At 02:10 on a Sunday a variable speed drive on a criticality-1 raw water pump trips on an internal hardware fault. The store shows no spare. The manufacturer lists the module as obsolete, with a last-time-buy window that closed three years ago. The replacement drive has a different footprint, needs a new communications card, and triggers re-commissioning of the control system graphics. Earliest reinstatement is fourteen weeks, on standby capacity throughout (figures illustrative). The maintenance regime did nothing wrong: the PM was completed on time and the drive was nineteen years old. The end-of-life notice arrived as an email to a project engineer who left in 2023.
That is an information failure with a capital consequence. Obsolescence management converts a manufacturer’s lifecycle notice into a dated, ranked and funded replacement while the equipment is still running, and it depends entirely on where that notice is recorded.
The obsolescence register lives on the asset record
Obsolescence data held in one engineer’s spreadsheet goes stale within a quarter. The register has to sit where planners, reliability engineers and buyers already work: as attributes on the asset and item records in the CMMS, reportable without opening a document.
| Attribute | Source | Decision it supports |
|---|---|---|
| Manufacturer, model, hardware revision | Nameplate survey, commissioning records | Matching the installed population to an OEM notice |
| OEM lifecycle status, and the date it was read | Manufacturer lifecycle portal | Whether the item is a watch item or a funded case |
| Announced discontinued date, last-time-buy date | OEM end-of-life notice | The window in which spares can still be bought new |
| Successor part and its migration dependencies | OEM migration guide | The true scope: cabinet, I/O, protocol, functional safety re-validation |
| Count in service, and locations | Asset register | Whether one failure removes redundancy across a site |
| Spares on hand, and consumption over three years | Inventory and issue history | Months of cover at current demand |
| Criticality rating of the parent asset | Criticality assessment | Ranking against everything else competing for capital |
In IBM Maximo Manage these sit as classification attributes on the asset and item master records. The work is the survey that populates them and the owner who keeps lifecycle status current, usually the asset engineering lead for each equipment class.
OEM lifecycle status is the input that dates the risk
The manufacturer declares the state, and the major automation vendors publish those states in named tiers. Rockwell Automation classifies products as Active, Active Mature (fully supported, but a newer family exists), End of Life (discontinued date announced, last-time-buy in progress) and Discontinued (no longer manufactured, repair and exchange services may be available). Software and firmware carry their own tiers, from Preferred through to Retired.
Two operating habits turn that into usable data: a quarterly refresh of lifecycle status for the top tier of the register, recording the date it was read so stale entries are visible, and treating Active Mature as the planning trigger, because it arrives before any discontinued date is fixed and before a last-time-buy window starts running.
Criticality ranks the exposure the board will fund
A register across a large estate returns thousands of obsolete or maturing line items, and that number funds nothing. What a capital review can act on is the intersection: items at End of Life or Discontinued status, installed on high-criticality assets, where spares cover is below the migration lead time and no redundant path exists. On most estates that intersection runs to dozens of lines, short enough for an asset management board to review one by one.
Ranking runs on data the operator already holds: criticality rating, count in service, redundancy and spares cover. The same criticality data should already drive stocking policy for spares, so the register is cheaper to build than it looks, and it exposes every equipment class where criticality has never been rated.
Lead time and spares cover set the replacement date
The replacement date is set by the point at which spares cover runs out before a replacement can be delivered and commissioned. Cover is spares on hand divided by the consumption rate observed over the last three years, extended by what the aftermarket still supplies: Siemens, for example, provides original spare parts for selected products for up to ten years after discontinuation, across more than 70 countries, and Rockwell notes that repair and exchange services may remain available after a product is discontinued.
Migration lead time is the figure operators underestimate, because the part swap is rarely the scope: a replacement controller can pull in a new enclosure, different I/O terminations, a protocol converter, revised drawings, and re-validation where the loop carries a functional safety duty. Those dependencies belong in the register as named items, so the capital plan carries a date for the whole change rather than for the part number.
Last-time-buy decisions need a written authorisation path
A last-time-buy commits cash to inventory that may never be issued, and it is routinely decided informally. It needs a short paper and two signatures: the head of asset management for the risk position, and finance for the holding and write-off exposure. The paper states quantity, its basis (consumption rate multiplied by intended cover period), preservation requirements for electronic assemblies, and the year the stock is expected to be consumed or written off.
Refurbished and grey-market units are the alternative once the window closes, with no traceable service history, no assurance on firmware revision, and a counterfeit risk in the electronics supply chain. Where these are bought, the register records the supplier, test evidence and firmware revision against the item.
The contractual lever is stronger than either. IEC 62402:2019 sets requirements and guidance for obsolescence management, framed around organisations that depend on a supplier for the items they need. That points at the procurement document: a duty on the supplier to notify lifecycle status changes for the installed population, written into the framework agreement or support contract rather than requested after a notice is missed.
Obsolescence cases compete in the same capital pipeline as renewals
HSE’s Key Programme 4, which inspected 33 dutyholders on the UK Continental Shelf between 2011 and 2013 on their handling of ageing and life extension, found obsolescence to be an area of concern, particularly for electrical, control and instrumentation equipment, and recommended comprehensive lists identifying equipment or components that are or could become obsolete.
The register earns its keep when its ranked exposure enters the same investment pipeline as condition-driven renewals and growth schemes, scored on the same consequence basis, with cases sponsored by an asset engineering owner and reviewed quarterly. Operators running structured investment planning carry obsolescence interventions as their own funding category rather than as unbudgeted emergency work on the maintenance revenue line.
What stays hard
OEM announcements arrive unevenly. A large estate carries control and electrical equipment from dozens of manufacturers, few of whom publish machine-readable lifecycle feeds, and consolidation moves product lines between brands. Maintaining the register by hand is defensible for the top tier of critical items and unaffordable across every consumable.
Firmware obsolescence moves faster than hardware and carries a security consequence: a controller running a retired firmware revision is a patching problem as much as a spares problem, which puts obsolescence exposure in the same review as OT cyber security risk.
Nameplate data is the binding constraint on day one. A register cannot be built against an asset population recorded as “drive, various”, and the survey to fix that is field work on live plant with access restrictions.
Closing position
Obsolescence exposure is asset register data, and it should be presented to the board the way condition data is: ranked, dated, sourced and owned. The operator who can name, by part number, every item where discontinued equipment sits on critical duty with less than a year of cover is running obsolescence management. The operator who discovers it at 02:10 funds the same replacement at emergency prices, on standby capacity, with the availability figures already gone for the quarter.