Preservation work lists: keeping idle equipment alive until start-up.

1. Why preservation exists

On a capital project the gap between installation and first operation is routinely measured in years. During that period, bearings sit under static load, seals dry out, internal surfaces corrode, desiccant saturates, and instruments drift out of calibration.

Preservation is the programme of recurring interventions that prevents this. It is also a warranty condition: most vendors will decline a claim if the preservation regime they specified was not followed and cannot be evidenced.

2. What goes on a preservation work list

A preservation work list (PWL) is the register of every tag requiring preservation, the routine that applies to it, its cadence, and its responsible party. It typically covers:

• Rotating equipment — shaft rotation at a set interval, lubrication, coupling checks.
• Electrical equipment — space heaters energised, insulation resistance readings, enclosure inspection.
• Instrumentation — desiccant replacement, calibration validity, protection from ingress.
• Piping and vessels — nitrogen blanketing pressure, inhibitor dosing, drainage checks.
• Packaged units — whatever the vendor manual specifies, which is the source of truth for warranty.

3. Cadence is the hard part

Unlike ITRs, preservation routines do not complete — they repeat. A tag might need shaft rotation monthly for three years. That produces a stream of tasks whose value depends entirely on whether they happened on time, not just whether they happened.

This is why preservation is poorly served by a spreadsheet. A static list cannot tell you what is due this week, what is overdue, and which overdue items belong to equipment whose warranty is conditional on the interval being met. That calculation has to run continuously — see preservation management.

4. Who owns it

Preservation responsibility shifts across the project and this transition is where cycles get missed. Typically the vendor specifies the regime, the installing contractor executes it from delivery, and responsibility transfers to the commissioning team or operator at some defined point — often mechanical completion or RFSU.

Each transfer should be an explicit event with a record. The most common preservation failure on a project is not poor execution; it is a three-week gap during a handover that nobody noticed until an audit.

5. What good evidence looks like

• The routine performed, against the specific tag, with the date and the person.
• The reading or observation where one applies — pressure held, resistance measured, hours logged.
• A photo for anything visual, particularly enclosure and ingress condition.
• The vendor requirement it satisfies, so a warranty claim can be traced back to the specification.

If a claim is made two years later, the question will be whether the interval was met continuously. A list of completions with dates answers it. A folder of scanned sheets does not.

6. Where preservation programmes fail

1. The list is built late. Equipment arrives on site months before the PWL exists, so the first cycles are missed by default.
2. Cadence is not tracked. Tasks are completed when someone remembers, which is not the same as on interval.
3. Handover gaps. Responsibility transfers without an explicit date, leaving an unpreserved window.
4. No overdue visibility. Nobody sees the backlog until an audit or a failed start-up finds it.
5. Evidence separated from the tag. Sheets filed by week rather than by equipment, so per-tag history cannot be reconstructed.