Overview
EN ISO 16851:2013 (ISO 16851:2012) specifies a standard method for determining the net length of an endless (spliced) textile conveyor belt. It applies to all textile construction conveyor belting except belts containing steel cord reinforcement and is not valid for light conveyor belts covered by ISO 21183‑1. The method yields the true inside length in millimetres and is intended for manufacturers, testers and purchasers concerned with accurate belt measurement and quality assurance.
Key Topics and Requirements
- Apparatus
- Calibrated steel tape measure graduated in millimetres (inspection or calibration required).
- Preparation
- Lay the endless belt flat and free from tension. Use the flat part of the belt only for measurements.
- Measurement procedure
- Mark a start point A on the inside surface edge.
- Mark a second point B along the flat part. For individual segment lengths:
- For belts ≤ 30 m circumferential length: each measurement between 1/4 and 1/3 of the nominal circumference (final segment may be shorter).
- For belts > 30 m: each measurement between 7.5 m and 1/3 of the nominal circumference (final segment may be shorter than 7.5 m).
- Rotate the belt and take consecutive measurements AB, BC, CD … until the final segment XA.
- Measurements should be made at an agreed test atmosphere (see ISO 18573) in case of dispute.
- Calculation
- Net endless length l_e = (AB + BC + CD + … + XA) − π·d
- d = belt thickness. Subtracting π·d accounts for inside-surface compression; the flat measurements are along the neutral axis.
- Express results in millimetres.
- Test report must include
- Reference to ISO 16851, belt identification, net length (mm), and measurement date.
- Notes
- Length tolerances are specified in ISO 14890.
Applications and Users
- Practical for: conveyor belt manufacturers, quality-control and testing laboratories, procurement teams, site installers, maintenance teams and contractual inspectors.
- Typical uses: verifying delivered belt length, dispute resolution between supplier and customer, production quality checks, and acceptance testing for spliced endless belts.
- Keywords: textile conveyor belts, net length measurement, endless (spliced) conveyor belt, belt measurement procedure, conveyor belt testing.
Related Standards
- ISO 14890 - tolerances and specification for general-use rubber/plastics-covered textile conveyor belts.
- ISO 18573 - test atmospheres and conditioning periods for conveyor belt measurements.
- ISO 21183‑1 - defines light conveyor belts (method not applicable to such belts).
