Is PressureTrend free to use?

Yes. The core tool is currently free for everyone.

Does PressureTrend upload my pressure data or test results?

Nothing is sent to any external server for analysis. All file parsing, calculations, chart rendering, and report generation runs entirely in your web browser. Beyond loading the page itself, only aggregated usage analytics are collected—no pressure data, test results, or file contents are ever transmitted. No data upload: Your pressure logs and results never leave your browser. Works well offline: While the page stays open, import, analysis, and PDF export continue without an internet connection. Session persistence: Your work is saved locally. You can refresh the page and continue where you left off. You control your exports: Only you decide when to generate a PDF report or save a project file.

Can I use PressureTrend offline?

While the page stays open, import, analysis, and PDF export continue without an internet connection.

Do I need to install any software?

No installation is required. PressureTrend runs directly in your web browser after you export CSV or Excel from your logger software.

Is my work saved if I refresh the page?

Your work is saved locally. You can refresh the page and continue where you left off.

Which file formats are supported?

Keller: LOGGER_5, LEO Record, and PressureSuite exports (CSV · Excel). Auto-detects native Keller layouts on CSV and Excel. Import setup picks channel and time source when several are present. Crystal nVision: Standard nVision CSV and Excel exports (CSV · Excel). Pressure time series with run metadata on CSV and Excel. Import setup confirms gauge serial and calibration when the file lists several. Wonderware: Trend / historian CSV exports (CSV). Trend exports with timestamp and tag columns. Pressure columns are discovered automatically; import setup confirms the right ones when several are present. Other tabular exports: Flexible column fallback (CSV · Excel). When the file is not a known native layout, detection tries flexible time and pressure columns so many logger exports still import without a dedicated parser.

My file is not recognised automatically. What should I do?

Confirm time calibration and test start before analysis. If your file contains multiple time sources, gauges, or pressure channels, pick the correct ones—standard Keller and nVision exports rarely need extra choices. If your logger export is not recognised well, email contact@pressuretrend.com with your device and export format—we improve parser support for CSV and Excel from real user files without accessing your data.

Can I import multiple files at the same time?

Yes. You can queue and work with up to 10 files per session.

Which Keller and Crystal devices are supported?

Keller: LOGGER_5, LEO Record, and PressureSuite. Pressure time series with run metadata on CSV and Excel. Import setup confirms gauge serial and calibration when the file lists several. When the file is not a known native layout, detection tries flexible time and pressure columns so many logger exports still import without a dedicated parser.

How does the pass/fail logic work?

Passed or Not passed combines pressure change against your criteria %, optional minimum test pressure, and delta trend (on falling holds and stable holds with a net loss). Falling hold: pass when drop ≤ criteria %. Rising hold: pass when rise ≤ criteria %. Stable hold: pass when |change| ≤ criteria %. If allow below test pressure is off, pressure anywhere in the window must stay at or above the nominal test pressure. That check is separate from drop % or rise %. Start-to-end change vs criteria %; minimum test pressure can fail independently. Direction ↓ / ↑ / — when |change| is below 0.05% of start pressure. Delta colours show flattening vs steepening; red deltas can fail ↓ holds and — holds with net loss.

Can I adjust the pass/fail criteria?

Set start and end of your hold test on the chart; set nominal test pressure, criteria %, and 2–8 delta checkpoints in the test controls beside it. Optional minimum floor pressure can fail the test independently.

How do I export my results?

Review pass/fail, start-to-end change, delta trends, and temperature insight in the workspace. Export a PDF via your browser print dialog or save a JSON project file to continue later.

What are the coloured deltas in the results?

Green: this step’s |Δ| is not steeper than the previous step (flattening or stable rate of change). Red: the interval change grew compared with the step before. On falling holds—and stable holds with a net pressure loss—a red delta can fail the test. On rising holds, red deltas are advisory only (Δ advisory).

How is drop % calculated on a hold test?

Passed or Not passed combines pressure change against your criteria %, optional minimum test pressure, and delta trend (on falling holds and stable holds with a net loss). Falling hold: pass when drop ≤ criteria %. Rising hold: pass when rise ≤ criteria %. Stable hold: pass when |change| ≤ criteria %. ↑ next to the result means net pressure rose during the window; ↓ means it fell; — means the change was very small. A rising hold is common when the system warms. The app shows rise %, not a misleading negative drop %. Check temperature and your band limits before signing off a warming hold.

Does API 16C allow 5% pressure variation during a hold?

API 16C hydrostatic hold acceptance commonly requires no visible external leakage and that pressure during the hold does not vary by more than 5% or 500 psi, whichever is less. Your job is governed by the approved procedure and the API edition cited on your test pack—verify exact wording there. In PressureTrend, set criteria % in the test controls (for example 5%) and evaluate drop or rise over your hold window; when the dual limit applies, also check the absolute 500 psi cap against start pressure before sign-off.

Is PressureTrend a replacement for CrystalControl or PressureSuite?

No. Those tools export the data from your logger. PressureTrend analyses the export, helps you read pass/fail, and builds a hold-test report.

Where is my data processed?

All file parsing, calculations, chart rendering, and report generation runs entirely in your web browser. Beyond loading the page itself, only aggregated usage analytics are collected—no pressure data, test results, or file contents are ever transmitted.

Who can see my pressure test data?

Nothing is sent to any external server for analysis. Your pressure logs and results never leave your browser.

Is PressureTrend suitable for offshore use?

While the page stays open, import, analysis, and PDF export continue without an internet connection. Local browser processing suits restricted connectivity and sensitive environments.

My logger export doesn't work well. Can you help?

We actively improve support for different logger formats. Reach out with your device and export format—we improve parsers from real user files without accessing your data.

Where can I find more help?

Start-to-end change vs criteria %; minimum test pressure can fail independently. Pass/fail, hold direction (↑ ↓ —), delta colours, temperature, and test-pressure checks—the same rules as the result card. See the full guide for hold direction, delta colours, temperature, and test-pressure checks. Logger workflow guides live on the Guides page and in Resources below.

API 16C Hold Acceptance — 5% or 500 psi

Standards — dual acceptance limit

Understand the common API 16C dual criterion for subsea component holds and how to apply criteria % in PressureTrend while your procedure governs sign-off.

7 min readEngineer · Witness / QA

Procedure first — not compliance advice

This guide summarises a widely cited acceptance pattern from API 16C (subsea production systems) hydrostatic testing. It is educational only.

PressureTrend is not certified, endorsed, or approved by API. Your governing procedure, client specification, and the exact edition of the standard for your project define acceptance. When anything here differs from your test pack, follow the test pack.

The dual criterion

API 16C hydrostatic hold acceptance commonly requires no visible external leakage and that gauge pressure during the hold does not vary by more than 5% or 500 psi (3.45 MPa), whichever is less, relative to the hold start.

That means two limits apply at once: a percentage of starting pressure and an absolute cap. At high test pressures the 5% rule is usually tighter; at lower pressures the 500 psi cap can become the binding limit.

Example at 10 000 psi start: 5% = 500 psi — both limits are equal.
Example at 15 000 psi start: 5% = 750 psi — the 500 psi cap binds (smaller allowed change).
Example at 5 000 psi start: 5% = 250 psi — the 5% rule binds.

Visible leakage

The standard also expects no visible external leakage during the hold. PressureTrend analyses the recorded pressure trace only—it does not replace joint examination or visual leak checks required by your procedure.

Using PressureTrend today

PressureTrend evaluates pressure change over the hold window you select against a single criteria % (drop, rise, or stable hold). Set criteria % to 5 when your procedure uses the percentage limb of the dual rule.

The app does not yet apply the 500 psi absolute cap automatically. When your procedure uses the full dual criterion, compare the measured |ΔP| over the hold window against both 5% of start pressure and 500 psi before sign-off. A future preset will combine these limits in one pass/fail line.

Set the test window on the stabilized hold segment only.
Note start pressure at the window start (shown on the chart and result card).
If drop % ≤ 5%, check that absolute |ΔP| ≤ 500 psi as well when the absolute cap applies.
On rising or stable holds, use rise % or |change| % the same way your procedure defines acceptance.

Operator WHST and FAT packs

Many operator wellhead and subsea FAT procedures mirror API-style dual limits or specify their own percentage. WHST packs often use a single percentage (for example 2%) instead of the 5%/500 psi pair—always use the value on your procedure sheet.

See the WHST workflow guide for a typical wellhead hold path and the subsea FAT qualification guide for multi-hold campaigns.

Related guides

Open PressureTrend

← Hold analysis on the landing page