Overview
ISO/TR 29846:2008 - Tyres, valves and tubes - kPa/psi equivalencies for inflation pressures - is an informative ISO Technical Report that assigns specific kilopascal (kPa) values to whole pound-per-square-inch (psi) increments from 1 psi to 152 psi. Prepared by ISO/TC 31 (Tyres, rims and valves), this report provides standardized kPa equivalents intended for future applications in regions that continue to use psi for tyre inflation pressure. The document is informative (a Technical Report), not a prescriptive International Standard, and explicitly does not apply to past practices.
Key Topics
- Assigned equivalency table: a comprehensive table mapping whole psi values (1–152 psi) to assigned kPa values for tire inflation pressures.
- Unit harmonization: supports consistency between SI units (kPa/bar) used by ISO and customary units (psi) used in some countries.
- Scope and limitations: intended for future application in the tyre industry and related fields; not retroactive.
- Industry context: published by ISO/TC 31 to promote global standardization in tyre inflation pressure reporting and labelling.
- Informative nature: the report is a Technical Report - informative guidance rather than a mandatory standard.
Applications
ISO/TR 29846:2008 is practical for organizations and professionals who need consistent kPa/psi equivalents for documentation, labelling and operational use:
- Tyre manufacturers and designers - for printing vehicle and tyre pressure labels, technical datasheets and manuals.
- Vehicle OEMs and aftermarket suppliers - to harmonize pressure information across markets that use psi or kPa.
- Service centers and fleet maintenance - for maintenance protocols, PSI-to-kPa reference and training materials.
- Regulators and standards bodies - when drafting regional guidance or aligning national requirements with international practice.
- Valve and tube manufacturers, retailers - for product marking and user instructions that reference inflation pressure.
- Technical writers and translators - to ensure correct unit equivalencies in multilingual documentation.
Related Standards
- ISO/TC 31 outputs typically reference SI units (kPa, bar) for tyre inflation pressure; this Technical Report complements those outputs where psi remains in use.
- Use ISO/TR 29846 alongside ISO tyre, rim and valve standards to ensure consistent unit presentation.
Keywords: ISO/TR 29846, kPa/psi equivalency, tyre inflation pressure, psi to kPa conversion, tyre standards, tyres valves tubes.