Steel mills typically produce H-beams in lengths ranging from 6 meters to 18 meters, with 12 meters being the most common for ease of transportation. Longer beams (15–18m) are produced for large-scale projects like bridges or industrial facilities but require specialized transport (e.g., extended trailers or rail cars). Some mills offer custom lengths up to 24 meters for unique applications, though these are less common due to logistical challenges (e.g., difficulty in handling and shipping). The maximum length is also limited by rolling mill capabilities: longer beams require longer rolling lines and handling equipment. For projects needing longer spans, beams can be welded together on-site, but this adds labor and material costs compared to using a single long beam.