A visual inspection alone is not sufficient to ensure that a portable fire extinguisher is safe or will operate properly when needed. Over time, normal handling or workplace conditions can impact the structural integrity of a portable fire extinguisher and cause it to malfunction or burst. To prevent this from happening, all portable fire extinguishers are required to be inspected and pressure tested by a qualified facility using the proper equipment and facilities per 29 CFR 1910.157(f)(1).
Hydrostatic testing is the method used to pressure test a portable fire extinguisher’s critical components (cylinder, shell, hose assembly, etc.) for leaks and structural flaws. This 4 part series of articles will help you understand what you need to do to comply with the requirements for hydrostatic testing of portable fire extinguishers. Specific areas that will be addressed include:
- How does hydrostatic testing of portable fire extinguishers work?
- What are the types of hydrostatic tests for portable fire extinguishers?
- When is hydrostatic testing of portable fire extinguishers needed or required?
- What records from hydrostatic testing of portable fire extinguishers must be maintained?
Part 1 in this series will address How does hydrostatic testing of portable fire extinguishers work.
How does hydrostatic testing of portable fire extinguishers work?
To gain an understanding of how hydrostatic testing works to check a portable fire extinguisher cylinder and/or hose assembly for leaks or flaws, you need to first understand the actual procedure for conducting the testing.
First, the portable fire extinguisher valve is removed and the threads and interior of the cylinder are checked for corrosion, pitting, and any other abnormalities. If the cylinder passes the visual inspection, it is placed into a steel chamber, which is then filled with water at normal pressure. A measuring device attached to the side of the steel chamber will read zero, indicating normal or zero pressure of the chamber water. Water is then applied at high pressure to the interior of the extinguisher’s cylinder. As the pressure increases, the cylinder will expand and push water from the steel chamber through a small hole and into the expansion indicator. After the pressure is released, the cylinder will contract and the water will move from the expansion indicator back to the steel chamber. Depending on the results, the tester will either pass or fail the cylinder.
A portable fire extinguisher cylinder is considered unsafe and will fail the test if:
- The water level in the measuring device continues to rise while the specified pressure is applied. This could be due to a leak from the inside cylinder to the water in the steel chamber, or to a continual expansion of the walls of the cylinder, both of which would be a reasonable cause to fail the cylinder.
- The cylinder stretched and with the pressure released does not return to its original size (or close to it), it would mean the metal of the cylinder is not resilient enough to be considered safe for use. The expansion indicator can not have more than 10 percent of the displaced water remaining after the pressure is released.
The Jay L Harman Fire Equipment team understands your firefighting needs and is ready to help
Jay L Harman’s DOT Hydrostatic Testing facility and equipment meet all NFPA requirements for the hydrostatic testing of self contained breathing apparatus compressed gas cylinders in addition to testing ABC portable fire extinguisher cylinders.
Jay L Harman is the best and one of the biggest firefighting equipment suppliers and service providers in the region, specializing in fire suppression systems, fire extinguishers, emergency lighting, fire hoses, hydrostatic testing and more. Serving El Paso TX, Las Cruces NM and the surrounding areas, we pride ourselves on buying local and hiring local whenever possible.
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