The Pressure Sensitive Tape Test described by Hempel is a modification of ISO 8502-3 (Pressure Sensitive Tape test for dust) and is not mentioned in VIS-4.  The tape test can be used as a permanent record.  If lint deposition is a concern, the project specification may require use of a different technique to determine the level of flash rust, such as the pressure-sensitive tape test. Those responsible for establishing the requirements and those responsible for performing the work can agree to the use of a different technique to determine the level of flash rust

Place a piece of tape (as specified in ASTM D 3359) in a length of at least 5 cm (2 in) on the surface and rub thoroughly with a fingertip–not a nail–to make the tape adhere firmly.  Peel off the tape and place it on a piece of white paper for reference. Repeat this process 9 additional times (for a total of 10 tests) using a fresh piece of tape each time and apply the tape to the same spot.  Assess the appearance of the tape and the surface.

The results from the pressure sensitive tape test lead to the same conclusions as the tape tests.  For further details or training on this item, contact Dr. Frenzel.

Tape Test from a Moderate Flash Rust (MFR) Surface (Below).

 None
 Light
 Moderate
 Heavy
Adopt the method with which you feel most comfortable and that is portable to different projects and sites.

Examples of LFR on Swatch, wipe, and Brush

Example of MFR on swatch and brush wipe.

HFR on Swatch

HFR on Brush Wipe

HFR with Swatch, Brush, and Wipe

 Brushing flash rust is quick, simple, and very reproducible.
 Adopt a standard brush and standard cloth.
 Be consistent with one swipe and in the same direction and duration.
 Practice brush strokes with even pressure
 Keep the contact area consistent.
 Cloth can be cut at the area of color transfer and placed in permanent file or scanned for color.

Heavy Flash Rust formed from water coming from holes.
Different section where Light, moderate, and heavy flash rust had formed in close proximity.

Left to right, Light, Moderate, Heavy. Brush tests taken at the same time from three different areas.

Some color is transferred from light flash rust.

This view has the sun Illuminating the surface.  Substrate appears darker as it is in shadow. Inspection is biased by lighting angle.

 Easy to prepare the swatches.
 Keeps a constant light pressure.
 Gives a clear distinction between light, moderate, and heavy.
 The color transfers to only the cloth that is in contact with the surface. It can be difficult to interpret the various spots of color.

When do you evaluate the Flash Rust?
 Flash rust and the substrate (surface) condition are evaluated at or before the time of painting. 
 Look at the Project Documents to determine the length of time that can lapse between inspection points and paint application.
 Plan your inspection of flash rust so that the paint can be applied during the time periods allowed by the project documents between the inspection points and application.

 If the surface conditions change between time of inspection and time of painting, then typically this Change is a “stop” or “hold” point.  This requirement that the substrate condition remain the same between inspection and application is true also for dry abrasive blasting. 

 Prior to painting, compare the flash-rusted surface with the flash rust photographs.
 Wipe or use tape as a further determination.
 Prior to painting, the degree of flash rust must be in accordance with the contract specifications.
Keep in mind that you are evaluating is the surface apparent or obscures, and what is the quantity of loose rust dust.  The coatings manufacturer makes the recommendation about the suitability of the coating system over the amount of clean flash rust.  If there is a doubt about interpretation, talk with an experienced field representative or the technical support group of the coating to be applied.

Caution: Do not develop a technique where you wipe like the dickens in order to prove the flash rust is unacceptable based on “the ease of removing a lot of color.“ Any rusted surface will transfer some brown color to a rag if it is scrubbed against the surface.

In addition, Hempel describes a pressure sensitive tape test as a quantitative measurement.  This manual provides detail of the wipe tests, and does not include details of the tape test as it is not included in the “standard” definition.
Four Ways to Lightly Wipe the Surface
 Wipe with hand **
 Wipe with cloth held in hand
 Wipe with cloth in a swatch
 Wipe with cloth around a brush
ALL METHODS LEAD TO SAME CONCLUSIONS.

** SSPC SP-12 and VIS-4 describe the use of a cloth in the definitions.  While wiping with a hand is often done in the field, it should not be encouraged as the hand and fingers can leave a residue, such as sweat, on the substrate.

Different clothes might give different “pick-up” results.
Cloth will “stick” to the metal tips- so be consistent in the type of material. If lint deposition is a concern, consider other evaluation methods.
Consider using lint-free cloth wipes from laboratory supply

For example-Lint Free Wipes are available From VWR Laboratory Supply House
COTTON KNIT WIPING CLOTHS  VRW 82001-036 ,
Laboratory cotton precut lint free cloth  VRW TWTX309,
Clean Room quality cotton replacement  VRW TWTX609,

Just using rags out of the rag bin will lead to trouble with interpretation.

The cloth used in wiping is to be DRY, not wet. .  This is not a heavy scrubbing with a cloth.
The flash rust is occurring so fast that it forms loose powder (dust); it does not crystallize or consolidate to form a rust barrier layer. The wiping is to determine the quantity of clean, loose rust dust.