Transit testing sits in the gap between packaging being theoretically adequate and actually performing in the distribution environment. A lot of businesses have never tested their packaging under simulated distribution conditions. They've packed the product, it's arrived intact most of the time, and that's been good enough.
"Most of the time" is a reasonable outcome until you're launching a new product with a different fragility profile, moving to a new distribution channel, or dealing with a damage claim rate that's eating margin.
What Transit Testing Covers
Formal transit testing — based on standards like ISTA 2A (the most widely used for packaged products up to 68kg) or ASTM D4169 — simulates a product's journey through the distribution cycle.
Tests typically include:
Compression testing — simulating the stacking load a package experiences at the bottom of a pallet stack or in warehouse storage. Tests are sustained (not instantaneous) to simulate real storage conditions.
Drop testing — dropping the packaged product from specified heights onto different faces, edges and corners. Products get dropped during handling; packaging needs to absorb the shock and prevent product damage.
Vibration testing — sustained vibration on a test table simulating road or rail transport. Vibration can cause products to work loose from their fixing within packaging, move to the edges of boxes, or in some cases cause fatigue failure in fragile components.
Incline impact — simulating the forces experienced when packages are pushed into each other on conveyors or during sorting operations.
ISTA 2A in Practice
ISTA (International Safe Transit Association) 2A is the default test protocol for most consumer and commercial packaged goods. Most major retailers, Amazon included, require ISTA 2A compliance for packaging that will move through their fulfilment operations.
An ISTA 2A test involves atmospheric conditioning (the package is conditioned at specific temperature and humidity before testing), then a compression test, drop sequence and vibration sequence. The pass condition is no damage to the product and no failure of the primary packaging that would expose the product.
A packaging testing lab can run ISTA 2A for a few hundred pounds for a small shipment of samples. For a new product launch or a significant specification change, this is a modest cost.
When to Test
Test your packaging when:
- You're launching a new product or a new size variant
- You're changing your packaging specification (board grade, carton style, inner packaging)
- You're moving to a new distribution channel (e.g., from own-delivery to a third-party fulfilment centre)
- Your damage claim rate starts rising
- You're being asked by a customer to confirm transit testing compliance
Don't wait for a damage problem to find out your packaging doesn't pass. Testing is a fraction of the cost of a damage claim, let alone the cost of returns, replacements and customer service.
Doing It Yourself vs Using a Lab
Informal transit testing — putting a prototype pack through your own distribution, tracking what happens, looking at the result — is better than nothing and is a sensible first step for any new packaging design.
Formal ISTA or ASTM testing requires calibrated equipment that most businesses don't have. For certification purposes or retailer compliance, you need an accredited test lab.
Several UK labs offer transit packaging testing. PIRA (now Smithers), Intertek and IAPCO-accredited labs are established options. Lead times are usually a few weeks; plan accordingly when you're developing new packaging.