4. Based on the subjective methods, Flash Rust is classified as
           • None
           • Light
           • Moderate
           • Heavy

The following metric table was developed by Pete Ault, Elzly Technology Corporation. Click Table to enlarge.

Table of Metrics used in Flash Rust

ALL of the VISUAL GUIDES are used in the SAME WAY!
 Look at the flash rust
• straight on,
• within arm’s length,
• in good lighting,
• prior to painting.
 Allow time to remove, if necessary, excess loose flash rust prior to painting

Look at the surface and decide if you can see through the rust or if it obscures the surface.  Make sure that the rust is not splotchy black.

Look at the color.   Color can vary depending on the type of steel. The color is affected by the age and type of steel and, in the field, certainly might appear differently than the descriptive terms. Current language being adopted by NACE and SSPC will remove the COLOR language. 

Determine Quantity of loose rust dust. Lightly wipe the surface with a cloth.

The methods to evaluate Flash Rust are Subjective.
• Visual Appearance and
• Assessment of amount of Loose Dust
 Cloth Wipe in hand
 Cloth Swatch in hand
 Cloth around a Brush
 Tape

      Immediately after the cleaning, before the surface has flash rusted, (it might still be wet), evaluate the degree of Visual Cleaning.
The visual cleaning evaluation often occurs while the surface is still wet.

Courtesy Dr. Lydia Frenzel

A section was cleaned with hand-held lances over a period of 3 days.  Then the jetters moved to another section.  The visual cleanliness was evaluated at the time of coatings removal. The flash rust was evaluated on the day that it was painted.

Example of Visual Cleanliness (Thorough Cleaning) (Below).
Example of Moderate Flash Rust – at time of paint application.
Photo Courtesy of Dr. Frenzel

Conditions at time of Cleaning/Conditions prior to Cleaning

Example of Visual Cleanliness (Thorough Cleaning).
Example of Moderate Flash Rust – at time of paint application