NACE - National Association of Corrosion Engineers Inspection Instruments and Tests Questions and Answers

Question 1

An inspector is required to measure the dry film thickness (DFT) of a coating system on a large, flat steel surface totaling 500 square meters (approx. 5,000 sq ft).
According to SSPC-PA 2, how should the inspector determine the number of areas to measure?

Accepted Answer

Measure three 10 m² areas for the first 100 m², and then one additional 10 m² area for each subsequent 100 m².

Answer

Take five spot measurements randomly across the entire 500 m² surface.

Answer

Divide the surface into five equal sections and take one area measurement in each.

Answer

Measure one 10 m² area for every 50 m² of the total surface area.

Question 2

Which of the following instruments is used to perform a quantitative pull-off adhesion test as described in ASTM D4541?

Accepted Answer

A portable adhesion tester with a loading fixture (dolly)

Answer

A utility knife and pressure-sensitive tape

Answer

A cross-hatch cutter and a dolly

Answer

A Tooke gauge for measuring individual coat thickness

Question 3

A coating inspector is preparing to conduct holiday testing on a new protective coating with a specified dry film thickness of 15 mils (381 microns) on a conductive substrate. Which type of holiday detector is most appropriate for this application?

Accepted Answer

A low-voltage, wet-sponge holiday detector

Answer

A high-voltage AC spark tester

Answer

A high-voltage, pulsed DC spark tester

Answer

An ultrasonic thickness gauge

Question 4

An inspector uses replica tape and a micrometer to measure the surface profile of an abrasive blast-cleaned steel surface, following the procedure in NACE SP0287. What is the primary purpose of this test?

Accepted Answer

To measure the peak-to-valley depth of the surface anchor pattern

Answer

To determine the level of soluble salt contamination on the surface

Answer

To assess the degree of non-visible surface cleanliness

Answer

To quantify the adhesion of the primer coat to the steel

Question 5

During a coating application project, the specification requires adhesion testing according to ASTM D3359, Method A. This test is primarily intended for which of the following scenarios?

Accepted Answer

Field testing of coating systems greater than 5 mils (125 µm) in thickness

Answer

Laboratory testing of thin-film coatings under 5 mils (125 µm)

Answer

Determining the pull-off strength of a coating in psi or MPa

Answer

Evaluating the adhesion of coatings on non-metallic substrates like concrete

Question 6

Which of the following methods would be used to retrieve a sample for assessing the concentration of soluble salts on a steel surface prior to coating?

Accepted Answer

Using a Bresle patch or adhesive patch to extract surface contaminants

Answer

Taking a series of dry film thickness readings with a magnetic gauge

Answer

Performing a pull-off adhesion test using a dolly and adhesive

Answer

Conducting a cross-hatch adhesion test with pressure-sensitive tape