Micom Reviews the GM 1738NA Revision 4 Packaging Specification

The GM 1738NA packaging specification contains requirements for shipping containers used by suppliers for the transportation of production parts to GM facilities. One such requirement for palletised loads is that they must be tested to either ISTA 3E or ASTM D4169 by a certified laboratory. The requirement came into effect on February 1, 2020. 

One thing that immediately jumps out is that no Distribution Cycle (DC) or Assurance Level is specified for the ASTM D4169 specification. DC is chosen based on the transportation vehicle (ex: train, truck, plane) and the distribution pipeline (ex: parcel delivery, less than truckload, full truckload) of the product. Assurance level defines the severity of the test parameters. Level I is the most severe, Level II is moderate, and Level III the least severe. Given that ISTA 3E is a procedure for unitized loads, DC 6 would be the ASTM D4169 equivalent. Assurance Level 2, and a medium level truck spectrum for vibration, most closely matches the parameters of ISTA 3E; however test severity can be modified for each particular situation. A comparison of both test standards is given in the table below.

Comparison Table: ISTA 3E and ASTM D4169 Assurance Level 2 Packaging Tests

 

Test Category ISTA 3E ASTM D4169 DC6 Assurance Level 2 (Medium) Comments
Sequence Description Sequence Description
Conditioning 1
(Test Block 1)
Required Preconditioning: Laboratory ambient temperature & humidity for 12 hours
Optional Conditioning: Conditioning parameters chosen from chart based on anticipated conditions (if known)
1
(Section 6)
Standard Preconditioning: 23±1 and 50±2% RH for 72 hours required.
Alternate Conditioning: To be specified based on known transportation conditions.
ASTM D4169 has a more specific range for conditioning. GM 1738NA states that conditioning is optional provided a safety factor F>3.5 is used.
Forklift Handling N/A N/A 2
(Schedule A)
Truck Handling around test course; 5 round trips (Assurance Level 2) Not required by ISTA 3E
Impact 2
(Test Block 2)
Impact 4 vertical faces;
Impact Velocity=1.2 m/s
3
(Schedule A)
Impact 4 vertical faces;
Impact Velocity=1.22 m/s
(Assurance Level 2)
Identical test with Assurance Level 2
Rotational edge drop 3
(Test Block 3)
2 drops; height varies with unit weight:
-For weight≤500 lbs: 9 in drop height
-For weight>500 lbs: 6 in drop height
4
(Schedule A)
2 drops; height varies with unit weight:
-For weight≤500 lbs: 9 in drop height
-For weight>500 lbs: 6 in drop height
(Assurance Level 2)
Identical test with Assurance Level 2
Compression/Vehicle Stacking 4
(Test Block 4)
Compression load calculated based on pallet configuration. 5
(Schedule C)
Compression load calculated based on pallet configuration. Factor F dictated by Assurance Level and packaging type. GM 1738NA requires a compensating factor F>3.5 for compression tests.
Vehicle Vibration 5
(Test Block 5)
Random Vibration
Overall Grms=0.54
Duration=Transport distance (miles)/5
Max duration=240 mins
6
(Schedule E)
Random Vibration
3 Grms levels available, recommended to run all 3 in a one hour loop.
Vibration profiles of Truck Level Medium and ISTA 3E are identical.
Concentrated Impact N/A N/A 7
(Schedule J)
Only required for lightweight single wall corrugated shipping containers and plastic film wrapped packages Not required by ISTA 3E
Forklift Handling N/A N/A 8
(Schedule A)
Truck Handling around test course; 5 round trips (Assurance Level 2) Not required by ISTA 3E
Impact N/A N/A 9
(Schedule A)
Impact 4 vertical faces; Impact Velocity=1.22 m/s (Assurance Level 2) Not required a second time by ISTA 3E
Rotational edge drop 6
(Test Block 3)
2 drops; height varies with unit weight:
-For weight≤500 lbs: 9 in drop height
-For weight>500 lbs: 6 in drop height
10
(Schedule A)
2 drops; height varies with unit weight:
-For weight≤500 lbs: 9 in drop height
-For weight>500 lbs: 6 in drop height
(Assurance Level 2)
Identical test with Assurance Level 2
Warehouse Stacking N/A N/A 11
(Schedule B)
Compression load calculated based on pallet configuration. Factor F dictated by Assurance Level and packaging type. Not required again by ISTA 3E. GM 1738NA requires a compensating factor F>3.5 for compression tests.


In short, while ISTA 3E is a more condensed test plan that is quicker to execute, ASTM D4169 DC6 may be better suited to a client’s particular needs.

Micom offers both ISTA 3E and ASTM D4169 packaging testing services. For more information about either of these tests, we invite you to contact our material testing laboratory today. It will be our pleasure to answer any questions you may have.

Micom Laboratories is a third party industrial material testing laboratory accredited by the Standards Council of Canada, CGSB, ISTA and many other organizations.

Disclaimer

All of the information and opinions contained in this blog are made with the information, and the understanding that we have reviewed at the time of publishing. However, despite our efforts, we do not offer any guarantee of their accuracy, thoroughness of our investigation or validity. The author of this blog is not liable for any inaccuracies or any losses or damages that may result from the use of the information or data contained herein. This blog has not been reviewed or verified for its accuracy by any peer group associates prior to publication.