text: There are two rupture disc technologies used in all rupture discs, forward-acting (tension loaded) and reverse buckling (compression). Both technologies can be paired with a bursting disc indicator to provide a visual and electrical indication of failure.
  In the traditional forward-acting design, the loads are applied to the concave side of a domed rupture disc, stretching the dome until the tensile forces exceed the ultimate tensile stress of the material and the disc bursts. Flat rupture disc do not have a dome but, when pressure is applied, are still subject to tension loaded forces and are thus also forward-acting discs. The thickness of the raw material used in manufacturing (also known as web thickness in graphite discs) and the diameter of the disc determines the burst pressure. Most forward-acting discs are installed in systems with a 80% or lower operating ratio.
  In later iterations on forward-acting disc designs, precision-cut or laser scores in the material during manufacturing were used to precisely weaken the material allowing for more variables to control of the burst pressure. This approach to rupture discs, while effective, does have limitations. Forward-acting discs are prone to metal fatigue caused by pressure cycling and operating conditions that can spike past recommended limits for the disc, causing the disc to burst at lower than its marked burst pressure. Low burst pressures also pose a problem for this disc technology. As the burst pressure lowers, the material thickness decreases. This can lead to extremely thin discs (similar to tin foil) that are highly prone to damage and have a higher chance of forming pinhole leaks due to corrosion. These discs are still successfully used today and are preferred in some situations.
  Reverse buckling rupture discs are the inversion of the forward-acting disc. The dome is inverted and the pressure is now loaded on the convex side of the disc. Once the reversal threshold is met, the dome will collapse and snap through to create a dome in the opposite direction. While that is happening, the disc is opened by knife blades or points of metal located along the score line on the downstream side of the disc. By loading the reverse buckling disc in compression, it is able to resist pressure cycling or pulsating conditions. The material thickness of a reverse buckling disc is significantly higher than that of a forward-acting disc of the same size and burst pressure. The result is greater longevity, accuracy and reliability over time. Correct installation of reverse buckling discs is essential. If installed upside down, the device will act as a forward acting disc and, due to the greater material thickness, may burst at much higher than the marked burst pressure.