Rupture discs come in various sizes, materials, burst pressures, opening features and more.

But one of the most commonly asked questions about rupture discs is, “What are the differences between reverse-acting and forward-acting rupture discs?”

The first difference is the most obvious: The convex side of a reverse-acting rupture disc’s dome faces the process media, while the concave side of a forward-acting rupture disc’s dome faces the process media. Other differences between reverse- and forward-acting rupture discs include the following.

Reverse-Acting Rupture Discs

• Functions when the pressure creates an instability in the dome, resulting in reversal, or buckling, of the dome.
• Typically have longer cycle life than forward-acting designs because reverse-acting discs’ stresses are compressive in nature and do not promote crack propagation.
• Domes are typically supported on the outlet side to prevent movement of the dome prior to reversal.
• Scoring or cutting techniques are required to cause opening after reversal.
• Opening technique is related to the energy available during reversal. Vapor reversal is much more energetic than liquid reversal.

Fike’s reverse-acting rupture discs include

• Axius– Advanced design, superior-cycling performance, 95% operating ratio
• Axius SC – Advanced design, superior-cycling performance, sanitary applications, 95% operating ratio
• Atlas – Advanced design, superior-cycling performance, 95% operating ratio
• SR-H – Excellent liquid performance, scored, 90% operating ratio
• SRL – Good liquid performance, perimeter scored, 90% operating ratio
• SRX – Higher pressure applications, cross-scored, 90% operating ratio

Forward-Acting Rupture Discs

• Functions when the weakest portion of the disc exceeds its tensile strength.
• Typically have a finite fatigue life at higher operating ratios because the stresses are tensile in nature.
• Ability to support vacuum or backpressure is dependent on the inlet diameter supporting the dome, the bulge height and material thickness, or by the addition of vacuum support.

Fike’s forward-acting rupture discs include

• SHX – Higher pressure applications, cross-scored, 90% operating ratio
• POLY-SD – Ideal for polymerization processes, 90% operating ratio
• SCRD – High pressure applications, protection of pressure/safety relief valves, 90% operating ratio
• HO/HOV – Wide range of sizes, burst pressures, applications, 80% operating ratio
• AD/AD-H – Protection of atmospheric vessels, sanitary applications, 50% operating ratio

Fike offers a comprehensive collection of forward- and reverse-acting rupture discs to effectively fill any needs and applications. Contact us today to learn more about the rupture disc best suited for your organization.