 |
PERFORMANCE EVALUATION OF 48 X 48
COIL PALLETS MADE FROM RECYCLED PLASTIC |
Report No. PL-97-3
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PERFORMANCE EVALUATION OF 48 X 48
COIL PALLETS MADE FROM RECYCLED PLASTIC |
TABLE
OF CONTENTS
1. INTRODUCTION 1
2. PALLET DESCRIPTION 1
3. TEST METHODS 2
3.1 MODIFIED VPI
FASTRACK 2
3.2 PALLET STRENGTH
TESTS SIMULATING STACKS 1- AND 2-HIGH 2
3.3 PALLET STRENGTH TESTS USING FORKTINE SUPPORT 3
3.4LEADING DECK EDGE/ INCLINED IMPACT
TESTS, ASTM D1185-94, SECTION 9.4 3
3.5
STRINGER
END IMPACT TEST, ASTM D1185-94, SECTION 9.4. 3
4. TESTING RESULTS 4
4.1 VPI FASTRACK 4
4.2 PALLET STRENGTH TESTS SIMULATING STACKS 1- AND
2-HIGH 4
4.3 PALLET STRENGTH
TESTS SIMULATING FORKTINE SUPPORT 5
4.4 LEADING DECK EDGE/
INCLINED IMPACT TESTS 5
4.5 STRINGER END
IMPACT TESTS 6
5.
CONCLUSIONS AND DESIGN
RECOMMENDATIONS 6
6.
REFERENCES 7
7.
ACKNOWLEDGMENT 7
APPENDIX: PHOTOGRAPHS OF TESTING
(NOT INCLUDED IN THIS ELECTRONIC FILE BUT AVAILABLE UPON REQUEST)
ReTAP and the Clean Washington Center disclaim all warranties to this report, including mechanics, data contained within and all other aspects, whether expressed or implied, without limitation on warranties or merchantability, fitness for a particular purpose, functionality, data integrity, or accuracy of results.
1.
INTRODUCTION
The All Service All Packaging (ASAP) company of Green Acres, Washington contracted the William H. Sardo Pallet & Container Research Laboratory to conduct an evaluation of their new coil pallet made from 100% recycled material. The coil pallet was designed specifically for the “heavy capacity” shipment of aluminum and steel coil.
The purpose of this project is to test the strength and durability performance characteristics of a recycled content plastic pallet for use in for validation into the “heavy capacity” pallet market. To simulate the loading of aluminum and steel coil, a simulated coil ballast load was used whenever possible. The test objectives were:
·
To
determine the average number of loss of functionality of the ASAP pallet in a
simulated rough handling environment (as tested on the VPI FasTrack equipment).
·
To
determine the lateral collapse potential of the ASAP pallet.
·
To
determine the compression strength of the ASAP pallet when stacked 1-high and
2-high.
·
To
determine the compression strength of the ASAP pallet using forktine support.
·
To
determine the top deck edge impact resistance.
·
To
determine the stringer end impact resistance.
2.
PALLET DESCRIPTION
ASAP supplied Virginia Tech with sixteen 48 x 48 coil pallets. The pallets have three (3) stringers at 5-1/2 inch wide x 5-1/2 inches high x 48 inches long. The pallets have five (5) top deckboards at 5-3/8 inches wide x 1-1/2 inches high x 48 inches long. The pallets have no bottom deckboards. The stringers are constructed of recycled, high density polyethylene (HDPE) reinforced with recycled fiberglass. The deckboards are also made from 100% recycled HDPE. Five pallets had black deckboards and eleven pallets had gray deckboards. The recycled resin was supplied by two recycled plastic processors in Washington State. Figure 1 contains a photograph of two ASAP coil pallets with dummy loads.
3. TEST
METHODS
3.1
MODIFIED VPI FASTRACK
The VPI FasTrack is an
accelerated material handling simulation developed by Virginia Tech and Proctor
& Gamble for the grocery industry.
The FasTrack was modified to test the ASAP coil pallet design. A 20,000 pound, rubber-tired forklift, with
a 30,000 pound capacity was used for testing.
To simulate the actual load and support conditions, a ballast load of
10,000 pounds was applied to each pallet tested. The ballast load was a 48 inch diameter, concrete-filled metal
pipe.
The FasTrack consisted of
two test areas. Test area number 1 is a
gravel staging area for moving and stacking the loaded pallets in test and a
smooth concrete surface for pushing the pallets in test. Test area number 2 was an airport tarmac, which is a rougher, more abrasive
surface. Figure 2 contains a photograph of two ASAP pallets in the
FasTrack, as tested on the gravel/concrete surface (test area 1).
One FasTrack material handling cycle consists of the following steps.
1.
Load
two empty pallets with one 10,000 pound ballast load per pallet.
2.
Stack
pallet two on top of pallet one.
3.
Return
pallet two to unstacked position.
4.
Stack
pallet one on top of pallet two.
5.
Return
pallet one to unstacked position.
6.
Enter
pallets with forklift, and push loaded pallets 60 feet, one pallet at a time.
7.
Return
loaded pallets to staging area.
8.
Remove
load and inspect pallets for damage.
Each FasTrack cycle consists
of five individual handlings on average.
3.2
PALLET STRENGTH TESTS SIMULATING STACKS 1- AND 2-HIGH.
The pallet strength tests simulating stacks 1-high and 2-high were performed using a 30,000 pound dead load. Figure 3 contains a photograph of a loaded pallet. These tests were performed on the airport tarmac. The ambient temperature on the tarmac during testing was 123 degrees Fahrenheit. After the load was applied, the loaded pallet was inspected for damage. Three replicates of black deckboard pallets and three replicates of gray deckboard pallets were tested, for a total of six replicates.
3.3 PALLET STRENGTH TESTS USING FORKTINE SUPPORT
A 30,000 pound dead load was
used for the forktine support tests.
Four inch wide I-beams were used as simulated forktines. Figure 4 contains a photograph of a pallet
in test. The I-beams were placed with a
21.25 inch span center to
center. An empty pallet was placed on
the forktines and the 30,000 pound load applied. After the load was applied, the pallet in test was inspected for
damage. Three replicates of each color deckboard were tested (six replicates total).
3.4
LEADING DECK EDGE \ INCLINEDIMPACT TESTS, ASTM D1185-94, SECTION 9.4
The top deck leading edge
impact test were performed according to ASTM D-1185-94, section 9.4. The pallets were conditioned to -13 degrees
F prior to testing. The pallet was
positioned so that leading edge deckboards would be impacted on the center span
of each deckboard between stringers. A 700 pound cargo load was applied
throughout the test. The impact
distances began at 12 inches and progressed through 24 inches, 48 inches, 72
inches, and 96 inches. Ten (10) impacts
were performed at each energy level.
The test was terminated when a deckboard was removed or broken from the
stringer.
3.5
STRINGER END IMPACT TEST, ASTM D1185-94, SECTION 9.4.
The stringer end impact tests
were performed according to ASTM D-1185-94, section 9.4. The pallets are conditioned to -13 degrees F
prior to testing. The forktines are
positioned so that they impact the stringer ends on center. Figure 5 contains a photograph of the test
setup. The cargo load begins with 250
pounds at 6 inches. After 10 impacts
with a 250 pound cargo and 6 inch distance, the load is increased to 700 pounds
for the remainder of the test. The
impact distances with the 700 pound cargo begin at 6 inches and progress
through 12 inches, 24 inches, 48 inches, 72 inches, and 96 inches. Ten impacts are performed at each energy
level. The test is terminated when a
portion of the stringer end is broken off.
4. TESTING RESULTS
4.1 VPI FASTRACK
Table 1 contains the results from the VPI FasTrack. One-hundred percent of the failures occurring during FasTrack involved the shearing and withdrawal of the leading edge deckboard and fasteners from the stringer. Nine percent of the failures (1 pallet) included a combination of the deckboard/fastener removal and a broken stringer end caused by forktine impacts. Figures 6 and 7 contain both of the failure modes associated with the FasTrack. The lateral and horizontal forces which cause the shear and withdrawal of the deckboard stringer joint are associated with forkheel impacts and lifts from the forklift and from shifting of the coil on the pallet.
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Table 1: Durability Results
From the VPI FasTrack |
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Pallet ID |
Deckboard Color |
Test Area |
Actual Number of Handlings Until Failure |
Expected Number of Trips
Until Failure at 10 Handlings per Trip |
Expected Number of Trips
Until Failure at 15 Handlings per Trip |
|
1 |
Black |
Gravel/smooth concrete |
1160 |
116 |
77 |
|
2 |
Black |
Gravel/smooth concrete |
1120 |
112 |
75 |
|
3 |
Gray |
Gravel/smooth concrete |
535 |
54 |
36 |
|
4 |
Gray |
Gravel/smooth concrete |
175 |
18 |
12 |
|
5 |
Black |
Tarmac |
355 |
36 |
24 |
|
6 |
Black |
Tarmac |
270 |
27 |
18 |
|
7 |
Gray |
Tarmac |
310 |
31 |
21 |
|
8 |
Gray |
Tarmac |
415 |
42 |
28 |
|
9 |
Gray |
Tarmac |
380 |
38 |
25 |
|
10 |
Gray |
Tarmac |
370 |
37 |
25 |
|
11 |
Gray |
Tarmac |
405 |
41 |
27 |
4.2
PALLET STRENGTH TESTS SIMULATING STACKS 1- AND 2-HIGH
Under a compression load with a dead weight of 30,000 pounds, no pallet failures occurred. Because of the rigidity and flatness of the coil load, virtually no bending stresses are imparted to the top deck of the pallet. No failures were expected in this test. Three pallets with black deckboards and three pallets with gray deckboards were tested.
4.3
PALLET STRENGTH TESTS SIMULATING FORKTINE SUPPORT
As in the stack tests in section 4.2, no pallet failures occurred or were expected because of the rigidity of the coil load. Three pallets with black deckboards and three pallets with gray deckboards were tested.
4.4
LEADING DECK EDGE IMPACT TESTS / inclined plane impact test
Table 2 contains the results from the ASAP leadboard inclined impact testing, as well as results from impact tests on three 48” x 40” hardwood GMA style pallets owned by the Canadian Pallet Council.
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Table 2: Results of the ASTM
D1185 Inclined Plane Impact Tests on the ASAP Coil Pallets and Three Timber
Pallets from the Canadian Pallet Council |
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Sample # (and deckboard color for
ASAP pallets) |
Number of Impacts to
Leading Edge Failure |
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12 in. 700
lbs |
24 in. 700
lbs |
48 in. 700
lbs |
72 in. 700
lbs |
|
|
1 - Gray |
10 |
10 |
10 |
4 |
|
2 - Black |
10 |
10 |
8 |
--- |
|
3 - Black |
10 |
10 |
10 |
2 |
|
1 - Wood |
--- |
--- |
40 |
1 |
|
2 - Wood |
--- |
--- |
2 |
--- |
|
3 - Wood |
--- |
--- |
12 |
--- |
Figure 8 contains a
photograph of a typical failure of the ASAP pallet from inclined plane impact
testing.
4.5 STRINGER END IMPACT TESTS
Table 3 contains the results
from the stringer end impact tests on the ASAP pallets and the stringer end impact tests on three 48@ x 40@ hardwood GMA style pallets
owned by the Canadian Pallet Council.
Figure 9 contains a photograph of a typical failure mode in the stringer
end impact tests.
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Table 3: Results of the ASTM D1185 Stringer End
Impact Tests on the ASAP Coil Pallets and Three Timber Pallets from the
Canadian Pallet Council |
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Sample |
Number of Impacts to
Stringer End Failure |
|
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|
6 in. 250
lbs |
6 in. 700
lbs |
12 in. | ||||||