Hydrostatic Testing

Hydrostatic testing is required periodically to ensure extinguishers qualify for continued service. An extinguisher is placed inside a test jacket filled with water, and an internal water pressure is applied to the container within a closed system. The applied pressure to the extinguisher causes expansion which is then measured. Based on the extinguisher's hydrostatic test results, it can be determined whether the extinguisher is safe for continued use. If it has suffered from degradation in its structural integrity, it must be condemned.

For more information:
U.S. Department of Labor