Although standard pressure decay and differential pressure testing are similar, there are some stark differences that businesses should know about!
There’s absolutely no denying the overwhelming popularity of pressure decay leak testing, because manufacturing businesses all around the world utilize this leak testing method each and every day.
The Zaxis specialists are here to help your business with our state-of-the-art leak testing devices, but we’re also here to help ensure that your leak testing strategies are as affordable and as effective as possible. This means that business leaders need to understand the fundamentals of pressure decay leak testing, which includes some subtle variations like differential pressure and standard pressure decay leak testing.
Standard pressure decay testing is arguably the most common type of pressure decay testing, and this is partly because it’s an effective strategy for a wide variety of different testing purposes. However, more and more business leaders around the United States and across the world are beginning to understand the many advantages associated with differential pressure testing. Depending upon your unique products and applications, it’s possible for differential pressure testing to provide faster test cycle times and improved testing accuracy.
Below we’ll be comparing differential pressure and standard pressure decay testing so that you can understand what method is best for your unique applications!
What Exactly is Standard Pressure Decay Leak Testing?
Standard pressure decay leak testing involves introducing air into a test component until it reaches a pre-established amount of internal pressure. The leak tester then shuts off the air supply to the component in order to monitor any subsequent loss of pressure over a pre-established period of time.
The amount of pressure that’s lost during the testing period in accordance with a specified test limit will determine whether the component passes or fails.
What Exactly is Differential Pressure Testing?
Differential pressure testing is somewhat similar to standard pressure decay testing in that they both utilize similar testing parameters, but differential pressure testing measures pressure changes between both a test part’s volume and a reference air volume.
This means that both a reference volume and a test component are pressurized to a target pressure, until the air supply is shut off and both test pressures are allowed to stabilize. The reference air’s isolation valves are then sealed, while the exhaust valve is simultaneously opened in order to isolate pressure on both sides of a gauge transducer. The gauge transducer will then measure and compare any pressure variations between the non-leaking reference volume and the test component throughout the duration of the test.
Similar to standard pressure decay testing, a leak is ultimately detected when pressure ratings drop below a pre-determined test limit.
What Else Sets Differential Pressure Testing Apart From Standard Pressure Decay Testing?
Although there are several differences between both types of leak testing, the main thing that sets differential pressure testing apart from standard pressure decay testing is the overall resolution of the differential sensor. A simple definition of leak testing resolution is the ability to identify the smallest interval of pressure movement, and these pressure sensors are coupled with the ability to output related voltage levels in accordance with pressure changes.
On standard pressure decay sensors, the resolution is oriented around a full scale. An example of this would be if the test’s scale was 100psi and the equipment’s sensor output was 100mV, because this would create an analog output of 1mV/psi. When pressure changes occur (i.e. leaks), the sensor’s output will only subtly change. This subsequently means that the leak testing process will take longer in order to verify reliable readings.
On the other hand, differential pressure testing sensors offer a much greater resolution. This means that the leak test scales are much smaller, an example being 5psi and 100mV creating an analog output of 20mV/psi. The combination of a high-resolution sensor and smaller test scale results in faster test cycles, and this is largely because the pressure readings can ultimately be resolved more efficiently.
It’s important for business leaders to remember that pressure decay test measurements are always in a constantly moving, dynamic state. This is one of many reasons why more sensor resolution allows for more accurate test readings and faster test cycles!
Which Leak Testing Method Is Best For Your Business?
Although both leak testing methods have their merits for businesses in various industries, it’s safe to say that differential pressure testing provides higher sensitivity levels as compared to standard pressure decay tests. This subsequently means that differential pressure testing provides faster defect detection and test times.
Although standard pressure decay transducers can still provide accurate measurements, it’s known that these measurements typically come in at a lower resolution—which leads to less precise and repeatable test results.
Another reason why differential pressure testing provides higher resolution measurements is because it eliminates all sorts of thermal impacts that can occur while a test component is being pressurized. There’s absolutely no denying how differential pressure testing achieves unparalleled precision, which provides businesses with accurate data while determining faulty and acceptable parts!
What Components & Parts Are Best Suited For Standard Pressure Decay & Differential Pressure Testing?
Although a company’s leak testing needs may vary depending upon a wide number of unique factors, it’s generally known that standard pressure decay testing is best suited for medium-sized parts and components under lower test pressures. For instance, if you’re testing a component around 10 psi and aren’t worried about test cycle times, you likely won’t see many tangible advantages by using differential pressure testing as opposed to standard pressure decay.
But if your business is motivated to improve things like leak test repeatability and cycle times at higher test pressures, differential pressure testing would likely provide a wide range of benefits. Below are some specific applications that are ideal for both standard pressure decay and differential pressure testing:
- Testing non-expanding, large parts with high leak rates. This includes common automotive leak testing assemblies and parts like EV batteries, transmissions, engines, drive systems and coolant systems.
- Testing parts with small leak rates and miniscule pressure loss. This includes consumer electronics leak testing assemblies and parts like refrigerants, consumer electronics, and much more.
- Testing at very high pressures, including over 30 psig. This can include a wide variety of automotive products like hydraulic systems, brake lines, fuel lines, fuel pumps, oil passageways and fuel fittings.
- Testing pressure drops over long periods of time. This includes many medical equipment leak testing products like access sheaths, catheters and fluid bags.
The Zaxis Team Is Here To Help You Choose The Best Leak Testing Methods For Your Business!
Although this overview can go a long way to help you better determine if your business should utilize standard pressure decay or differential pressure leak testing, your company’s best solutions will ultimately depend upon your unique specifications and test applications.
Zaxis offers a world-renowned team of leak testing specialists who’ll work directly with you to fully understand your specific requirements, and we’ll always ensure that you’re getting the very best testing solutions to match your needs.
Reach out to us online or give us a call at 801-264-1000 to learn more about how our cutting-edge leak testing technologies can support your business!
