What is the primary function of pressure-relief devices in API 650 tanks?

• A. To improve vacuum insulation
• B. To serve as a decorative feature
• C. To prevent overpressure situations
• D. To increase tank weight

Answer: (C)

The primary function of pressure-relief devices in API 650 tanks is to prevent overpressure situations. These devices are crucial for safety, as they ensure that if internal tank pressure exceeds a certain threshold, typically due to heat or other factors causing vapor expansion, the pressure-relief system activates to release excess pressure. This helps prevent structural failure of the tank, which could lead to spills, leaks, or catastrophic failures that can endanger personnel, the environment, and property.

Pressure-relief devices are designed to keep the internal pressure of the tank within safe limits, thereby protecting both the tank and its contents. The effectiveness of these devices is essential in the operation of storage tanks, especially in processes where temperature fluctuations can lead to dangerous pressure build-up. Thus, maintaining the integrity of the tank through appropriate pressure regulation is a fundamental aspect of the storage system's design according to API 650 standards.