API 527 · API 576 · Set-pressure tolerance

The Valve Passed. Now Prove Why It’s On A Three-Year Interval.

A pass on a bench ticket is not a justification. When an auditor asks why this PSV goes three years between tests and that one goes twelve months, the answer is the run of in-tolerance as-found readings behind it — and that run is usually scattered across a filing cabinet, a shop cert and someone’s memory. This keeps the register, judges every reading, and holds the evidence per valve.

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Two psi or three percent — and the
crossover is where people get caught.

The set-pressure tolerance changes at 70 psig. Below it a valve gets a flat two psi either way; above it the band opens to three percent of set, which is a different number for every valve on the site. Worked out in your head at the bench, that is where a marginal reading quietly gets written up as a pass.

Set pressure at or below 70 psig
±2 psi

A flat band

A 60 psig valve is in tolerance from 58 to 62 psig. Anything outside that is a failed as-found reading, whatever the as-left says afterwards.

Set pressure above 70 psig
±3%

A band that moves with the valve

A 250 psig valve gets 242.5 to 257.5. A 1,440 psig valve gets 1,396.8 to 1,483.2. The app computes the band from the stamped set pressure and shows it before you save.

No lift at test limit
Fail

Numbers don’t enter into it

A valve that will not lift is recorded as a failed as-found test regardless of what happens after it is freed. It breaks the streak and demands a corrective action.

A column of pop pressures is a record.
It is not an interval justification.

The reading is judged as you enter it

Type the as-found and the verdict appears immediately: deviation in psi, deviation as a percentage, and the exact band it was measured against. No mental arithmetic at the bench, no marginal reading talked into a pass.

🕑

Each valve runs on its own clock

Interval is a per-valve figure, not a site-wide setting. Change one valve to twelve months and its next-due date moves; the register can be filtered to overdue and due-within-30-days without anyone rebuilding a sheet.

📈

The streak is the evidence

Every valve carries its consecutive in-tolerance count and the date of its last failure. That is the specific thing an auditor wants when the interval is longer than the default, and it is on the screen rather than reconstructed from paperwork.

🔑

A failure cannot just sit there

An out-of-tolerance as-found, a seat leak or a no-lift will not save without a corrective action written against it. The gap that normally opens between finding a problem and recording what was done about it is closed at entry.

The fields an auditor actually asks for

Valve identity
Tag number, location or equipment protected, service fluid, size and orifice, type, manufacturer and model.
Set pressure
The stamped figure. Every tolerance band on that valve is derived from it.
Test interval
Months, per valve. Drives that valve’s next-due date and its overdue / due-soon status.
Each test
Date, bench or in-service, technician, work order or shop cert number.
As-found
First-lift pop pressure, or a recorded no-lift. Judged against the band and stored with the deviation.
As-left
Pop pressure after any adjustment, or the same figure where nothing was touched.
Seat tightness
Pass, fail or not tested. A seat failure fails the test even when the pop was in tolerance.
Disposition
Returned to service, repaired and returned, replaced, or removed.
Corrective action
Mandatory on any failure. Free text, carried through to the CSV export.

Built for a phone in the valve shop, not a desktop in the office.

PSV Test & Interval Tracker
StatusNew testTest historyValve registerExport
34
Valves
212
Tests
2
Overdue
5
Due 30d
1
Out of tol
26
Clean
Needs attention
PSV-1042 · 250 psig
Separator V-201 · Last as-found 265.0 psig, outside the 242.5–257.5 psig band
failed
Retest scheduled
PSV-318 · 60 psig
Vapour recovery skid · Due in 19 days on 8 Sep 2026
due
19d
Interval justification
PSV-880 · 36-month interval
6 consecutive in-tolerance tests out of 7 on record · Last failure 12 Mar 2014
6 pass
Due 4 Apr 2028
PSV-1042 · 12-month interval
0 consecutive in-tolerance tests out of 9 on record · Last failure 10 Aug 2026
0 pass
Interval under review
Out-of-tolerance as-found readings will not save without a corrective action recorded against them.

Works with no signal

A valve shop with a metal roof and a wellsite forty miles out have the same problem. Everything runs on the device, offline, once the page has been opened.

Install it like an app

Add to home screen on a phone or tablet and it opens full screen, no browser bar, no account, no login to remember at six in the morning.

Light by default

High contrast for a screen in direct sunlight, with a dark theme a tap away for a night shift. It remembers which you picked.

Your data stays yours

No account, no server, no sync. The register lives in your browser storage, backs up to a JSON file, and exports to CSV whenever you want it elsewhere.

One caveat worth stating plainly. This records and computes — it does not replace your written PSV programme, and the interval you put on a valve remains your decision to justify. What it gives you is the evidence trail behind that decision, kept as you go rather than assembled the week before an audit.
How a valve reads on the register

Every valve carries one status, worked out from its own interval and its own last reading.

  • Never tested — in the register, no test on record yet.
  • In date — last as-found was in tolerance and the next due date is more than 30 days out.
  • Due — the next-due date falls within 30 days. It shows on the status screen before it becomes a problem.
  • Overdue — past its due date, with the number of days shown against it.
  • Passing streak — consecutive in-tolerance tests, newest first, with the last failure dated.

One payment. Yours to keep.

$19
One-time purchase · no subscription · no account
  • Unlimited valves and unlimited test records
  • API 527 / 576 tolerance computed on every as-found reading
  • Per-valve interval, next-due dates, overdue and due-soon filters
  • Consecutive pass streak and last-failure date per valve
  • Test history and full register export to CSV
  • Installs to the home screen and runs offline
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Works in any modern browser on a phone, tablet or desktop. No refunds. All sales are final.