Megger Building and Industrial Thermal Imagers
Building and Industrial (Commercial) Thermal Imagers save time, energy, reduce downtime, and find problems that exist before failures or disasters occur. Thermal Imagers are used to measure surface temperature and temperature differential and are especially important when attempting to locate existing or potential problems. They are now considered to be an essential tool utilized in many industries for evaluating operating conditions, machinery safety, personal safety and building diagnostics used in, but not limited to, Process Control, Predictive Maintenance and Building Diagnostics. They are used by consultants, electrical contractors, mechanical contractors and personal safety professionals in wide and varied applications World Wide.
The following images are representative of observations in the Industrial marketplace using a Thermal Camera. Figure A displays liquid level in a tank and Figure B displays the condition of fuses in a circuit. Figure C details a three phase connection and Figure D shows the equivalent Thermal Image. Notice the possibility of problems in connections of Figure D and the condition of fuses in Figure B. These are typical pieces of information that assists the facility manager when reviewing existing conditions.
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Figure A: Liquid Level
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Figure B: Fuses in a Circuit
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Figure C: 3 Phase Connection
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Figure D: Thermal image of Fig. C
Below Thermal Image (Figure E) of a motor bearing details the significant temperature differential of the bearing to the motor case and a possible cause for concern. In Figure F, the utility transformer observed may have an internal fault.
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Figure E: Motor Bearing
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Figure F: Utility Transformer
The following images are representative of applying a Thermal Imager used for Building Diagnostics. Figures G and H indicate possible missing or damaged insulation. Note that Figure H displays possible water ingress in the ceiling corner and Figure I details possible water damage to a roof.
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Figure G: Residential
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Figure H: Building
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Figure G: Ceiling Leak![thermal_roof]()
Figure H: Rook Leak
Thermal Imagers do not use visible light that the human eye might see, but measure the infrared energy, or thermal energy, radiated from their surface. Since surfaces do not behave in a standard manner by which energy is radiated, we use emissivity to adjust for surface and radiated energy. The result image that you see is a combination of many variables, but always includes the lens you choose, the pixel matrix and the sensitivity of the detector. Many cameras have built in unique and important characteristics. See below for parameters that may be important to your application.
Thermal Imaging provides information on your system and application that otherwise would not be known until a problem becomes evident. It is an important tool to use in evaluating conditions that are important in day to day operation. For complete product information and details on what product may provide the very best results based on your needs and application, please call and speak to our Certified Level I Thermographer and other Experts.
Typical Professions using Thermal Imagers
- Building Inspectors: Industrial, Commercial, and Residential
- Electricians and Electrical Contractors
- General Contractors
- Industrial and Residential Building Diagnostic Consultants
- Plant and Building Maintenance Professionals and Managers
- HVAC Electrical and Mechanical Contractors
- Mold Remediation Professionals
- Roofing Specialists
Typical Applications for Thermal Imagers
- Utility. Transformers, Insulators, Hipots, Transmission Towers
- Electrical. Unbalanced Loads, Overloads, Wiring, Circuit Breakers, Motor Windings, Rotating Belts, Couplings, Control Panels, Component Failure, Fuses, Switches, Circuit Boards
- Mechanical. Steam Traps, Couplings, Bearings, Valves, Lubrication, Gearboxes
- HVAC. Ducts, Furnaces, Gaskets, Seals, Roofing
- Building Envelope Confirmations
- Equipment Maintenance
- Building Energy Audits
- Process Maintenance
- Moisture & Water Damage Recognition and Restoration
- Refractory Insulation
- Tank and Vessel Levels
- Preventative Maintenance
- Predictive Maintenance
- Energy Loss – Heating/Cooling, Power, Power Consumption and Flow
- Transportation
Features to consider for Thermal Imagers
- IR Resolution or Pixel Size
- Thermal Sensitivity NETD
- Temperature Range
- Temperature Accuracy
- FOV - Field Of View
- Refresh Rate (Hz)
- Focus Capability - Manual / Automatic
- Digital Display – Standard or Augmented Visual Display Systems
- Memory and Data Logging Capability
- Wi-Fi or Bluetooth Capability
- Lens Capability and Interchangeability
- Software Display Capability
- Alarm Capability
- Standard or Additional Color Palettes
- Adjustable Emissivity Capability
- Voice Annotation
- Output Capability
- Flashlight or Laser Capability
- Battery Life and Replacement
- Enclosure IP and CAT Location Ratings
- Drop Test Capability
IR Resolution (Pixel Array)
Detector resolution is based on the pixel array that each camera contains. Using larger pixel arrays, 640X480, (as well as the lens “Field of View” selected and any special electronics being added to the optical circuit), cameras can measure smaller targets at a longer distance that would be sharper and in greater detail. All cameras display temperature gradient. As the pixel array increase in size, the average temperature spot measured becomes smaller. This will increase the information gathered by the camera.
When discussing pixel size, the specific application must be taken into consideration. Please be aware that the detector resolution is different than the display resolution. It is the detector resolution that matters the most. Higher resolution thermal imaging not only provides more accurate quantitative results, but it is also very important when presenting those results to customers. Please see FOV, “Field of View” paragraph below. Given a fixed pixel array, the FOV will determine the detail of temperature being displayed.
Compare two resolutions of the same image
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Figure 1: 60×60 pixel array, 3600 pixels
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Figure 2: 240×480 pixel array, 307,200 pixels
Compare two images at the same resolution: 640x480 pixel array @ 307,200 pixels
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Figure 1: Electrical Panel
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Figure 2: Building Thermal Image
Thermal Sensitivity
The standard measurement used in Thermal Imaging for sensitivity is called “Noise Equivalent Temperature Difference” or NETD. NETD is accepted as a standard industry acronym. This measurement is basically the measure of the least temperature differential range (smallest temperature range) that the camera can detect and display. When considering Cameras to use, a lower NETD may offer increased visibility of temperature differentials which in turn details smaller temperature changes in viewed objects and under test.
Sensitivity is commonly shown as deg C and mK (millikelvins) and when shown in the product specifications, usually indicates the camera sensitivity at a calibrated temperature, i.e. the sensitivity may read: 0.10deg C at 30°C target temperature (or ambient temperature). It should be noted that with lower sensitivity, there usually is an increase in accuracy of readings as well as increases in the details on captured images. Whether there are increases in detail, product color variations, minor modifications on wall intersections or product detail specifics, a lower sensitivity is certainly an important factor you may want to consider. Below are two panel board-circuit breaker images. These are not the identical images, but they are used to demonstrate the variety of results when using two different sensitivities.
Figure 1- is an image from a camera with 4800 pixels and a sensitivity of 0.15°C (150 mK). The general temperature differential is shown, but the detail is not as complete.
Compare sensitivities of two different images of electrical panels
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Figure 1: 4800 pixels, 0.15 deg C (150 mK)
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Figure 2: 307, 200 pixels, 0.04 (40 mK)
In Figure 1, the general temperature differential is shown, but the detail is not as complete. Please note that although the pixel difference details an increase in the sharpness and clarity, the sensitivity allows us to see all the specific temperature details including wiring. The choice of cameras and sensitivity is also only one of other specifications to consider. Temperature range, pixel capability, application, pricing, and many others may also be appropriate.
Temperature Range
The Temperature Range required is application specific and applies to where the Thermal Image Camera will be used. The primary temperature range may vary since cameras can be used for a variety of applications. Industrial facilities may require a higher temperature span for the equipment and operations that will be inspected and evaluated more so than that of Building Diagnostics. The primary troubled area of concern usually dictates temperature, but future testing, evaluations, and optional site use may also offer other temperature ranges. If using one Imager for all applications, consider the minimum and maximum temperature ranges required. As a user for present and future applications, you will dictate the preferred temperature range of the camera.
FOV - Field Of View
The FOV or “Field of View” is the area of the image that is measured and viewed on the imager screen. The lens has the greatest influence on the total view, but a larger pixel array (matrix) may provide greater detail of desired temperature gradient. Compare the following illustrations.
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![thermal_FOV3]()
For more information on choosing the correct lens for your application, click here.
Refresh (Frame) Rate
In traditional Industrial, Commercial, and Building Diagnostics applications, refresh rate or frame rate is the accepted frames per second update for the image being transmitted to the display. Rates are commonly listed as 9Hz, 30Hz, or 60Hz. Higher frame rates are usually found on cameras with better resolution as well as cameras used for First Responder applications involving motion. If the application anticipates using video output, a higher refresh rate is preferred. The choice is based on application and camera specifications.
Display Capability – Standard or Augmented Visual Display Systems
There are a variety of systems that are inherent in many cameras available that have the ability to augment a captured Thermal Display and present that display in greater and finer detail. Each manufacturer offers a specialized technology that enhances picture quality. FLIR offers MSX technology, which automatically extracts the critical details from the visible image and embosses them on to the thermal image. Below is an image representative of MSX display capability. The upper portion displays the enhanced display. Note the detail in the upper portion.
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Fluke offers their IR-OptiFlex focus system which assists the inspection process significantly faster using this revolutionary, ultra-rugged focus system. IR-OptiFlex offers optimum focus by combining focus-free ease-of-use from four feet (1.2 M) and beyond with the flexibility of manual focus for distances of less than four feet. The following link describes the Industrial and Building Diagnostics capability of the Fluke system.
Digital Display with Thermal Display
Many cameras contain a digital display (much like a digital camera) as well as a thermal display. This allows increased information on site and problem areas. These cameras usually allow the operator to snap a digital picture as well as a thermal one. Overlaying the images is useful in identifying the location of problems. Below are “Picture in Picture” and “Auto Blend” examples of capturing both Digital and Thermal Images at the same time. Usually these features are used for visual identification of the site being evaluated as well as a Thermal Footprint.
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Possible problem with a plug
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Heat distribution in a breaker panel
Wi-Fi or Bluetooth Capability
Some Thermal Cameras have Wi-Fi or Bluetooth capability to disseminate the collected Thermal Footprint information to other instruments, such as a PC, a smart phone or a tablet device. These features save time compared to saving, recording, and downloading information using memory cards and digital connection cables. This feature also allows the user to instantly share images and information with co-workers and management.
Emissivity
Emissivity is the ratio of energy radiated (invisible heat) by a material to the energy radiated by a black body at the same temperature. Emissivity numbers range from 0.0 to 1.0. A surface with a value of 0.10 (typical for shiny copper) radiates a much smaller amount of energy than that of the human skin, which has an emissivity of 0.98. A “Black Body” would have an emissivity of 1.0.
If precise temperature values are desired, choose a camera with an adjustable emissivity. Adjustable emissivity will offer the user an opportunity for accurate results. There are many tables available that define the emissivity for most materials that can be measured. Many products have internal emissivity tables, and many camera images contain a variety of materials with different emissivity.
If differential temperatures are desired (i.e. relative differences between regions being examined), emissivity, although always important, is not as critical. The camera image below shows a photo of wiring connections with the relative temperature differentials. This allows the inspector or professional to understand the heat produced in various locations of the panel.
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Review
Whether you will be using a Thermal camera for detection of problems or maintaining records for review and comparison over time, for Industrial and Building Diagnostic use, a camera that suits your needs and budget can be found at TEquipment.
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