Choosing a conveyor belt comes down to five decisions, made in order: what the belt carries, which rubber cover survives it, how strong the carcass must be, how many plies the pulleys allow, and how thick the covers should be. Get those five right and the belt lasts; get one wrong and it fails early, usually at the cover or the splice.
This guide walks through each decision the way our engineers do when a customer sends us a conveyor. It uses the designation system of IS 1891 and DIN 22102, so the result is a belt you can name exactly on a purchase order, for example EP 630/4 6+2 X.
1. Start with the material
The material decides the cover grade. Note four things: what it is, its largest lump size, its temperature at the loading point, and whether it carries oil, grease or chemicals. Also note whether the conveyor runs underground or in an area where fire codes apply.
Sand, coal, grain, fertiliser and general aggregate are ordinary duties. Granite, ore, slag, crushed stone and sinter are abrasive and sharp. Clinker, hot sinter and foundry returns are hot. Oil seeds, wood chips and some chemicals are oily. Sugar, grain and packed food may need a food grade cover.
2. Pick the cover grade
Each grade is a rubber compound built to resist one kind of damage. The table shows the grades we build, with their names in both standards so a tender written to either reads straight across.
| Grade | Type | IS 1891 | DIN 22102 | Tensile, min | Elongation, min | Abrasion, max | Temperature |
|---|---|---|---|---|---|---|---|
| Y | General purpose | IS 1891 N17 | DIN-Y | 17 MPa | 400% | ≤ 200 mm³ | – |
| X | High abrasion | IS 1891 M24 | DIN-X | 24 MPa | 450% | ≤ 150 mm³ | – |
| W | Super abrasion | - | DIN-W | 18 MPa | 400% | ≤ 90 mm³ | – |
| T1 | Heat resistant T1 | IS 1891 Pt 2 HR | DIN-T | – | – | – | up to 100°C |
| T2 | Heat resistant T2 | IS 1891 Pt 2 HR | DIN-T | – | – | – | up to 125°C |
| T3 | Super heat resistant T3 | IS 1891 Pt 2 SHR | DIN-T | – | – | – | up to 150°C |
| G | Oil resistant | IS 1891 Pt 4 OR | DIN-G | – | – | – | – |
| FR | Fire resistant antistatic | IS 1891 Pt 5 | DIN-S/K | – | – | – | – |
| FG | Food grade | - | White FDA type | – | – | – | – |
3. Work out the rating (strength)
The rating is the belt’s breaking strength per metre of width, in kN/m. It comes from the belt tension at the drive. Effective tension is the force needed to lift the load, move it and overcome friction in the idlers. The tight side tension is larger again, because the drive pulley needs slack side tension to grip.
Divide the tight side tension by the belt width to get the working tension per millimetre, then multiply by a safety factor, usually 8 to 10 for textile belts with hot vulcanised splices, to allow for splices, starting surges and ageing. Round up to the next standard rating.
The standard ratings we build are 200 kN/m (2 plies), 250 kN/m (2 or 3 plies), 315 kN/m (2 or 3 plies), 400 kN/m (3 or 4 plies), 500 kN/m (3 or 4 plies), 630 kN/m (3 or 4 plies), 800 kN/m (4 or 5 plies), 1000 kN/m (4 or 5 plies, on order), 1250 kN/m (5 or 6 plies, on order).
4. Choose the number of plies
The same rating can be built with different numbers of plies. More plies make a thicker, stiffer belt that resists impact and holds mechanical fasteners better. Fewer plies make a lighter belt that bends round smaller pulleys and troughs more deeply.
The smallest pulley on the conveyor often decides it: a thick, many-ply carcass on a small pulley suffers ply separation. The pulley calculator gives the minimum pulley diameter for each build.
5. Set the cover thickness
The top cover takes the wear, so its thickness follows how abrasive the material is, how big the lumps are, how far they fall at loading, and how often a given piece of belt passes the loading point. A short conveyor running fast wears its cover faster than a long one at the same tonnage.
As a starting point: light duty 3+1.5 mm, general mining and quarrying 5+2 or 6+2 mm, heavy lumps and hot clinker 8+3 mm and up. The cover pairs we build are 1.5+1.5, 2+1, 3+1.5, 4+2, 5+2, 6+2, 6+3, 8+2, 8+3, 10+3 mm.
Putting it together: reading the designation
The five decisions give the designation. EP 630/4 6+2 X means EP (polyester warp, nylon weft) fabric, 630 kN/m rating, 4 plies, a 6 mm top cover and 2 mm bottom cover, in X grade (high abrasion, IS 1891 M24 equivalent).
Add the width and the length and you have a complete order: for example, EP 630/4 6+2 X, 1000 mm wide, 250 m, hot vulcanised endless.
Questions
What is the most common conveyor belt?
For general bulk handling in India, an EP fabric belt in general purpose (IS 1891 N17 / DIN-Y) or high abrasion (M24 / DIN-X) grade, 400 to 800 kN/m, in 3 or 4 plies, with 5+2 or 6+2 mm covers, covers most duties.
What safety factor is used for conveyor belts?
For textile belts with hot vulcanised splices, a safety factor of 8 to 10 on the running tension is usual. Belts with mechanical fasteners or frequent heavy starts need more.
Can a manufacturer select the belt for me?
Yes. Send the conveyor length, lift, width, speed, capacity and the material, and our engineers select the rating, plies, covers and grade and reply with a datasheet.
Need the belt chosen for you?
Send your conveyor, our engineers select the belt
Length, lift, width, speed, capacity and the material. We reply with the rating, covers and grade, a datasheet and a quotation, usually the same working day.