Hold-Test Drop %, Criteria & Pass/Fail
Methodology — window, criteria, deltas
Understand drop % vs criteria %, rising and stable holds, delta colours, and minimum test pressure checks before sign-off.
8 min readEngineer · Witness / QA
Test window
You define the hold period by selecting start and end on the pressure chart. All change and delta calculations use samples inside that window.
Overall pass/fail
- Falling hold (↓): pass when drop ≤ criteria %.
- Rising hold (↑): pass when rise ≤ criteria %.
- Stable hold (—): pass when |change| ≤ criteria %.
- Optional: pressure must stay at or above nominal test pressure for the full window when that check is enabled.
- Red delta checkpoints can fail the test on any hold direction.
Hold direction
↑ means net pressure rose during the window; ↓ means it fell; — means the change was very small relative to start pressure.
A warming system often produces a rising hold—the app shows rise % instead of a misleading negative drop %.
Delta checkpoint colours
- Green: this step’s |Δ| is not steeper than the previous step.
- Red: the interval rose on a falling hold, fell on a rising hold, or the |Δ| magnitude grew compared with the step before.
- A red delta checkpoint can fail the test on any hold direction.
Temperature
When the logger exports temperature, review the trace beside the chart. Cooling can look like a leak; warming can explain a rising hold.
Optional temperature-adjusted drop affects pass/fail only if you enable it and your procedure allows it.
Procedure first
PressureTrend helps you read a hold test; your written procedure, client specification, and code rules govern sign-off when they differ from the app.