What You Need to Know About Hydrostatic Testing Pumps

Apr. 29, 2024

What You Need to Know About Hydrostatic Testing Pumps

Hydrostatic testing is a critical process for many industries and applications that use equipment subjected to high pressure. In the end, however, a hydrostatic pressure test is only as good as the pump used to perform it. In other words, not only should the system being tested be structurally sound and perform as it should, the pump testing it also needs to be just as reliable and maintain appropriate pressure levels.

Are you interested in learning more about hydrostatic test equipment? Contact us today to secure an expert consultation!

In today’s article, we’ll explain how hydrostatic testing works, common applications, and what to look for when choosing the best hydrostatic testing pump.

What is Hydrostatic Testing?

Hydrostatic testing (also referred to as hydro testing) is a type of test that fills a pressure vessel or pipe system with fluid to a specified PSI to ensure it can safely hold the amount of pressure it is rated for and maintain structural integrity. The item being tested must maintain its PSI for a designated period of time without leaking or rupturing. The length of time and PSI rating for each application’s hydrostatic test is typically determined by the manufacturer or government agency regulations.

A closed loop system must be created to perform a hydrostatic test which, in most cases, involves shutting off a supply valve. Most commonly, the pressurized fluid is water (from the Greek word hydro), and it is sometimes dyed to aid in visual inspection of leaks. Hydrostatic tests are often necessary after equipment shutdowns, repairs, or prolonged time sitting idle to verify that it will operate properly when it returns to service.

Common Hydrostatic Testing Applications

In theory, any system that needs to maintain pressure greater than the ambient pressure has the potential to benefit from a hydrostatic test. The following industries and applications are the most common examples of hydrostatic testing:

Sprinkler systems. By code, many sprinkler systems need to be tested periodically to ensure that they can maintain pressure when activated and operate properly. A pump is hooked up to the main sprinkler system line and pressurized to 250 PSI, which it needs to maintain for at least 15 minutes.

Fire hoses. Critical applications like fire hoses need to be tested to ensure they don’t rupture or fail in service. They are typically tested prior to being installed in fire trucks or brought to fire stations. Inspectors will flood hoses with fluid and pressurize it to a minimum of 300 PSI, in accordance with National Fire Protection Association (NFPA) specifications.

Pipe manufacturers. Commercial pipe manufacturing plants will perform hydrostatic testing on pipes of varying lengths, especially those supplied to government agencies. They need to prove that every pipe meets specifications and that they won’t experience failure in critical applications like naval defense vessels.

Cooling systems. Cylinders or coils for A/C or refrigeration units are routinely tested, particularly in facilities where climate control is critical like hospitals. Industrial electrical enclosures also use these types of refrigerants to cool down electronics, as do military vehicles used in extremely hot climates. Municipal vehicles like city buses also utilize cooling systems, and some state Department of Transportation agencies may require periodic testing to ensure safety and proper operation.

Miscellaneous. There are numerous other applications where hydrostatic testing is conducted, including oil and gas pipelines, irrigation systems, gas cylinders, boilers, sewer water lines, plumbing, and more.

What to Look for in a Hydrostatic Testing Pump

As you can see, a hydrostatic testing company might provide services to multiple industries. As such, it will require the use of a pump that can operate at different pressures that meet the desired specifications.

For example, a company might test fire sprinklers one day and fire hoses or plumbing systems the next. An operator could use a pump rated up to 1,200 PSI for when an application calls for it, and then turn it down to 250 PSI for a sprinkler test. The pump’s pressure is adjusted with the use of a pressure regulator to achieve that threshold. In the sprinkler test example, as soon as the pressure hits 250 PSI, it will bypass any additional pressure to maintain levels in the line.

Maintaining consistent pressure, however, is where the real value comes in. A hydrostatic test cannot have fluctuating pressure, which is what makes an electric plunger pump ideal. Unlike a diaphragm pump with flexible components, a plunger pump’s pressure will not ebb and flow. Both are considered positive displacement pumps, but have distinct differences.

Operators are also concerned with the amount of flow output that a pump can deliver. They don’t want to be standing around all day waiting for a system to fill and reach the desired PSI. The higher the flow rate of a pump, the faster the system will fill.

For many applications like fire hoses and sprinkler systems, you typically don’t want any less than 3.0 GPM. When used with a pressure gauge and regulator, our 350U and 356U series pumps have a lot of varying flow potential. When operating around 250 PSI, they can achieve a tremendous amount of flow and fill lines quicker so operators can get in and out of jobs faster, saving on labor costs.

Electric plunger pumps are not only ideal for their quiet operation and consistent flow and pressure, they’re also compact, portable, and easily maneuvered to fit into tight spaces.

Failure isn’t an option in critical systems or the hydrostatic testing pumps used to test them. Learn more about what sets Pumptec hydrostatic testing pumps apart from the competition, and how our engineers can customize a solution to your precise specifications. Speak with a pump expert today.

To learn more about plunger pumps and how they compare to other types of pumps, download our Pump Comparison Cheat Sheet below.

Hydrostatic Test Pump Features for Standpipes and Fire ...

Portability, durability, and power source make some hydrostatic test pumps better for some jobs than others

Leaks — whether they’re in a sewer system, a plumbing set-up, or fire sprinkler and standpipe systems — can kill the performance of water-based systems, lead to structural damage, and make a building unsafe. Hydrostatic tests prove that a system is drip-free, identifying problems that can be overlooked during a visual inspection. In this article, we look at the hydrostatic test pump features that are important for professional contractors specializing in the installation, testing, and maintenance (ITM) of standpipes and fire sprinklers.

While all test pumps share core features, not all models provide equal power, durability, portability, or control.

If you’re shopping for a hydrostatic test pump, feel free to skip directly to our selection, including lightweight Tru-Test models (250 PSI/2.2 GPM) and more powerful HT-454 (400 PSI/3.0 GPM), HT90E, and HT89A models (both at 300 PSI/3.0 GPM).

Did you miss our primer on the basics of hydrostatic testing standpipes and fire sprinklers? Click here.

Water pours into an industrial building through an opening left by a missing fire sprinkler head. A hydrostatic test would have of course identified a problem like this — as well as any loose fittings or damaged pipe — prior to system acceptance.

Hydrostatic test pump features: the necessary pressure and flow rates vary with the size of the system

The two most critical specs for a hydrostatic test pump are the maximum pressure in pounds per square inch (PSI) and the volume in gallons per minute (GPM) that the pump can move. Larger, more powerful gas-powered pumps generally have higher horsepower (HP), PSI, and GPM, and can more quickly pressurize larger systems. Electric pumps have less HP but are more convenient, and can deliver the speed and pressure required for most fire protection system applications.

If you want to learn more, please visit our website hydrostatic pressure pump.

Pumps with higher GPM will add pressure to a system more quickly — and fill it faster, if needed. Our previous piece on hydrostatic testing elaborates on these factors, but the key considerations for how much pump is needed include the system size, whether or not a system is already pressurized, and the building’s height.

How heavy is your hydrostatic test pump?

Weight is a major consideration when choosing a hydrostatic test pump. Most people with a healthy back lifting from waist height — say, from the back of a truck bed — can safely and repeatedly pick up 70 pounds with good technique. The maximum safe load becomes significantly less when picking that object back up at ground level: about 20 pounds or lower for repeated lifting.

Some lighter hydrostatic test pumps are designed with a handle that enables carrying them with a single hand, while large-dimension and heavier pumps may require two people to lift them and are often mounted on wheels. In general, weight increases with the power of the pump. However, there are also big differences in weight and size between many otherwise comparable pumps.

Aluminum pump components are considerably lighter than those made from other metals; a cubic foot of aluminum weighs roughly three times less than the same volume of copper, iron, or steel. In addition to being lighter, pumps that use aluminum are much more resistant to freeze damage; some older models have casings made of cast iron or other metals that can crack when vibrating in freezing temperatures. Compact models can also be built without metal cases, roll cages, or other protective components that make pumps larger and heavier.

Common pumps rated at between 220 psi and 500 psi provide all the pressure required for nearly all fire sprinkler and standpipe testing applications — and many can provide that power at a weight under 40 pounds. Models powered by hand or a cordless or electric drill, for example, can weigh less than 10 pounds but have a low GPM (less than 2.0). While it’s certainly possible to conduct hydrostatic tests with these pumps, their limited power (along with the inconvenience of needing to hand-pump or squeeze the drill’s trigger) makes them a less common choice.

On the other hand, kit-style pumps enclosed in a carrying case strike a balance between power and portability. For example, Triple R’s Tru-Test pump weighs only 22 pounds, including the protective metal case.

The weight of larger electric models varies significantly. Both Triple R and Reed manufacture pumps in the 250 psi to 500 psi range with weights of just over 30 pounds. Triple R’s HT-90E weighs only 32 lbs., while the Triple R HT 89-A weighs slightly more (35 lbs.). Both of them weigh less than their competitors:

Reed EHTP500 – 37.5 lbs.
Reed EHTP500C – 48 lbs.
Rice EL1 – 58 lbs.
Rice EL1A – 74 lbs.

The weight of the latter three models is high, in part, because they are built with a roll cage.

Pump hoses and electric cords are hydrostatic test pump features that provide flexibility

Every hydrostatic test pump needs both a supply of energy and a supply of water. Pumps powered by gas and those that are hooked up to a battery can operate in buildings that don’t yet have a functioning power source. Long lengths of cable (like the 25 feet included with Triple R’s 12-Volt Tru-Test pump) facilitate connections over a long distance and make it easier to connect to a battery in a parked vehicle. Meanwhile, other electric pumps have shorter lengths of cord — in the neighborhood of six feet — that can be coupled with standard extension cords.

Hydrostatic test pumps use both outlet and inlet (supply) hoses to move water from the source to the system undergoing testing. Outlet hoses connect pumps to the fire sprinkler, standpipe, or plumbing system undergoing testing and, when supplied, are designed to withstand high pressures. Inlet hoses — typically threaded with basic garden-hose connections — connect the water source to the pump. Because longer lengths of supply hose may collapse due to suction, a sturdy and short hose (read: not a full-length garden hose) may offer better performance.

The hose length included with hydrostatic test pumps varies with each manufacturer: Rice’s model EL series ships without a hose by default, Reed’s electric hydrostatic test pumps include 15 feet of outlet hose, and Triple R supplies 10 feet of quick disconnect outlet hose with all models and 5 feet of supply hose with the HT-454 and Tru-Test.

A quick-disconnect coupling includes a one-way valve that allows the hose to separate easily from the pump, which comes in handy when demonstrating to fire officials that the system is successfully maintaining pressure. It’s worth noting that the threaded end that connects the hose to the system is smaller than the 2 1/2″ NPT-threaded swivel found on most FDCs, where many systems will be tested. Additional reducers or adapters will be needed.

Hydrostatic test pump features that maintain and manage pressure

Hydrostatic test pumps need some way of maintaining system pressure after disconnecting the supply line or outlet hose. Some pumps close off that pressure using a manually-operated valve at the supply line. Others use an in-line check valve which activates automatically when water flows in the wrong direction (as happens when shutting off a pump). Supply hoses also typically feed into a suction-side strainer that blocks debris from the water supply; this prevents damage to the pump and the possibility of clog-caused flooding.

Certain pumps, such as Triple R’s HT-89A, have a pressure regulator designed to keep system pressure in check. This can be set to detect when the outlet pressure reaches a specific number and then automatically close off the supply; a full-flow bypass diverts water directed at the outlet hose back into the pump itself. Pressure regulators are a useful fail-safe and don’t require minute-by-minute monitoring, but it’s still important to keep an occasional eye on the pump, as friction from recirculation causes water to become increasingly hot. You wouldn’t want the bypass to operate for a full 45 minutes, for example. Nevertheless, a pressure regulator is a great feature that can prevent damage to the pump and free you up to do other tasks.

Liquid-filled pressure gauges ensure durability and readability

Hydrostatic test pumps should include a gauge used to indicate the pressure being supplied to the system (unlike system pressure, which is measured using a separate gauge). Liquid-filled gauges use silicone, glycerin, or other substances to stabilize the gauge’s needle.

Like pretty much every pump, hydrostatic test pumps have moving components that pulse, vibrate, and generate heat. These forces slowly damage the sensitive parts on a gauge, including links and pivots. Vibration can lead to permanent damage and inaccurate readings and is, in fact, the leading cause of gauge failure. Liquid-filled gauges also limit the build-up of condensation, lubricate moving parts, and protect against sudden changes in temperature.

This short video models vibration’s effects on a gauge’s internal components:

But if dry gauges lack all of these benefits, then why aren’t all gauges liquid-filled?

While liquid-filled gauges offer substantial improvements to gauge life and performance, dry models don’t run the risk of leaking, have no fill line, and never need to be refilled. They can also operate at as low as -40 degrees Fahrenheit, whereas liquid-filled gauges generally have higher minimum operating temperatures (around -4 degrees Fahrenheit). These temperatures aren’t an issue in most hydrostatic test pump applications, however, so it’s typically best to opt for a liquid-filled gauge.

Portable, light, and durable hydrostatic pumps for standpipes and fire sprinklers

There are a number of hydrostatic test pumps on the market that can get the job done. But QRFS supplies four of the most user-friendly, lightweight, and reliable models for tests of fire sprinkler and standpipe systems.

Triple R’s Tru-Test delivers on the best of many hydrostatic test pump features described above: these pumps weigh only 22 pounds, come in a durable carrying case, feature a liquid-filled gauge, and include substantial lengths of cord and hose. Both the electric 120-volt Tru-Test and 12-volt Tru-Test move 2.2 GPM at up to 250 PSI, and the 12-volt model can be hooked to a car battery for power-source convenience.

Triple R’s HT-89A and 90E are some of the lightest pumps in their PSI/GPM class. The HT-90E operates at 3.0 GPM and 300 PSI and is designed to be carried with a single-handed grip. The HT-89A is almost identical to the HT-90E but also has a pressure regulator to ensure that the pump doesn’t exceed the target pressure. Finally, the HT-454 is rated at 400 PSI and 3.0 GPM, has a compact design of only 12″x12″x8″, and, like the Tru-Test, features a protective case and 5’ of inlet hose.

To learn more about choosing the right model and QRFS’s hydrostatic test pumps, give us a call at 888.392.3362, email support@qrfs.com, or fill out our contact form.

This blog was originally posted at blog.QRFS.com. If this article helped you, check us out at Facebook.com/QuickResponseFireSupply or on Twitter @QuickResponseFS.

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