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Walk-in Temperature and Humidity ChamberDEF STAN 81-41 Part 3: Packaging of Defense Material

The Defensive Standard 81-41 evaluates a package or enclosure when subjected to environmental conditions. As an ISO-17025 accredited environmental compliance test lab, we realize the importance of testing. Meeting the Defense Standard (DEF STAN) 81-41 Part 3 requirements can be difficult. We understand the challenges and guide companies through the process.

When products do not meet the requirements, Keystone Compliance assists with finding solutions. We are in constant communication throughout the entire test process. Lastly, our comprehensive reports are delivered shortly after completion of the military environmental standard test.

Request a quote and find out first hand about our competitive pricing, timely process, and outstanding reputation. Contact us to receive more information on DEF STAN 81-41 Part 3 compliance testing.

Summary of DEF STAN 81-41 Environmental Testing

Environmental package testing assesses the overall ability of a package to provide a required level of protection. This protection is provided for an enclosure material while it is being stored or transported.

Environmental package testing also assists in determining a level of confidence in the ability of the package to meet expected hazards. Likewise, sufficient data for a fair performance can be gained by subjecting the package to climatic and physical testing conditions. 

More specifically, DEF STAN 81-41 Part 3 package testing evaluates environmental and physical hazards usually expected in a package life cycle for military usage.

Note that some procedures within this standard may need to comply with the respective test method in the Defense Standard 00-035 Part 3. For more information on this standard, please follow the links below:

On occasion, other tests such as electromagnetic compatibility testing may be required to assess suitability against further criteria. These tests are not specified within this standard.

Lastly, the DEF STAN 81-41 does not cover certification testing of packaging for the supply or carriage of dangerous goods.

Defense Standard 81-41 Part 3: Environmental Package Testing Program

Before testing, the package’s faces, edges, and corners are identified.

For rectangular packages, the edges are identified by the numbers of the two adjacent faces. A corner is identified by the number of three adjacent faces. The manufacturers’ joint is located on the near end of face 5 at edge 5/2.

For cylindrical packages, the quarter points around the top edge of the package are designated as points 1, 3, 5, and 7. Those located around the bottom edge are edges 2, 4, 6, and 8. Imaginary lines joining the top and bottom edge quarter points are to be parallel.


First, a package is conditioned. Unless otherwise specified, the conditioning is not less than 16 hours or until temperature stabilization is reached.

Temperature and relative humidity conditioning must comply with ISO 2233. However, the temperature tolerance is not always required to maintain similar relative humidity tolerances.

Test Procedures

Test B: Damp Heat Test. The damp heat test of DEF STAN 81-41 assesses the climatic protection of a package. This test also evaluates the effects of tropical climates on a package.

The unit under testing is subjected to either 4, 21, or 28 24-hour cycles of damp heat.

Test C: Dry Heat Test. Dry heat testing determines the effects of drying on the protective properties of the package. Negative effects of drying include the shrinkage of timber and loosening of fastenings.

The test is conducted for 48 hours and the temperature is held at +55 C.

Test D: Horizontal Impact Test. This test method demonstrates the ability of a package to withstand horizontal impacts. More specifically, impacts are simulated from crane lifting, rail shunting, and other violent movements.

DEF STAN 81-41 impact testing is carried out when the impact is on a face or edge. The package must strike the impact surface with a velocity of 2.5 m/s.

Test E: Vertical Impact Test. The vertical impact procedure evaluates the integrity of a package when subjected to vertical impacts by dropping. Vertical impact testing can be used as either a single test or part of a sequence of tests.

The sequence of vertical impact tests is designed to measure the ability of a package to withstand a distribution system that includes vertical impact hazards.

Test G: Low-Temperature Test. Low-temperature compliance testing is intended to determine the condition of a package and its contents when affected by low temperature.

The package is placed in a suitable test chamber under standard laboratory conditions. Next, the chamber temperature is maintained for 16 hours after the package has reached the test temperature.

Test H: Static Load Test. The DEF STAN 81-41 Part 3 static load test subjects packages and packaging systems to compressive loads.

The procedure applies loads to lower containers in a stack of identical containers. This test can also assess the protective quality of the container in compression whereas buckling, crushing, or partial collapse of the container is unacceptable.

Test K: Vibration Test. DEF STAN Part 3 vibration testing is performed to demonstrate the ability of a package to withstand vibration over a frequency range encompassing transportation.

Test N: Dry Heat Exposure Test. This test procedure conditions a package for assessing its physical protective quality when subjected to movement and handling in hot, dry, climatic environments.

The dry heat exposure test is run for 4 or 10 cycles.

Test Q: Topple Test. The topple test usually pertains to damage through bending or shock. This test is similar to the roll test below.

Test R: Rolling Test.  The roll test evaluates a package’s integrity when handling and toppling on a face or edge. The lack of proper equipment or impractical lifting facilities is generally the cause of rough handling and the toppling of a package

Test T: Water Immersion Test. Water immersion testing evaluates a package’s ability to resist water penetration from a static head of standing water. This type of testing is also known as ingress protection testing or IP Code testing.

Water immersion testing may simulate flooding or the accumulation of water. The unit under testing is subjected to an exposure duration of roughly 20 minutes.

Test V: Cornerwise Rotational Drop Test. Corner drop testing is used to determine the integrity of a large shipping container when subjected to impacts on its corner.

Test W: Edgewise Rotational Drop Test. Similar to corner drop testing, edge drop testing applies to a package and its contents when subjected to being dropped on its edge.

Test X: Mechanical Handling Test. The DEF STAN 81-40 mechanical handling test determines the ability of a package or container to withstand handling by mechanical handling equipment.

Test Report

After the completion of the test procedure, a test report is compiled with the following information:

  • Package design reference number
  • Packaging level
  • Gross package mass
  • External package dimensions
  • Visual description and recording of any damage or deviations from the specification
  • Any malfunction of the fittings and hardware
  • Damage to or spillage of the package contents

Expert DEF STAN 81-41 Part 3 Environmental Package Testing

Unlike other NRTLs, our team strives to give our customers more time and energy on product development instead of testing. In addition to environmental standard testing, Keystone has a full scope of expertise including EMC/EMI, shielding effectiveness, and package. Lastly, our full lab of test equipment permits us to provide short lead times on scheduling. 

Ready to get started? Contact us for more information on Defensive Standard 81-41 Part 3 environmental testing.

For more information on Defense Standard regulatory compliance testing, please follow the links below:



DEF STAN 00-035 Part 3: CHEMICAL