Continental Disc’s ZAP (insert assembly pictured here) and KBA reverse-acting rupture discs utilize knife blades to open the rupture discs as reversal occurs. The rupture discs are differential-pressure relief devices that provide instantaneous full opening for protecting equipment, vessels, and systems from overpressure conditions. Designed for nonfragmentation, ZAP and KBA rupture discs respond in milliseconds to overpressure situations, allowing them to be used in a variety of applications. The rupture discs have the media pressure acting on the convex side of the rupture disc, placing it in compression. When the burst pressure rating of the rupture disc is reached, the compression loading on the rupture disc causes it to reverse, snapping it through its neutral position and through the knife blades resulting in a full opening.