slipping is happened, by
the occurred slip at the entire surface of the ground contact area of the sole.
2. Non slip occupational footwear on the powder showed a characteristic that is hard to slip asexpected. This footwear's cleat design has become a structure that repels powder when youground. Therefore, we have considered that there was no slip, because the powder is hard toenter between the surface of the cleat and the floor.
3. In addition, there is something unclear and clear of difference of the perceived of the slip bydifference of the powder depending on the type of powder. As a standard powder of theevaluation test, Baby powder is felt most clearly difference perceived of the slip, Toyoura
sand is follow as next one.
4. The angle of the inclined plate, angle 15°was felt easier the difference perceived of the slip
than angle 15°. From above, the conclusion is, in the method of measuring the dynamicfriction in powder slip resistance test, we found the discrepancy between perceived anddynamic friction coefficient number. Therefore, we felt the need to consider a new test
method. It is not reached the stage of development of test methods at the moment. About thedevelopment of test method that matches the perceived, we are thinking continuously trying
to make the effort.

The slip on the ice
At the end, we made study of the slip on the ice.
Whether happening the difference of perceived of the slip on ice, was tested using the shoes
from A to F with a different dynamic friction coefficient in the slip resistance test of JIS standard.
The result, we have found that there is no correlation at all between the difference of dynamicfriction coefficient and the perceived of the slip. In the slip resistance test on the ice, it is hard toslip in the state in which ice is completely frozen. It was a result that it starts to slip suddenly
when the surface begins to melt.

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The above figure is that are creating asmooth surface of ice by device tomake the ice, and walking on the ice by
wearing protective shoes, thereby wechecked the state of perceived of theslip.
Figure 6. An example of the ice slip test device

Figure 7. An example of the slip test on
the iceFirst, after experienced perceived of the slip in the state which the overall surface of the ice
was started melting. Then experienced perceived of slip after changing to the state to freeze
completely the surface. After that, we made the experience of perceived of slip by the creating astate of partial melts.
Table 2. Slip experience test results of different sample different states on the iceSample

State that thesurface wasmeltedState that thesurface wascompletely frozen

State that thesurface waspartially melted

FA
×××
ᇞ
B×××
ᇞ
C××ࠐ
A to E are the same as
D××ࠐ
the powder slip
E×××‫۔‬resistance testFࠐ‫۔‬ࠐ signify the slip perceived strongly. × signify the slip perceived.
‫ ڹ‬signify the slightly slip perceived.  ‫ ۑ‬signify the few slip perceived.
‫ ۔‬signify not slip perceived.
Sample F which was added to test new is non-slip protective shoes on the ice. (Dynamicfriction coefficient 0.20) Size is 26.0.
From these test results, the following conclusions were derived.
1. In the slipping perceived test on the ice, there is completely no correlation with the dynamicfriction coefficient, but is influenced on the state of the surface of the ice. Therefore, it isindicating the easy to slip on the wetted ice despite was evaluated as non-slip shoes by theslip resistance test of JIS standard.
2. Non slip safety shoes on the ice showed a characteristic that is hard to slip as expected. This
footwear's cleat design has become a structure that mounting the fabric to the ground contact
surface. Therefore, we have considered that there was no slip, because water is hard to enter
between the surface of the cleat and the floor.
3. In fact, the state of the surface of the ice have unevenness surface and is not as same as theflat surface like the ice surface of the test, therefore ground contact surface is easy tobecome to the point contact, consequently we guess that it become more slippery. Fromabove, the conclusion is, in the method of measuring the dynamic friction in ice slip
resistance test, we found the discrepancy between perceived and dynamic friction coefficientnumber.
Therefore, we felt the need to consider a new test method, but it is very difficult to keep the- 221 -evenness surface state of the ice in the slip test, and we consider that the establishment of thereproducible test method is very difficult at this point.

Conclusion
We think that need more long term investigation for establishment of the test method of thepowder slip and the ice slip.
Therefore, about standardization of the slip resistance test of JIS standard this time, from theresults and consideration of the perceived test by the slip, decided that make a description todraw attention to the user about the risks of the working on the ice and the powder, by the formof Annex (Information).
Establishment of the slip resistance test is necessary for the development of the protective
equipment which reduces the fall disaster.
Japan protective footwear manufacturers association will be thinking to try continually best
effort for establishment of the slip test method, in the future.

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