For the last decade, RETTEW has been providing North America’s largest flat-rolled steel producer with visual structural inspections of its infrastructure, including bridges, overhead cranes, and crane runways. Their plant has been operating since 1847 and employs more than 400 people. RETTEW has also provided topographic mapping and is moving into high-resolution aerial Light Detection and Ranging (LiDAR) scanning services as we expand our service offering to this client. LiDAR is a remote sensing technology that uses the pulse from a laser to collect measurements, which are used to create 3D models and maps of objects and environments. The on-site surveying and inspection of beams and structural supports (primarily crane rails) occurs in one of the most dangerous environments RETTEW has ever worked in. To keep things running smoothly and support this rail producer’s 1-million-net-tons annually, we make safety a top priority.

Much of this surveying and inspection work is made possible with the help of drones. Drones allow RETTEW to complete this work safely and allow the steel plant to maintain their production schedules. They minimize risk by flying over and through many confined and hazardous spaces not suitable for humans, and enable workers to be safe while keeping the equipment and manufacturing processes running.

Our drone program at this steel plant uses a search and rescue drone with a clear camera and flood lights, which works well in low-light conditions. Many areas of the plant are grimy, and some are pitch black – even in the middle of the day. The drone’s bright lights are essential to navigating through the darker areas. In addition to poor lighting, other challenges include excessive dust, moving parts, and some extremely hot areas. RETTEW deploys three very skilled drone pilots to manage this work.

Physical inspection is usually completed from a high reach by a RETTEW inspector, with an up-close/hands-on inspection occurring every six months to five years, based on usage. The inspector will identify loose bolts or cracks in beams, and will either monitor or recommend repairs depending on the potential damage. More recent inspections have been conducted using drone flights first, depending on the circumstances.

RETTEW’s surveyors often capture high-definition drone footage of the support and the beams, allowing the inspector to better plan for a hands-on inspection. The footage can be closely scrutinized in a safe office environment to visually identify potential structural issues such as new or legacy cracks needing attention. The inspector then conducts a physical hands-on inspection in a boom lift, based on their review of the surveyor’s footage. The drone footage doesn’t eliminate the need for a physical hands-on inspection; however, it increases the efficiency and safety of the inspection process.

When it comes to surveying and mapping, RETTEW has the experience and discipline to work in almost any environment and do it right the first time. Drones are just one of the many surveying tools RETTEW has in its toolbox. This technology allows us to go where humans can’t or shouldn’t enter, and that is a tremendous advantage in today’s manufacturing facilities.