Key Dielectric Fluid Classes for Fire Safety

ANSWER:

IEC 61039 identifies “less flammable fluids” as those with a fire point >300°C. These are designated as K class fluids.

According to IEC 61936 transformers filled with K-class fluids can have reduced fire protection measures.

In addition, certifiers such as FM Global provide a list of approved Less Flammable Transformer Fluids and guides for safe installation.

Using a high fire point fluid significantly reduces the chance of a pool fire.

What does this mean for MIDEL? There has never been an oil fire reported in the past 40 years in transformers using MIDEL ester fluids.

More questions on ester fluids?

This post is one of the 15 top questions we get asked on retrofilling transformers with ester fluids. Here is the full list of the frequently asked questions on ester fluid retrofilling:

1. Miscibility: Which transformer oils are compatible with Midel ester fluids for retrofilling?
2. Free-breathing: Can I use Midel fluids in breathing transformers?
3. Insulation Regeneration: Will Midel fluids heal existing problems in a transformer?
4. Fire Safety: Which dielectric fluids classifications are important to understanding fire safety?
5. Cold Weather: How do Midel fluids perform in the cold?
6. Moisture: What happens to the performance of Midel fluids when they absorb moisture?
7. Acid Levels: If Midel fluids have high acid levels, how do I recondition my fluid?
8. DGA: How can I use dissolved gas analysis on Midel fluids?
9. Power Factor: What is the Power Factor of Midel fluids?
10. Materials Compatibility: Are Midel fluids compatible with all transformer materials?
11. HV Applications: Can I use Midel fluids to retrofill transformers at high voltages?
12. Interfacial Tension: Is interfacial tension a meaningful property for Midel fluids?
13. Reusability: How are used Midel ester fluids processed and handled?
14. De-rating: Will there will be any derating of a transformer by changing it from mineral oil to a Midel ester fluid?
15. Retrofill Process: Are there extra requirements or steps when retrofilling transformers with Midel fluids?