ISO 24966:2026 is the new international standard for Modified Continuously Closed Cup Flash Point (MCCCFP) testing. The ISO 24966 method provides laboratories with a recognised procedure for determining the flash point of fuels, lubricants, chemicals, aviation turbine fuels, diesel fuels and biodiesel blends using a continuously closed cup flash point tester.

ISO 24966 represents an important development for laboratories seeking a modern alternative to conventional flash point methods while maintaining confidence in safety, precision and regulatory compliance.

What is ISO 24966?

ISO 24966 specifies a flash point test method based on the Modified Continuously Closed Cup Flash Point (MCCCFP) principle.

The method uses:

• A continuously closed test chamber
• Approximately 2 mL sample volume
• Controlled heating rates
• Flash point detection using pressure increase
• Electric spark ignition rather than an external flame

The standard covers a wide range of products including petroleum fuels, lubricants, chemicals and biodiesel blends. Precision has been established across a flash point range of 24.5 °C to 229.5 °C.

Benefits of the MCCCFP method

Improved laboratory safety

Traditional flash point testing methods use larger sample volumes and sometimes use an open flame as the source of ignition.

ISO 24966 utilises small sample volumes and an enclosed test environment, helping reduce operator exposure to flammable vapours during testing.

Reduced sample consumption

The method requires only a small test specimen compared with many conventional flash point procedures, making it attractive for:

• High-value chemicals
• Specialty products
• Research and development applications
• Limited-volume samples

Fast throughput

Modern MCCCFP instruments can achieve rapid heating and cooling cycles, allowing laboratories to increase sample throughput while maintaining compliance with a recognised standard.

Excellent repeatability

The controlled closed-cup environment helps minimise the effects of sample evaporation and operator variability, contributing to consistent test results.

Industries that can benefit from ISO 24966

ISO 24966 is applicable across a wide range of industries, including:

• Petroleum refining
• Lubricant manufacturing
• Chemical production
• Aviation fuel testing
• Biodiesel production
• Waste and recycling operations
• Research laboratories

ISO 24966 compliant flash point testing with the Setaflash CCC Preparing for the future of flash point testing

The publication of ISO 24966 marks an important milestone in flash point determination. As laboratories continue to seek improvements in safety, speed and sample efficiency, the MCCCFP method provides a recognised international framework for modern flash point testing.

For organisations evaluating adoption of ISO 24966, selecting a compliant instrument is the first step toward realising the benefits of this new standard.

Learn more about the Setaflash CCC and ISO 24966 compliant flash point testing >