BRIDGE COATINGS INSPECTOR PROGRAM
EXAM SCRIPT 2026 COMPREHENSIVE EXAM
Q&A STUDY GUIDE
◉ Frequency of Testing Recirculated Abrasives. Answer: Tested prior
to the start and at the end of each day's blast cleaning operations,
and at least once every four hours during normal operation.
◉ Determination of Steel Surface Contamination. Answer: Some
signs to look for:
1. The prepared surface may not have the typical "dry" appearance
or may look slightly darker.
2. The surface may look like it is covered with small, dark spots
other than embedded abrasive.
3. Airborne dust may stick to the surface and be more difficult to
remove with compressed air.
◉ Removing Oil Contamination from Steel. Answer: Solvent wiping
is NOT effective at removing contamination from blast cleaned steel
surfaces. Other methods of solvent cleaning that are more effective,
such as vapor degreasing or solvent washing followed by a clean
solvent rinse, should be used whenever possible. Except for small
parts that have been solvent washed and rinsed in clean solvent, all
surfaces should be reblasted after oil contamination has been
removed by one of the above methods.
,◉ Source of Oil Contamination. Answer: Oil is often added to steel
shot and grit at the mill as a rust preventative. The oil should be
removed before the abrasive is used for blast cleaning. This can be
done by mixing the abrasive with diatomaceous earth, which
absorbs the oil, and then cycling the abrasive through a cyclone
separator to remove the diatomaceous earth. The abrasive should be
tested to verify that the oil was removed.
Other sources are cutting oils and other lubricants that get on the
surface of steel during fabrication. Since hey may contaminate
recirculated abrasives, they should be removed by solvent cleaning
prior to blast cleaning.
◉ Effects of Oil Contamination. Answer: Since oil is a release agent, it
may interfere with the satisfactory adhesion of the applied coating
or lining to the surface and result in an adhesion failure. A coating
applied over an oil-contaminated surface usually has the appearance
of "fish eyes" in the finish.
◉ Accept Criteria for Recirculated Abrasives. Answer: Clouding or
discoloration of the water, but no oil film or slick on the surface of
the water tested in accordance with this procedure.
,◉ Why Test Compressed Air Supply. Answer: To ensure air quality is
clean, dry, and oil free. Oil mist and spots on a surface to be coated or
lined will cause premature failure of the coating or lining system.
◉ Procedure for Testing Compressed Air Supply. Answer: 1. Test air
supply at an outlet downstream from oil and moisture traps and as
close as possible to the equipment using the air. Hold blotter or test
material in the airstream for a minimum of two minutes. The blotter
or test material should be held within a distance of 24" from the
source. If air from abrasive blast nozzles is being tested, ensure
abrasive source is cut off. If air is being discharged at several
locations drawing from a common manifold, it is not necessary to
test cleanliness at each location. The test should be run at each point
of use if more than 100 feet of air hose is used or if several distant,
separate outlet locations are used.
2. Examine test material immediately after test is completed for
evidence of contamination, oil, or moisture. Test visually and by
touch and smell.
◉ Frequency of Compressed Air Tests. Answer: Refer to
specifications. Always test prior to use and at least once every four
hours thereafter during continuous operation. When relative
humidity is high, test more frequently. If compressor operation is
interrupted for longer than 5 minutes, retest since condensation can
form in the lines.
, ◉ When Compressed Air Test Not Required. Answer: Not necessary
if compressed air will not come in direct contact with the surface,
abrasives used for surface prepartion, or coating or lining materials.
Ex: air used for operation of air driven motors on units for airless
spray painting.
◉ Power Tool Cleaning. Answer: If power tool cleaning is the final
step in surface preparation, dry, oil-free air must be used to operate
air-driven power tools. Power tool cleaning must be followed by
complete solvent cleaning or chemical cleaning if oil is added to the
compressed air supply for the purpose of lubricating air-driven
power tools.
◉ Oil Free Compressors. Answer: Testing still required because they
are still prove to moisture.
◉ Source of Oil Contamination. Answer: Almost always the
equipment, usually caused by worn poston rings. Also could be due
to excessive residual oil in lines caused by malfunctioning oil and
moisture traps. Clogged filters should be replaced and traps should
be coninuously bled so they cannot fill up and overflow back into the
line. Last resort, the compressor requires an overhaul.
◉ Source of Water Contamination. Answer: Air entering the
compressor contains varying amounts of water vapor, depending on
the prevailing ambient temperature and relative humidity. The
saturation point drops as air is compressed, making the air "wetter."
EXAM SCRIPT 2026 COMPREHENSIVE EXAM
Q&A STUDY GUIDE
◉ Frequency of Testing Recirculated Abrasives. Answer: Tested prior
to the start and at the end of each day's blast cleaning operations,
and at least once every four hours during normal operation.
◉ Determination of Steel Surface Contamination. Answer: Some
signs to look for:
1. The prepared surface may not have the typical "dry" appearance
or may look slightly darker.
2. The surface may look like it is covered with small, dark spots
other than embedded abrasive.
3. Airborne dust may stick to the surface and be more difficult to
remove with compressed air.
◉ Removing Oil Contamination from Steel. Answer: Solvent wiping
is NOT effective at removing contamination from blast cleaned steel
surfaces. Other methods of solvent cleaning that are more effective,
such as vapor degreasing or solvent washing followed by a clean
solvent rinse, should be used whenever possible. Except for small
parts that have been solvent washed and rinsed in clean solvent, all
surfaces should be reblasted after oil contamination has been
removed by one of the above methods.
,◉ Source of Oil Contamination. Answer: Oil is often added to steel
shot and grit at the mill as a rust preventative. The oil should be
removed before the abrasive is used for blast cleaning. This can be
done by mixing the abrasive with diatomaceous earth, which
absorbs the oil, and then cycling the abrasive through a cyclone
separator to remove the diatomaceous earth. The abrasive should be
tested to verify that the oil was removed.
Other sources are cutting oils and other lubricants that get on the
surface of steel during fabrication. Since hey may contaminate
recirculated abrasives, they should be removed by solvent cleaning
prior to blast cleaning.
◉ Effects of Oil Contamination. Answer: Since oil is a release agent, it
may interfere with the satisfactory adhesion of the applied coating
or lining to the surface and result in an adhesion failure. A coating
applied over an oil-contaminated surface usually has the appearance
of "fish eyes" in the finish.
◉ Accept Criteria for Recirculated Abrasives. Answer: Clouding or
discoloration of the water, but no oil film or slick on the surface of
the water tested in accordance with this procedure.
,◉ Why Test Compressed Air Supply. Answer: To ensure air quality is
clean, dry, and oil free. Oil mist and spots on a surface to be coated or
lined will cause premature failure of the coating or lining system.
◉ Procedure for Testing Compressed Air Supply. Answer: 1. Test air
supply at an outlet downstream from oil and moisture traps and as
close as possible to the equipment using the air. Hold blotter or test
material in the airstream for a minimum of two minutes. The blotter
or test material should be held within a distance of 24" from the
source. If air from abrasive blast nozzles is being tested, ensure
abrasive source is cut off. If air is being discharged at several
locations drawing from a common manifold, it is not necessary to
test cleanliness at each location. The test should be run at each point
of use if more than 100 feet of air hose is used or if several distant,
separate outlet locations are used.
2. Examine test material immediately after test is completed for
evidence of contamination, oil, or moisture. Test visually and by
touch and smell.
◉ Frequency of Compressed Air Tests. Answer: Refer to
specifications. Always test prior to use and at least once every four
hours thereafter during continuous operation. When relative
humidity is high, test more frequently. If compressor operation is
interrupted for longer than 5 minutes, retest since condensation can
form in the lines.
, ◉ When Compressed Air Test Not Required. Answer: Not necessary
if compressed air will not come in direct contact with the surface,
abrasives used for surface prepartion, or coating or lining materials.
Ex: air used for operation of air driven motors on units for airless
spray painting.
◉ Power Tool Cleaning. Answer: If power tool cleaning is the final
step in surface preparation, dry, oil-free air must be used to operate
air-driven power tools. Power tool cleaning must be followed by
complete solvent cleaning or chemical cleaning if oil is added to the
compressed air supply for the purpose of lubricating air-driven
power tools.
◉ Oil Free Compressors. Answer: Testing still required because they
are still prove to moisture.
◉ Source of Oil Contamination. Answer: Almost always the
equipment, usually caused by worn poston rings. Also could be due
to excessive residual oil in lines caused by malfunctioning oil and
moisture traps. Clogged filters should be replaced and traps should
be coninuously bled so they cannot fill up and overflow back into the
line. Last resort, the compressor requires an overhaul.
◉ Source of Water Contamination. Answer: Air entering the
compressor contains varying amounts of water vapor, depending on
the prevailing ambient temperature and relative humidity. The
saturation point drops as air is compressed, making the air "wetter."
