Infrared thermography has been used in medically related litigation for several years. In past years its use has increased in areas of non-medical litigation. The use of infrared thermography in non-medical legal matters usually revolves around complex technical issues connected with loss or life or loss of property. Losses involving fire and explosion often deal with heat transfer phenomenon readily observed and recorded by infrared scanners. Infrared thermography is a powerful visual media that simplifies the presentation of physical phenomenon to lay people who often decide as judge or jury the outcome of a court action involving a loss. Several examples of infrared thermography utilized in fire and explosion investigation are presented. Examples of infrared thermography usage in fire origin investigation, explosion investigation, equipment failures and potential equipment failures are presented.

A certification is granted to show that an individual has the qualifications to perform a function. These qualifications may include certificates of completion. This paper will discuss these terms in the context of their use in industry and in the professions.

This paper provides information about the Infraspection Institute program which serves the infrared thermographic industry. We focus on the Institute's certification program, including what it is, who develops the examinations and how a person can become a Certified Thermographer.

Over the years, constant developments and improvements have been made in the portability of infrared equipment. The ability to move around and travel from job to job easily greatly enhances the effectiveness of most in-field infrared thermographic surveys. Many vehicles have been modified to offer mobile infrared thermographic services. This paper describes one approach, and the results, to mobile infrared thermography. It covers the various stages in adapting a vehicle for mobile infrared thermography (IR) and problems encountered along the way. Originally designed for scanning electrical distribution lines, the "IR Van" also serves as a mobile unit for building diagnostics. The paper addresses building diagnostic applications for mobile IR and some of the findings recorded during an initial community investigation.

A comprehensive data base is a critical component of a cost-effective bridge management program. Data is needed in order to assess the overall condition of the bridge network, establish priorities for repair, select the most appropriate methods for bridge repair, and prepare contract documents. The most practical and economic method of collecting this information is to use indirect measurement. techniques. Such non-destructive techniques do not directly measure the physical properties of the structure and the condition must be inferred using signal processing methods. A number of bridge testing techniques were investigated by the Ontario Ministry of Transportation over a period of almost ten years. The product of the studies is the Deck Assessment by Radar and Thermography (DART) system. As the acronym implies, DART utilises two basic systems: impulse radar and infrared thermography. This paper describes the main features of the DART infrared system. A theoretical two-dimensional heat transfer model for estimating temperature profiles in bridge decks is also presented. Actual temperature measurements are provided for comparison with the theoretical model.

Thermography is an extremely useful tool for the investigation of roofing problems, such as wet or missing insulation, which manifest themselves as thermal anomalies. However, there are many conditions which can significantly affect the pattern of thermal anomalies on the roof. In fact, under certain conditions, the images of the thermal anomalies may disappear or become indistinct and roof scanning cannot produce any useful information. The problem that the thermographer faces is that these conditions can change, sometimes radically, over the course of a single evening. It is, therefore, essential that the thermographer understand under what conditions the "scanning window" will be open. The expression "scanning window" is a convenient term which refers to the cumulative effect of a number of conditions which affect thermal images. When the scanning window is open, the thermal images from the scan generate useful information for roofing analysis. When the scanning window is closed, it is impossible to obtain any useful information from the thermographic scan. The factors that affect the opening and closing of the scanning window for roofing applications will be discussed in this paper.

This paper deals with the development of a diagnostic testing and calibration system for infrared imaging equipment used in building analysis. The purpose of the research, conducted between 1982 and 1985, was to investigate, measure and document thermographic equipment performance under conditions in which building science investigations are carried out. The research focused on obtaining calibration data collected under a wide range of repeatable, laboratory controlled and simulated climatic conditions. Three hundred tests on twelve government owned thermal imaging systems were conducted. It was found that while object surface temperature played a more significant role than environment in the accuracy of temperature measurement, scanner drift increases as environmental temperatures increase. Of significance was the finding that the calibration curves used prior to this research did not accurately predict measurements in Canadian winter climate, particularly on surfaces below OoC. Of additional importance, was the discovery of other curve fitting formula for predicting instrument performance which is more accurate than the previous used. Although tested equipment was owned by one entity which may have biased results due to use, care and high level of preventative maintenance, significant variance was found in comparison of similar thermographic systems. The findings of this research will also benefit the private sector, provincial, and foreign governments their agencies and standards organizations.

Airborne infrared roof moisture surveys can be conducted by using the following method. Maps of the area and plans showing the location of buildings to be surveyed are studied prior to the flights. Permission for the flights is secured and local authorities are notified of the work. An infrared imaging system is mounted on the helicopter and headsets are installed to ensure that all members of the team can communicate. Color airphotos are obtained of each roof early in the afternoon. The flight crew and the spotter are each provided with maps of the installation, with numbers and highlighting used to indicate each building to be surveyed. The spotter has a clear plastic overlay on his copy that he marks to indicate buildings completed. The daytime photographic flight serves to train the team for the more difficult thermographic survey that evening. The color film is submitted to an over-night print processor just after the flight.

A comprehensive roof moisture survey includes visual examination, non-destructive testing for roof moisture, and professional engineering analysis with recommendations for repair. This paper provides a case history which illustrates the importance of these essential elements for cost-effective maintenance of built-up roofing.

Detailed analysis of thermographic data for 440 km (250 miles) of district heating networks demonstrates that there is a strong connection between the condition of the heating culvert and the radiative surface temperature and surface temperature pattern. Provided the thermogram has a good geometric image it is possible to make an accurate determination of the position and extension of the damage of the culvert. However, to get this results one got to know what infrared system to use for a specific application, how to operate it, and during what weather conditions. In this paper is presented a project aiming at developing operational routines, and determining operational advantages and limitations for airborne and groundbased thermography for district heating applications. A comparison is made of the information content of thermograms from an airborne longwave infrared line-scanner, helicopterborne and groundbased mobile longvawe Thermovision. Thermal registration was performed repeatedly, for the same investigation area, during similar weather conditions. Evaluation of operational advantages and limitations for the different systems used was performed according to (a) an indicating method (qualitative), mainly pointing out areas with undefined damage of culverts, and (b) an analysis method (quantitative) , which gives temperature classified data for determing the condition of the network studied.

In this paper is discussed the conditions for applying aerial or groundbased thermographic methods to the detection of sites of leaks or not properly functioning insulation on buried hot water or steam distribution pipes. A comparison is made between a set of climatic criteria for the application of thermographic methods and statistics from meteorological records. It is demonstrated how different climatic criteria may reduce the number of occasions in a year and the length in hours of every occasion where thermographic methods can be applied. Using an analytic model, an analysis is made of how different environmental factors affect the surface temperature profile above a buried pipe. The influence of factors such as thermal properties of the ground and rapid variations in the heat transfer mechanisms between the ground and the athmosphere are discussed.

The Army's program for Infrared Automatic Mass Screening (TRAMS) of printed circuit boards was described in last year's THERMOSENSE proceedings. Two systems were deployed. The first system was installed at an Army depot for where day-to-day mass screening could be performed and a test data base could be developed. The second system was installed in an infrared nondestructive inspection (IRNDI) laboratory where failure mechanisms could be studied in greater detail. The TRAMS preliminary research plan was submitted and accepted for the period extending through Fiscal. Year 1988. This paper will review the original aims of the program, discuss progress to date, and project plans for the future utilization of the TRAMS systems.

Traditionally, Infrared Thermography, when used for printed circuit board applications, has been used only as a tool to isolate defects in printed circuit boards so that they may be repaired and returned to the manufacturing line. There are many processes involved in the manufacturing of printed circuit boards, all of which must be under control to ensure the manufacturability of a quality product. Process excursions result in defective boards that may or may not be able to be repaired. Those that are repairable are generally repaired at a substantial expense. This large expense is justifiable due to the fact that many of today's printed circuit boards are complex, multi-layered printed circuit boards which are very expensive to manufacture and therefore, represent a substantial investment in the final form. Infrared Thermography may be utilized, not only as a tool to locate defects within a product, but also as a tool for process control for the identification of process excursions, however infrequent. With adequate identification methods and proper communications within the manufacturing environment, these process excursions can be identified and resolved with minimum manufacturing impact. This paper addresses the impact Infrared Thermography has had on process control at one particular plant, and how others may utilize these tools to facilitate process controls for their individual applications.

Monitoring and Analyzing the Dynamic Junction Temperature Distribution of RF Power Transistors by Using RM-50 Infrared Micro-Imager

Infrared thermographic nondestructive inspection of superplastically formed diffusion bonded (SPF/DB) titanium structures is discussed. Nondestructive testing (NDT) of the structures produced by this recently developed method is vital for construction of modern fighter aircraft. Forming and bonding parameters can be optimized by proper interpretation of NDT results. Currently, ultrasonic inspection is used for NDT on these parts. In an effort to reduce cost and inspection time required by ultrasonic testing, a thermographic investigation of panel response to rapid heating was undertaken. Panels were uniformly illuminated for a duration of up to four seconds by high intensity lamps. Infrared images of temperature variation due to panel thickness were observed. Correlation of thermograms with ultrasonic and destructive investigations indicate that lack of bonding and panel formations can easily be observed. We have demonstrated that thermographic inspection provides an equally sensitive and lower cost alternative to ultrasonic inspection. Finally, thermographic inspection facilities for large scale inspection are suggested.

The ability to monitor manufacturing processes in an adaptive control mode and perform an inspection in real time is of interest to fabricators in the pressure vessel, aerospace, automotive, nuclear and shipbuilding industries. Results of a series of experiments using infrared thermography as the principal sensing mode are presented to show how artificial intelligence contained in infrared isotherm, contains vast critical process variables. Image processing computer software development has demonstrated in a spot welding application how the process can be monitored and controlled in real time. The IR vision sensor program is now under way. Research thus far has focused on fusion welding, resistance spot welding and metal removal.

Infrared thermography, down through the years, has most typically been applied to inanimate objects, for example; building enclosures, roof assemblies and several others. With the significant advancements in computers, thermographic software/hardware and scanning techniques, the application field has advanced dramatically. Recently, the Canadian Government's Public Works Regional Facilities Maintenance and Agriculture branches have devoted numerous man-hours to thermographically scanning various livestock, such as; cattle and swine. These totally new research experiments are possibly embarking on new solutions for Agriculture Canada's livestock exporting ventures. The primary influencing factor which Agriculture Canada is trying to analyze and manipulate is stress. Significant research into human related stress has proved invaluable. In comparison, little is known concerning animal stress. The end result which all wholesalers, retailers and consumers are concerned with is, top quality meat products. These high quality products are especially desired by foreign countries. Thermography has given the scientists at Agriculture Canada the inside track for inspecting an animal prior to and during the initial meat processing process, for monitoring meat quality related to stress. This paper reveals the present day innovative research techniques which the Canadian Government is conducting on beef cattle.

At the last Thermosense conference, many individuals expressed concern regarding the issue of performance guidelines. This became the focus of last year's Facilities and Utilities Subcommittee. Information was requested from those in attendance at that meeting who expressed a desire in developing guidelines for electrical distribution surveys. The information received came from large insurance companies to private infrared service firms. From the review of the information, key issues identified were safety and "how hot is too hot?". The greatest concern involves recruiting active members for the workshop group. Arranging meetings is difficult with such a wide spread group of thermographers. It is one of the goals of the Facilities and Utilities Workshop Subcommittee to organize some method of communication and feedback.

Electrical bus duct is a common feature in both manufacturing facilities and high rise buildings. In the past, bus duct testing involved labor-intensive manual inspection and maintenance and a significant power outage. Infrared thermography can be useful in situations where bus duct loads are balanced and uniform; however, these conditions are not usually found in the field. Resistive load banks combined with infrared thermography provide a controlled and accurate non-destructive test method for electrical bus ducts. Labor and downtime are both reduced and testing may be varied from light to full load.

Five California Utilities participated in an electric power transmission and distribution system survey in the late fall of 1987. The survey consisted of visual and Infrared (IR) inspection of 12.5-kV to 230-kV AC transmission lines and equipment. This paper summarizes the results of the survey, including a cost/benefit analysis. The participating utilities, under Western Area Power Administration's sponsorship, were the City of Lodi, City of Roseville, Plumas-Sierra Rural Electric Cooperative, Sacramento Municipal Utility District, and Sierra Pacific Power Company. Three hundred miles of line and thirty substations were inspected using a helicopter and a high resolution infrared camera with visual recording capabilities. The transmission and distribution system covered a broad range of terrain; valleys, foothills, and mountains. All five utilities recognized the value of the IR inspection. The procedure gave the maintenance staff advanced notice of problem areas such as (1) loose connections on switches, (2) unbalanced lines, (3) poor splices, and (4) capacitor and transformer bank malfunction. In addition, the staff saw its potential in environmental and safety applications. The initial data shows an increased capacity carrying and reliability providing capability of about 50 KW per 100 transmission line miles. This capability increase results in a B/C ratio of about three. Other applications in transmission system surveys are worthy of study. These applications include power theft and vandalism. Also, the Utility can use technology as an effective public relations tool with customers by providing services such as roof and building envelope inspections.

For the past ten years Ontario Hydro has used mobile infrared thermographic equipment as an integral part of its substation maintenance program. Because of the geographic size of the Province of Ontario, the frequency of inspection required, and the capital cost of the inspection equipment, each region carries out its own thermographic inspection using mobile equipment provided by Head Office. In order to provide a high level of diagnostics and information transfer, the latest generation of van has been outfitted with a thermal imager which is not gas or nitrogen cooled, a video camera, computer, printer and custom analysis software. Both the thermal and video images are digitized, redisplayed and analyzed by the computer, with only supervisory input from the operator. A report, complete with images, is automatically printed in the van and as well, a file is created which is sent to the Head Office for review, storage, and inclusion into a maintenance data-base. The use of automatic data collection and expert-system based software effectively leads the part-time operators through the complex operation of the equipment, radiometric quantification, and common interpretation of the thermal imagery.

When a sewer caves in, it often takes the street, sidewalks, and surrounding buildings along for the ride. These collapses endanger public health and safety. Repairing a sewer before such a cave-in is obviously the preferred method. Emergency repairs cost far more than prevention measures - often millions of dollars more. Many combined sewers in the St. Louis area, as in many of America's cities, are more than 125 years old and are subject to structural failure. In 1981 alone, St. Louis had 4,000 sewer collapses and an astronomical repair bill. These and similar problems have been described as "a crisis of national proportions. The question addressed by this paper is how to detect unseen problem areas in sewer systems before they give way. At the present, progressive sewer administrations may use crawl crews to inspect sewers when problems are suspected. This can be extremely costly and dangerous, and a void around the outside of the sewer is often invisible from within. Thus, even a crawl crew can fail to detect most voids. Infrared Thermography has been found by sewer districts and independent evaluation engineering firms to be an extremely accurate method of finding sewer voids, before they can cause expensive and dangerous problems. This technique uses a non-contact, remote sensing method, with the potential for surveying large areas quickly and efficiently. This paper reviews our initial paper presented to The International Society for Optical Engineering in October of 1983 and presents an update of our experience, both successes and failures, in several large-scale void detection projects. Infrared Thermographic techniques of non-destructive testing will have major implications for cities and for the engineering profession because it promises to make the crisis of infrastructure repair and rehabilitation more manageable. Intelligent, systematic use of this relatively low cost void detection method, Infrared Thermography, may revolutionize the way sewer problems are handled in the future.

A plug calibrator is a solid piece of metal with thermocouple or thermistor instrumentation embedded near a viewing surface. A heat source controls the temperature of the plug which is measured by the thermocouple and assumed to be that of the surface. An infrared imager views the surface obtaining a calibration at various temperatures. This paper reviews several designs for plug calibrators and their utility in quantitative analyses. Calibrator design parameters such as internal thermal resistance, location of instrumentation, surface quality and heat source location are discussed. The plug calibrator is a useful tool in quantitative analyses.

This paper presents a numerical approach to analyzing thermography data. In this method, referred to as the hybrid technique, measured surface temperature data is used to derive a set of interpolation and extrapolation functions for an entire surface. Although a number of constraint equations can be used in deriving these functions, the heat conduction equation was chosen here in an attempt to retain some physical characteristics of the surface behavior. Surface temperatures obtained from an application of the hybrid method are compared to those obtained in an independent finite element computation.

Temperature measuring on targets with low emissivity is difficult to take in the range of 0,1 - 0,2 by conventional methods and measuring equipment. In the temperature range below 200°C this type of measuring can not be carried out at all. Due to the low emissivity, the measuring result is to a large extend distorted by the ambient radiation reflected on the target. In addition to this, the emissivity is not exactly known in most cases and can change in the course of measuring. The innovative measurement system cited above is an answer to these difficulties. It is operated by 2 pyrometers of the same wavelength. Ambient conditions are defined for both pyrometers and measured as well. All signals are fed into a computer-aided interpretation system and are subsequently interconnected. The actual emissivity as well as the target temperature can be retrieved from this data.

Based on encouraging results on the Army's programs for infrared mass screening of printed circuit boards at the depot level, the US Army CECOM (Communication-Electronics Command) undertook a one-year investigation of the applicability of similar techniques to screening and diagnostics of mechanical assemblies. These included tanks, helicopters, transport vehicles and their major subassemblies (transmissions, engines, axles, etc.) at field and depot levels. Honeyhill Technical Company was tasked to classify candidate assemblies and perform preliminary measurements using Army-owned general-purpose thermal imaging equipment. The investigations yielded positive results, and it was decided to pursue a comprehensive measurements program using field-mobile equipment specifically procured for the program. This paper summarizes the results of the investigations, outlines the measurements techniques utilized, describes the classification and selection of candidate assemblies, and reports on progress toward the goals of the program.

Infrared Signature Analysis: Real Time Inspection of Manufacturing Processes

The electromagnetic(EM) scattering from a solid metal cylinder and a solid metal cylinder with a complex coating is investigated experimentally. Infrared detection of the heating patterns produced on a thin lossy carbon screen by the scattered EM field is used to map this field. Results are presented in the 2 to 4 GHz range at several angles of incidence.

The measurement of temperature and emissivity of objects is of significant importance in science, industry, and other areas. A lingering question regarding the validity of temperature and emissivity values determined using two-color ratio radiometric measure-ments has been answered. Although generally valid, certain spectral-band configurations can produce ambiguous results. General guidance in the selection of the spectral bands to maximize the sensitivity of the ratio with respect to temperature is presented. Several techniques to measure the emissivity of materials are discussed along with representative experimental results.

A hush house is a hangar-like structure designed to isolate, from the surrounding environment, the noise produced by extended aircraft engine operations during diagnostic testing. While hush houses meet this intended need by suppressing audible noise, they do emit significant subaudible acoustic energy which has caused structural vibrations in nearby facilities. As a first step in mitigating the problems associated with hush house induced vibrations, it is necessary to identify the mechanism responsible for the low frequency acoustic emissions. It was hypothesized that the low frequency acoustic waves are a result of acoustic Cherenkov radiation. This radiation is in the form of a coherent wave produced by the engine exhaust gas flow. The speed of sound in the exhaust gas is quite high as a result of its elevated temperature. Therefore, the gas flow is sonic or subsonic relative to its own sound speed, but is supersonic relative to sound speed in the surrounding cooler air and, as a result, produces acoustic Cherenkov radiation. To confirm this hypothesis, thermographic surveys were conducted to image the thermal structure of the engine exhaust gas within the hush house. In the near-field, these images revealed that the exhaust gases did not behave like a high Reynolds number turbulent jet, but rather, the transition to turbulence is delayed by a suppression in growth of the self-excited instability wave as a result of acoustic Cherenkov radiation.