A tick in the box is not a working detector. Three separate clocks decide whether a portable gas monitor can be trusted this morning — the daily bump test, the calibration on that instrument's own interval, and the shelf life of the cylinder you tested it with. This tracks all three, per instrument, and refuses to call a unit good when the gas behind the result was dead.
One-time purchase. No subscription. No account. Works offline.
Checked before each day's use. The clock is measured in days since the last one, so an instrument bumped yesterday reads as due today, and one missed for a week reads as overdue — not quietly as fine.
You set the interval in months for each instrument, from that instrument's own manual. A three-month unit and a twelve-month unit sitting on the same bench are banded differently, because they are different. There is no site-wide default to get wrong.
The calibration gas has its own expiry date and its own lot number, tracked as a third axis. You can see the cylinder going out of date before it silently invalidates everything you test with it.
Record a bump test or a calibration against a cylinder that had already expired on the day of the test, and the event is kept in the history exactly as entered — but the instrument does not go green. It bands as unverified: a result exists, and nothing valid stood behind it.
The same applies when no lot number and no cylinder expiry were entered at all. A test you cannot tie to a specific cylinder proves nothing about the instrument, and this refuses to pretend otherwise.
OSHA guidance is plain: a unit that fails a bump test needs a full calibration before it is used again. So a failure puts the instrument out of service and keeps it there. Recording a passing bump test the next morning does not lift it — only a calibration recorded on or after the failure does.
And the two rules meet: a calibration recorded against an expired cylinder cannot release a blocked instrument either. Clearing a failure with gas that proves nothing is precisely the gap this closes.
Every instrument sits in exactly one band — the worst one that applies — so the register can be read from the top down. An instrument with nothing recorded is not treated as clean; it lands in the emptiest band of all, because no evidence is worse than bad evidence.
Make and model, serial or asset ID, location or crew, and who is carrying it.
O2, LEL, CO, H2S as standard, plus anything else the unit carries typed in free.
Calibration interval in months, set per instrument from its own manual. Never assumed.
Bump or full calibration, the date, pass or fail, and who carried it out.
Cylinder lot number and cylinder expiry date, recorded against the event — not the instrument.
A dated audit page: instrument, both clocks, cylinder lot, current band, and why it is flagged.
Every band tile on the dashboard opens the register filtered to exactly those instruments. There is no counted band you cannot act on — a number you can see but not drill into is a number that gets ignored.
It does not calibrate anything. It does not set the interval or tell you what the interval should be. It does not replace the manufacturer's instructions or your employer's procedure, and it does not decide whether an instrument is fit to use. It records what was done, when, with which gas, by whom — and what is out of date.
Everything stays on your device. Nothing is uploaded, no account is created, and the app keeps working when the gas shack has no bars.