For more than 30 years, FR3® natural ester fluid has set the benchmark for transformer performance. From its earliest validation tests and growing to 5+ million installations worldwide today, FR3 oil continues to lead the industry in fire safety, reliability, and resilience. Its higher flash point (compared to mineral oil) delivers a significant fire safety advantage, while its proven dielectric performance supports longer-lasting, higher-performing transformers than transformers using mineral oil. With FR3 oil, you gain the confidence and performance today’s power systems demand.
Why FR3 fluid
Grid resiliency
Grid resiliency that pays in more ways than one
A transformer's operating limits are constrained by the thermal properties of solid insulation and dielectric fluid. Because of FR3 fluid’s high thermal properties and its ability to reduce the aging rate of paper insulation, transformers containing FR3 oil can operate up to 20 °C warmer than mineral-oil-filled equivalents – enabling increased loading capability by up to 20% or more, especially when the transformer is purpose-built for FR3 fluid. This added thermal margin gives utilities the flexibility to respond to fluctuating power demand without accelerating insulation aging, and in many cases, may extend overall transformer life.
Superior performance
Superior performance through exceptional moisture tolerance
Moisture—whether from external leaks, free water forming in cold environments, or water released as insulation paper ages—can significantly reduce capacity and lead to dielectric failure in mineral-oil-filled transformers. FR3 fluid behaves very differently. With a much higher moisture saturation point than mineral oil, and its ability to remove water via hydrolysis, FR3 oil dramatically reduces failure risk associated with moisture compared to mineral oil. Its unique chemistry even allows it to absorb free water during hydrolysis, slowing the aging rate of the transformer’s solid (paper) insulation system.
Sustainability benefits
Biodegradable, bio-based, K-class fluid
FR3 fluid is derived from vegetable oil and is >99% bio-based according to ASTM D6866. It is 100% biodegradable in as little as 10 days (OPPTS 835.3100) and is non-hazardous according to GHS, which reduces environmental impact in the case of a transformer leak or spill. In addition, FR3 oil is classified as a K-class fluid. It has 2 times the flash point of mineral oil, and there have been zero reported fires with FR3 fluid-filled transformers in over 5 million installations worldwide.
Cost savings
Delivering business value
Partnering with Cargill and choosing FR3 fluid over mineral oil delivers meaningful business advantages—from stronger grid reliability and greater resilience to improved cost control through a more efficient transformer system.
By deploying FR3 oil across your transformer fleet, you can unlock significant long-term operational value, reduce total cost of ownership, and support the communities you serve with greater reliability and confidence.
Average total cost of ownership savings
Up to 20% more load capacity than mineral oil
Up to 8X longer insulation life
Mineral oil's flash and fire points
Reported fires
Installations worldwide
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