PADI Divemaster Certification Practice Exam

What does the burst disk do when a cylinder is over-pressurized?

1. It releases gas slowly

2. It opens a release valve

3. It seals the cylinder

4. It balances the pressure

The correct answer is: It opens a release valve

The burst disk is a critical safety component in gas cylinders designed to protect against over-pressurization. When pressure inside the cylinder exceeds a predetermined limit, the burst disk ruptures, allowing gas to escape rapidly from the cylinder. This action prevents the cylinder from bursting or causing more severe damage, effectively acting as a safety valve. The burst disk is a passive device that does not control the rate of release; it simply opens up to alleviate excess pressure. This mechanism is crucial for ensuring the safety of the cylinder and its contents, especially in diving applications where maintaining proper pressure is essential for both the diver's safety and the integrity of the equipment. Other options do not accurately describe the function of the burst disk. For instance, it does not release gas slowly; rather, it is designed to rupture suddenly under excess pressure. It also does not seal the cylinder or balance pressure, as these functions are served by different components of the cylinder's design. The primary role of the burst disk is straightforward: to provide a fail-safe method of releasing excess pressure, thereby preventing dangerous situations.