Published In April 2007
Thermal imaging helps contractors determine data:Thermal imaging is not new to the electrical industry; for several decades, a principal commercial application of thermal imaging has been for the inspection of electrical systems by performing infrared scans of connections, fuses, junction boxes, switchgear and other electrical components. Results of thermal sweeps are documented by digital images that can be downloaded to a computer for further analysis and saved as records of the inspections.
Compact, handheld infrared cameras with the sensitivity to make temperature measurements with extreme accuracy are used to sweep electrical installations for temperature differences caused by bad connections, load imbalances, overloaded transformers and other deviations within a system. Overheated components or those that are breaking down can be invisible to an electrician but are immediately apparent to trained thermal imaging specialists using infrared cameras.
Detecting and correcting such problems can avert fires and shutdowns that can have catastrophic consequences for manufacturing plants, commercial organizations and government facilities.
An organization’s information communication technology (ICT) infrastructure is an indispensable element in its operations, regardless of what an organization’s product or service is or even whether an organization is public or private. Many data centers operate 24 hours a day, seven days a week and require reliability in the high nines (nine 9s means a system must be operable 99.9999999 percent of the time).
While no two data centers are exactly the same, each has the same basic components, including the utility transformer, standby generator, transfer switch, main switchboard, uninterruptible power supply (UPS), power distribution units (PDUs) and server racks. Because precise temperature control is necessary in the data center, the facility’s heating, ventilating and air conditioning systems are critical.
“Every component in the data system is interconnected and dependent on the others,” said Paul Twite, thermographer, Fluke Corp., Everett, Wash. “They can be viewed as a series of dominoes—if one goes down, the others fall. Electrical components of a data center are different than other systems; a failure takes a lot with it as other failures occur.
Because a data center’s components and systems within the larger network system operate on electrical power, thermal imaging is a primary method of inspection for maintenance. Infrared thermal scans of components is encouraged and, in some cases, mandated by most of the insurance carriers covering data centers.
When thermal image inspections uncover power-related problems—often requiring immediate attention—electrical contractors make repairs, but typically electrical contractors have not made the infrared scans to diagnose potential problems.
“It traditionally has not been common for electrical contractors to perform the scans,” Twite said. “Although, some contractors do outsource the scans to thermographers.”
However, Twite believes electrical contractors are becoming aware of thermography’s potential. “Today, there is a fairly small group of electrical contractors active in data center work. But we see a growing awareness in the industry, and more electrical contractors of all sizes are beginning to add thermal imaging to the services they offer,” he said.
David Francoeur, director of marketing for FLIR Systems, Wilsonville, Ore., believes thermal imaging for data center clients has untapped potential for electrical contractors. “We don’t have statistics documenting how active electrical contractors are in thermal imaging data center work, but we believe there is room for a lot of growth,” he said.
Francoeur said thermal-imaging scans of data center components may be done by personnel working for the company operating the data center and more often by infrared consultants.
Francoeur agreed that electrical contractors are beginning to get into the thermal imaging market. “And not just high-end contractors; we see small- and medium-size electrical contracting companies expanding into the field.”
Such a decision makes sense, Francoeur said. “When electrical problems are identified by the infrared scans, the electrical contractor is able to immediately address the issue,” he said. “In a way, the contractor is being paid to find new work. In addition, having the capability of performing thermal imaging in data centers gives the contractor an added competitive edge for business. We are seeing some contractors actively promoting thermography on their vehicles, in advertising and mailers. It is a good time to bring infrared into the business.”
For the data center owner, it makes sense to have electrical contractors do infrared maintenance scans.
“Energized medium-voltage equipment can only be opened by qualified personnel,” Twite said. “With licensed electricians on hand during the scans, repairs can be started immediately. If an infrared specialist uncovers an issue, all he or she can do is report the problem, and the data center calls an electrician who must have a new scan done to confirm the problem. That takes time and can be costly.”
Twite said data centers are ranked by reliability of power and density of its servers. System categories include the following:
- N, single system, no redundancy
- N+1, with “fail-over” capacity and components
- 2N, two fully independent systems, 100 percent redundant
- 2 N+1, two fully independent N+1 systems
For making inspections, Twite has a four-wheeled cart on which he carries the thermal camera, a handheld device to monitor environmental conditions and electrical test tools. He prefers to begin thermal inspections outside at the utility transformer. He makes the following checkpoints on a data center’s basic components:
- Utility transformer (secondary windings and coils): Lugs, terminations, torque, compression, imbalance, debris and damage
- Standby generator: Lugs, terminations, torque, tooling system and exhaust system
- Transfer switch: Lugs, terminations, torque, compression, and imbalance
- Main switchboard: Lugs and buss connections, terminations, torque, compression, imbalance, fuses and clips
- Server racks (with integral distribution):
- Wiring connections, plug strips, bent, loose plugs, interior heating and heat dissipation
- PDU: Main lugs, terminations, torque, circuit breaker terminals, on-board transformer, if not straight-through voltage
- HVAC or CR A/C units: Input connections, torque, fan motor, belts, pulleys (if accessible), fuses and clips, evaporator or chilled-water coil; beware of icing, outdoor condenser or cooling tower motors, fuses, terminations and cooling tower water flow and leaks. In addition, each component always should be inspected for visible damage and for debris.
- UPS: Input connections, terminations, torque, inverter section electronics (small fuses and capacitors), battery section or sections, including terminal posts, casings and feeders and on-board transformer, if not straight-through voltage
Conducting thermology scans of electrical components is not in itself difficult; cameras are compact and easy to use. Training ranges from several levels of certification from basic to full-fledged thermographer. To make and interpret thermal scans starts with training and builds on experience.
“The challenges are collecting good, solid data, understanding what images on the screen represent and make the correct diagnosis,” Twite said. “To do that, the technician must have an understanding of electricity and see scanned images through the eyes of an electrician and understand the physics of what data represents. It is also essential to understand environment variables.” EC
GRIFFIN, a construction and tools writer from Oklahoma City, can be reached at 405.748.5256 or email@example.com.