Chapter 16 Dry Film Thickness Measurement Instrumenmtation

Question 1

If the specification does not state a required standard, then it is good practice to chose a standard, such as _______, whose guidelines are broadly accepted in the coatings industry.

Answer 1

SSPC-PA 2

Question 2

Common errors that can produce inaccurate readings when using a Wet Film Thickness gauge include:

Answer 2

Using a damaged gauge

Dragging a gauge through wet coating (this causes a false high reading)

Placing the gauge along the circumference of a pipe or curved surface, rather than along the longitudinal axis, when measureing WFT on pipes or curved surfaces

Question 3

Common errors that may produce inaccurate readings when using a Dial-Type Magnetic Pull-Off DFT Gauge include:

Answer 3

• Failure to determine the BMR
• Rotating the dial too fast when taking measurements
• Taking measurements too close to the edge or on vibrating surfaces
• Measuring dirty, tacky, or soft films

Question 4

Name a few of the most commonly used standards that govern DFT measurement:

Answer 4

• SSPC-PA 2
• ASTM D 7091
• ISO 19840, 2808, 2178
• IMO Resolution MSC.216 (82), Annex 3

Question 5

SSPC-PA 2 requires 5 spot measurements (a minimum of three readings per spot are needed to account for surface irregularities within the ______ circle of the spot.

Answer 5

4 cm [1.5 in.]