How It Works

Pressure Decay Leak Test

System leak rate can be estimated from pressure decay over time using the fluid bulk modulus:

Leak Rate = V × dP / (B × t)

  • V = System volume (in^3)
  • dP = Pressure drop (psi)
  • B = Bulk modulus of oil (~200,000 psi typical)
  • t = Test time (minutes)

Severity Classification

  • Acceptable: < 1 drop/min (0.003 GPM)
  • Minor leak: 1-10 drops/min
  • Major leak: > 10 drops/min or visible stream

Leak Rate Calculator

Estimate system leak rate from pressure decay test data. Calculate GPM, drops/min, severity, and annual loss.

Typical mineral oil: 200,000-250,000 psi

Leak Severity

ACCEPTABLE

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Leak Results

Leak Rate--
Drops per Minute--
Severity--
Annual Oil Loss--
Leak per Hour--
Leak cc/min--

Leak Severity Reference

RateDrops/minSeverityAction
<0.003 GPM<1AcceptableMonitor
0.003-0.03 GPM1-10MinorSchedule repair
>0.03 GPM>10MajorRepair immediately