Load restraint, explained
The performance standards every load must meet, how tie-down and direct restraint work, friction, pre-tension, and a worked example of how many straps a pallet load needs.
The short answer
Every load must be held against 0.8 g forward and 0.5 g backward and sideways. With tie-down lashings, friction does most of the work: 12,000 kg of pallets on a steel deck needs 10 straps of 50 mm webbing, or 3 when blocked against a headboard.
The performance standards
Braking hard pushes a load forward with up to 0.8 of its weight; cornering and reversing push it sideways and back with 0.5. The restraint system has to hold those forces without the load moving enough to make the vehicle unstable or unsafe.
Friction does most of the work
| Friction | Coefficient | Example |
|---|---|---|
| High | 0.60 | Rusty steel on timber, smooth steel on rubber load mat |
| Medium | 0.40 | Smooth steel on timber (e.g. timber pallets on a steel deck) |
| Low | 0.25 | Smooth steel on smooth steel |
| Very low | 0.20 | Plastic on plastic, wet or greasy surfaces |
Lower friction means more lashings. A rubber load mat moves a load from medium to high friction and can cut the number of straps needed.
Pre-tension and angle
Each lashing clamps the load with its pre-tension, not its rated strength. A 50 mm strap with a pull-down ratchet averages about 600 kgf. The steeper the lashing, the more of that tension presses down: at 30° only half of it does.
Direct restraint for machinery
Heavy machines are chained at their tie-down points so the chains take the forces directly. Each direction needs enough chain capacity once the angle of each chain is allowed for; the DepotOps calculator does this for a four-chain pattern and suggests the smallest chain grade that works.
Common questions
What are the load restraint performance standards?
A load must be restrained against 0.8 g forward, 0.5 g rearward and sideways, and 0.2 g vertically (for loads not fixed by other means).
How many straps do I need?
It depends on the load weight, the friction between load and deck, the strap pre-tension and the angle. For example, 12,000 kg on timber pallets over a steel deck with 50 mm webbing and pull-down ratchets needs 10 straps with no headboard, or 3 when blocked against a rated headboard.
What is the difference between tie-down and direct restraint?
Tie-down presses the load onto the deck so friction holds it. Direct restraint holds the load with the lashings themselves, like chaining a machine at its tie-down points.
Sources
- NTC Load Restraint Guide 2018 — checked 2026-09-29
A guide, not legal advice. Your permit, notice, registration or accreditation can set different limits; check them before you rely on a figure here.