What is def stan 81-41 packaging? General requirements and testing

If your company supplies products to the UK Ministry of Defence or other businesses working with the military, it is vital you understand what is def stan 81-41 packaging.

Def-Stan is shorthand for Defence Standard. These detail a series of material standardisations developed by the UK Ministry of Defence (MOD). The standards support improved interoperability and more effective acquisition. Def stan 81-41 are the standards relating specifically to packaging.

This guide provides a detailed overview of def stan 81-41, the criteria your must business must meet when supplying packaged goods to the UK military, processes, testing, markings and more.

In simple terms, defence standard 81-41 is the criteria the UK Ministry of Defence (MOD) specifies for military packaging. The aims are to safeguard goods from deterioration and physical or mechanical damage and ensure consistency and interoperability across the MODs’ operations. The standards also allow for more effective acquisition across the organisation.

Def stan 81-41, divided into six parts, primarily concentrates on environmental conditions to ensure the preservation of items during storage, general handling, and distribution or transit via rail, road, sea, and air.

The six components of Defence Standard 81-41 are:

• Part 1: Military packing levels
• Part 2: Design
• Part 3: Environmental testing
• Part 4: Service Packaging Instruction Sheet (SPIS)
• Part 5: Production processes
• Part 6: Package markings

It is important to note that, in accordance with def stan 41-81, packaging can be one of three different levels:

• J – for items which may be stored anywhere in the world, within any climatic condition for up to 2 years.
• N – for items which could also be stored anywhere in the world, in non-climatic conditions (clean and dry), for up to 5 years.
• P – Similar to commercial packaging, and can be designated to items that need to be stored for up to 5 years but only in normal storage conditions.

Determining which level your packaging should meet allows you to ascertain suitable design and material(s).

The UK military packaging design requirements correspond to the military packing levels required for your item.

Your packaging provider typically requires the following:

• A Nato Stock Number(NSN), a 13-digit unique identification code assigned to each item the MOD utilises.
• The name and description of the item slated for packaging.
• The specific department within the MOD (Army, Navy, or RAF) overseeing the item.
• The manufacturer’s part number.
• Dimensions and weight of the items.
• Primary Package Quantity (PPQ).
• Information on whether the MOD will store the item and the anticipated duration.
• Fragility factor of the items.
• Resistance level of the items to g-force.
• Centre of gravity for the items, crucial for safe lifting and loading during transportation.

By knowing the specifications for your item and the type of packaging, it can be pre-determined how the packaging will respond to testing and environmental conditions.

Before testing begins, your provider must identify the package’s faces, edges, and corners.

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

For cylindrical packages, quarter points around the top edge are designated as points 1, 3, 5, and 7, while those around the bottom edge are edges 2, 4, 6, and 8. Imaginary lines joining the top and bottom edge quarter points should be parallel.

Initially, a package undergoes conditioning, with a minimum duration of 16 hours or until temperature stabilisation (unless otherwise stated).

The temperature and relative humidity conditioning should adhere to the standards outlined in ISO 2233 – a standard specifically for conditioning transport packages and unit loads.

Nevertheless, maintaining analogous relative humidity tolerances may not always necessitate the same temperature tolerance.

After identifying the packaging’s faces and conditioning, the packaging must undergo another series of tests.

There are four tests focused on temperature and its effect on packaging and its contents:

• Test B: Known as the damp heat test in def stan 81-41, gauges the climatic resilience of a package and assesses its ability to withstand tropical conditions. The testing unit undergoes either 4, 21, or 28 cycles of damp heat, each lasting 24 hours.
• Test C: Known as the dry heat test, examines how drying impacts the protective characteristics of the package. Adverse effects, such as timber shrinkage and fastening loosening, are evaluated. The test is conducted over 48 hours, maintaining a temperature of +55°C.
• Test G: Designated as the low-temperature test, aims to assess the state of a package and its contents under the influence of low temperatures. The tester positions the package within an appropriate test chamber under standard laboratory conditions. Subsequently, the chamber temperature is sustained for 16 hours after the package reaches the specified test temperature.
• Test N: The dry heat exposure test conditions a package to evaluate its physical protective attributes during movement and handling in hot, dry climatic conditions. The test involves 4 or 10 cycles.

Four drop tests ascertain if the packaging can withstand varying impacts.

• Test D: The horizontal impact test illustrates a package’s capability to endure horizontal impacts, specifically simulating forces from crane lifting, rail shunting, and other abrupt movements. Def stan 81-41 mandates impact testing when the impact occurs on a face or edge, requiring the package to strike the impact surface at a velocity of 2.5 m/s.
• Test E: The vertical impact test examines the package’s integrity when exposed to vertical impacts through dropping. This type of impact testing can function as a standalone evaluation or as part of a series of tests.

The series of vertical impact tests is strategically designed to gauge the package’s resilience within a distribution system encompassing vertical impact hazards.

• Test V: Rotational corner drop test. This type of testing assesses the resilience of a sizable shipping container when experiencing impacts on its corners.
• Test W: Rotational edge drop test. Comparable to corner drop testing, edge drop testing evaluates the impact on a package and its contents when dropped on its edge.

Test H is a static load test exposing packages and packaging systems to compressive loads. The method involves applying loads to the lower containers within a stack of identical containers.

This test evaluates the container’s protective capability under compression, considering factors such as buckling, crushing, or partial collapse deemed unacceptable.

Test Q, the topple test, primarily concerns potential damage caused by bending or shock.

Not only does this help protect the products within the packaging, but depending on the weight or shape of the packaging, this test can help outline and prevent injury during handling.

The rolling test, Test R, assesses the structural integrity of a package during handling and potential tipping on either a face or edge, which is why the tester records the faces at the beginning of the testing phase.

Rough handling and package tipping are typically attributed to inadequate equipment or impractical lifting facilities.

Test K, the vibration test in def stan 81-41: part 3, tests a package’s capacity to endure vibrations across a frequency range that includes transportation. It includes the variation between road, rail, sea and air.

Defence standards also require Test T, a water immersion test.

This test assesses a package’s resistance to water penetration from a static head of standing water.

This form of testing, also referred to as ingress protection testing or IP Code testing, simulates conditions such as flooding or water accumulation. The testing involves subjecting the unit to an exposure duration of approximately 20 minutes.

Finally, Test X, a mechanical handling test, assesses the package or container’s capacity to endure the rigours of mechanical handling equipment.

Following the conclusion of the test procedure, the generation of a comprehensive report encompasses the following details:

• Package design reference number.
• Packaging level.
• Gross package mass.
• External package dimensions.
• Visual depiction and documentation of any damage or deviations from the specification.
• Identification of any malfunction in fittings and hardware.
• Evaluation of damage or spillage of the package contents.

The Service Packaging Instruction Sheet (SPIS) is a comprehensive manual outlining procedures for the upkeep, cleaning, and packing of military equipment/materiel.

An MPAS packaging provider can request the status of an SPIS design using a DEFORM 129A. This request provides insights into the existence of an SPIS and whether a Standard Family Specification (SFS) has been applied to the item slated for packaging.

Furthermore, the DEFORM 129A serves the dual purpose of soliciting authorisation to receive a copy of the SPIS, update an existing SPIS, transition to an SFS, or create a new SPIS design.

The production process is evaluated as set out in def stan 81-41 and is conclusive of the materials and processes required to manufacture the packaging.

The item being packaged and the environment in which the MOD will store and transport it influence the specific requirements.

Packaging manufacturers are required to stay up to date on the current version of the defence standards.

The labelling procedure must conform to the military packaging requirements specified in defence standard 81-41 (Part 6).

Suppliers must use either a waterproof and transparent strip of tape equipped with pressure-sensitive adhesive or a layer of adhesive emulsion and polyvinyl acetate to protect external paper labels. Further detailed instructions for these materials are available in the Defence Standard, outlined explicitly in Def Stan 75-3 and Def Stan 80-132, respectively.

Alternative labels such as IPSM15 already exist for pallets, where the wood undergoes heat treatment to facilitate international goods shipments.