Overview
ISO 251:2012 - "Conveyor belts with textile carcass - Widths and lengths" is an international standard that specifies nominal widths and permissible tolerances for textile‑carcass conveyor belts. It also defines tolerances on belt lengths measured without tension and clarifies that belt lengths themselves are not standardized. This edition (4th, 2012) replaces ISO 251:2003.
Key topics and technical requirements
- Nominal widths and width tolerances for open (cut‑edge) textile carcass conveyor belts are specified in a list of standard sizes. Examples include:
- 300 mm ±5 mm
- 400 mm ±5 mm
- 500 mm ±5 mm
- 600 mm ±6 mm
- 800 mm ±8 mm
- 1000 mm ±10 mm
- 1600 mm ±16 mm
- 2000 mm ±20 mm
- 3000 mm ±30 mm
- 3200 mm ±32 mm
(Full nominal width table and tolerances are given in the standard.)
- Length tolerances (measured without tension) are given for belts without ends (endless belts) by length ranges:
- ≤ 15 m: ±50 mm
-
15 m but ≤20 m: ±75 mm
-
20 m: ±0.5% of the belt length in metres
- Open belt length tolerances (for belts supplied as open lengths or in multiple lengths) are addressed in a separate table; tolerances depend on the delivery mode (single length or multiple lengths). Refer to ISO 251:2012 for the full treatment and exact allowable deviations.
- Scope exclusions: The standard does not apply to light conveyor belts covered by ISO 21183‑1; tolerances for some light cut‑edge belts are given in ISO 15147.
Practical applications
- Procurement and specification: Use ISO 251:2012 to define acceptable belt widths and length tolerances in purchase orders and technical specifications.
- Manufacturing and quality control: Belt manufacturers apply the nominal widths and tolerance limits during production, cutting and inspection.
- Installation and maintenance: Installers and maintenance teams use the tolerances to assess acceptance, splicing accuracy and replacement suitability.
- Conveyor system design: Engineers incorporate standardized widths and realistic length tolerances when designing belt paths, pulley widths and splicing procedures.
Who uses this standard
- Conveyor belt manufacturers
- OEMs and system integrators
- Procurement and quality assurance teams
- Mechanical and materials engineers in bulk handling, mining, logistics and manufacturing sectors
- Inspection and testing laboratories
Related standards
- ISO 21183‑1 - Light conveyor belts: characteristics and main applications
- ISO 15147 - Tolerances on widths and lengths for certain light cut‑edge conveyor belts
Keywords: ISO 251:2012, conveyor belts with textile carcass, widths and lengths, nominal widths, length tolerances, conveyor belt standards, belt manufacturing, belt procurement.
