The burst point is defined by analyzing three key parameters:
- MAWP (maximum allowable working pressure) of the protected equipment.
- Maximum continuous operating pressure.
- Regulatory requirements (ASME Sec. VIII, API 520/521, EN ISO 4126, etc.).
Industry practice is to choose a disc whose burst value exceeds the maximum operating pressure by 10 % to 20 % but never exceeds the MAWP. The disc's operating ratio (for example, 80 % or 90 %) must also be checked to ensure that normal fluctuations do not fatigue the diaphragm.
Other criteria are: process temperature, corrosivity of the fluid, presence of pressure cycles, possible vacuum, required certifications and compatibility with the pressure relief valve (if any). A suitable selection maximizes safety and reduces unexpected shutdowns.
Complete guide: How to select a rupture disc step by step