Best Practices for Air Inleakage Testing: A Step-by-Step Guide for Plant Performance Engineers

Air inleakage testing only pays off when it's done right. A rushed or poorly planned survey can miss real leak points, waste operator time, and leave a plant no better off than before the test began. Whether you're running your first air inleakage survey or refining a program you've had in place for years, following a consistent, repeatable process is what separates useful data from guesswork.

1. Establish a Performance Baseline First

Before any technician walks the plant with a detector, pull recent condenser performance data: backpressure trends, dissolved oxygen readings, and any recent heat rate deviations. This baseline tells the testing team where to focus first and gives you a clear before-and-after comparison once repairs are made.

2. Test Under Representative Operating Conditions

Air inleakage behaves differently at partial load versus full load. Testing during unusually low load periods can under-represent the true scope of the problem. Whenever possible, schedule testing during normal or near-full load operation so the results reflect what the unit experiences most of the time.

3. Work Systematically, Not Randomly

Effective survey teams move through the plant in a defined sequence rather than chasing whichever area seems suspicious. A typical path covers:

• Condenser expansion joints and manways

• Low-pressure turbine shaft seals and packing

• Valve stem packing on condensate and feedwater systems

• Instrument connections and sample lines below the waterline

• Any recent maintenance or gasket work

4. Document Every Finding, Not Just the Big Ones

Small leaks add up. A thorough survey logs every suspected point, even minor ones, with location, estimated severity, and a photo when possible. This creates a prioritized repair list instead of a single anecdotal number.

5. Verify After Repairs

Once repairs are complete, retest the same points to confirm the fix held and to check whether backpressure and dissolved oxygen levels have improved. This closes the loop and gives plant management hard evidence of the return on the testing investment.

Ready to get ahead of leaks before they cost you? Contact StrongForce, Inc. at 833-735-3257 or info@StrongForceInc.com to schedule a survey or speak with one of our field engineers.