Round Robin
– g-max and HIC
One of the
stated aims of the ISSS is the assessment and standardisation
of test methods for sports surfaces. To this end we have conducted
a round Robin of impact testing equipment and techniques used
for soft fall material testing.
Time frame
During the
period November 2000 to November 2001 samples were circulated
to 6 testing laboratories for impact testing.
Trial Controller:
H.J. Kolitzus
Samples
The 2 samples
circulated for testing were:
Sample
1 PUR Bound Rubber Fibres (Tile) roughly 61 mm thick
Sample
2 PUR Bound Rubber Fibres (Tile) roughly 41 mm thick
Testing Regime
The laboratories
were requested to conduct impact tests on the samples under the
following conditions:
Sample temperature
– reported ambient after conditioning for at least 24 hr
Base – thick
concrete of thickness in excess of 100 mm, with smooth finish
Drop Heights
– 4, 5 and 6 feet
Determined
values of g-max and HIC for the first drop were to be reported
for each of these drop heights for each sample.
LaboratoriesEquipment
| Acousto-Scan,
Sydney, Australia |
5 kg
ISO J head |
| CST,
London, England |
10 lb
EN1177 hemi head |
| IST,
Eschenz, Switzerland |
10 lb
EN1177 hemi head |
| Labosport,
Le Mans, France |
10 lb
EN1177 hemi head |
| North
West Testing Laboratory, Seattle, USA |
10 lb
EN1177 hemi head |
| USSL,
Hopewell, VA, USA |
10 lb
EN1177 hemi head |
Two of the
laboratories tested the samples twice, once early in the trial
and again at the end of the trial (eg. Lab02-2 in 2001 and Lab03-2
in2002) to check on changes to the samples.
Results
The results
of the testing (laboratories coded) are summarized in Fig. 1
and 2.
These figures
show the deviations from the global average of each of the laboratory’s
tests.
Comments
The results
indicate a remarkable consistency of test results considering
the range of laboratories, testing and equipment.
The consistency
within each laboratory’s results is very high showing a small
range of variability. The variations between laboratories indicate
systematic differences in their equipment and techniques. However
this should be viewed in terms of the general uncertainty of the
measurements. Acousto-Scan has calculated the uncertainty of its
g-max determination at 4 % and of its HIC at 5 % using the methods
outlined in the ISO publication Guide to the Expression of
Uncertainty in Measurements, 1993
HJK+JID
Nov 02
