Under EN 12195-2, all complete lashing assemblies are engineered to a strict 2:1 safety ratio between their rated Lashing Capacity (LC) and their Minimum Breaking Strength (MBS). For the raw woven webbing alone, the standard requires an even higher margin (MBS ≥ 3 × LC) to account for long-term friction and flexural fatigue.
Woven from 100% high-tenacity continuous multifilament polyester (PES) yarn, the webbing exhibits working elongation ≤ 7% at full LC. This ensures the tension applied at departure holds firm without slackening under dynamic road vibrations.
SHF (Standard Hand Force = 50 daN): The manual pulling effort exerted on the handle (≈ 50 kg).
STF (Standard Tension Force): The residual downward tension locked into the strap. A higher STF rating (e.g., 500 daN) enables fewer total straps to satisfy legal hold-down requirements.
EN 12195-2 mandates a blue label for polyester (PES). The label must explicitly state the manufacturer, standard, LC, STF, SHF, elongation percentage, production year, and serial traceability batch number on both the fixed and loose ends.
The table below outlines technical parameters across standard EN 12195-2 compliant commercial ratchet tie-down systems:
| Technical Model Code | Webbing Width (mm) | Lashing Capacity (LC) - Straight | Lashing Capacity (LC) - Loop | STF (daN) | MBS (daN) | Fixed End Length (m) | Application Scope |
|---|---|---|---|---|---|---|---|
| RTD-25-08 | 25 | 400 daN (0.4 t) | 800 daN (0.8 t) | 100 | 800 | 0.3 | Light van cargo, internal box tracks |
| RTD-35-20 | 35 | 1,000 daN (1.0 t) | 2,000 daN (2.0 t) | 175 | 2,000 | 0.5 | Medium rigid trucks, pallet freight |
| RTD-50-40 | 50 | 2,000 daN (2.0 t) | 4,000 daN (4.0 t) | 350 | 4,000 | 0.5 | General EU flatbeds, steel, timber |
| RTD-50-50 | 50 | 2,500 daN (2.5 t) | 5,000 daN (5.0 t) | 500 (Ergo) | 5,000 | 0.5 | Heavy machinery, export steel coils |
| RTD-75-100 | 75 | 5,000 daN (5.0 t) | 10,000 daN (10.0 t) | 750 | 10,000 | 0.8 | Heavy civil plant, oversized transport |
The ratchet handle has a direct effect on how much tension (STF) the strap actually delivers to the load:
| Ratchet Handle Type | Operation Motion | Typical STF Value | Best Application |
|---|---|---|---|
| Standard (Short Handle) | Push UP to tension | ≈ 300 - 350 daN | General cargo where extreme downward tension isn't critical; cost-effective. |
| Ergo (Long Handle) | Pull DOWN to tension | 500+ daN | High-tension jobs; provides greater leverage with significantly less back strain. |
Selecting the correct restraint layout is the core calculation governed by EN 12195-1. Riggers and drivers deploy ratchet straps in two fundamentally distinct engineering modes:
In frictional lashing, the strap passes over the top of the load to apply a downward vertical clamping force (FV), increasing friction between the load base and trailer deck to prevent sliding. The formula relies heavily on the tension force (STF):
Ffriction = μ × (m × g + n × STF × sin α) ≥ 0.8 × m × g
Where μ is the friction factor (using anti-slip rubber mats increases μ to ≥ 0.6). The vertical lashing angle α must be maintained as close to 90° as possible. If α < 30°, frictional efficiency collapses.
[ TOP-OVER RATCHET STRAP ]
|
Residual Tension (S_TF)
|
v
+-------------------------------+
| |
| COMMERCIAL CARGO LOAD | ====> Inertia (0.8g)
| Payload Mass (m) | Forward Brake
| |
+-------------------------------+
|
==============v===============================
Deck Friction: F_f = μ · (m·g + 2·S_TF·sin α)
In direct lashing, straps hook directly into dedicated lashing lugs on the machine and trailer chassis. Here, restraint capacity is governed directly by the Lashing Capacity (LC) rather than STF:
Frestraint = LC × cos(α) × cos(β)
Where α is the vertical angle and β is the horizontal angle. Direct lashing provides positive physical retention, making it the required method for heavy tracked excavators, heavy castings, and slick oily machinery.
Under EN 12195-2, VDI 2700, and European Road Transport Enforcement inspections, straps must be inspected prior to every haul:
| Lashing Component Vector | Code Discard Maximum Threshold Parameters | Required Field Corrective Action |
|---|---|---|
| Webbing Transverse Edge Tears | Any edge cut, slit, or tear exceeding 10% of total webbing width. | CUT AND DESTROY STRAP ASSEMBLY IMMEDIATELY |
| Missing / Illegible Blue Label | The permanent blue specification tag is missing, torn off, or completely illegible. | CONDEMN ASSEMBLY (Considered unrated by transport police) |
| End Hook Throat Deformation | Double J-hook or claw hook throat opening permanently widened by more than 5%. | Scrap the affected end; replace with certified hook fitting. |
| Ratchet Drive Pawl Binding | Sprocket teeth rounded, chassis frame twisted, or handle spring pawls sticking. | Scrap the ratchet buckle; do not hammer straight. |
| Friction / Chemical Fusion | Glazed, stiff, melted, or chemically charred areas on the polyester weave. | Retire strap from service; chemical or heat attack degrades core fibers. |
Calculate the restraint force first, using EN 12195-1. Then choose a webbing width and handle type whose LC and STF cover that force with margin. Use Ergo ratchets where high tension or operator comfort matters, and match the end fitting to the anchor points on your trucks.
For international operations moving cargo by road, rail, or sea, correctly specified tie-down equipment is a direct line item in regulatory compliance. A clear, legible blue label is your proof of EN 12195-2 compliance — reject any strap that doesn't have one.
