In the past, extension springs were safer to install but didn’t have containment cables running through the center of the spring. Without cable, these springs become dangerous, heavy whips when they break. They also tend to be noisier than torsion springs, and we recommend you use them only if you don’t have the 12 in. of headroom above the door that a torsion spring requires and fix commercial shutters .
Torsion springs have three advantages over extension springs. They’re quieter, safer, and easier to fine-tune. Torsion springs are quieter because you don’t have a spring knocking against a roller track. They’re safer because when a spring breaks, it usually stays on the bar.
Finally, you can fine-tune the tension on a torsion spring so the door is perfectly balanced. Setting the tension on torsion springs has always been very dangerous, but torsion and extension spring systems with easy.
Safe door …