In modern pressure equipment design, regulatory compliance is no longer limited to selecting a relief device, but rather ensuring certified performance, traceability and operational reliability. In this context, rupture disks (Rupture Disks, RD) are consolidated as a solution fully supported by international standards.
ASME BPVC Section XIII currently regulates overpressure protection for vessels operating at a pressure > 15 PSI, he includes rupture discs within non-recoverable devices, establishing comprehensive requirements for design, materials, manufacturing, inspection, assembly, testing, capacity certification and marking. This implies that its performance is not theoretical: it must be verified and certified.
Additionally, ISO 4126-2:2018—current and confirmed—defines the specific requirements for bursting disc safety devices, covering everything from design to certification and marking of the device. This international standard reinforces a key principle: the rupture disc is a critical safety element, not a generic component.
From an engineering point of view, rupture discs offer differential technical advantages:
- Instant opening and total relief area, without modulation
- Absolute tightness, eliminating leaks in normal operation
- High resistance to corrosive and severe environments
- Operation free of moving parts, reducing maintenance
- Repeatable performance when correctly specified
Additionally, in configurations combined with safety valves, they allow the PSV to be isolated and protected, improving system reliability and extending its useful life.
Flexilatina de Colombia SAS, together with Fike technology, offer rupture discs designed under these standards, accompanied by specialized technical support to ensure their correct application in each project.
The rupture disc is not an alternative: it is a normative, precise and highly reliable solution for overpressure protection in modern systems.
What is overpressure (the danger)?
The system exceeds its maximum allowed limits. If left uncontrolled, overpressure can cause leaks, mechanical breakdowns, or catastrophic failures.
What is pressure relief (the solution)?
A safety feature that activates when pressure reaches a predetermined limit value, providing a controlled path for pressure to escape.
Pressure relief exists for a reason:
To protect people, equipment and facilities when a system is stressed.
beyond their safe operating limits.
Pressure relief is not about saving equipment. It is about preventing catastrophic and uncontrolled failures.
When understood and applied correctly, pressure relief transforms an abnormal event into a manageable event, protecting lives, preserving assets, and maintaining operational integrity.
Causes of overpressure
1) Outlet blocked → Overpressure
- Any downstream valve (manual or control) may close or fail
- If flow or energy continues inside the container, the pressure will increase rapidly.
- This is the most common overpressure scenario in plants. Typical cause: operator error, valve misalignment, control failure.
2) Thermal expansion of the trapped liquid
- Liquid trapped between two closed valves will expand when heated.
- Liquids are essentially incompressible → small increase in temperature = large increase in pressure.
- Neither the relief valve nor the rupture disc can be sized for this scenario. Classic mistake: assuming that “there is no flow, therefore there is no risk.”
3) Isolation or malfunction of relief valve
- If there is an isolation valve upstream or downstream of the relief valve:
It is possible that it is closed for maintenance and has not reopened.
- Relief valves can also:
– Sticking or failing seal
– Loss of adjustment pressure due to corrosion or dirt. Result: the system appears protected, but it is not.
4) Rupture disk installed but incorrectly selected/lack of advice
Common failure modes:
- Disk installed backwards
- Incorrect burst pressure
- The reduction in burst pressure due to temperature effect was ignored
- Fragmentation affecting downstream equipment.
5) Inadequate discharge system
Even if the relief device works perfectly:
- Discharge pipe may be undersized
- Excessive back pressure may develop.
- Two-phase flow may not be taken into account.
- Venting can occur in unsafe areas, result: secondary failure outside the container.
6) Exposure to external heat or fire
- Fire causes rapid vaporization and an increase in pressure.
Relief devices can be:
Insufficient size in case of fire.
Not rated for elevated temperatures
- Structural supports may fail before relief is effective. This is usually the worst design scenario.
7) Control system failure
- Control valve fails closed
- Air or energy is lost for instrument operation
- The process continues feeding energy or mass.
Never apply the concept of: “…….this has never happened in the plant.”