The threat of a virulent strain of influenza, severe acute respiratory syndrome (SARS), tuberculosis, H1N1/A virus
(swine flu) and possible mutations are a constant threat to global health. Implementation of pandemic infrared
thermographic screening is based on the detection of febrile temperatures (inner canthus of the eyes) that are correlated
with an infectious disease. Previous attempts at pandemic thermal screening have experienced problems (e.g. SARS
outbreak, Singapore 2003) associated with the deployment plan, implementation and operation of the screening
thermograph. Since this outbreak, the International Electrotechnical Commission has developed international standards
that set minimum requirements for thermographic system fever screening and procedures that insure reliable and
reproducible measurements. These requirements are published in IEC 80601-2-59:2008, Medical electrical equipment
- Part 2-59: Particular requirements for the basic safety and essential performance of screening thermographs for
human febrile temperature screening. The International Organization for Standardization has developed
ISO/TR 13154:2009, Medical Electrical Equipment - which provides deployment, implementation and operational
guidelines for identifying febrile humans using a screening thermograph. These new standards includes
recommendations for camera calibrations, use of black body radiators, view field, focus, pixels within measurement site,
image positioning, and deployment locations. Many current uses of thermographic screening at airports do not take into
account critical issues addressed in the new standard, and are operating below the necessary effectiveness and efficiency.
These documents, related thermal research, implications for epidemiology screening, and the future impact on medical
thermography are discussed.
Issues concerning the certification of thermographers continue to command a great deal of interest within our profession
and among the customers we serve. A recent literature search suggests the topic is as poorly understood as ever.
In the United States the only viable means of establishing certification is through compliance, to one degree or another,
with the standards and guidelines of the American Society for Nondestructive Testing (ASNT). These means, which,
interestingly, also serve well the needs of ten additional NDT methods, are widely recognized throughout much of the
rest of the world.
Unfortunately for thermographers and their customers, ASNT-compliant certification for our NDT method has failed to
gain significant "traction" over the years despite being used by a number of large companies and for many critical
applications. The reasons are numerous and diverse. However, the gap has also not been filled by any other viable means
of certification. One of the consequences of our failure to embrace uniform, meaningful certification is that our impact
has been inconsistent and falls far short of the optimum possible.
The framework for qualifying and certifying thermographers still exists, ready, as it has been since 1992, to be filled and
used effectively in all applications.
In this paper we discuss the thermal properties of water as they relate to the structures, buildings in particular, thermographers routinely inspect. Interestingly, it is the unique thermal properties of water that allow us, under the right conditions, to locate its very presence in a building. Unfortunately, when conditions are less than ideal, water is often all but impossible to detect thermally. It is important then, to understand both the properties and behavior of this common substance as well as the conditions that cause it to be revealed.
To this end we will also show examples of the interaction of water and heat and the surrounding materials as we observed them in several controlled situations. We will also apply the lessons learned to a wider variety of real world thermal imaging situations
Thermography is a powerful tool for locating or verifying levels
in tanks and silos. But one could ask “Why bother?” All too often
existing level indication instruments are simply not reliable or
positive verification of instrumentation readings is required.
When properly used, thermography can reveal not only the
liquid/gas interface, but also sludge buildup and floating
materials such as waxes and foams. Similar techniques can be
used to locate levels and bridging problems in silos containing
This paper discusses the parameters and limitations that must be
addressed, shows techniques that can be employed, and illustrates
the discussions with numerous thermal images.
Thermography is widely used for inspecting electrical systems where costly problems are often preceded by telltale thermal signatures. Many thermographers, or their customers, however, mistakenly rely on radiometric temperature data to prioritize these findings. Due to the inherent limitations of radiometry and the complexities of heat transfer in the components being inspected, the data is all too often either inaccurate or misunderstood. Routinely, however, thermographers proceed as if nothing is amiss. This is due to an understandable, but misguided, attempt to simplify the decision-making process regarding repair priorities. The result is that predictions of repair priorities are not as accurate as they could be. On the one hand failures still occur while on the other repairs are often made inappropriately. In this paper we discuss the problems encountered when collecting and interpreting radiometric data. We will also outline a simple, effective system that thermographers are using to dramatically improve the predictive value of the technology. Improved results are achieved first separating the often intertwined questions of 'when will the component fail?' and 'what will be the consequences of failure?' The second improvement comes from incorporating all relevant data in the decision making process and weighing the impact each has. The system described, which can easily be adapted to diverse needs, is being used successfully and with repeatable results that have been shown to improve with usage.
Thermography has been used with great success for number of years to inspect building fenestration, both during design and production, as well as after installation.1 Typically double-glazed windows exhibit a well-understood pattern of increased heat loss around the perimeter, due mainly to thermal bridging or edge-effect losses. In this paper we present the findings of an investigation about a very different, and unusual, thermal pattern discovered on windows in the home of one of the authors. The pattern was first illuminated by condensation in the central portion of the window. This thermal pattern was verified with a radiometric thermal imaging camera as well as thermal contact probes. After additional investigation we found the cause of this anomalous pattern is related to the loss of some of the insulating argon gas installed in the window during manufacturing. We also discovered the problem was a not uncommon for certain types of windows. As these windows age, the problems usually become more pronounced and, in some cases, a total failure of the window by implosion results. We hope that publication of this information will rove useful to others who may have been mystified after seeing similar patterns.
Thermographers are often at risk when inspecting electrical systems. While electrocution is always a hazard, a far greater danger is injury associated with accidental exposure to an arc flash explosion. Because of the potential for serious injury, and because of new government regulations, more and more companies are now taking steps to prevent arc flash injury and to minimize damage if and when it does occur. In this paper, which would not have been possible without the able assistance of Lowry Eads, global resource for infrared thermography in Dupont, I will discuss why arc flash explosions happen and what damage they can do; I will also show how thermographers can both reduce their risk of being exposed to one and, if they are exposed, their injury from the explosion.
Inspecting compression splices on transmission and distribution lines has long been accomplished using infrared thermography but the results have too often been disappointing. There are instances of splices failing within months of infrared inspections. An understanding of the actual condition of the splices had been `masked' by one or more of the factors discussed in this paper. A number of factors are involved, including a poor understanding of the application of the technology; inadequate training of some service providers; environmental factors; low electrical loading; the resolution limitations of the inspection equipment; low emissivity of the components, and a poor understanding of how to interpret the data.
The American Society of Nondestructive Testing (ASNT) has recently established a new central certification program. This program will allow individuals who meet the requirements to receive a 'portable' certificate. Augmenting the existing employer-based certification, this program will have significant impact on industries that may ultimately require nondestructive testing (NDT) personnel to have central certification. This paper explains show ASNT has structured central certification and when and how it will effect thermal/infrared thermography (T/IRT) personnel. The paper also discusses the industry specific certification process.
Hydraulic systems are the life blood of many industrial processes, especially the many forming presses used in the automotive industry. The loss of a press due to a hydraulic system failure can be very expensive, both in terms of reduced machine availability and diminished product quality. Thermography has proven to be an excellent maintenance inspection tool because the performance of hydraulic systems are easily characterized by their thermal signatures. Thermography also provides instantaneous, real time thermal data which is essential to understanding a dynamic system like hydraulics. This paper, based on many of Milan Plastics' six years of experience with hydraulic systems, outlines the key components that can be inspected with thermography and discusses problems that are typically found.
Written inspection procedures are an essential element of acquiring valid data on a repeatable basis. They are also vital to the safety of the thermographer, and may, for that reason alone, be required by a company or regulatory agencies. Many thermographers are working with either no procedures or procedures that have not been developed specifically to meet their needs. To date only a few of the necessary procedures have been developed by recognized standards organizations. The lack of procedures is limiting the use of thermography. Where the technology is being used without procedures, results are often less than optimum. This paper (1) surveys existing procedures and standards; (2) discusses current efforts by standards organizations to develop standards and procedures; and (3) presents a general methodology from which written inspection procedures can be developed for many thermographic inspections.
The primary value of using infrared thermography to inspect electrical systems is to find problems made apparent by their thermal differences. Thermographers have also begun collecting radiometric temperature data as quantitative imaging systems have become more reliable and portable. Throughout the industry the use of temperature data has become a primary means of prioritizing the severity of a problem. The validity of this premise is suspect for several reasons, including the lack of standard data collection methods; the often poor understanding of radiometric measurements by maintenance thermographers; field conditions that vary widely enough to defy standardization; and the almost total lack of scientific research on the relationship between heat and time with regard to the failure of the components being inspected. Several possible solutions to the problems raised, as well as other suggestions for improving the usefulness and reliability of qualitative inspections, are offered.
The success of a thermographic program hinges on many factors. These include, among others, the selection of appropriate inspection equipment training of personnel having the necessary backgrounds and technical skills; and creating a management plan. Also critical to success is developing the day to day protocol of the program. These guidelines and procedures not only help the thermographers optimize their inspections, they also ensure the fmdings will produce maximum benefits within the organization. This paper discusses a general protocol of operations developed from examples of practicing thermographers. During the early stages of developing a program, there is protocol that creates an organizational climate conducive to utilizing thermography, while also establishing some of the logistics needed to support inspections. The inspections themselves benefit greatly from structure—everything from plotting inspection routes to creating data files. After the inspection further protocol suggests how the fmdings will be analyzed and reported. Other issues, such as safety, education, and designing inspectable equipment, must be addressed on an on-going basis to maintain and refme a program. While no single protocol is right for all situations, the generalizations presented in this paper will serve as a valuable framework for many thermographers, both those who work within organizations as well as those providing consulting services. We have found the end result of a well developed protocol is a more efficient inspection program and a program that produces higher quality and more consistent benefits.
This paper summarizes the results of a survey of over three hundred maintenance personnel who use imaging equipment within their company or organization. All had previously participated in one or more of our training programs. The companies took in a broad range of industry, including, among other, power generation, pulp and paper, metals, mining, petrochemical, automotive and general manufacturing. The organizations were mainly quite large, either commercial or public, and included governmental agencies, military, colleges and universities, municipalities, and utilities. Although we had a very tight time line for the survey, we were pleased to have a 15% response rate. The results show that some of the causes of success and failure in infrared programs are not unlike those associated with any type of program in an organizational structure, i.e. the need for accurate and timely communications; justification requirements; etc. Another set of problems was shared more closely with other startup maintenance technologies (for example, vibration monitoring), such as the need for trending data; providing appropriate technical training; achieving reproducible results; etc. Finally, some of the driving mechanisms are more specific to this technology, such as re-designing equipment so that it can be thermally inspected; establishing effective documentation strategies; etc.