PTW isolation and lockout/tagout: every isolation point on the permit, with its trail
Before work starts, the equipment has to be isolated from energy and process. In OPEREX those isolations live on the permit, point by point: which method, what, which on-site reference, who applied it and who restored it — and all of it is on the PDF and in the report.
In short
- Isolation points are part of the permit: six methods (blind flange, LOTO, valve closure, electrical isolation, drain/depressurise, other), each with its on-site reference — for example the padlock number.
- Every point has a traceable state: planned → applied → restored, with a name and a time.
- The isolation certificate is a signature in the permit’s signature chain; whether a missing one blocks or warns at issue is set by the site’s policy.
- Gas testing lives on the same permit: the gate always checks the latest test, and a test cannot be deleted.
- What it does not have: second-person verification per point, a site-wide isolation register, or conflict detection across permits.
What is isolation in a permit to work?
Isolation means separating the equipment to be worked on from every source of energy and material that could hurt someone during the work: electrical energy, pressurised lines, hazardous substances. In practice that is inserting a blind flange, closing a valve, electrical isolation with lockout/tagout (LOTO), draining and depressurising.
A permit to work records that the work may start — and isolation is one of its most important conditions. When isolations live on a separate sheet or logbook, the permit does not show what exactly is isolated or who restored it. OPEREX therefore keeps them as part of the permit, in the spirit of an integrated safe system of work (ISSOW).
Isolation points on the permit
A separate box on the permit’s page lists the isolation points. One row is one point.
The six methods
- Blind flangea physical break in the line
- Lock-out / tag-out (LOTO)with a padlock and a tag
- Valve closuregate valve or valve closed
- Electrical isolationelectrical energy disconnected
- Drain / depressurisethe system emptied and depressurised
- Otheranything that does not fit the above
For every point
- Number
- The point’s number on the permit. A new point never reuses an old number, even if a row is archived — the tag on site refers to that number.
- What
- What was isolated, as free text — for example “P-51 suction-side gate valve”.
- Reference
- The on-site identifier: the blinding instruction number, the isolation log entry or the LOTO padlock number.
- Applied / restored by
- The name of the person recording it and the time, at both steps.
The box shows when the work permit template asks for it, when the template requires an isolation certificate, or when a point has already been recorded. Otherwise one button brings it up.
Planned → applied → restored
Every point has three states, and each step goes on the permit with a name and a time.
Planned
The point is recorded on the permit — typically while the issue is being prepared.
Applied
The isolation is in place on site: the “Record as applied” button saves the name and the time.
Restored
At the end of the work the isolation is removed and the equipment may be re-energised. It asks for confirmation, and only an applied point can be restored.
Every step goes into the audit log. Isolation points can be edited from the draft up to an expired permit; on a handed-back, closed or revoked permit they are read-only, but they stay.
The isolation certificate — and when it blocks
Next to the isolation points, the permit can carry a separate isolation certificate (alongside the fire safety, confined space entry, work-area handover, decontamination and contractor assignment documents). It takes a reference number, a validity time and an attached file (PDF or image).
The certificate’s “Attest” button is not a tick but a signature: it goes into the permit’s signature chain with a name and a time. The chain is hash-linked, so it cannot be rewritten afterwards without it showing.
- The template
- decides which permit types need an isolation certificate — among the built-in templates, for example, electrical work and confined space entry ask for one.
- The policy
- decides whether a missing, unattested or expired certificate blocks the issue, warns, or is ignored.
Gas testing on the same permit
After isolating, there is often a measurement to take before anyone enters or starts hot work. The gas test lives in the same grid as the isolation points.
- Five measured values: O₂ (vol%), LEL (%), H₂S (ppm), CO (ppm) and a toxic substance (ppm, with its name), plus the measuring point and the instrument.
- The pass / fail verdict is entered by the person measuring — the system sets no thresholds; it tracks whether there is a valid, complete measurement.
- Validity is set in minutes. The gate always checks the latest test; on an extension an old test that is still valid is not enough, a new one is needed.
- A recorded test cannot be edited or deleted: if there was a mistake, record a new test.
Hand-back and closing: isolations still in place
If an isolation is still in place at hand-back or closing, the permit warns: restore it, or hand over the retained isolation in writing.
This is deliberately a warning and not a block. Keeping an isolation in place can be a conscious decision — for example when the next job continues on the same equipment. A block would push people to “restore” it on screen when it was not restored on site.
On paper and in the report
- The printed and PDF permit lists the isolation points in a separate table: number, method, what, reference, and state with its time.
- The permit report can be exported at isolation level: method, what, reference, who applied it and when, who restored it and when — and how many minutes it stayed open.
What it does not do today
So you know what to expect, we say this too: the isolation points are the isolation list of one job, not a full isolation management system.
- No second-person verification per point: the recording person’s name and time are saved, but there is no separate verifier signature on the point. (Attesting the certificate is a signature.)
- The points on their own do not gate the issue — the gate checks the isolation certificate.
- Restoring is not required for hand-back: it warns, it does not block (see above for why).
- No site-wide isolation register and no conflict detection across permits, and no lock inventory or group lockbox.
- Isolation points are not linked to the maintenance asset register, and they are not shown on the QR live-status page.
If one of these is missing for you, tell us — real plant needs decide the development order.
Further reading
Frequently asked questions
What does LOTO mean in a permit to work?
LOTO (lockout/tagout) locks and tags the energy source of the equipment so it cannot be switched on during the work. In OPEREX, LOTO is one of the isolation point methods: the padlock number goes on the point as its reference, and the permit records who applied it and who removed it.
Can the system block a permit because of a missing isolation?
Because of the isolation certificate, yes: if the template asks for one and the site’s policy is set to block, a missing, unattested or expired certificate stops the issue. The individual isolation points are not checked by the gate today.
What happens if an isolation is still in place at the end of the work?
At hand-back and closing the permit warns about isolations that have not been restored. It does not block, because keeping an isolation can be deliberate; it then has to be handed over in writing.
Are isolations shown on the printed permit?
Yes. The PDF and the printed permit list every isolation point in a separate table, with its method, reference and state.
Does the system track one blind flange across several permits?
No. Isolation points live per permit; there is no site-wide isolation register and no conflict detection across permits today.
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