ISO 12924:2023

Overview

ISO 12924:2023 specifies requirements for Family X (greases) within ISO’s Class L system for lubricants, industrial oils and related products. It defines how greases intended primarily for anti‑friction bearings (machines, vehicles, etc.) are classified, tested and designated at the time of delivery. The standard is written for global application across different climatic conditions and incorporates environmentally acceptable (EA) grease criteria introduced in this edition.

Key topics and technical requirements

• Designation format: Grease identification follows the pattern
  ISO‑L‑X‑symbol1‑symbol2‑symbol3‑symbol4‑NLGI (optionally with suffix EA for environmentally acceptable greases).
• Symbol 1 - Lower operating temperature: Determined by one of three methods with a suffix indicating the method used: starting/running torque (ASTM D1478 or NF T60‑629) - (L), flow pressure (DIN 51805‑2) - (F), or low‑temperature penetrability (ISO 13737) - (P).
• Symbol 2 - Upper operating temperature: Assessed using FAG FE9 roller bearing tests (DIN 51821‑1 and DIN 51821‑2). For high base‑oil viscosity greases, an alternate rotating speed is allowed and noted by suffix (S).
• Symbol 3 - Water contamination and rust protection: Specifies resistance to water washout and rust-prevention characteristics (see ISO 11009, ISO 7120, ISO 11007‑1).
• Symbol 4 - Load carrying ability: Indicates grease performance under high loads.
• NLGI consistency number: Defined via cone penetration testing (ISO 2137) and used in the designation string.
• Environmentally acceptable greases (EA): The 2023 edition adds EA classification and references biodegradability and aquatic toxicity tests (ISO 9439, ISO 14593, ISO 7346‑1, ISO 6341, ISO 14669, ISO 10253) and related EN/ASTM methods.
• Sampling and delivery: Sampling is covered by ISO 23572; requirements establish the state of grease at delivery and testing precision guidance (ISO 4259‑2).

Applications and who uses this standard

ISO 12924:2023 is intended for:

• Lubricant manufacturers - formulation, quality control and product labeling.
• OEMs and machine designers - specifying greases for bearings and lubrication systems.
• Maintenance and reliability engineers - selecting appropriate greases for temperature, water exposure and load conditions.
• Procurement and compliance teams - verifying delivered product meets classification and EA/environmental claims.
• Independent test laboratories - performing standardized tests for certification and dispute resolution.

Practical applications include bearing lubrication across industries (industrial machinery, automotive, wind turbines, marine equipment) where consistent performance under diverse temperatures, contamination and load conditions is required.

Related standards

• ISO 6743‑9 (classification: Family X greases) - intended companion document
• ISO 12925‑3 (greases for gear applications)
• ISO 2137, ISO 13737, DIN 51821 series, ISO 23572 and various ISO/EN/ASTM methods referenced for specific tests

Keywords: ISO 12924:2023, greases specification, lubricants Class L, Family X, NLGI, environmentally acceptable grease, lower operating temperature, upper operating temperature, FAG FE9, grease testing.