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Scott Wood

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    Building Science Thermographer

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  1. The Testo merge function (super resolution) can provide some awesome images. It is always better to have higher resolution, especially if you cannot fit the scheduling into the proper environmental conditions. Can't upload the image from the Test T890 at super resolution (1280 x 960) due to its size 4.9mb, but believe you me, its one sharp image, making interpretation quite easy.
  2. And you could also use a spot radiometer as well... I will have to agree, an IR imager in my back pocket would be useful if I didn't have my imager available. Though I'm trained to use it and interrupt the images I provide. I cannot see someone who is unwilling to get a decent imager because its too expensive, paying for the needed training to correctly interpret the images for reporting. If you feel all home inspectors will now use a FLIRone, we are in trouble if this becomes the standard of the industry. Please, lets also understand its possible use in showing "issues" onsite to sorta-kinda showing our clients, but never for a published report with its thermal images. The low resolution will not provide the clarity necessary for a report (most of the time), nor will it help support you as a thermographer with its low resolution. Though that "see through walls" promo may still get you some marketing
  3. Nice discussion on thermal imagers. A couple of points and some nit-picky details you should all be aware of if using a thermal imager in your investigations. The two most important considerations for thermal imagers are resolution and thermal sensitivity. In both cases the better, the easier the image will be to resolve the thermal patterns. But, in the cases of great temperature differences (think evaporating water, insulation anomalies when temperature difference is high) a cheap, low end, usually will provide a thermal pattern you can see. Nice looking image for your client, NOT! And you will miss many of the details of subtitle thermal patterns that provide inspectors clues to a possible issue. If you plan on provided the image in your report to your client or utilize thermography as a primary tool for your investigations, a minimum resolution of 320x240 is a good idea. Thermal sensitivity is the other part of the equation and should be a minimum of 50mK. The better the sensitivity (lower value) the better the ability of the imager to see subtitle temperature differences and thus a better resolve of thermal patterns. This is especially true in the shoulder seasons when temperatures inside and out are similar. Overlapping or merging visual images into the thermal can provide details that the low resolution cannot. I feel it a trade-off that maybe necessary when getting a cheap imager. It even allows you to see through glass Testos super resolution is software manipulation, merging multiple images together, usually providing greater detail. I've used it on all Testo imagers that have it and find it does help create a sharper image (most of the time). Remember though, thermal sensitivity. If the imager cannot "see" it, no matter what you do you cannot make it appear like magic. Of course, price point is a very important consideration. Don't go bankrupt on a purchase, but do consider the best (resolution and thermal sensitivity) your money can afford. For building investigations, I'm not sure why you would not use one. Though I've heard stories of the past when home inspectors did not use moisture meters, assuming it was a liability to use one. Forget the iPhone add-on as a professional tool, though it would be nice to carry one at all times, just to have something in your back pocket to provide more information. We are not yet at the point to have quality thermography in smart phones. Tim, excellent images. Let me put my BST (Building Science Thermography) hat on: As a trained thermographer you should be aware of the following, though easy to forget they are important: In most building applications, specific temperatures are rarely relevant. We look for thermal patterns to locate issues with a building we cannot see with our eyes. Those pattern specific temperatures will vary considerable, hour by hour, and are usually of little import. One important temperature contribution for building investigations is dew point. In this case temperatures below dew point are important and useful to investigate further when observed. And forget using numbers to calculate heat loss. It is a difficult science to correctly interpret temperatures to assign an energy loss value. Though it can provide details of where energy loss is occurring and with a lot of work some SWAG to the amount of loss. I notice you provide a spot temperature on all your images. Though some of the lower end imagers do not have the ability to remove that spot, it can usually be removed later when post processing. Because post processing can eat up bunches of office time, I rarely see the spot removed when these imagers are used for reports. However, when the spot can be removed pre-imaging, you should do so unless you find it provides relevant data within the image. If you use temperature data, adjusting for correct parameter settings are required for correct temperatures values. Even I rarely tweak with the parameter settings onsite, instead entering the information later from the data that was collected during the site visit, but only if necessary when I need to include temperatures. In some of your images the tilde symbol "~" is present. This indicates the imager has not had time to equalize its temperature or come to a constant temperature. It requires a Non-uniformity correction (NUC) and the tilde symbol warns you the temperature measurements are not accurate! Bottom line, thermography is a great tool. In most cases it's very easy to operate and the costs (and quality in some cases) are coming down so anyone can buy one and easily save an image. Inappropriate use can lead to unresolved issues or misinterpretations. Proper training is critical to successful operation and your future as a professional.
  4. Yes, glass is a smooth spectral surface, providing sharp reflections in infrared, even though only about 14% reflective. Ghost hunters often use this in "discovering" ghosts with a thermal imager. If you look carefully you can see yourself waving back on some very smooth painted surfaces and always on glass surfaces. Brushed stainless is incredibly reflective in infrared, sometimes surprising the unsuspecting.
  5. Solid materials have differing degree of transparency at different wavelengths. The thermal imager's lens is made of a metal! Borosilicate glass is 90% transmissive between 0.5-2.5 micrometers(um) (visible is 0.49-0.75um), dropping off to 5% at wavelengths around 3.5 um, becoming opaque at wavelengths greater than 5.0 um. The cooled detectors of the midrange thermal imagers (3-5um) can see through glass to some degree. However, most are familiar with a room temperature detector, which are longwave detectors (8-14um). None of these imagers can "see" through glass as described above. You mention coatings. It does get more complicated with coatings. Some absorb visible wavelengths, blocking them, re-emitting the energy as a longer wavelength (infrared) that we feel as heat. Some of these coating can cause the fenestration's glazing to heat up so much, that it expands shattering the glazing.
  6. As pointed out, the FLIR One has many applications. Unfortunately, the low resolution makes visualizing the thermal patterning pretty poor. They "enhance" the image using the MXS process that overlays visual outlines over the thermal image. In addition I hear that multiple thermal images are merged, also helping fill in the thermal's initial low resolution. Both create a computer generated image that looks much better then the initial low resolution image. An interesting false image the MXS produces is the perception that you can see through glass. The visual overlay provides an image that looks like IR can see through glass. The low cost and suggested marketing features will create from the untrained owners, many false assumptions. As a professional thermographer I foresee many future discussions needed with clients who use this device, explaining away their perceived false interpretations. Maybe now is a good time to require proper certifications when used for commercial applications. Especially those following ASNT, BINDT or other independent organization's guidelines. This along with application specific training from a competent organization.
  7. John, This is a sad day for infrared thermography's use in building applications. I suppose in a capitalistic environment this maybe a big coup for Nick's pocketbook. It is hard to understand how thermography's use in buildings for ...energy inspections or energy audits, indoor air quality inspections or termite inspections... was not prior art since publications as early as 1974 show it was shown to be developed by taxpayer funds at CRREL: 1. CRREL, Hanover, NH, October 1974, R.H. Munis, R.H. Berger, S.J. Marshall, M.A. Bush, Detecting Structural Heat Losses With Mobile Infrared Thermography. Part I Description of technique. ABSTRACT A method to assess quickly the insulation effectiveness of buildings using mobile infrared thermography has been developed at USA CRREL. In contrast to the infrared thermography done in Sweden, this method concentrates on obtaining useful data by measuring the outside surface temperature of structures. This report outlines the basic principles involved in these measurements, and discusses field measurements and the inherent advantages of infrared thermography. Typical thermograms are presented in the appendixes. 2. CRREL, Hanover, NH, September 1975, R.H. Munis, R.H. Berger, S.J. Marshall, M.A. Bush, Detecting Structural Heat Losses With Mobile Infrared Thermography. Part II Survey of Peace Air Force Base, Portsmouth, New Hampshire. ABSTRACT During the winter of 1973-74 a mobile infrared thermography system was used to survey housing units and base facilities at Pease Air Force Base, Portsmouth, New Hampshire. This report provides both qualitative and quantitative evidence regarding heat flow out of the eave vents of these housing units. Calculations indicate that a significant amount of heat is being lost in this manner due to inadequate attic (cap) insulation. Possible evidence of incomplete ventilation could explain the presence of condensation in the housing units. Analyses of thermograms are presented to show the possible existence of low and high pressure areas around a structure and how they relate to heat loss. 3. Popular Science Magazine, September 1975: pp. 86-87, 132-134, Herbert Shuldiner, Infrared Scanners can cut your home energy bills. 4. CRREL, December 1975, R.H. Munis, R.H. Berger, S.J. Marshall, M.A. Bush, Detecting Structural Heat Losses With Mobile Infrared Thermography Part III-Survey of USA ABSTRACT During the winter of 1973-74 a mobile infrared thermography system was used to survey the USACRREL building at Hanover, New Hampshire. This report provides a description of excessive heat losses at several locations around the building. This report also discusses the need to carefully monitor meteorological conditions before starting a survey of a building exterior to determine if solar radiation decay from the building surface might interfere with thermographic analysis by masking the heat emanating from within the building. 5. Popular Science Magazine, February 1976: p. 138, Al Lees, Plugging Home Energy Leaks. 6. CRREL, September 1976, R.H. Munis, R.H. Berger, S.J. Marshall, M.A. Bush, Detecting Structural Heat Losses With Mobile Infrared Thermography Part IV. Estimating Quantitative Heat Loss at Dartmouth College, Hanover, New Hampshire. ABSTRACT During the winter of 1973-74 a mobile infrared thermography system was used to survey campus buildings at Dartmouth College, Hanover, New Hampshire. This report provides both qualitative and quantitative data regarding heat flow through a small area of a wall of one brick dormitory building before and after installation of aluminum reflectors between radiators and the wall. These data were used to estimate annual cost savings for 22 buildings of similar construction having aluminum reflectors installed behind 1100 radiators. The data were then compared with the actual savings which were calculated from condensate meter data. The discrepancy between estimated and actual annual cost savings is explained in detail along with all assumptions required for these calculations. 7. Popular Science Magazine, January 1978: p. 83, Herbert Shuldiner, Heat-leak locator thermographic scanner charts insulation gaps.
  8. I only posted an abbreviated list and may have left off some great references for pre 2005 building thermography citations. If you have specific citations (or complete publications) please feel free to forward and I'll include them in the growing list. Currently I'm at about 56 citations that discuss the utilization of thermography in building applications and have not looked at all publications yet.
  9. Below are the first 20 citations I've located, starting in 1974 that discuss the use of thermography in building applications. I have an additional 37 references stopping at 2004 citations. Contact me and I'll be happy to provide additional citations or add those I've missed. 1. CRREL, Hanover, NH, October 1974, R.H. Munis, R.H. Berger, S.J. Marshall, M.A. Bush, Detecting Structural Heat Losses With Mobile Infrared Thermography. Part I Description of technique. 2. CRREL, Hanover, NH, September 1975, R.H. Munis, R.H. Berger, S.J. Marshall, M.A. Bush, ?Detecting Structural Heat Losses With Mobile Infrared Thermography. Part II Survey of Peace Air Force Base, Portsmouth, New Hampshire. 3. Popular Science Magazine, September 1975: pp. 86-87, 132-134, Herbert Shuldiner, Infrared Scanners can cut your home energy bills. 4. CRREL, , December 1975, R.H. Munis, R.H. Berger, S.J. Marshall, M.A. Bush, Detecting Structural Heat Losses With Mobile Infrared Thermography Part III-Survey of USA 5. Popular Science Magazine, February 1976: p. 138, Al Lees, ?Plugging Home Energy Leaks.? 6. CRREL, September 1976, R.H. Munis, R.H. Berger, S.J. Marshall, M.A. Bush, ?Detecting Structural Heat Losses With Mobile Infrared Thermography Part IV. Estimating Quantitative Heat Loss at Dartmouth College, Hanover, New Hampshire. 7. Popular Science Magazine, January 1978: p. 83, Herbert Shuldiner, Heat-leak locator thermographic scanner charts insulation gaps. 8. Science.gov, December 1982, C.C. Jr. Roberts, Infrared thermography is a useful tool for the diagnosis of problems in building systems. 9. ISO 6781 Thermal Insulation, (first published 1983) Qualitative Detection of Thermal Irregularities in Building Envelopes, Infrared Method. American National Standards Institute. 10. Manual for Thermographic Analysis of Building Enclosures (149-GP-2MP). 1986/02/01 Canadian General Standards Board, Ottawa, Canada K1A 1G6. 11. Thermosense III, September 1980, D. T. Harrje, G. S. Dutt, K. J. Gadsby, Isolating the building thermal envelope. 12. Thermosense III, September 1980, Dag Holmsten, ?Thermographic study of transient heat-flow in residential dwellings.? 13. Thermosense III, September 1980, Stephen J. Marshall, Detecting moisture in buildings using infrared thermography. 14. Thermosense III, September 1980, Dag Holmsten, Thermographic study of transient heat-flow in residential dwellings. 15. Thermosense III, September 1980, Stephen J. Marshall, Detecting moisture in buildings using infrared thermography. 16. Thermosense V, October 1982, Ronald J. Ward, Thermographic inspections and the residential conservation service program (RCS). 17. Thermosense VI, October 1983, J. B. Fang, R. A. Grot, K. W. Childs, G. E. Courville, Heat loss due to thermal bridges in buildings. 18. Thermosense VI, October 1983, K. J. Gadsby, D. T. Harrje, Use of thermography in the diagnostics of energy use in multifamily dwellings. 19. Thermosense VI, October 1983, Y.-M. L. Chang, R. A. Grot, The role of thermography in the assessment of the thermal integrity of federal office buildings. 20. Thermosense VI, October 1983, S. A. Seeber, Use of infrared thermography for the identification of design and construction faults in buildings.
  10. Additional information and posts of HomeSafe's patents on the use of thermography has spread to other forums including, LinkedIn's RESNET BPI Energy Audit and Home Performance. It seems that once a patent is issued, little can be done to prevent it's enforcement without incurring huge legal expenditures. This may be the reasoning for the lack of visible fight from FLIR when the letters first went out in 2008. Seems time is ripe for home inspection organizations and imager manufactures to team up on this issue.
  11. Nick, Thank you for your post and involvement regarding the legal action. Could you be more specific on the reasoning behind HomeSafe's lawyers dropping legal action?
  12. NPR can provide great information, like this one, excellent. Thanks for the link David.
  13. To better understand "..not fancy enough" they should have describe the gas finder better. David above has mentioned the detector wavelength as a requirement for gas detection. The longwave imagers (E60BX) are not able to detect the wavelengths that gases absorb at, nor are they sensitive enough for detection of low levels of gases. These $30K plus imagers, unlike the room temperature detectors common for building applications, are cooled detectors and specially filtered. This allows the user to "see" the specific wavelengths required for gas observations. FLIR does have a radiometric version that can function for both gas finding and temperature evaluations. An advantage of these imagers is the thermal sensitivity (NEDT) is a whole lot better then the building application imagers (<15mK)! I've used them for exterior viewing of the building cladding. With that sensitivity they provide more patterning, helping to evaluate of the cladding system. On the flip side they are cost prohibitive for most to justify the expense. If anyone is interested FLIR has additional information and training for the specific applications of gas finding. Adding gas finding to your business may help justify the cost.
  14. Regarding up to date, you are correct that some homeowners "upgrade" the envelope and the data is historical. The intent is to show those who are not aware of the energy losses of their building(s) the areas of most concern and a possible loss (or gain when fixed) that the "leak" provides.
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