What is a Rupture Disc?
A Rupture Disc is a non-mechanical safety device for relief when it occurs that excessive pressure is over the critical pressure in a pressure system.
Application of Rupture Disc
When using a single safety device;
(Primary Case)
ASME CODE shall be set as lower than MAWP when a Rupture Disc is used as the only safety device, and it should be the size that can prevent the increase of pressure over 10% or over 3psi.
When using single more than two safety devices;
(Secondary Case)
When multiple devices are used, only one safety device needs to be set to have lower pressure than MAWP. The pressure set for the rest of the safety devices cannot exceed 105% of MAWP except for FIRE CASE.
The pressure container shall have a size that can prevent an increase of more than 16% of MAWP or 4psi.
In the case of the combination with a safety valve;
(Combination Case)
A Rupture Disc device can be installed between a safety valve and the process or exit of the safety valve when sufficient discharge capacity is guaranteed. It prevents leakage through the pressure safety valve and protects safety valves from corrosion. When it is installed at the entrance side, the actual discharge capacity is considered as 90% of the discharge capacity marked at the safety valve (When it is tested under the same conditions, the actual capacity is acknowledged).
When it is combined with the safety valve, the rupture of the Rupture Disc shall not interfere with the function of the safety valve, and there should be enough space between a safety valve and Rupture Disc or a device that can detect pressure (manometer-pressure gauge, Excess Flow V/V, or Pressure Switch).
When it is used as a safety device against external fire;
(External Fire Case)
If there are additional hazardous elements such as fire or unexpected external heat, there should be an additional pressure discharge device to protect from the exceeding pressure. In this case, it should have sufficient discharge not to increase pressure over 21% of MAWP. Set pressure shall not exceed 110% of MAWP.
When compressed liquid gas without a permanent supply connection is stored at room temperature, it should be able to protect the pressure container from external heat sources including fire and the pressure discharge device should be able to prevent a pressure increase of over 20% of MAWP.
※ MAWP (Maximum Allowable Working Pressure or Design Pressure): maximum pressure that the original performance of the container is not affected. Under normal pressure, it means maximum pressure, while it means minimum pressure in a vacuum.