ISO 16851:2012

Overview

ISO 16851:2012 specifies a reproducible method to determine the net length of an endless (spliced) textile conveyor belt. The procedure applies to all textile construction belts except those containing steel-cord reinforcement and is not suitable for light conveyor belts covered by ISO 21183-1. The standard is intended to support consistent acceptance testing, splicing verification and quality control of conveyor belting.

Key Topics

• Apparatus

  • A calibrated steel tape measure graduated in millimetres is required.

• Preparation and procedure

  • Lay the endless belt flat and free from tension; measurements are taken on the inside (flat) surface only.
  • Mark a start point A on the inside edge. Mark B at a distance determined by belt circumferential length:
    • For belts up to 30 m: each individual measurement is between one quarter and one third of nominal circumference (final segment may be shorter).
    • For belts greater than 30 m: each measurement shall be between 7.5 m and one third of nominal circumference (final segment may be shorter than 7.5 m).
  • Measure sequential segments AB, BC, CD, … until the final segment XA is recorded.
  • In case of dispute, measurements should be taken at a standard atmosphere as specified in ISO 18573.

• Calculation

  • The net endless length l is obtained by summing the consecutive measured segments and deducting the allowance for inside-surface compression:

    l = (AB + BC + CD + ... + XA) - π·d

    where d is the belt thickness and results are expressed in millimetres.

• Test report - the report shall include reference to ISO 16851, belt identification, net length (mm) and measurement date.

Applications

ISO 16851:2012 delivers practical value for:

• Splicing and installation - verify that splice length and belt circumference meet specifications before fitting.
• Quality control and acceptance - standardised net length measurement for supplier/customer agreements.
• Inventory and maintenance planning - accurate length data supports spare-belt stock and refurbishment decisions.

The method improves repeatability of length measurement, reduces disputes, and helps ensure correct belt tracking and equipment compatibility.

Related Standards

• ISO 18573 - test atmospheres and conditioning periods referenced for measurement conditions.
• ISO 14890 - provides tolerances on lengths of endless conveyor belts.
• ISO 21183-1 - covers light conveyor belts (this ISO 16851 procedure is not suitable for those belts).

For procurement, acceptance testing and technical documentation, reference ISO 16851:2012 to ensure consistent, defensible net length measurement of textile endless (spliced) conveyor belts.