Classification of Flash Rust
Posted on 15. Mar, 2009 by charles frenzel in NSRP
Light Flash Rust
Light (L) flash rusted surface: A surface that, when viewed without magnification, exhibits small quantities of a rust layer through which the steel substrate may be observed. The rust or discoloration may be evenly distributed or present in patches, but it is tightly adherent and not easily removed by lightly wiping with a cloth.
There most likely will be a light color transferred to the cloth.
Moderate Flash Rust
A surface which, when viewed without magnification, exhibits a layer of rust that obscures the original steel surface. The rust layer may be evenly distributed or present in patches, but it is reasonably well adherent and leaves light marks on a cloth that is lightly wiped over the surface.
International Paint (1994) Commentary
When viewed without magnification, a layer of light tan-brown rust will obscure the original metallic surface. This layer may be evenly distributed or patchy in appearance, but it will be heavy enough to mark objects brushed against it.
The inspector should expect to see that some of the loose “rust dust” will be transferred to a cloth wipe
Heavy Flash Rust
A surface which, when viewed without magnification, exhibits a layer of heavy rust that hides the initial surface condition completely. The rust may be evenly distributed or present in patches, but the rust is loosely adherent, easily comes off, and leaves significant marks on a cloth that is lightly wiped over the surface.
International Paint (1994) Commentary
When viewed without magnification, a heavy layer of dark tan-brown rust will completely obscure the original metallic surface. This layer of rust will be loosely adherent and will easily mark objects brushed against it.
The inspector should expect to see large quantities of color transferred to a cloth wipe.
Hempel has further descriptions of Flash Rust determined by swiping with a hand and the use of pressure sensitive tape. They are useful as they provide additional information about dark loose rust dust that has formed under the upper brown rust dust.
