PADI Divemaster Certification Practice Exam

Why does the burst disk weaken over time?

1. It is exposed to high temperature

2. It flexes each time the cylinder is filled and used

3. It is made of a non-durable material

4. It is affected by the surrounding water pressure

The correct answer is: It flexes each time the cylinder is filled and used

The correct choice highlights a key reason for the wearing and eventual weakening of a burst disk. Burst disks are designed to provide a safety mechanism in high-pressure systems, such as scuba tanks, by allowing gas or pressure to vent if it exceeds a certain threshold. Each time the cylinder is filled and used, the burst disk undergoes repeated flexing due to the stress changes associated with filling and emptying the tank. This repeated flexing can lead to material fatigue over time, which weakens the disk and may result in failure when needed. While factors like temperature, material quality, and surrounding pressure can also impact the overall integrity of safety devices, the cyclical stress from usage is a direct mechanical factor that contributes significantly to the deterioration of the burst disk's physical structure. Understanding this mechanism is crucial for maintaining equipment properly and ensuring diver safety.