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What Is a Leak Test?

What is an air leak test? Air leak testing determines if an object, product, or system functions within a specified leak range. As leaks always flow from higher to lower pressure, air leak testers use pressure to generate and monitor that flow. Air leak detection matters because leaks from manufacturing defects such as holes, cracks, or weak seals impact the final product’s performance.

How to Calculate Leak Rate (SCCM)

A leak rate is expressed as a volume per unit of time. The rate is found by measuring the change in pressure multiplied by the volume. That number is then divided by the change in time multiplied by the surrounding atmospheric pressure to calculate the leak rate (SCCM).

ATM = Atmospheric pressure (PSIA)
V = Test volume (cm3)
Δp = The decay in pressure during test time
Δt = The amount of decay time (min.)
SCCM = Standard Cubic Centimeters per Minute

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For example:
Leak rate = .02psi/0.05min * 50cm3/14.7psia
Leak rate = 0.4 * 3.401
Leak rate = 1.36 SCCM

If you require assistance identifying any of these metrics or want to learn more about how to calculate SCCM for your leak detection application, call 801-264-1000 today. Our highly trained team will help you with calculations for determining SCCM.

Standard Types of Leak Tests

Air leak detection is an essential step in any manufacturing process. Both destructive and non-destructive standard air leak tests are available for manufacturing lines and OEMs to meet your specifications and satisfy any regulations.

The test type is dependent upon your product and its application. For example, only a chamber test can be run on an enclosed object whereas objects with a single opening may use multiple other tests. The most common tests include Pressure Decay (PD), Vacuum Decay (VD), Occlusion (Occ), Mass Flow (F), Burst (B), Crack (C), and Chamber (PR).

Pressure Decay

Pressure decay is one of the most widely used non-destructive air leak testing methods. It is ideal for small, sealed components with a single access port. During this test, any decrease in air pressure over time signifies a leak.

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Mass Flow

Mass flow testers measure the flow rate through an object, with failure occurring when the flow rate does not pass through the maximum and minimum standards. Mass flow applies to parts with two ports open to the atmosphere.

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Vacuum Decay

Vacuum decay air leak tests are the inverse of pressure decay tests. Instead of pressure falling, any rise in pressure indicates that a leak is present.

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Occlusion air leak testing measures air movement through an object and determines if the object’s passage is blocked. It is a non-destructive test.

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Downstream Occlusion

As noted by the name, downstream occlusion is an occlusion test that includes a downstream release for more precise results.

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Burst air leak testing is a destructive pressure test that measures the maximum pressure at catastrophic failure.

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Pressure Cracking

Similar to a burst test but more sensitive, pressure cracking is often used to detect events such as a valve opening.

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Chamber leak tests are used to find leaks in sealed devices such as electronics or packaging that do not have an access port. Chamber testing is ideal for products that need to meet IP67 standards.

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Other Types of Air Leak Testing

In some cases, standard air leak tests are not enough. At Zaxis, we offer several high-precision specialty air leak detection tests to ensure product viability. When paired with a standard air leak test, specialty tests provide quality assurance during the development and manufacturing of any product.

Specialty Air Leak Tests

  • Backpressure Flow
  • Pressure Increase
  • Valve Reseat
  • Creep/Ramping Fill
  • Pressure Exercise
  • Vacuum Exercise

Additional Air Leak Detection

  • Methods
  • Bubble/Submersion
  • Hard Vacuum (Helium)
  • Helium Accumulation, Sniff, or Spray
  • Tracer Gas
  • Ultrasonic

If you are unsure which non-destructive test or other air leak detection method is best for your manufacturing line, contact Zaxis. Our expert team will work with you to find the best solution for your production.

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