The letters at the start of a belt designation name the fabric in the carcass: the first letter is the warp (the threads along the belt, which carry the tension), the second is the weft (across the belt, which gives troughability and impact resistance). E is polyester, P is polyamide (nylon), N is nylon in the older notation.
The fabric decides how much the belt stretches, how it troughs, how it takes impact and how it behaves wet.
EP: polyester warp, nylon weft
EP (Polyester-Nylon). The most widely used conveyor belt fabric. Polyester warp gives low elongation along the belt, so take-up travel stays short. Nylon weft is flexible across the belt, so it troughs well in 30° to 45° idlers and absorbs impact at the loading point.
EE: polyester warp and weft
EE (Polyester-Polyester). Polyester both ways makes the carcass stiffer across the width and very stable in length and in wet conditions. It suits long centre conveyors, flat belts and wet duties where dimensional stability matters more than deep troughing.
NN: nylon warp and weft
Nylon both ways stretches more than polyester, so it needs more take-up travel, but it is tough under impact and flexible. It suits short conveyors with heavy loading and frequent starts. Most modern specifications have moved to EP for the lower stretch.
Side by side
| EP | EE | NN | |
|---|---|---|---|
| Warp (along the belt) | Polyester | Polyester | Nylon |
| Weft (across the belt) | Nylon | Polyester | Nylon |
| Elongation | Low | Low | Higher |
| Troughability | Very good | Fair | Very good |
| Impact resistance | Good | Fair | Very good |
| Wet stability | Good | Very good | Fair |
| Typical use | Most bulk conveyors | Long and flat conveyors, wet duty | Short, heavily loaded conveyors |
The reinforcement fabric chart
A fabric is named by its strength per ply in N/mm: EP 200 is one ply of polyester-nylon rated 200 N/mm. Plies × ply strength gives the belt rating, so four plies of EP 200 make an 800 kN/m belt (EP 800/4).
| Fabric | Strength per ply | Gauge per ply | Weight per ply | Belt ratings it builds |
|---|---|---|---|---|
| EP/EE 100 | 100 N/mm | 0.95 mm | 1.05 kg/m² | 200/2 · 300/3 · 400/4 · 500/5 |
| EP/EE 125 | 125 N/mm | 1.05 mm | 1.20 kg/m² | 250/2 · 500/4 · 630/5 |
| EP/EE 160 | 160 N/mm | 1.15 mm | 1.35 kg/m² | 315/2 · 500/3 · 630/4 · 800/5 |
| EP/EE 200 | 200 N/mm | 1.30 mm | 1.50 kg/m² | 400/2 · 630/3 · 800/4 · 1000/5 |
| EP/EE 250 | 250 N/mm | 1.50 mm | 1.70 kg/m² | 500/2 · 800/3 · 1000/4 · 1250/5 |
| EP/EE 315 | 315 N/mm | 1.70 mm | 1.95 kg/m² | 630/2 · 1000/3 · 1250/4 |
| EP/EE 400 | 400 N/mm | 1.95 mm | 2.25 kg/m² | 800/2 · 1250/3 |
| NN 100 | 100 N/mm | 0.90 mm | 1.00 kg/m² | 200/2 · 300/3 · 400/4 |
| NN 160 | 160 N/mm | 1.10 mm | 1.30 kg/m² | 315/2 · 500/3 · 630/4 |
| NN 200 | 200 N/mm | 1.25 mm | 1.45 kg/m² | 400/2 · 630/3 · 800/4 |
Questions
What does EP mean in a conveyor belt?
EP means the carcass fabric has a polyester (E) warp and a polyamide or nylon (P) weft. It is the most common conveyor belt fabric because it combines low stretch with good troughing.
Is EP better than NN?
For most conveyors, yes: EP stretches less, so it needs less take-up travel and holds its length. NN is tougher under impact and suits short conveyors with heavy loading.
What does EP 800/4 mean?
An EP fabric belt rated 800 kN/m breaking strength per metre of width, built with 4 plies (here 4 × EP 200).
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