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How Much Load Containment Force Do You Actually Need? (ASTM D4169 Explained)

Most operations judge a wrap by how much film is on the pallet. The number that actually matters is containment force, and it's measurable, targetable, and often not what people assume.

Houston Stretch Wrappers · Insights

Published September 24, 2026

The takeaway

Containment force, the inward holding force the film applies to a load, measured in pounds-force with a handheld gauge, is what keeps a pallet stable, not the amount of film on it. Stable loads generally need less containment than unstable or top-heavy ones, and the number comes mostly from pre-stretch percentage and wrap pattern, not from adding more wraps. Past the right target, extra film is cost with no added safety.

Ask most dock crews how they know a pallet is wrapped tight enough and the answer is usually a look, or a squeeze. It's a reasonable instinct, but it isn't a measurement, and it's the reason so many pallets are either over-wrapped, burning film for no benefit, or under-wrapped and one bad turn away from a claim. There's an actual, testable answer to how much holding force a load needs, and it comes from a framework built around ASTM D4169, the standard that governs performance testing for shipping containers and systems.

What containment force actually means

Containment force is the inward holding force that stretched film applies against a load. It's what physically resists the load shifting, leaning, or coming apart as the pallet rides through a trailer, gets forked on and off a truck, and absorbs the vibration of a Houston freeway. It's expressed in pounds-force (lbf), and it comes from two things: how far the film is stretched before it reaches the load, and how many layers overlap at any given point on the pallet. Neither of those is the same thing as how much film, by weight or footage, ends up on the load.

How containment force is measured

Containment force is checked with a handheld force gauge pressed flat against the wrapped film. The gauge reads the force in pounds at that specific spot, and because containment can vary by height on a pallet, the standard practice is to test at the base, mid-height, and top, not just wherever is easiest to reach. A load that reads strong at the middle but weak at the top has a real weak point, one that a single measurement would miss entirely. If you're evaluating your own wrap quality, testing at all three heights is the only way to know what you actually have.

Typical target ranges by load type

There's no single containment number that applies to every pallet, because the right target depends on what's being shipped and how it's stacked.

  • Stable, uniform loads, boxed goods on a square, even footprint, generally need the least containment force. The load's own geometry does a lot of the work; the film mainly has to keep it from separating.
  • Unstable, irregular, or top-heavy loads, mixed cartons, uneven stacking, or a load with a narrow base and wide top, need meaningfully more containment, in some cases close to double a stable load's target, because there's less inherent structure holding the stack together.
  • Food and beverage loads often run tighter, more consistent targets across the board, both because product and case integrity are sensitive to any looseness and because many food shippers apply their own internal wrap standards on top of general practice. See our food and beverage packaging page for how that plays out in practice.

The practical takeaway is that "wrap it tighter" isn't a strategy. Knowing what your specific load type needs, and testing to confirm you're hitting it, is.

Containment force isn't about how much film is on the load. It's about how far that film was stretched before it got there, and how it's distributed across the pallet.

How pre-stretch and wrap pattern drive the number

Pre-stretch percentage, how far the film is elongated by the machine's rollers before it touches the load, is the single biggest lever on containment force. Film that's properly pre-stretched grips the load with real tension and recovers slightly, cinching down over time. Film applied with little or no stretch, the way most hand-wrapping goes on, has almost none of that holding power no matter how many times you walk it around the pallet. Wrap pattern matters too: consistent overlap, and deliberate reinforcement at the base and top where loads are most likely to fail, does more for containment than simply adding wraps in the middle where the load is already stable. Our stretch film pages cover gauge and pre-stretch specs by film type if you're comparing what's on your line now against what a given load calls for.

Why over-wrapping doesn't add safety

Once a load hits its target containment force, additional wraps stop adding meaningful holding power. The film is already doing its job; extra layers are largely just extra film, extra cost, and extra weight and bulk on the pallet without a corresponding gain in stability. This is the flip side of the under-wrapping problem, and it's just as common: a well-meaning operator, unsure what "enough" looks like, defaults to wrapping more, and the operation pays for it in film cost every single day without the loads actually being any safer. A machine set to the right pre-stretch and wrap count for your load type gets you to target containment without the guesswork, in either direction.

Getting your own loads dialed in

  • Test containment at base, middle, and top on a sample of current pallets to see where you actually stand.
  • Separate your load types, stable versus unstable, and don't wrap them the same way by default.
  • Check your machine's pre-stretch setting against what your film and load type call for, rather than relying on wrap count alone.

For more on getting wrap patterns and film choice right for your specific loads, see our pallet wrapping best practices guide. And if you want a second set of eyes on whether your current setup is over- or under-wrapping, send us a photo of a typical load and we'll tell you straight, at the best price in the market either way.

Answers

Common questions

What is containment force in stretch wrapping?
Containment force is the amount of inward holding force the stretched film applies to a load, usually expressed in pounds-force (lbf). It's what actually keeps boxes from shifting, leaning, or separating in transit. Containment force comes from how far the film is stretched and how many wraps overlap a given point on the load, not from how much film is physically on the pallet.
How is containment force measured?
Containment force is measured with a handheld force gauge pressed against the wrapped film at various heights on the load, giving a reading in pounds-force at each point. Testing is typically done at the base, middle, and top of the pallet, since containment often varies by height, and the goal is to confirm the load meets a target range everywhere, not just at one convenient spot.
What containment force do most pallets need?
Stable, uniform loads like boxed goods on a square footprint typically need lower containment, often in a range where the load holds together without excessive force. Unstable, irregular, or top-heavy loads need more, sometimes close to double, to keep them from shifting. Food and beverage loads often carry tighter, more consistent targets because of how sensitive product packaging and stacking can be to loose film. There's no single number that fits every load, which is why testing your own pallets matters more than following a generic figure.
Does adding more wraps of film increase containment force?
Only up to a point, and less efficiently than most people assume. Containment force comes primarily from how much the film is pre-stretched before it touches the load, not from stacking on extra wraps. Once a load has adequate overlap and wrap count, adding more film increases cost and waste without meaningfully increasing containment. Getting pre-stretch percentage and wrap pattern right matters far more than adding rolls.