High Voltage Holiday Instruments

Question 1

High Voltage Pulse-type DC Holiday Detectors are designed to locate holidays in a 1___ coating applied over a 2___ substrate.

Answer 1

1. Non-conductive.

2. Conductive

Question 2

High Voltage Pulse-type DC Holiday Detectors are preferred for use on:

1. ___ ___ coatings.
2. ___ (fiberglass coatings) that could become electrostatically charged.

Answer 2

1. Carbon impregnated.

2. Plastics

Question 3

HV Pulse-type DC HD’s consist of:

1. ___ ___ DC unit.
2. Various probes for different ___ and ___.
3. ___ accessories.
4. ___ unit.
5. __ wires.
6. General ___.

Answer 3

1. High voltage DC unit.
2. Various probes for different substrates and configurations.
3. Calibration accessories.
4. Charging unit.
5. Ground wires.
6. General accessories.

Question 4

Generally, each manufacturer/model has particular differences related to safety or operation that operators need to know.

Answer 4

For example: Tinker and Rasor’s APS Stick Type: is equipped with a release trigger that instantly turns the instrument off. Hold the handle down on the grip to operate the instrument. Release the handle and the unit shuts down. The feature increases job site safety since the instrument cannot be left energized while unattended.

Question 5

The general operating procedure of most HV Pulse-type DC HD’s are as follows:

When the electrode is passed over the surface, a 1___ arcs through the air gap or coating to the substrate at any holidays, voids, or discontinuities, which simultaneously causes to detector to emit a sound.

The ground wire should be connected directly to the metal structure where possible. If impossible, use the HV HD with a 2___ ___ ___, provided the structure is also connected to the ground. If the building cannot be connected to the ground, establish direct contact or connect a ground wire at some point between the ground and the structure.

On concrete structures, attach the ground to rebar in the concrete, or lay the bare ground wire on concrete, cover it with a burlap bag filled with damp sand,.

Set the voltage as stated in either the specification or the referenced standard.

Answer 5

1. Spark

2. Trailing ground wire.

Question 6

If there is no referenced standard for the use of HV DC HD’s the rule of thumb is to use a voltage setting of ?

Answer 6

100 volts per mill of coating thickness.

Question 7

When the voltage is set too high the coating may be damaged. The same damage can occur if the coating is tested before 1___ or ___ of the ___ has ___. Once a spark generates though the coating the substrate, a specific holiday now exists, even if there was none before the test was performed.

Answer 7

1. Most or all of the solvent has evaporated.

Question 8

When testing, move the electrode at a rate of 1__ ___ ___, in a 2___ ___ according to NACE SP0188.

Answer 8

1. 1 ft per second.

2. Single pass.

Question 9

Moving the prove too quickly may 1___ a ___. Moving too slowly may create 2___ at ___ ___, or prove to be more exacting than was intended by the specification.

Answer 9

1. Miss a void.

2. Damage at thin spots,

Question 10

Moving the prove too quickly may 1___ a ___. Moving too slowly may create 2___ at ___ ___, or prove to be more exacting than was intended by the specification.

Answer 10

1. Miss a void.

2. Damage at thin spots,

Question 11

Standards that may need to be consulted with use of HV Pulse type DC HD’s, depending on the specification and substrate type inlcude.

Answer 11

AS/NZS 3894.1

ASTM G62-07

ASTM D5162-08

ASTM D4748-08

NACE SP0274-2011

NACE SP0490-2007

NACE SP0188-2006

ANSI/AWWA C213-07

ANSI/AWWA C214-07

ISO 2746:1998

Question 12

HV Pulse-Type DC HD’s come calibrated from the manufacturer and cannot be calibrated by the user. Check the 1___ ___ periodically, following manufacturer instructions. If there is ever a question about accuracy, take the detector 2___ of ___ and return it to the supplier for service.

Answer 12

1. Voltage output.

2. Out of service.

Question 13

Before using a HV Pulse-type DC HD ensure:

1. Coating ___ is ___.
2. __ ___ is complete.
3. ___ of ___ is complete.
4. ___ ___ is complete.
5. 1. Coating thickness needs to be above ___ ___.
6. 2 LV testing of coatings below __ __ is complete.

Answer 13

1. Coating cure is complete.
2. Visual inspection is complete.
3. Acceptance of inspection is complete.
4. Thickness testing is complete.
5. 1. Coating thickness needs to be above 6 mils
6. 2 LV testing of coatings below 6 mils is complete.

Question 14

HV Pulse-type DC HD’s generally have a voltage output range from ___ to ___ volts.

Answer 14

800 to 60,000 volts.

Question 15

HV Pulse-type DC HD’s are used on protective coating films ranging in thickness of?

Answer 15

6 to 240 mils.

Question 16

When checking the output voltage from the probe, use of a high input ___ ___ is required to prevent the flow current and subsequent voltage drop from the power supply.

Answer 16

Impedance voltmeter

Question 17

Most HV HD’s have a wide range of electrodes available including:

1. Flat section rolling springs used to test ___ ___.
2. Smooth neoprene flaps, impregnated with conductive ___, used for thin film coatings such as ___ ___ ___.
3. Copper-bronze-bristle brushes used on ___ ___ ___ coatings.

Answer 17

1. Flat section rolling springs used to test pipeline coatings.
2. Smooth neoprene flaps, impregnated with conductive Carbon, used for thin film coatings such as fusion bonded epoxy.
3. Copper-bronze-bristle brushes used on glass-reinforced plastic coatings.

Question 18

Most HV HD’s have a wide range of electrodes available including:

1. ___ ___ ___ ___ used to test pipeline coatings.
2. ___ ____ ___, impregnated with conductive Carbon, used for thin film coatings such as fusion bonded epoxy.
3. ___ ___ ___ ___ used on glass-reinforced plastic coatings.

Answer 18

1. Flat section rolling springs used to test pipeline coatings.
2. Smooth neoprene flaps, impregnated with conductive Carbon, used for thin film coatings such as fusion bonded epoxy.
3. Copper-bronze-bristle brushes used on glass-reinforced plastic coatings.

Question 19

DC stands for?

Answer 19

Direct Current.

Question 20

Accuracy for the voltage setting is generally -/+ 5 percent. Depending on the model (Voltage Range) resolution is at?

Answer 20

10 or 100 V.

Question 21

Some high voltage holiday detectors allow the sensitivity of the alarm to be adjusted so that it doesn’t not sound when a steady flow of current from the probe to charge the surface of the coating is present. Or when the coating is partially conductive (due to conductive pigments such as Carbon Black).

Answer 21

Personal Note: Seek Clarification.

Question 22

When the sensitivity is set to a low value, the audible alarm when a high current spark is present. When the sensitivity is set at a high value, all current flows from the probe will cause the alarm to sound.

Answer 22

Personal Note: Seek Clarification.

Question 23

When the sensitivity is set to a low value, the audible alarm when a high current spark is present. When the sensitivity is set at a high value, all current flows from the probe will cause the alarm to sound.

Answer 23

Personal Note: Seek Clarification.

Question 24

Equipment based errors include:

Lack of display due to low battery or bad/missing fuses.

Continuous alarm due to damp surface, moving the probe too quickly, conductive pigments in the coating, or certain coatings which hold an electrical charge on the surface causing current flow of the probe as it passes.

Answer 24

No alarm on fault. On conductive substrates could be due to too low voltage sensitivity settings, or a bad ground connection. On concrete substrate, no alarm on fault could be due to insufficient conductivity.

No spark at the probe tip due to lead or connection failure.

Question 25

The conductivity of concrete is due to 1___. Less than 2___ can mean insufficient conductivity.

Answer 25

1. Moisture.

2. 5 percent.

Question 26

HV Constant Test Current DC HD’s are used to detect holidays in 1___ (___) type coatings on 2___ surfaces.

Answer 26

1. Dielectric (Insulation)

2. Conductive

Question 27

HV AC HD’s use a 1___ or ___ power supply. They are based on the principle of the 2 ___ ___ and do not use a 3___ ___. The probe emits a blue corona which is attracted to any ground. This type of detector is relatively rare.

While these AC units are available they present a much higher risk of 4___ ___ during use than DC or Pulsed HV HD’s. Use AC units with extreme care at all times.

Answer 27

1. 110 or 220 V
2. Tesla Coil
3. Ground Wire.
4. Severe Shock.

Question 28

HV AC HD’s use a 1___ or ___ power supply. They are based on the principle of the 2 ___ ___ and do not use a 3___ ___. The probe emits a blue corona which is attracted to any ground. This type of detector is relatively rare.

While these AC units are available they present a much higher risk of 4___ ___ during use than DC or Pulsed HV HD’s. Use AC units with extreme care at all times.

Answer 28

1. 110 or 220 V
2. Tesla Coil
3. Ground Wire.
4. Sever Shock.

Question 29

HV AC HD’s operate on a different 1___ ___ but the test procedure is the same as for HV DC HD’s.

This instrument comes calibrated from the supplier and cannot be calibrated by the user.

Answer 29

1. Electrical Principle

Question 30

Use HV AC HD’s to test 1___ ___ on ___ ___.
(e.g. ___, ___, or ___ ___.

AC Testers have a variety of voltages but typical use is for 2___ ___ coatings with test voltages in the range of 3___ to ____ v.

Answer 30

1. Non-conductive linings on steel substrates. (I.e. Rubber, glass, or sheet linings.)
2. Very thick.
3. 25,000 to 60,000 V

Question 31

Usa AC-Type HD’s to test 1___ ___ on ___ ___.
(e.g. ___, ___, or ___ ___.

AC Testers have a variety of voltages but typical use is for 2___ ___ coatings with test voltages in the range of 3___ to ____ v.

Answer 31

1. Non-conductive linings on steel substrates. (I.e. Rubber, glass, or sheet linings.)
2. Very thick.
3. 25,000 to 60,000 V

Question 32

There are many factors inspectors must consider before performing holiday detection. Some factors effect what instrument and/or procedure are chosen to perform the test. Some factors include?

1. Work environment.
2. Type of Substrate and/or Coating type.
3. Anticipated coating thickness.
4. Specification requirements.
5. Standards to follow.

Answer 32

1. Work environment.
   Any instrument that can generate a spark is not intrinsically safe.
2. Type of Substrate and/or Coating type.
   This can effect which HD is best suited for the job.
3. Anticipated coating thickness.
   LV on coatings under 20 mils. HV is for higher film thickness.
4. Specification requirements.
5. Standards to follow.

Question 33

There are many factors inspectors must consider before performing holiday detection. Some factors effect what instrument and/or procedure are chosen to perform the test. Some factors include?

1. Work environment.
2. Type of Substrate and/or Coating type.
3. Anticipated coating thickness.
4. Specification requirements.
5. Standards to follow.

Answer 33

1. Work environment.
   Any instrument that can generate a spark is not intrinsically safe.
2. Type of Substrate and/or Coating type.
   This can effect which HD is best suited for the job.
3. Anticipated coating thickness.
   LV on coatings under 20 mils. HV is for higher film thickness.
4. Specification requirements.
5. Standards to follow.

Question 34

Before testing for holidays check the following items.

1. Are non-intrinsically safe items allow in the work environment.
2. What are grounding and safety issues.
3. Have the Spec and Standards been reviewed and understood.
4. I the proper instrument at hand.
5. Is the batter charged and the unit in working condition.
6. Has the operating manual been read and understood.
7. Has the voltage output been checked to ensure accuracy.
8. Have the signal return cable and electrode connections been checked to ensure there is no electrical resistance in the circuit.

Answer 34

1. Are non-intrinsically safe items allow in the work environment.
2. What are grounding and safety issues.
3. Have the Spec and Standards been reviewed and understood.
4. I the proper instrument at hand.
5. Is the batter charged and the unit in working condition.
6. Has the operating manual been read and understood.
7. Has the voltage output been checked to ensure accuracy.
8. Have the signal return cable and electrode connections been checked to ensure there is no electrical resistance in the circuit.

Question 35

This uses a 110 or 220 V power supply, is based on the principle of the tesla coil, does not have a ground wire and emits a blue corona, which is attracted to any ground.

Answer 35

HV AC HD

Question 36

This is used to detect coating holidays in dielectric coatings.

Answer 36

HV Constant Current HD

Question 37

This is ideal for use in moist conditions. Pass the electrode over the surface, a spark will arc at air gaps in holidays, voids, or discontinuities, causing the detector to beep.

Answer 37

HV Pulse-type DC HD.

Question 38

This instrument is sensitive, low voltage electronic devise powered by a battery with an output voltages of 5 to 120 DC.

Answer 38

LV HD

Question 39

HV AC HD’s have a voltage range of? 25,000 to 60,000 V

Answer 39

25,000 to 60,000 V

Question 40

Non-conductive linings on steel substrates. (I.e. Rubber, glass, or sheet linings.) are testing using an?

Answer 40

HV AC HD.