MRO Magazine

Thermal imaging finds hot spots in electrical preventive maintenance programs


October 25, 2012
By PEM Magazine

Thermography provides the means by which ongoing preventive maintenance can be carried out. It enables engineers to inspect vital HVAC equipment, cooling systems, electrical switchgear, power distribution units (PDU) and other electrical devices quickly and easily. Thermal imaging, or infrared thermography, visualizes and measures infrared radiation emitted from objects. This technology can therefore be applied in any application where the performance or condition of a component can be revealed by means of thermal difference.

What an IR camera shows
The amount of infrared radiation emitted by a surface depends on both its temperature and its emissivity. Surfaces that are good reflectors (e.g. polished metal) are poor emitters, while surfaces that are good emitters (e.g. human skin) are poor reflectors. The emissivity of a surface is the ratio of energy radiated by that surface to energy radiated by a black body at the same temperature. Infrared energy makes up one part of the electromagnetic spectrum.

The naked eye cannot see infrared energy because it is emitted from objects as heat, not as light. The hotter an object, therefore, the more thermal energy it emits. Infrared thermal imaging cameras provide a visual representation of IR energy emissions. Where quantitative information is required, the thermal camera can also provide accurate surface temperature values of the object being viewed. The images generated can then be saved for later analysis and report generation.

Electrical parts that are damaged or about to fail will emit heat. The thermal camera detects any excessive heat in relation to the ambient temperature. For data centre maintenance engineers, thermal imaging technology can help:
•     check for loose or
over-tight connections;
•     identify overloaded components;
•     evaluate uneven voltage distribution; and
•     recognize failed or fatigued components within a distribution system without having to isolate circuits.


As an example, let’s look at a specific component of a data centre’s electrical infrastructure: switchgear. It is not unusual for switchgear to experience surges in current that can lead to connections working themselves loose. This problem can go undetected when relying on the naked eye to notice it. Poor connections can lead to loss of connectivity, overheating, fires and power outages—all of which would be potentially disastrous. Using thermal imaging, it is possible to identify hotspots within switchgear to detect potential problems, and allow the engineer to repair them.

The benefits of deploying thermal imaging to the data centre are significant. First, because it may be possible to avoid shutting down the facility to fix the detected problem, there is no disruption to normal operations. Second, regular monitoring with thermal imaging cameras to ensure the data centre’s power distribution boards, isolators and automatic switching panels are in working order can help the business comply with regulations.

In addition, regularly checking the system will lead to better diagnosis of any problems and enable maintenance engineers to formulate a more effective plan of action to overcome issues. Also, the use of real-time data provided from regular monitoring can extend the life of the system and result in significant cost savings. By identifying the inevitable degeneration of power equipment, replacement activity can be planned at the optimum time, avoiding major disruption.

Infrared imaging for saving energy
Along with using thermal imaging for preventive maintenance, the technology offers significant energy saving benefits. Green issues are prominent in the data centre industry. Analysts estimate that the increased shift towards cloud computing will triple the information and communications technology sector’s energy consumption by 2020.

Companies can achieve major cost savings by identifying areas where they are losing energy. Thermal imaging can provide a complete picture of a building envelope and its energy performance or, more specifically, a particular zone, room or piece of equipment. For example, it is possible to scan computer rooms to identify problems like overloaded racks and power cables, or even when IT equipment is placed backwards and is blowing hot exhaust back into a cold aisle. This can have a dramatic impact on the efficiency of the cooling system. The same can be said for when cold air escapes under a rack where a brush grommet should have been placed.

When thermal imaging is used to assess cooling systems and heat generating equipment it allows engineers to locate zones and the degree to which temperature-controlling units are actually cooling or heating the room. Systems then can be arranged for optimal performance, helping to increase the premise’s energy efficiency and lower operational costs.

Enhanced ease-of-use coupled with lower prices have made thermal imaging cameras standard equipment for in-house maintenance engineers. Where once a data centre would employ a specialist to carry out formal checks, in-house engineers can now do regular preventive maintenance and energy efficiency auditing themselves. In many cases, it only takes one problem to be identified and fixed for the thermal imager to pay for itself.

Infrared camera selection considerations
There are a number of key features to look out for when selecting a thermal imaging camera. Primarily, the quality of the image should be a major consideration. Owing to technological developments, it is now possible to find a device that delivers an exceptional high-resolution thermal image at an affordable price. Another important consideration is a detector that is fully radiometric, meaning it will capture temperature measurements over the entire image.

Image fusion allows the user to view the subject as either a digital or a thermal image, or a blend of both. By combining visible and thermal images, the user is able to get a clear image of the equipment being monitored while easily seeing potential faults.

Temperature sensitivity is also a key feature to look for when choosing a thermal imaging camera because it can affect the accuracy of the temperature measurements. The industry standard for temperature accuracy is ±2ºC.

Thermal imaging has become an accessible technology that is enabling data centres to replace traditional maintenance programs with predictive maintenance strategies. In addition, with the green agenda high on data centres’ agendas, this technology can help comply with energy efficiency obligations.

Article contributed by Ideal Industries Inc. This was originally published in Electrical Business magazine.