Overview
ISO/TR 29944:2010 - "Powered industrial trucks and tractors - Brake performance - Determination of measurement procedures" is an ISO Technical Report that explains how the stopping distance and braking force values used in ISO 6292 are selected and calculated. It documents research and the rationale behind the stopping-distance (SD) and drawbar-drag (DBD) measurement approaches, defines a brake reaction time (BRT) basis, and derives practical formulas for calculating stopping distance and braking force for different truck groups. It does not specify test procedures, control forces or component strength requirements.
Key topics
- Scope and purpose: Clarifies how SD and DBD values in ISO 6292:2008 were determined and why stopping-distance measurement was introduced alongside drawbar drag.
- Brake reaction time (BRT): Uses a BRT basis of 0.54 s (excluding human reaction time) as the input for stopping-distance formulas.
- Stopping-distance decomposition: Defines stopping distance (s0) as the sum of brake reaction distance (sr) and braking distance (sb).
- Brake reaction distance formula: sr = 0.15·v (v in km/h).
- Braking distance formulas are derived from mean deceleration values and vary by velocity range and truck group (A1, A2, B, and revised values for Group C).
- Mean deceleration and braking force: Relates braking capacity C (percentage of g) to deceleration (a) and braking force F = m·a, enabling conversion between deceleration requirements and drawbar drag forces.
- Group-specific treatment: Maintains mean deceleration values for Groups A1/A2/B from ISO 6292:1996, introduces adjusted deceleration principles for Group C where previous standards were incompatible.
- Research basis: Summarizes measurement data from multiple countries and truck families (electric, IC, reach trucks, order pickers), and discusses safety considerations (limiting max deceleration to avoid load loss/instability).
Applications and who uses it
- Equipment designers and OEMs - to calculate required braking performance and specify control‑system behavior consistent with ISO 6292.
- Test laboratories and compliance engineers - for interpreting stopping-distance and braking‑force criteria when applying ISO 6292.
- Fleet safety managers and ergonomics/safety specialists - to evaluate stopping performance and set safe operating parameters.
- Standards committees and regulatory bodies - to understand the technical basis for braking performance criteria and to harmonize methods (SD vs DBD).
Related standards
- ISO 6292:2008 - Brake performance and component strength (values and measurement methods).
- ISO 611 - Vocabulary and timing definitions for braking.
- ANSI/ITSDF B56.1 and regional regulations (e.g., EU Directive 71/320/EEC) - referenced for comparison and historical context.
Keywords: ISO/TR 29944:2010, powered industrial trucks, brake performance, stopping distance, brake reaction time, drawbar drag, ISO 6292, braking force, mean deceleration.
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