Certified Infrared Thermographer Level II

A thermographer measures a surface temperature of 85°C on a motor with an assumed emissivity of 0.95. The actual surface is bare aluminum with an emissivity of 0.05. The reflected temperature is 22°C. What is the most accurate statement about this measurement?

• AThe reading is accurate because the camera was factory-calibrated
• BReflected ambient radiation dominates the signal, so 85°C is unreliable
• CAn emissivity of 0.05 makes the reading exactly 5% below the true value
• DReflected temperature compensation has no effect once emissivity is entered

Which emissivity correction method is MOST appropriate when you cannot touch or coat the surface being inspected?

• AReference emitter method using black tape applied to the surface
• BContact thermometer readings used to fix a reference temperature
• CReflected apparent temperature from a crumpled foil reflector
• DSetting emissivity to 1.0 and subtracting the background by hand

A Level II thermographer inspects electrical switchgear through a germanium IR window rated at 80% transmittance across the 8-14 um band. The camera measures 68°C on a busbar. What correction must be applied?

• ANo correction is needed because the window rating covers the loss
• BDivide the measured Celsius temperature by 0.80 to get the true value
• CEnter 0.80 as the camera transmittance so it compensates internally
• DAdd 20% to the measured Celsius temperature to offset the window

Using the similar-components column of ANSI/NETA Table 100.18, a busbar connection measures 2°C above a similar connection under similar loading. Which recommended action applies?

• AMajor discrepancy; repair immediately
• BIndicates probable deficiency; repair as time permits
• CMonitor until corrective measures can be accomplished
• DPossible deficiency; warrants investigation

When setting up a camera for an outdoor inspection on a cold day (ambient 5°C), which parameters must the thermographer enter to ensure accurate temperature measurement?

• AObject emissivity only; ambient conditions do not matter outdoors
• BEmissivity, reflected temperature, air temperature, humidity, distance
• CObject emissivity and reflected apparent temperature, but nothing more
• DAtmospheric temperature and humidity only, since outdoor emissivity is 1.0

Black electrical tape of emissivity 0.95 is applied to a painted pipe and allowed to equilibrate. With the camera emissivity set to 0.95 the tape reads 51°C and the adjacent bare paint reads 48°C. What is the correct next step to find the paint emissivity?

• ARaise the camera emissivity on the bare paint until it reads 51°C
• BLower the camera emissivity on the bare paint until it reads 51°C
• CReport 48°C for the paint and 51°C for the tape as measured values
• DAverage the two readings and report 49.5°C as the pipe temperature

ISO 18434-1 governs infrared thermography within machinery condition monitoring. What does it provide for judging the severity of a hot bearing housing?

• AA fixed 60°C alarm limit that applies to every rolling-element bearing
• BA requirement to judge every machine on absolute temperature alone
• CGeneral procedures and comparison methods, but no fixed severity limits
• DA four-zone A to D table carried over from the ISO 10816 vibration work

A thermographer compares two images of the same circuit breaker taken six months apart. The first shows a 4°C difference against a similar breaker; the current image shows 12°C under the same load. The BEST interpretation is:

• ACamera calibration has drifted, so the two images are not comparable
• BThe fault is progressing; shorten the re-inspection interval
• CThe change is within measurement uncertainty and can be disregarded
• DThe fault has stabilised because 12°C is still below the 15°C limit

What is the primary purpose of establishing a thermal baseline for electrical switchgear?

• ATo record the camera model and settings used during the inspection
• BTo give later inspections a reference for detecting thermal change
• CTo establish the ambient air temperature at the time of inspection
• DTo satisfy an OSHA requirement for infrared inspection recordkeeping

Which of the following emissivity values is MOST accurate for polished stainless steel?

• A0.05–0.10
• B0.12–0.18
• C0.45–0.60
• D0.85–0.95

During a building envelope inspection a thermographer observes a cold spot on an interior wall. Under ASTM C1060, the suggested minimum interior-to-exterior temperature difference to hold for four hours before the inspection is:

• A5°C (9°F)
• B10°C (18°F)
• C17°C (30°F)
• D25°C (45°F)

A Level II thermographer reviewing work from a Level I inspector notices the Level I used an emissivity of 0.95 for a copper bus bar and reported a temperature of 74°C. The actual emissivity of the oxidized copper bar is 0.40. What action should the Level II take?

• AAccept the report because the Level I used the camera default value
• BRecalculate with the correct emissivity and amend the reported value
• CRe-inspect with a contact thermometer to confirm the 74°C reading
• DClassify it immediately as a major discrepancy without recalculating

The Stefan-Boltzmann law underlies quantitative IR thermography. Which statement BEST describes its relevance to emissivity correction?

• ARadiated power varies as the fourth power of absolute temperature, so radiance is not pro…
• BRadiated power varies as the square of absolute temperature, so emissivity corrections st…
• CEmissivity correction is unnecessary below 100°C because the law behaves linearly in that…
• DThe law describes ideal blackbodies only and therefore has no bearing on emissivity corre…

A thermographer applies black paint to a small area of a motor housing to use as an emissivity reference. After temperature equilibration, the paint area reads 62°C. The unpainted area reads 58°C with the camera set to the paint emissivity (0.95). What is the most likely explanation?

• AThe motor housing has a higher emissivity than the black paint patch
• BThe unpainted surface has lower emissivity, so it reads too cool
• CThe paint absorbs more heat than the metal, raising its own temperature
• DThe camera field of view is too narrow to resolve the small paint patch

For a flat roof inspection using IR thermography, which environmental condition would MOST interfere with the ability to detect wet insulation?

• AClear sky with significant radiative cooling after sunset
• BRain two days earlier, with the membrane now completely dry
• CStrong wind above 15 mph during the inspection
• DInspection performed within 1 hour after sunset

For an ASTM C1060 thermographic inspection of insulation in frame wall cavities, which inspection mode is preferred for detecting missing insulation?

• AExterior mode in direct sunlight to maximise thermal loading
• BInterior mode during the heating season, interior warmer
• CExterior mode at midday with ambient temperature above 25°C
• DEither mode; the two produce identical results in practice

A Level II thermographer is reviewing a thermal image of a three-phase motor. One phase shows a significantly higher temperature than the other two phases under similar loading. The MOST likely interpretation is:

• AThe camera emissivity was set incorrectly for that one terminal
• BA high-resistance connection or load imbalance heats that phase
• CThe motor is at rated load and this pattern is normal operation
• DThe image must be recalibrated before it can be interpreted

Under ANSI/NETA Table 100.18, a component measured 30°C above the ambient air temperature falls in which recommended-action band?

• AMajor discrepancy; repair immediately
• BPossible deficiency; warrants investigation
• CMonitor until corrective measures can be accomplished
• DIndicates probable deficiency; repair as time permits

When performing quantitative temperature measurement through an IR window with 93% transmittance, the thermographer sets the camera transmittance to 0.93. What additional parameter adjustment is required?

• ANo adjustment beyond the transmittance value is required here
• BThe window's own emission must be compensated as a background term
• CThe target emissivity must be raised by 7% to offset window losses
• DThe distance must be cut by 7% because the window blocks path length

What emissivity value should be used when measuring the temperature of still water or a water-based surface using a longwave IR camera (8–14 µm)?

• A0.50
• B0.72
• C0.85
• D0.98

A thermal image shows a uniform hot pattern across the entire surface of a three-phase transformer. This pattern is MOST consistent with:

• AA single failing high-voltage winding inside the transformer
• BOverall overloading of the transformer beyond rated capacity
• CA loose neutral connection causing unbalanced phase loading
• DAn incorrect emissivity setting producing a uniform offset

Which of the following is a key QA/QC responsibility of a Level II thermographer when reviewing Level I inspection data?

• ARe-inspecting every item the Level I covered to confirm the findings
• BVerifying camera parameters were correct and temperatures are valid
• CApproving all Level I findings because Level I is a qualified role
• DEnsuring the Level I inspector used the newest camera model available

A thermographer inspecting a fuse block finds one fuse at 45°C while adjacent identical fuses under the same load read 28°C. Applying the similar-components column of ANSI/NETA Table 100.18, this 17°C difference calls for:

• APossible deficiency; warrants investigation
• BMajor discrepancy; repair immediately
• CIndicates probable deficiency; repair as time permits
• DMonitor until corrective measures can be accomplished

What is the recommended minimum load level for meaningful electrical IR inspections per industry standards?

• A10% of rated load
• B40% of rated load
• C80% of rated load
• D100% of rated load at peak demand

A Level II thermographer must write a finding report for a medium-voltage switchgear anomaly. Which element is REQUIRED in a technically complete IR inspection report?

• AA photograph of the thermographer performing the inspection work
• BThe camera model's maximum frame rate and detector specification
• CAmbient and load conditions, camera settings, and recommended action
• DA comparison of the camera's purchase cost against competitor models

Which emissivity value is MOST accurate for heavily oxidized carbon steel at temperatures above 200°C?

• A0.05–0.10
• B0.20–0.30
• C0.60–0.80
• D0.95–0.99

An opaque surface has an emissivity of 0.65. In the camera's radiometric equation, what fraction of the background radiation falling on that surface is reflected back toward the camera?

• A0.02, or 2 percent
• B0.10, or 10 percent
• C0.35, or 35 percent
• D0.65, or 65 percent

During a mechanical inspection, a bearing housing shows a temperature of 72°C with a baseline from six months ago of 55°C. Load and ambient conditions are identical. The rate of temperature rise is most concerning if:

• AThe rise occurred gradually across six months at a stable load
• BThe rise occurred within the last two weeks under a stable load
• CThe rise tracks a seasonal increase in the ambient temperature
• DThe baseline was recorded at a higher load than the current one

Which of the following materials has an emissivity closest to 0.95 and requires the LEAST emissivity correction for accurate temperature measurement?

• APolished aluminum
• BUnoxidized copper
• CFlat black paint
• DGalvanized steel

A thermographer inspects overhead power lines from a safe distance of 15 metres. Which parameter matters far more here than it would during a 1 metre indoor inspection?

• AEmissivity assigned to the aluminium conductor surface
• BAtmospheric attenuation from humidity and path length
• CThe camera's frame rate in frames per second
• DThe physical size of the detector array in pixels

A Level II thermographer receives thermal images of motor stator windings captured by a Level I inspector. The images show the emissivity was set to 0.95 for varnish-coated copper windings. The Level II determines this is:

• AIncorrect — varnish-coated copper windings have emissivity of approximately 0.30
• BCorrect — varnish and enamel coatings have high emissivity near 0.90–0.95
• CIncorrect — bare copper emissivity of 0.03 should have been used
• DCorrect — all electrical winding temperatures should be measured at ε=0.95

ISO 18434-1 describes comparative thermography. What is the recommended way to assess bearing temperatures on two identical machines running under identical conditions?

• ACompare the absolute housing temperatures on the two machines
• BCompare the difference between corresponding components on each unit
• CCompare each machine's bearing temperature against the ambient air
• DCompute the average of the two machines and compare each to that mean

A thermographer detects a hot spot on a 480V motor control center bus bar, but the load is only 18% of rated. The ΔT compared to adjacent bus bars is 9°C. What is the BEST action?

• AReport it as a probable deficiency based on the 9°C difference
• BDocument it, note the load was under 40%, re-inspect under load
• CReport it as a major discrepancy because low-load faults worsen
• DLeave it out of the report; 9°C is normal variation at any load

What is the purpose of the 'reflected apparent temperature' (RAT) measurement in quantitative IR thermography?

• ATo find the surface temperature of individual hot objects nearby
• BTo compensate for the reflected share of the received radiation
• CTo calibrate the camera against its internal blackbody reference
• DTo measure the temperature of the camera lens during the survey

An IR inspection report on electrical equipment must document load conditions at the time of inspection because:

• AOSHA regulations require load documentation for electrical inspections
• BResistive heating scales with current squared, so load sets severity
• CLoad data is needed in order to calculate the camera's field of view
• DInsurance carriers require load data as a condition of policy cover

A thermographer inspecting a high-voltage substation measures a suspension insulator string. One insulator disk shows a uniformly cool pattern compared to adjacent disks under voltage stress. This is MOST consistent with:

• ANormal unit-to-unit variation in disk capacitance
• BA cracked or shorted disk carrying no voltage gradient
• CSuperior insulation quality causing less leakage current
• DA camera emissivity error on the glazed ceramic surface

Which of the following scenarios would produce the MOST accurate temperature measurement using a non-contact IR camera?

• APolished aluminium pipe at 1 m, emissivity 0.95, no reflected value
• BBlack rubber gasket at 1 m, emissivity 0.95, reflected value 22°C
• CPainted steel at 15 m, emissivity 0.90, no atmospheric correction
• DGalvanised conduit at 1 m, emissivity guessed 0.20, reflected 25°C

A thermographer discovers a Level I inspector reported a 25°C temperature differential on a circuit breaker but failed to note the load at the time of inspection. What is the Level II's appropriate response?

• AAccept the finding and classify it from the 25°C difference alone
• BReject the whole report and require a complete site re-inspection
• CRecord severity as indeterminate and re-inspect at documented load
• DReduce the severity by one band to allow for the missing load data