IRISNDT

THERMOGRAPHY (Infrared)

Everything around us is constantly losing heat to the environment in the form of invisible infrared radiation. We can feel infrared radiation, but cannot see it. The technique for detecting this invisible heat loss is called "Thermography".

This nondestructive testing method provides a visual examination of an object's heat gradient through the use of infrared imaging systems capable of detecting thermal anomalies. With thermography instruments, we can observe infrared radiation on a standard television monitor or video screen. This data can be video recorded or stored on CD's and DVD's for future evaluations. Costly heat related problems caused by poor design, workmanship or material failure in electrical and mechanical systems can be pinpointed.

Thermographic inspections are an indispensable predictive maintenance tool that provides visual evidence of heat related problems.

Thermography can be performed on all organic or inorganic materials. This inspection method measures surface temperatures; therefore, the surface condition can affect the results. Proximity to the item inspected increases the quality of the results; the technician must have a direct line-of-sight to the area of interest.

Some of the main thermography applications are as follows:

ELECTRICAL SYSTEMS & COMPONENTS

The term "Infrared Electrical Inspection" refers to the procedure of utilizing an infrared imaging and temperature measurement system to identify abnormal thermal patterns (qualitative) and deriving accurate temperature measurements (quantitative) of electrical components while they are in service and energized.

These patterns are usually caused by:
Loose, corroded, or deteriorated connections,
Overload conditions,
Load imbalances,
Faulty components.

Infrared inspections can uncover a multitude of potentially dangerous situations. Proper diagnosis and remedial action of these situations can help to prevent numerous major losses. Infrared inspections of electrical systems are beneficial to reduce the number of possible catastrophic equipment failures, therefore preventing major power losses and unscheduled plant shutdowns.

Thermograph and photograph of circuit breaker, showing lose and/or corroded connections (identified by the increased temperature of the connections)

Thermography is commonly performed on motor control centres; motors/generators; batteries/UPS systems; transmission lines; transformers.

Thermography can:
Locate problems quickly, without interrupting service.
Determine priorities for corrective actions.
Minimize preventive maintenance and trouble-shooting time.
Eliminate unscheduled power outages.
Document problems before warranty expires.

Routine electrical inspections should be performed semi-annually because of seasonal loading or operational fluctuations. More frequent infrared inspections should be performed when warranted by:
Equipment failures,
Installation of new electrical equipment,
Environmental conditions,
Operational conditions,
Load change conditions.

COMMERCIAL AND RESIDENTIAL BUILDING ENVELOPES

The thermal performance of building envelopes for new and existing edifications is diagnosed with thermography. Thermography surveys identify roof moisture, envelope heat losses, residential insulation deficiencies and thermal floor tubing heating system anomalies.

Thermography surveys identify building envelope surface temperature variations associated with structural problems. The surface temperature is also influenced by airflow within or through the envelope of the building. Surface temperature distribution analysis can be used to detect thermal irregularities due to air leakage (convection losses) or conductive losses such as deficient insulation, thermal bridging or moisture content.

By identifying the source of the building's thermal irregularities, thermography can play an important role in identifying design, construction, and material problems, as well as deterioration of components constituting the external envelope.

Thermograph and photograph of a building detailing areas where insulation is lacking or missing.

Thermograph and photograph of a refrigerated trailer showing areas with poor insulation.

Thermograph of a low slope roof showing areas of wet insulation.

Thermography can:
Locate missing or damaged insulation.
Identify air leakage, which results in energy loss.
Evaluate the thermal performance of any retrofits.
Identify and locate roof membrane containing moisture degradation.
Reduce costly roof membrane repairs.
Identify small problems before they become serious.
Plan accurate budgets based on facts.
Extend roof life.
Document problems before warranty expires.

PETROCHEMICAL AND REFINERY PRODUCTION PROCESSES AND MACHINERY

Thermography is commonly performed on process machinery; rotating equipment; generators; pumps; steam trap surveys; storage; tank sludge level/build up; boiler and pressure related process systems; furnace tubes; location and assessment of deteriorated refractory lined furnaces.

Thermograph and photograph of a storage tank showing sludge and product levels.

Thermography can:
Identify leaking steam traps, valves and lines.
Locate damaged refractory in furnaces, boilers, and pressure related process systems.
Provide predictive maintenance of rotating equipment.
Serve as an effective quality control tool.
Document problems before warranties expire.

Thermographic inspection results are documented in accordance with client requirements and a report is issued with thermograms and photographs identifying anomalies.