ISO 505:2025

Overview

ISO 505:2025 - "Conveyor belts - Method for the determination of the tear propagation resistance of textile conveyor belts" defines a standardized laboratory method to measure the tear propagation resistance of textile conveyor belts (full thickness or carcass only). It is intended for belts used in installations at risk of longitudinal tearing and provides repeatable procedures for sampling, specimen preparation, tensile testing and reporting.

Key topics and technical requirements

• Test principle: Tensile testing of a prepared initial tear, measuring the force required to propagate the tear at a controlled speed.
• Apparatus: Dynamometric tensile testing machine sized so measured forces fall within the upper 90% of its capacity, adjustable jaw separation speed to (50 ± 10) mm/min, and a free jaw distance of at least 300 mm. A graphical recorder is required to capture tear force over distance.
• Test pieces (sampling & dimensions):
  • Cut from the belt in the longitudinal direction, at least 50 mm from edges.
  • Rectangular specimens, nominal 300 mm length and (100 ± 1) mm width (width may be increased to 300 mm if weft threads pull out).
  • Test both sense A and sense B (two specimens).
  • Covers may be removed by stripping or buffing; special handling when a breaker ply is present.
• Conditioning and atmospheres:
  • Specimens prepared at least 16 h after manufacture; minimum conditioning time 8 h (in practice a 72 h period is specified in case of dispute).
  • Condition according to ISO 18573 using atmospheres D or E (or B/C for light belts and carcass samples). Test atmosphere must match conditioning and be reported.
• Procedure and results:
  • Mount cut ends so inner cut edges are centered in jaws; continue until tear extends at least 100 mm.
  • Analyze multi-peak traces per ISO 6133; the median peak force is reported as the mean tear resistance.
  • Report results for each specimen and the mean of the two.

Applications and users

ISO 505:2025 is used by:

• Conveyor belt manufacturers for quality control and product development.
• Testing laboratories and third-party certifiers performing mechanical property verification.
• OEMs and end-users (mining, bulk handling, ports, quarrying, cement and aggregate industries) assessing suitability of textile belts where longitudinal tearing is a risk.
• R&D teams validating carcass integrity and cover removal effects on tear propagation resistance.

Practical benefits include consistent test data for material selection, design decisions, failure analysis and contractual specifications.

Related standards

• ISO 18573 - Conveyor belts: Test atmospheres and conditioning periods (referenced for specimen conditioning).
• ISO 6133 - Analysis of multi-peak tear resistance traces.
• ISO 21183-1 - Light conveyor belts - principal characteristics and applications (conditioning guidance for light belts).