Hydrostatic testing is a way of using water and pressure to test the strength of a vessel. It ensures that the vessel is strong enough to hold pressure and durable enough to avoid leaking. What kinds of items qualify as vessels that need hydrotesting? Pressure vessels, pipes, boilers, and other types of tanks. For example, sometimes water pipes develop a leak. In order to determine if the pipes are leaking, your plumber may perform a hydrostatic test.
This would help determine if the pipes are leaking or able to hold water. Pressure vessels refer to a closed container holding liquids or gases at a higher or lower pressure than the surrounding pressure. For example, your refrigerator holds pressurized coolant in order to stay much colder than the air outside of the refrigerator. Or, your paintball gun has a carbon dioxide (CO2) tank which holds pressure. This pressure is high so that it can force out the paintballs when released.
Now that you know what hydrostatic testing is, why is it important? Hydrostatic testing may not be sexy, but it is highly important. We take many things for granted until we NEED them. For example, you might never use your parking brake in Florida, until you travel to Georgia and park on the side of a hill. If it didn’t work, the results could be disastrous. If you forgot to pack your Swiss Army knife, it might not end in disaster.
Unless…you needed to open a can, a bottle of the wine cut some twine or pulled a particularly wicked splinter from your toe. Maybe you never read the expiration date and contents of baby formula. When a baby develops a milk allergy or has an upset stomach, you’ll appreciate them more. It’s a good thing that someone thought to keep you safe from yourself, even if you were totally unaware. This is the case with hydrostatic testing.
In the field of fire extinguishers and suppression systems, hydrostatic testing keeps everyone safe. Boring? Perhaps. But…everywhere you go has a fire extinguisher. Look at your current surroundings. If you are not working from home, there should be a fire extinguisher visibly accessible less than 75 feet away from you.
Do you have a minute? Go check! If the extinguisher is brand new it was tested by the manufacturer. If not, there may be a label stuck to the side to indicate the last hydrostatic testing performed. If you can’t find it, you can always call the company indicated on the sticker. They can help you determine when the cylinder will need testing. In the case of most pressurized vessels, the schedule of testing is determined by its age, contents, and materials. This is true for vessels outside of the fire industry as well.
You already know what’s coming next: why? Well, when you turn on your faucet you expect water to run. When you rely on oxygen, you expect it to be released from its tank when you turn it on. When you need to put out a fire, you need the extinguisher to work! Hydrostatic testing ensures that your fire extinguisher (or faucet or oxygen tank) expels the suppressant it contains.
The gases or liquids inside must be pressurized to come out quickly enough to extinguish the fire. In other words, what might happen if your extinguisher has not been properly hydrotested? In the best of times, you might be fine. Maybe the gas leaked out. When you pull the pin and level to use the extinguisher: nothing happens. Or, the cylinder is damaged.
You walk toward the fire and the extinguisher gets hotter. Now the contents are under more pressure and the extinguisher explodes before you can use it. Is this likely, no. Is it possible? Yes. Permitted or certified personnel perform hydrostatic tests to ensure compliance with safety standards and business practices. These people use different methods depending upon the vessel that needs testing. The general process uses water, pressure gauges, and a timer. The tester determines the amount of pressure for the test based upon the contents, materials, and manufacture specifications.
If the tester is unsure of the specifications for the procedure, each industry publishes its standards and the tester looks them up. The vessel is then filled with water and attached to a gauge. The tester records the pressure levels and used the proper time for the test. If the vessel passes, it can be dried and reused. If it fails, it is condemned and replaced. In the fire extinguisher industry, the vessels are properly labelled after testing. This allows the consumer to know the date and location of the testing performed. If you still have your office fire extinguisher nearby? See for yourself.