FABRIC CONVEYOR BELTS

How to Read a Fabric Belt Designation

A fabric-belt designation gives a practical starting point for a quotation: carcass material, tensile class, ply count, cover thickness and cover notation. Confirm the standard edition, test method and any project-specific requirements in the purchase specification, because ISO and DIN notation is not interchangeable by name alone. The example below decodes EP 500/4 6+2 Y as a format, not as a universal selection rule.

EP

Carcass fabric typeEP means a polyester warp running lengthwise and a polyamide/nylon weft running crosswise. NN uses nylon in both directions. In comparable constructions, EP commonly has lower lengthwise elongation while NN can offer greater elasticity. Take-up travel, impact behaviour and troughability must be checked against the actual construction and conveyor geometry.

500

Full-belt tensile strength (N/mm)The rated breaking strength per millimetre of belt width, measured across all plies together — not per ply. An EP 500 belt at 800 mm width therefore has a total rated breaking strength of 400 kN. That rating is not the allowable working tension: the final design must account for the conveyor calculation, splice method, safety factor and the applicable project standard.

/4

Number of fabric pliesFour fabric layers bonded together with rubber skim coats. More plies can raise bending stiffness, which affects minimum pulley diameter and transition length. At an equal tensile class, fewer plies of stronger fabric can reduce stiffness, but the choice still depends on available pulley geometry, loading conditions and the supplier's construction data.

6+2

Cover thickness, top + bottom (mm)A 6 mm top cover and a 2 mm bottom cover. The top cover faces the material and carries most impact and abrasion; the bottom cover runs over idlers and pulleys. Select both values from the material abrasiveness, maximum lump size, drop height, support arrangement and minimum pulley diameter rather than using one cover ratio for every duty.

Cover grade

Cover grade (DIN 22102)Y, W, X and G labels are commonly encountered in DIN-style documents, while ISO-style documentation can use different cover-class notation. State the required abrasion, oil, temperature or flame behaviour together with the applicable test method and acceptance criterion; do not select a cover only from a letter printed on an old belt.

ISO 14890 is a useful reference for textile construction conveyor belts, but the order should state the applicable edition, cover test method and required result.

Use the official ISO 14890 standard record alongside the project specification.

Continue Your Belt Selection

Use these references to compare construction options, decode an existing belt and prepare a replacement enquiry. They support, but do not replace, a review of the conveyor's calculated tensions and operating conditions.

Common Specification Mistakes

Four errors appear repeatedly in fabric belt enquiries; each one either shortens belt life or inflates cost with no operational benefit in return.

• Specifying tensile class without declaring the splice method

  The safety factor — and therefore the tensile class — depends directly on how the belt will be joined. A design based on a vulcanised splice should not be changed to mechanical fasteners without recalculating the applicable requirements. Declare the splice method first, then select the belt around it.

• Over-specifying ply count instead of upgrading tensile class

  More plies can increase bending stiffness, pulley-diameter requirements, transition length and belt mass. A stronger fabric with fewer plies may be suitable in some cases, but it must be checked against the actual pulley geometry, troughing requirement and available construction data.

• Choosing cover grade on price rather than material abrasiveness

  Cover grade is dictated by the material, loading point and required test performance, not by the unit price line on the quotation. Define the abrasion, cut, oil, heat or flame requirement and the acceptance test before comparing supplier proposals.

• Ignoring transition distance at the terminal pulleys

  As the troughed profile flattens approaching a pulley, the belt edges travel a longer path than the centre and can pick up additional tension. A transition that is too short can contribute to edge cracking and splice fatigue. Check transition geometry at both the drive and tail pulley against the selected construction and project requirements.

FREQUENTLY ASKED QUESTIONS