Transcript Reduce Pallet Costs by Changing the Load on the Pallet

Determining Pallet Maximum
Working Loads From
Nominal Load Measurements
Marshall S. White
Wilbur Dibling
Ralph Rupert
John McLeod
Most Loads on Pallets do not act
Like Airbags or Two Rigid Bars as in
Draft ISO 8611-1 Tests 1 and 3
Certain Loads on Pallets will “Bridge”
across the Pallet Deck.
In Warehouse Racks, Some Loads will
Shift Stresses from the Center of
the Pallet to the Rack Supports
We Tested
Different Load
Configurations
To Determine
The Level Of
Load Bridging In
A Warehouse
Rack
We Tested The Following
Load Stabilizers
• Interlock Stacking
• Stretch Wrap
• Strapping (steel and poly)
• Breakaway Adhesive
• Pallet Tie Sheets
• Stretch tape
We Used Plywood To Simulate
Pallets And Used 4 Different
Stiffness Levels of Pallets
5.3 kN per cm of deflection
3.6 kN per cm of deflection
2.3 kN per cm of deflection
1.6 kN per cm of deflection
Each Load Was Lifted 5 Times
To Simulate Typical Loosening
Of Load After Palletization
Medium
Airbag
Tie Sheets
Column
Column,SW
Column,ST
Interlock
Interlock,SW
Interlock,ST
10.0
Airbag
Stretch Tape
Tie Sheets
Column
Column,SW
Adhesive
Column,ST
Interlock
Interlock,SW
Interlock,ST
Airbag
Column
Stretch Tape
Tie Sheets
Column,SW
Adhesive
Column,ST
Interlock
Interlock,SW
Interlock,ST
Airbag
Column
Stretch Tape
Adhesive
Column,SW
Tie Sheets
Column,ST
Interlock
Interlock,SW
Interlock, ST
Deflection (mm)
Case Goods, Average Deflections at 4.5 kN
25.0
Low
20.0
Medium-Low
15.0
High
5.0
0.0
0.0
Interlock,
ST
Interlock,
SW
Interlock
Column,ST
Tie Sheets
Column,SW
Adhesive
Stretch Tape
Column
Airbag
Deflection (mm)
Case Goods, Average Deflections at
4.5 kN, Low Stiffness Panel
25.0
20.0
15.0
10.0
5.0
0.0
Interlock
Interlock, ST
Interlock, SW
Column
10.0
Column, SW
Column, ST
Airbag
Interlock
Interlock, SW
Interlock, ST
Column
Column, SW
Column, ST
Airbag
Interlock
Interlock, SW
Interlock, ST
Column, ST
Column
20.0
Column, SW
Airbag
Interlock
Interlock, ST
Int, Plas Strp
Interlock, SW
25.0
Column, ST
Column, SW
Column
Airbag
Deflection (mm)
Sacks, Average Deflections at 4.5 kN
Low
Medium-Low
15.0
Medium
High
5.0
Interlock
Interlock,
ST
Int, Plas
Strp
Interlock,
SW
Column,
ST
Column,
SW
Column
Airbag
Deflection (mm)
Sacks, Average Deflections at 4.5kN, Low Stiffness Panel
25.0
20.0
15.0
10.0
5.0
0.0
0.0
Column, ST
Column, SW
Column
Airbag
Column, ST
Column,SW
Column
10.0
Column, Tape
Airbag
Column, ST
Column,SW
Column, Tape
20.0
Column
Airbag
Column, ST
Column, Tape
25.0
Column
Column,SW
Airbag
Deflection (mm)
Pails, Average Deflections at 4.5 kN
Low
Medium-Low
15.0
Medium
High
5.0
0.0
Column, SW
Column, ST
Medium
Column
Airbag
Column, SW
Column, ST
Column
Airbag
Column, ST
Column, SW
Column
Airbag
Column, SW
Column, ST
Column
Airbag
Deflection (mm)
Drums, Average Deflections at 4.5 kN
25.0
Low
20.0
Medium-Low
15.0
High
10.0
5.0
0
Interlock
Medium
Column
Airbag
Interlock
Column
Airbag
Interlock
Column
Airbag
Interlock
Column
Airbag
Deflection (mm)
Blocks, Average Deflections at 4.5 kN
30
Low
25
Medium-Low
20
15
High
10
5
The Effect of Load Geometry on Load Bridging
During Warehouse Rack Storage on Pallets
Percent Deflection
Average Pallet Deflection as a Percent of Airbag Deflection
100
80
100
99
87
82
70
54
60
40
20
0
Airbag-no Cinderblock- SacksCases5gal pails- 55gal drumsload bridging column stack column stack column stack column stack column stack
Load Geometry
The Effect of Load Stabilizers on Load Bridging
During Warehouse Rack Storage
of Cased Goods on Pallets
Average Pallet Deflection as a Percent
Percent Deflection
of Column Stacked Deflection
100
100
100
96
94
87
80
80
61
60
40
20
0
Column
Stretch
Interlock
Pallet
Stretch
Stacked
Tape
Stacked
Sheets
Wrap
Load Stabilizers
Adhesive Strapping
The Effect of Load Stabilizers on Load Bridging
During Warehouse Rack Storage
of Sacked Products on Pallets
Percent Deflection
Average Pallet Deflection as a Percent
of Column Stacked Deflection
120
100
80
60
40
20
0
100
100
Column Stacked
Interlock Stacked
108
114
Stretch Wrap
Strapping
Load Stabilizers
The Effect of Load Stabilizers on Load Bridging
During Warehouse Rack Storage
of Column Stacked 5 Gallon Pails on Pallets
Percent Deflection
Average Pallet Deflection as a Percent
of Column Stacked Deflection
120
100
80
60
40
20
0
100
100
79
52
Column Stacked
Stretch Tape
Stretch Wrap
Load Stabilizers
Strapping
The Effect of Load Stabilizers on Load Bridging
During Warehouse Rack Storage
of 55 Gallon Drums on Pallets
Percent Deflection
Average Pallet Deflection as a Percent
of Unbound Drum Deflection
120
100
80
60
40
20
0
100
Unbound Drums
52
47
Stretch Wrap
Vertical Strapping
Load Stabilizers
Implications of Load Bridging Tests on
Estimates of Maximum Working Loads
for pallets as described in Draft ISO
TS8611-3
1. Geometry and mechanical properties of the
package or container on the pallet affect the
maximum working load estimate
2. The types of load binders used affect the
maximum working load estimates
3. The tension applied to the load binders affects
the maximum working load estimates
Implications of Load Bridging Tests on
Estimates of Maximum Working Loads
for pallets as described in Draft ISO
TS8611-3
4. The package or container stacking patterns
affect the maximum working load estimate
5. The stiffness of the pallet affects the
maximum working load estimates
6. Normal movement of the unit load changes
unit load stiffness and therefore affects the
maximum working load estimates