NACE CIP Level I Chapter 21: High
Voltage and Low Voltage Holiday Testing
Instrumentation
High-voltage holiday detectors - CORRECT ANSWER-can detect weaknesses in the
coating that do not penetrate to the conductive substrate (metal or concrete with
moisture present).
5-120 V DC - CORRECT ANSWER-Low-voltage (wet sponge) holiday detectors are
powered by baterries with output voltages ranging from ______.
7.4 mL (1oz) to 1 L (1 gal) - CORRECT ANSWER-(Low-voltage) Concentration of
wetting agent ______.
1 linear foot per second - CORRECT ANSWER-(Low-voltage) Wipe the coated surface
with the wetted sponge at a maximum rate of ______. Use a double stroke over each
area.
High-voltage pulse-type DC holiday detectors - CORRECT ANSWER-______ are
designed to locate holidays in nonconductive coatings that are applied over a
conductive substrate.
Preferred for use on:
* Carbon-impregnated coatings i.e. carbonated rubber
* Plastic/Fiberglass type coatings
* Thick coatings
High-voltage Holiday Instruments proper use - CORRECT ANSWER-*The ground wire
should be connected directly to the metal structure, where possible.
* On concrete structures, attach the ground to rebar in the concrete, or if there is no
rebar, lay the bare ground wire on the concrete and anchor it with a burlap bag filled
with damp sand.
* US Industry's rule of thumb 100 V/mil of coating thickness
General Types of Holiday Detectors - CORRECT ANSWER-* Low-voltage DC
* High-voltage DC
* High-voltage pulsed DC
* High-voltage AC
Holiday Testing common found defects or discontinuities - CORRECT ANSWER-*
Pinholes
* Fisheyes
* Cratering
Voltage and Low Voltage Holiday Testing
Instrumentation
High-voltage holiday detectors - CORRECT ANSWER-can detect weaknesses in the
coating that do not penetrate to the conductive substrate (metal or concrete with
moisture present).
5-120 V DC - CORRECT ANSWER-Low-voltage (wet sponge) holiday detectors are
powered by baterries with output voltages ranging from ______.
7.4 mL (1oz) to 1 L (1 gal) - CORRECT ANSWER-(Low-voltage) Concentration of
wetting agent ______.
1 linear foot per second - CORRECT ANSWER-(Low-voltage) Wipe the coated surface
with the wetted sponge at a maximum rate of ______. Use a double stroke over each
area.
High-voltage pulse-type DC holiday detectors - CORRECT ANSWER-______ are
designed to locate holidays in nonconductive coatings that are applied over a
conductive substrate.
Preferred for use on:
* Carbon-impregnated coatings i.e. carbonated rubber
* Plastic/Fiberglass type coatings
* Thick coatings
High-voltage Holiday Instruments proper use - CORRECT ANSWER-*The ground wire
should be connected directly to the metal structure, where possible.
* On concrete structures, attach the ground to rebar in the concrete, or if there is no
rebar, lay the bare ground wire on the concrete and anchor it with a burlap bag filled
with damp sand.
* US Industry's rule of thumb 100 V/mil of coating thickness
General Types of Holiday Detectors - CORRECT ANSWER-* Low-voltage DC
* High-voltage DC
* High-voltage pulsed DC
* High-voltage AC
Holiday Testing common found defects or discontinuities - CORRECT ANSWER-*
Pinholes
* Fisheyes
* Cratering
