Finding Electrical Hotspots Before They Turn Into Fires: The Role of Thermographic Scanning

Bangladesh Fire Service and Civil Defense officials believe that a majority of fires in RMG factories occur due to electrical faults and malfunctions. For this reason, the Alliance places a high priority on remediating electrical hazards as a means of preventing disasters like those that have plagued the industry in the past.

Infrared imaging – also known as thermographic scanning – is the most effective tool available to our engineers for identifying urgent electrical risks. IMG_4608Unlike conventional cameras, infrared scanners capture radiation and produce images that show the relative temperature of electrical equipment. At a minimum, there are 40 types of electrical equipment that should be scanned (if found onsite), such as fuse boxes, water and vacuum pump electrical systems, and fan and coils panels. The greatest concerns arise when we see the largest temperature differential. Regular scans of all equipment should be done every few years, though the required frequency of this task may increase based on past incidence of hotspots.

As part of Alliance electrical inspection requirements, qualified assessment firms inspected all factories with infrared imaging equipment and produced thermographic scan reports. The thermographic scan reports note areas and/or machines in the factory where there is a difference in temperature between electrical equipment and the surrounding (ambient) air, and the severity of those differences.Pages from Example Thermographic Report ThePages from Example Thermographic Report temperatures are divided into categories to indicate risk level, with the lowest category often considered normal and the other three categories requiring more extensive remediation. The type of action required could be as simple as cleaning or tightening a connection, or as extensive as system replacement due to improper design.

  • HIGH PRIORITY: Items placed in the highest category show high heat contrast between equipment and ambient air temperatures. Equipment temperatures 40C above ambient temperatures often present a reasonably high risk of starting a fire. Items in this category include overloaded circuits, worn or improperly maintained motors, crimped or pinched conductors, overloaded terminals, and mechanically damaged switches and circuit breakers. In most cases, remedial action involves replacing the damaged or worn items.
  • MODERATE PRIORITY: Items in the two categories between low and high represent less hazardous but nonetheless significant issues. As such, infrared scanning provides an early indication of potential failure and affords maintenance electricians a good indication of where preventive attention is needed.

The Alliance recommends that factories purchase their own scanning devices so they can monitor equipment temperatures on their own and predict when equipment may fail. By doing so, factories can identify problems before they become serious and repair components during scheduled repair windows. Regular maintenance and scanning can save factories money by reducing the possibility of equipment being out of service unexpectedly or production shutdowns due to urgent remediation requirements.

  • LOW PRIORITY: Low priority items have heat signatures that are only slightly higher than ambient conditions. In some cases, these heat signatures are within the normal limits for the equipment and if the factory can verify this to be the case, no remedial action is required.

All Alliance factories had findings in all categories, though the number varied widely depending upon the scale of the factory. Most factories had 10 to 25 high priority findings requiring immediate action but fewer than 100 findings overall. With Alliance factories inspected and Correction Action Plan (CAP) meetings completed, Alliance engineers are now performing remediation verification visits to confirm that factories are making progress to address these issues. During these visits, Alliance staff emphasize the importance of taking immediate action on high priority findings in the thermographic scan reports and discuss how thermographic scan findings relate to non-conformities found during the broader electrical inspection required of Alliance factories.

The Alliance is committed to helping factories prioritize and plan their efforts throughout the remediation process. Most electrical remediation can only be conducted when the factory is not operating due to power interruption, i.e. during nights and weekends. Careful scheduling is required to make consistent progress, so Alliance engineers are advising factories on the development of clear timelines and specific accountabilities for electrical remediation. Acting on these plans – and being guided by the sound diagnostic details provided in thermographic scan reports – will help factory management address the most pressing electrical non-conformities, thus reducing the risk of factory fires.