All objects, both natural and manmade, emit infrared energy as heat. By detecting very subtle temperature differences of everything in view, infrared (or thermal imaging) technology reveals what otherwise would be invisible to the naked eye. Even in complete darkness and challenging weather conditions, thermal imaging gives users the ability to see the unseen. Infrared thermography is a proactive troubleshooting and predictive maintenance tool. In the hands of a thermographer an infrared camera can be used to make the world that is invisible to the human eye come to life.
Human eye can see visible light or s mall part of electromagnetic spectrum. Human eye cannot see ultraviolet light and infrared light. Infrared energy is just one part of the electromagnetic spectrum that encompasses radiation from x-rays, gamma rays, ultra violet, and a thin region of visible light, radio waves infrared, and microwaves. To remotely determine the temperature of an object, infrared radiation is used.
Thermal energy is part of electromagnetic spectrum and makes upper part of infrared of light spectrum. Infrared light lies between the visible and microwave portions of the electromagnetic spectrum.
Infrared light has a range of wavelengths, just like visible light has wavelengths that range from red light to violet. "Near infrared" light is closest in wavelength to visible light and "far infrared" is closer to the microwave region of the electromagnetic spectrum. The longer, far infrared wavelengths are about the size of a pin head and the shorter, near infrared ones are the size of cells, or are microscopic.
Energy can come in many forms, and it can change from one form to another but can never be lost. This is the First Law of Thermodynamics. A byproduct of nearly all energy conversion is heat, which is also known as thermal energy.
When there is a temperature difference between two objects or two areas within the same object, heat transfer occurs. Heat energy transfers from the warmer areas to the cooler areas until thermal equilibrium is reached. This is the Second Law of Thermodynamics. When the temperature of an object is the same as the surrounding environment, it is said to be at ambient temperature.
Thermal energy transfer occurs through three mechanisms; conduction, convection, and/or radiation.
Conduction occurs primarily in solids and to a lesser degree in fluids as warmer more energetic molecules transfers their energy to cooler adjacent molecules. Convection occurs in liquids and gases, and involves the mass movement of molecules such as when stirring or mixing is involved. The third way that heat is transferred is through electromagnetic radiation of energy.
Radiation needs no medium to flow through and, therefore, can occur even in a vacuum. Electromagnetic radiation is produced when electrons loose energy and fall to a lower energy state. Both the wavelength and intensity of the radiation is directly related to the temperature of the surface molecules or atoms.
Infrared thermography technique which is non-contact, nondestructive test method uses an infrared imaging to detect, display and record thermal patterns and temperature across the surface of an object. Thermography can be applied to any situation where thermal profile and temperature will provide meaning data about a system or object. It is equipment which senses infrared radiation by converting it into temperature and displays image of temperature distribution.
Since infrared radiation is emitted by all objects based on their temperatures, according to the black body radiation law, thermography makes it possible to “see” one’s environment with or without visible illumination.
The amount of radiation emitted by an object increases with temperature; therefore thermography allows one to see variations in temperature. If the temperature an object gets hot enough, above 525°C the energy from that object will radiate energy in the visible spectrum. This is when we see an object like the burner on an electric stove “glowing” red.
In fact many times an object will emit or reflect energy in the same frequency of our eyes we will see it. All objects emit a certain amount of black body radiation as a function of their temperatures.
The higher an object’s temperature is the more infrared radiation as black-body radiation it emits. A special camera can detect this radiation in a way similar to an ordinary camera does visible light. It works even in total darkness because ambient light level does not matter.
A thermal imaging camera is capable of processing algorithms to interpret that data and build an image. Although the image shows the viewer an approximation of the temperature at which the object is operating, the camera is actually using multiple sources of data based on the areas surrounding the object to determine that value rather than detecting the actual temperature.
Applications of Infrared Thermographys are:
- Electrical Thermography
- Mechanical Thermography
- Building Thermography
- Aerial thermal imaging
- Corrosion Detection
- Water leak detection
- GAS Leaks detection
- Under Floor Heating Systems
The Thermographic survey of Electrical distribution systems & components is currently the most established survey undertaken. These surveys are non-invasive, relatively quick to carry out, cost effective and can form part of any predictive maintenance strategy.
Electrical components such as connections, joints and contacts are subject to deterioration over time due to corrosion, loosening, over tightening, contamination and overloading, all of which causes an increase in electrical resistance and subsequently an increase in temperature. If left, further deterioration occurs, resulting in possible equipment failure, fire and even explosions.
Carrying out regular Thermographic surveys results in your Electrical distribution systems and components being evaluated and any maintenance intervention can be scheduled as part of a predictable maintenance strategy.
We therefore recommend regular Thermographic surveys of the following types of equipment:
- Fuse boards
- Distribution boards
- Equipment control panels
- PLC systems
- Motor control centers
- High & Low main voltage systems
- Electrical switchgear
- Bus-bar systems
- UPS and battery systems
The survey is carried out by a Level II thermographer and a report is produced giving comprehensive details of all the items surveyed, highlighting faults and advising on the most effective solution.
A survey report will also demonstrate that as a business you are taking positive action to ensure thatyour electrical infrastructure is of a reasonable condition and that regular maintenance is being undertaken.
This also demonstrates that you are taking reasonable steps in relation to fire prevention in the electrical systems as it is becoming more and more relevant as insurance companies require or recommend Thermographic surveys as part of their Fire risk assessment of your business.
A Thermographic survey of building envelope will record the thermal properties of each elevation by detecting the infrared energy emitted from those areas.
These properties are then converted into a thermal image and by using these images we can evaluate temperature measurements to identify potential problems. The survey is carried out with minimal disturbance by being non-invasive and allows detection of the following potentially problematic areas:
- Missing or defective insulation
- Thermal bridging causing break in the continuity or a penetration of insulation
- Energy loss through heat escape from doors, windows, chimneys, roofs etc
- Water leaks from feed and drainage pipework and under floor heating systems
- Damp causing mold growth, condensation and moisture ingress
Thermographic surveys Ltd can help you identify where energy is being wasted and how energy efficiency can be improved by surveying the external overview of each elevation of the building.
Reasons to have a Building Survey
AERIAL THERMAL IMAGING
Aerial Thermal imaging is used when looking at looking at wide areas as it provides an overview of the whole site. Aerial Thermal imaging is often used for surveying roof areas to provide an indication of where there are problems.
Aerial surveys can be conducted from a helicopter or a drone which is a lightweight unit, Thermal imaging surveys can be an excellent way of analysing your site Aerial inspections are ideal for surveying roof areas and provide an initial indication of problems in a cost effective way.
We have experience from looking for leaking aqueducts to leaking underground hot water pipes, herd counts and aerial flat roof inspections. We use a sophisticated system that enables us to capture full radiometric .avi files, still images, full digital video which has a GPS overlay directly onto the image showing where the images are taken at all times.
Surveys can be carried out from helicopters, Drones, or extending poles having the ability to detect:
- Underground Landfill Fires
- Water / Steam Leaks
- Large Area Heat Loss Surveys
- Flat Roof Leaks
- Heat Loss
We can also provide with you with aerial video footage which can be handy for analyzing the situation or incorporating it within your own or clients portfolio providing a clear presentation or base for planning and construction projects.
CORROSION DETECTION USING THERMOGRAPHY
A thermography program is an effective method for identifying existing Corrosion under Insulation (CUI), as well as areas that may be at risk. It is also useful for quickly assessing insulation integrity.
Thermography allows the user to detect areas of water/moisture ingress within insulation, where CUI may be occurring and where there is potential for it to occur in the future. When water or moisture gets into insulation, it changes the thermal capacity of the insulation. After a number of cycles that “change in insulation capacity” becomes permanent. This allows users to inspect surface temperature profile and identify anomalies.
Corrosion under Insulation (CUI) is a severe form of external corrosion. It occurs inside insulated carbon and low alloy steel equipment. Water is absorbed (or collected) within the insulation and as a result, corrodes the pipework that is hidden out of sight.
When water or moisture gets into insulation, it changes the thermal capacity of the insulation. After a number of cycles that “change in insulation capacity” becomes permanent. by applying the correct inspection principles and techniques, it is possible to profile data and identify these risk areas for further investigation. While wet insulation does not always mean corrosion is taking place, it provides an indication where problems will develop over time, therefore allowing us to eliminate them early to avoid costly problems in the future.
- Identify risk areas where CUI is likely to form. Prevent significant process leaks that can result in costly plant shut down.
- Selectively De-lag risk areas only.
- Identify improperly installed or damaged insulation.
- Confirm insulation integrity.
- Detect water intrusion or moisture build up early.
- Scan large areas quickly and effectively.
- Minimize scaffold requirements, saving additional costs.
WATER LEAK DETECTION USING THERMOGRAPHY
The detection of leaks is the first issue that has to be worked on whenever any kind of water leakage arises either in the offices or households.
The potential loss that the leakage may be responsible for is not dependent on whether it evacuates plenty of water or not. Instead, a small hidden lake is all the more dangerous than the huge and clearly visible one.
On the whole, though, the most impressive and outstanding leak detections methods have undoubtedly been the Infrared Thermography This method of detection is generally hailed as the latest scientific innovation which allows the thermal imaging systems to analyze the radiated energy to spot the fault lines.
The accuracy of the detection of any leakages mainly relies on the skills of the thermographer.
Listed and explained below are some of the top benefits of utilizing the Infra-red Thermography for the detection of water leakage
It generally operates with 100% accuracy. This is mainly because it makes use of the latest Infra-red Thermal technology. As such, its performance is more accurate and proactive.
This method is generally more cost-effective than the traditional leak detection methods. These assessments are scientifically proven and subsequently spare you from the need to spend too much money on having the whole process executed.
Your building’s safety has to be of primary concern. Other than ensuring your safety, the Infra-red Thermography operates faster than any other available alternative in the market.
This method only requires you to take photos of the affected area and analyze them. It is for this reason that experts hail it as the safest leak detection method in vogue today.
It operates more like scanning the leaked areas and ascertaining the origin of the leakage in particular. You will not have to dig the floors or break the walls to be able to detect the leakages.
As opposed to the traditional ‘dig-and-drill’ methods, the infra-red thermography does exactly what is expected of it.
This high-tech leakage detection mechanism makes use of the infra-red energy to apportion the sources of moisture in sensing the sources of the leaks with the least amount of trespass possible.
It aids the thermographers in finding out the sources of the leakages without necessarily going through intense difficulties at all.
External assessments of the buildings by use of the Infra-red Thermography give room for the thermographers to estimate the most accurate possible locations of the leaks.
Lastly, whether you require your house, office, or buildings to be detected of any leaks, the Infra-red Thermography may be a good place to start with.
The technology is so comprehensive that only a few unique companies have the wherewithal necessary to effectively handle it.
INFRARED ROOF MOISTURE SURVEYS
Infrared Thermography Inspections Detect and Document Roof Moisture Problems.
Infrared roof inspection is a proven method for detecting trapped moisture problems in flat roofs.
Infrared roof Thermography can prevent equipment down time, production losses and help building owners and property management companies find roof problems.
Due to the high cost of replacing a damaged roof, Thermographic roof inspections should be performed whenever a building is purchased, sold or leased.
Infrared roof surveys provide the diagnostic information necessary for developing an effective roof maintenance program, planning capital budgets and for making informed decisions when considering roof repairs, replacement or resurfacing with one of the popular new roof coatings.
Our high-resolution Infrared thermal imaging cameras, find the trapped moisture.
Wet areas are identified and marked to show exactly where tactical repairs are to be made. By marking wet areas directly on the roof, they can be seen by building owners and roofing contractors after the survey is performed. Often, we find that the infrared survey shows it is not necessary to replace an entire roof that only a few sections are “wet” and repairs can be made surgically to only these areas.
4 Types of IR Moisture surveys are
Identifying roof moisture in a commercial property’s roof system is vital to protecting a business owner’s investments and securing the safety of workers, visitors, residents and anyone else who has cause to be inside the facility. Thanks to today’s infrared detection technology, even the largest roofs can be inspected without destruction and in a timely manner.
IR thermography technicians use four types of surveys to detect moisture on commercial roofing:
On-the-roof (also called on-roof or walking the roof) moisture survey
Most roof moisture surveys done with infrared thermography are performed by technicians using their equipment while standing on a business’ roof. A visual inspection by trained individuals can identify tears and poor seals around equipment and pipes on the roof where water is draining inside the facility, as well as detect places where unseen leaks may be wreaking havoc on the roof’s structure and underlying insulation.
Under-the-roof (or under-roof) moisture survey
IR detection can be done from underneath the roof, between the interior ceiling and the roof structure. By using infrared thermography, IR Test technicians can find specific spots where moisture is being trapped under the roof so that you can repair only those areas.
Elevated roof moisture survey
From an elevated position above the roof, IR thermographers can create a highly accurate roof moisture map of even the largest commercial roof. Few signs of leaks are missed from this perspective. Naturally, an elevated roof moisture survey is best done on a clear day.
Aerial roof moisture survey
This is the most efficient way to conduct a commercial infrared roof moisture survey. Every nook and cranny of the roofing is exposed, so nothing prevents the IR thermography from detecting even the smallest signs of a leak.
Keeping a commercial building’s roofing insulation dry will help the roof last longer, keep electrical systems from malfunctioning, prevent the interior ceiling from falling in and eliminate mold growth. Infrared thermography identifies specific areas in need of repair, which means owners and contractors know exactly where to concentrate their work. Spot repair is significantly less expensive than replacing an entire roof.
Before any business owner or manager makes the decision to repair or replace the roof of a commercial building, an IR thermography roofing moisture survey is vital to saving time and unnecessary expense. Don’t assume your new roof is leak-proof, either! Get it inspected now for peace of mind (and safety) the rest of the year.
GAS LEAKS DETECTION USING INFRARED THERMOGRAPHY
Many chemical compounds and gases are invisible to the naked eye. Yet many companies work intensively with these substances before, during and after their production processes.
Several gases have a high global warming potential and strict regulations govern how companies trace, document, rectify and report any leaks of harmful gaseous compounds, and how often these procedures are to be carried out.
Greatly Improved Efficiency Experience shows that up to 84 percent of leaks occur in less than 1 percent of the components in a refinery*. This means that 99 percent of what are expensive, time-consuming inspection tools are being used to scan safe, leak-free components.
Using a Gas Detection camera you get a complete picture and can immediately exclude areas that do not need any action. This means you can achieve enormous savings in terms of time and personnel.
Another advantage is that systems do not have to be shut down during the inspection. They can be carried out remotely and rapidly and – most important of all – problems can be identified at an early stage.
Increased worker safety Leak detection of gases can be performed in a non-contact mode, and from a safe distance. This reduces the risk of the inspector being exposed to invisible and potentially harmful or explosive chemicals.
The FLIR GFx320 detects and visualizes invisible hydrocarbon gas Emissions, such as methane, and common volatile organic compounds (VOCs) found at oil and natural gas facilities. It carries certifications to Global standards and is recognized as Intrinsically Safe, explosion-protected equipment by the International Electro technical Commission. Standard temperature range is –20°C to 350°C (–4°F to 662°F) The first camera with the Intrinsically Safe designation, the GFx320 allows Surveyors to improve their safety and work with more confidence on the Job site. The camera is also verified to meet sensitivity standards.
The FLIR GF300 detects methane, other hydrocarbon, and volatile organic compounds resulting from the production, transportation, and use of oil and natural gas. This camera can scan large areas and visualize potential gas leaks in real-time, so you can check thousands of components over the course of one survey. Temperature range is -20°C to 350°C (-40°F to 662°F) Designed with the user in mind, the GF300 is lightweight, offers both a viewfinder and LCD monitor, and has direct access to controls.
Refrigerant gases are used worldwide in industrial refrigeration systems for production, storage and retailing of food. Refrigerant gas is also used in the chemical, pharmaceutical and automotive industries and in air conditioning systems. Keeping an industrial refrigeration system running is of great importance due to the value of the cooled goods. The FLIR GF304 is a gas imaging camera which was especially developed for the detection of refrigerant gases without the need to shut down the operation. visualizes temperatures from -20°C to +500°C. it can be used both for finding gas leaks and maintenance inspections. High voltage, low voltage, mechanical and many other inspections
Optical gas imaging cameras from can visualize and pinpoint gas leaks. With an optical gas imaging camera it is easy to continuously scan installations that are in remote areas or in zones that are difficult to access. Continuous monitoring means that you will immediately see when a dangerous or costly gas leak appears so that immediate action can be taken. Optical gas imaging (OGI) are widely used in industrial settings such as oil refineries, natural gas processing plants, offshore platforms, chemical/ petrochemical industries, and biogas and power generation plants. Its temperature range is –20°C to 350°C (–4°F to 662°F) up to 1,500°C (2732°F) or up to 2,000°C (3,662°F) optional OGI cameras like the FLIR A6604 can detect harmful greenhouse gases that can seriously harm the environment. It can detect the following gasses Benzene, Ethanol, Ethylbenzene,Heptane, Hexane, Isoprene, Methanol, MEK, MIBK, Octane, Pentane, 1-Pentene, Toluene, Xylene, Butane, Ethane, Methane, Propane, Ethylene and Propylene.
THERMAL IMAGING OF UNDER FLOOR HEATING SYSTEMS
A thermal imaging survey of an under floor heating system involves capturing thermal images of the floor with the heating system on. Under the appropriate conditions it is possible to identify the location and route of the sub-surface pipes by way of a temperature difference on the surface of the floor.
Surveys of an under floor heating system are carried out for a number of reasons including:
- To locate and map the network of sub-surface pipes
- To verify that the installation meets with the design specification
- To assist in diagnosing the causes of poorly performing areas
- To assist in locating the source of water leaks
UV INSPECTION TECHNOLOGY
UV inspection is reflected in its ability to pinpoint corona and arcing, denote failure location, assist predict unavoidable crisis, display both the emitting objects and the emitted radiation, and assess severity of the case under inspection
Power companies and utilities focus on reliable ongoing power supply without outages. At the same they strive to reduce maintenance costs and seek methods to predict the remaining life time of their assets.
Corona phenomena emit ultra violet light. To detect these emissions in daylight special UV cameras were developed with blocking and transmitting (filtering) capabilities.
Features Of UV Inspection
- Detects Corona
- Voltage dependent (e-field) No line loading needed
- All lighting & weather conditions
- Detection at Earlier of Degradation (i.e. Commissioning)
- Transmission distribution
- Switchgears, high & medium voltage rotating machines (motors, generators)
- Commissioning of new installations.
What Is Corona & Effects Of Corona
Corona discharge is a luminous partial discharge from conductors and insulators due to ionization of the air, where the electrical field exceeds a critical value.
- Corona Creates Corrosive Materials: Ozone, Nitrogen oxides which in presence of water vapor yield Nitric acid.
- Generation of corrosive materials, like ozone and nitrogen oxides that yields nitric acid under conditions of high humidity. These corrosive materials shorten the life span of high voltage lines and substations components.
- Corona causes damage to HV insulators, especially non- ceramic ( NCI) insulators. /
- Radio interference (RI/ RFI) mainly to AM transmissions.
- Audio noise. Radio interference and audio noise may raise customer complaints.
- Corona generates only little heat and therefore is not detected with thermo vision cameras.
- Processes involved with corona phenomena emit ultra violet light. To detect these emissions in daylight special UV cameras were developed with blocking and transmitting (filtering) capabilities. cameras are called solar blind bi-spectral UV- Visible cameras since they incorporate both filtering and transmitting qualities.
- UV inspection is reflected in its ability to pinpoint corona and arcing, denote failure location, assist predict unavoidable crisis, display both the emitting objects and the emitted radiation, and assess severity of the case under inspection.
Corona cameras are being used by the following:
- Electrical Utilities
- Heavy Industries
- Manufacturing Industries
- Service Contractors
Electrical Utilities Inspection
Corona discharges are the starting points of many important processes involved in surface degradation. Factors involved with corona discharges are: electric field distortion, high quantity of released energy, the presence of oxygen etc. Discoloration, chalking, cracking, erosion and roughness are some visual consequences of the corona discharge.
Material degradation due to corona discharges influences the electrical and mechanical performance of the power grid. It has been proven that partial discharge processes induce loss of hydrophobicity, increase leakage currents lead to arcs and dry bands formation, tracking and erosion and eventually to flashover.
It is important to mention that under corona discharges alone the temperature would never reach the threshold of 200-300 °C required to initiate thermal degradation.
Use of daylight UV cameras is convenient because measurements can be performed during the day. However, the shape of discharges cannot always be identified due to the non-direct means of detecting photons generated by corona. By contrast, night vision cameras allow such discharges to be more easily observed by illuminating them.
Comparison of a digital daylight camera and two analogous night vision cameras was conducted in a controlled laboratory setting. Care was taken to ensure that the test object as well as the distance between it and the different cameras was representative of what one would find in the field. Measurements were then performed under dry and wet conditions with the specimen insulator fully hydrophobic.
these kinds of cameras are valuable tools to help identify corona problems that can adversely impact a power network. Further research, this time under DC voltage, is planned and the eventual findings of this Working Group are highly anticipated by utilities and other camera users.
permanent corona discharge on metallic hardware might cause only high frequency disturbances, an insulation material in that same location can degrade in a short time.
most desirable for system operators is that a camera system measure corona intensity and provide a ‘red’ or ‘green’ signal corresponding to the potential for risk of discharges. However, the diversity of possible corona sources and the impact of environmental variables such as humidity does not allow for this type of a simple ‘red/green’ conclusion
In general, based on years of experience with the different available technologies, corona discharges from unsuitable design of insulator strings should not normally occur. Yet the reality is that even insulators in service at lower transmission voltages now encounter these types of problems due to intense competition among suppliers and pressure on cost reduction
weather, this string caused permanent corona discharges with such intensity that they could affect electronic control of the substation. Several insulators were then removed for visual inspection. As expected, the ground-side that was free of corona showed no damage. But signs of degradation were evident on the energized side