ISO 6743-1:2002

Overview

ISO 6743-1:2002 defines the classification system for Family A (Total loss systems) within Class L - Lubricants, industrial oils and related products. It establishes a coding scheme and product categories for lubricants intended for total-loss applications (where the lubricant is consumed or not recovered). This part is intended to be read with ISO 6743-99 (General) and references the ISO 3448 viscosity classification.

Key topics and requirements

• Detailed classification by code: Categories are designated by multi-letter symbols beginning with A (family identifier). The second letter groups product types (e.g., AY, AN, AB, AC).
• Product composition categories:
  • AY: Mildly refined mineral oils for rough applications (axles, railway points). Note: some products may contain components harmful to health/environment.
  • AN: Refined mineral oils for lightly loaded parts (rolling bearings, plain hydrodynamic bearings).
  • AB: Refined mineral oils containing bitumen or additives to improve adhesiveness, extreme pressure or corrosion protection - used for open gears, wire ropes, chains.
  • AC: Oils from mineral, animal, vegetable or synthetic origins with additives for specific properties (e.g., saw chains). Annex A indicates additional sub-categories for low-temperature operability, oxidation stability and environmental acceptability (toxicity, biodegradability).
• Viscosity designation: Categories AY, AN, AB are designated by ISO viscosity grades (VG) per ISO 3448 - e.g., ISO‑L‑AN 32 or L‑AN 32.
• Environmental/regulatory note: Products that may be directly discharged to the environment must comply with applicable national regulations.
• Scope limitations: Greases for some applications (open gears, wire ropes, exposed chains, bearings) may be used and are addressed separately.

Practical applications

• Classification and selection of lubricants for total-loss systems such as:
  • Axles and railway switching points
  • Open gears, wire ropes and cranes
  • Chains (including saw chains and guide bars)
  • Lightly loaded bearings and plain bearings in hydrodynamic regimes
• Useful for creating product datasheets, procurement specifications, maintenance schedules, and compliance assessments where lubricant recovery is not feasible.

Who uses this standard

• Lubricant manufacturers and formulators
• Equipment OEMs and designers specifying lubrication regimes
• Maintenance engineers and reliability teams
• Procurement and specification writers
• Regulatory and environmental compliance professionals

Related standards

• ISO 6743-99: Classification - General (must be read with Part 1)
• ISO 3448: Industrial liquid lubricants - ISO viscosity classification
• Other ISO 6743 parts: (F, D, H, T, C, M, R, X, Y, P, Q, G, U, E, etc.) for other lubricant families
• ISO 11679 (in development at time of publication): Specifications for saw chain and guide bar lubricants (referenced in Annex A)

Keywords: ISO 6743-1, Family A, total loss systems, lubricant classification, industrial oils, ISO viscosity, saw chain lubricants, open gear oil, chain oil, railway point lubrication, lubricant specifications, biodegradability.