LEAK TESTING · ENGINEERING CALCULATOR
Fit a straight line to 3–100 pressure measurements, calculate Q = Vb and subtract an independently measured background load.
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Model
Calculate
Assumptions and use
Times must increase strictly. Constant volume, suitable temperature stability and an approximately linear interval are required. R² is a diagnostic, not proof that the signal is a leak. A negative net result calls for review of background and drift; it is not a negative physical leak.
Worked example
The default six-point series has slope 0.083 Pa/s. For 0.75 m³, total load is 0.06225 Pa·m³/s; after subtracting 0.001 Pa·m³/s, net load is 0.06125 Pa·m³/s.
Record the units, gas, temperature, background and instrument settings with every result. Confirm the model assumptions before applying a calculated limit to a real test.
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