Which type of liquid is recommended for hydrotesting fire extinguishers?

The recommended liquid for hydrotesting fire extinguishers is water or another non-compressible fluid. Hydrotesting is a vital test to ensure that fire extinguishers maintain their structural integrity under pressure. Water is a readily available and cost-effective option that is also non-compressible, allowing for accurate pressure measurements during the testing process. Using water minimizes risks related to flammability or chemical reactions, as might be the case with oil, alcohol, or glycol.

Water's non-compressible nature translates to uniform pressure distribution across the extinguisher's internal surfaces, which is crucial for identifying any weaknesses or leaks. During testing, the extinguisher is filled with water, and pressure is applied to help identify any potential fails in the vessel. This practice helps ensure that the extinguisher will function properly in an emergency.

Other fluids, such as oil, alcohol, and glycol, do not serve the same purpose and can introduce complications, including safety hazards and ineffective pressure testing results. Those fluids may also be flammable or harmful, making them unsuitable for this critical safety procedure. Therefore, using water or a similar non-compressible fluid remains the standard practice in hydrotesting fire extinguishers.