Pressure Test gone bad! (Tank Launched)

On January 26, 2006, a factory in Brazil witnessed a significant accident during a pneumatic pressure test involving a tank and pipework. The incident occurred because blind flanges were not used to isolate the pipework connected to the tank. Instead, only the valves were closed. This oversight led to the possibility that one or more valves failed or were not fully closed, leading to the tank itself to undergo the pressure test.  As can be seen in the pics below, the outcome was catastrophic.

A massive amount of energy built up within the tank, causing it to launch and ultimately land on top of the installation. This incident served as a stark reminder of the dangers inherent in pneumatic testing and the dire consequences that can result from overlooking safety measures.

Due to compressed gas energy, pneumatic tests entail a higher potential for danger. Ensuring system suitability, careful joint examination, and incremental pressure steps are essential.

ASME B31.3 Guidelines for Pneumatic Testing

ASME B31.3, a well-respected process piping code, provides safe pneumatic testing guidelines. Here’s a concise summary of the relevant sections:

Precautions: Pneumatic testing involves the hazard of released energy stored in compressed gas. To avoid brittle failures, it is vital to ensure material choice and consider temperature.

Pressure Relief Device: A pressure relief device must be present with a set pressure that does not exceed the test pressure plus a specific value.

Test Fluid: The test fluid (if not air) must be nonflammable and nontoxic.

Test Pressure: The test pressure should be at least 1.1 times the design pressure and not exceed certain limits.

Procedure: The pressure must be gradually increased, steps must be taken to equalize piping strains, and leaks must be examined after reducing the pressure.

The incident in Brazil reminds us of the gravity of safety in our field. Let’s learn from such incidents, adhere to standards, and prioritize safety in every engineering endeavor.