Conveyor belt tensile rating calculator
Preliminary minimum belt rating in N/mm from maximum belt tension, belt width, safety factor and splice efficiency.
Result
How it works
A belt must carry the maximum working tension with an adequate safety factor, and the splice is usually its weakest point. Dividing the maximum tension by the belt width gives the working tension per millimetre of width.
Multiplying by the approved safety factor and dividing by the splice efficiency gives a preliminary minimum nominal rating to compare with standard belt ratings (for example EP 315, EP 400, EP 500).
Formula
S,min = Tmax × 1000 × SF / (B × η,splice) Tmax in kN, B in mm → S,min in N/mm
| Symbol | Meaning | Unit |
|---|---|---|
| S,min | Preliminary minimum nominal belt rating | N/mm |
| Tmax | Maximum belt tension (normally at start-up or at the drive) | kN |
| B | Belt width | mm |
| SF | Approved safety factor | — |
| η,splice | Verified splice efficiency, 0–1 | — |
Worked example
Inputs: Maximum belt tension Tmax = 50 kN; Belt width B = 1200 mm; Approved safety factor SF = 10 ratio; Splice efficiency η = 0.9 0–1.
- Working tension per mm = 50 × 1000 / 1200 = 41.67 N/mm
- S,min = 41.67 × 10 / 0.9 = 463.0 N/mm
- Then select the next standard rating at or above this value, subject to the supplier’s and the standard’s requirements.
Assumptions and limits
- Use the maximum belt tension, including start-up, not the running effective tension.
- The safety factor and splice efficiency must come from your design standard, the belt manufacturer or your site specification. This tool has no built-in values.
- This is a preliminary minimum, not a complete belt specification: carcass type, ply count, minimum pulley diameters, troughability and load support also need checking.
Screening estimate, not a design approval. Verify measured inputs, current standards, manufacturer limits and site procedures before purchasing, cutting or installation. Isolate and lock out equipment before any hands-on measurement.
Questions
Can I use the effective tension Te here?
No. Use the maximum belt tension (usually T1 at start-up), which is higher than the running Te.
What about minimum pulley diameter?
A higher rating often needs larger pulleys. Check the manufacturer’s minimum pulley diameters for the selected belt.
Source notes
- Tension-per-width with safety factor and splice efficiency. Required factors are set by the applicable standard (e.g. DIN 22101) or the belt manufacturer.
Related calculators
More: Belt roll length · Conveyor belt length · Belt sag · Pulley speed (rpm) · Conveyor capacity · Te & belt tensions · Belt cover wear · Spare reorder point
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