Testing of Recycled-Content
Gym Floor Against
Various Other Althetic Surfacing
This report acquired performance
data on shock absorption characteristics to enable comparison of a recycled-content
athletic surface to traditional athletic turf and hardwood gym surfaces.
Shock absorption testing measured the impacts maximum acceleration
and duration of pulse to calculate the head injury criteria.
These measures indicate the ability of the surface to protect against
impact injuries. The test is conducted per American Society for
Testing and Materials (ASTM) methods.
Because there was no official safety standard for athletic playing surfaces at this time (1997), this data collection is important in developing specifications for sports playing surfaces that provide maximum protection for athletes of all types with minimal compromise of playability.
BACKGROUNDThe SmartCellsTM athletic surface is a unique playing surface system developed by [formerly] SATECH, of Kirkland, Washington. The surface system incorporates a cellular cushion pad molded from a mixture of recycled rubber and used athletic shoes blended with a virgin rubber compound. The 1.75 thick pad is bonded to a base and covered with a specially formulated urethane coating that simulates a traditional wood finish. The resulting surface exhibits the look and feel of a hardwood floor
The recycled content flooring
system hopes to capture a significant niche market in athletic surfaces (gym
floors, indoor football and soccer floors, aerobics floors) and non-sport
utility flooring (health care facilities, nursing homes, schools, commercial
and light industrial flooring). However,
this flooring system faces a market barrier that is common to many recycled-content
products - a lack of performance specifications and data to allow side-by-side
comparison with existing traditional products, including hardwood floors,
and natural and artificial turf surfaces.
A SmartCellsTM
regulation-size basketball court floor was installed at Puget Sound Christian
College in Edmonds, Washington in early 1996 as a demonstration project. This floor is comprised of 40% recycled rubber
and fiber, using approximately 15,000 used sports shoes and 525 tires in the
full-size gym floor. The floor continues
to perform well under daily use, and has logged good reviews from amateur
and professional players, including post-practice evaluations by several NBA
teams. A second demonstration installation
is planned for the downtown Seattle area.
The CWC funded a series of
testing projects focusing on performance characteristics of the SmartCellsTM athletic surface. Previous testing has included both shock absorption
and friction resistance. This report
details the results from shock absorption testing conducted in April 1997
on the SmartCellsTM flooring and a traditional
hardwood gym floor. This report is
subsequent to shock absorption test reports issued in 1995, conducted on the
flooring and traditional hardwood gym floors.
Shock absorption testing was
conducted in accordance with ASTM F1292 (Standard Specification for Impact Attenuation
of Surface Systems Under and Around Playground Equipment) and ASTM F355,
Procedure C, (Standard Test Method
for Shock-Absorbing Properties of Playing Surface Systems and Materials),
both of which are standards under the jurisdiction of ASTM Committee F-8 on
Sports Equipment and Facilities, and Subcommittee F08.52 on Playing Surfaces
and Facilities. The two measurements
observed in these test methods are the maximum impact acceleration (G-max)
and head injury criteria (HIC), which indicate the ability of the surface
to protect against serious impact injuries.
TESTING CONDUCTED (APRIL 1997)
To compare the shock absorbing
properties of different types of athletic playing surfaces, impact testing
was performed in accordance with ASTM F1292-95 (Standard Specification for
impact Attenuation of Surface Systems Under and Around Playground Equipment
), and ASTM F355-95, Procedure C ( ANSI C
Headform) (Standard Test Method for Shock-Absorbing Properties of Playing
Surface Systems and Materials).
The number and location of
impact sites on the SmartCellsTM floor were determined in
accordance with the document, "Of Basketball Playing Surfaces", Revised 6th
April, 1995, written by Martyn Shorten, Ph.D. (Biomechanics. Also chaired the ASTM subcommittee F.08.54 for
Athletic Footwear.). The number and
location of impact sites on the natural grass and artificial turf fields were
determined at each test site by consensus from Bernard Martin, Ph.D. Ergonomics,
and representatives from CWC, adidas International Corporation, and SATECH.
The sample locations included
three (3) artificial turf fields, three (3) natural grass fields, and one
(1) recycled content (SmartCellsTM) floor, all located in the
greater Seattle area.
Field identification and type
follow:
Surface Location Surface Type
1. University of Washington Husky Stadium (UW )
Artificial Turf
2. West Seattle High School Stadium (WSS) Natural Grass
3. Seattle Center Memorial Stadium (SCS) Artificial Turf
4. KingDome (KD)
Artificial Turf
5a. Seahawks Practice Facility West, Field #1 (SPF)
Natural Grass
5b. Seahawks Practice Facility East, Field #2 (SPF)
Natural Grass
6. Puget Sound Christian College Gym (PSCC) SmartCellsTM
CONCLUSION:
Table 1 presents the test
results for the seven (7) athletic playing surfaces tested.
Table 1: Shock Absorption
Test Results Comparing
SmartCellsTM to
Other Athletic Surfaces
| Field ID # | Location | Surface Type | Height Value at Which Surface Met Performance Criteria Per ASTM F1292 |
| 1 | UW | Artificial Turf | 3 feet |
| 2 | WSS | Natural Grass | 4 feet |
| 3 | SCS | Artificial Turf | 3 feet |
| 4 | KD | Artificial Turf | 3 feet |
| 5a 5b |
SPF West, Field #1 East, Field #2 |
Natural
Grass Natural Grass |
3 feet |
| 6 | PSCC (Gym) | SmartCells™ (Recycled Content) |
6 feet |
TEST EQUIPMENT
NOTE: XYTEK Industries, Inc.
used equipment that meets the calibration requirements of MIL-STD-45662A.
7
KME: HIC Computer; Model Series
300, Calibrated prior to test
7
PCB, Accelerometer; Model
356A11, ID 2676, Calibrated to 9/23/97
7
K1A, Magnesium Alloy Headform
7
XYTEK, Drop Tower per ASTM
F1292-95
7
Fluke, Multimeter, Model 23,
ID 0323, Calibrated to 4/1/98
Testing Procedure for Artificial
Turf and SmartCellsTM
2. The impact tower was placed
over each predetermined test location and impacted one time at different heights
to predetermine the three testing heights for the remaining test location.
3. Each site was then subjected
to three (3) impacts, starting at 1 foot below the predetermined height, with
each impact hitting in the same location.
4. Testing would be discontinued
if any of the following occurred:
A.
Maximum average value of the second and third impact exceeds 200 G.
B.
Maximum average value of the second and third impact exceeds 1,000
HIC.
C.
Maximum height of more than 12 feet.
5. The HIC values from the
second and third impacts are averaged for each impact height.
6. The G-Max values from the
second and third impacts are averaged for each impact height.
Procedure for Natural Grass
2. The impact tower was placed over each predetermined
test location, and impacted three (3) times at one height.
The tower was then moved approximately fourteen (14) inches away, and
the height increased by one foot. This
was repeated to determine the three (or more) testing heights for each surface.
3. Each of the remaining sites was then subjected
to three impacts, starting at one foot below the initial, predetermined height.
With each height change the drop tower was moved.
All three impacts hit in the same location at each height.
4. Testing would be discontinued if any of the following
occurred:
A.
Maximum average value of the second and third impact exceeds 200 G-Max.
B.
Maximum average value of the second and third impact exceeds 1,000
HIC.
C.
Maximum height of more than 12 feet.
5. The HIC values from the
second and third impacts are averaged for each impact height.
6. The G-Max values from the
second and third impacts are averaged for each impact height.
Test conditions:
If any one test location of
the surface fails beginning at the minimum impact height of one foot, the
entire surface area fails.
If the average of the second
and third impacts at a specific impact height was less than or equal to 200
G-Max and 1,000 HIC, the sample was listed as a pass. If the average of the second and third drop
at a specific impact height exceeded 200 G-Max and/or 1,000 HIC, the sample
was listed as a failure.
On surfaces that compact upon
impact, (e.g., wood chips, dirt, sand, gravely earth, and sod ), it is imperative
that the impact site be moved several inches away after each set of three
impacts at one given height. This ensures
the subsequent impact values will not reflect the compaction that occurs during
drop testing.
Disclaimer Notes: This impact attenuation data is for purposes
of comparison only. The Consumer Product
Safety Commission states, "It is self evident that a fall onto a shock absorbing
surface is less likely to cause a serious injury than a fall onto a hard surface.
However, it should be recognized that all injuries due to falls cannot
be prevented no matter what playground surfacing material is used."
Surfacing meeting these test
measurements and ASTM specifications will not prevent non-life threatening
injuries.