In this article6 sections
A spare parts list is the register of replacement parts held in store to keep installed equipment running, with each part tied to the tags it fits. For instruments and valves it names each part, its manufacturer part number, how many are fitted, how many are recommended in each spare category, the unit of measure, the lead time and how the part must be stored. A seal kit for control valve FCV-302 and an electronics module for transmitter PT-101 each take a row, with the tags they serve beside them. The list is built during the project from vendor recommendations, issued to the owner-operator at handover, and loaded into the CMMS material master as stock items.
That makes the spare parts list part of the asset register a CMMS is loaded from. Equipment records come from the instrument index and the valve list, and the spares attach to those records, so a planner raising a work order on a transmitter sees which parts fit it and whether any are in store.
Spare categories on instrument and valve packages
Projects group spares by when they are needed and who buys them. Owners and contracts name the categories differently, and the four below cover most instrument and valve packages.
| Category | What it covers on instruments and valves | When it is specified | Who holds it |
|---|---|---|---|
| Commissioning spares, or start-up spares | Parts consumed or damaged before handover, such as gaskets, valve packing, O-rings, fuses and filter elements | In the material requisition, delivered with the equipment | The construction or commissioning contractor until handover |
| Operating spares, often two-year operating spares | Parts for routine maintenance in the first period of operation, such as packing and seal kits, transmitter electronics, positioner modules and solenoid coils | On the vendor's SPIR after the order is placed, then reviewed and ordered by the owner or by the contractor on its behalf | The owner-operator's warehouse |
| Capital or insurance spares | Long-lead assemblies kept against an unlikely failure that would stop the unit, such as a spare actuator, a valve body with trim or a complete analyzer | By the owner during the project, often on a separate order | The owner-operator, sometimes pooled across sites |
| Special tools | Tools and test equipment the vendor's maintenance procedure calls for, such as a seat-lapping tool or a configuration interface | In the material requisition, delivered with the equipment | The owner's maintenance workshop |
The two years in two-year operating spares is a contract term set in the owner's specification or the purchase order, and some owners use one year or the period to the first planned shutdown. Capital spares are often capitalised like plant equipment, so a spare actuator can sit in the fixed asset register and in the stores catalogue. Special tools sit outside the spare categories, but vendors list them on the same form, so they travel with the list.
Spare parts list, SPIR and bill of materials
Three documents describe spares on a project, and they share enough columns to be confused.
Bill of materials. The vendor's breakdown of an item into its parts, from body and bonnet down to bolts and gaskets, whether or not a spare of each part is held.
SPIR. The spare parts interchangeability record is the vendor's form for one purchase order. It proposes the parts to hold, with part numbers, a quantity for each spare category and columns showing which tags on the order share each part. It is usually a line on the supplier document requirements list, while the commissioning spares are named earlier, in the material requisition.
Spare parts list. The owner's record of the spares held across the plant. It consolidates many SPIRs, received on many forms, into one list with one description per part, keyed by tag and by part, and it loads the stores catalogue.
Columns on an instrument and valve spare parts list
A spare parts list prepared for a CMMS load carries these columns, whatever the owner's template calls them.
| Column | What it holds | Where the value comes from |
|---|---|---|
| Tag | The instrument or valve tag the part serves, or the list of tags that share it | Instrument index and valve list |
| Equipment served | The item type and model code, such as a flow transmitter or a globe control valve | Instrument index, valve list and datasheet |
| Item description | The part name in the owner's description standard | Vendor SPIR, rewritten to the owner's standard |
| Manufacturer part number | The manufacturer's name and the number it sells the part under | Vendor SPIR and vendor drawings |
| Interchangeability | The other tags that use the identical part, often as a group code | SPIR interchangeability columns, checked against model codes |
| Quantity installed | How many of the part are fitted in each tag | Vendor bill of materials |
| Quantity recommended | The quantity proposed for each spare category | Vendor SPIR, then the owner's review |
| Unit of measure | Each, set, kit, pair or metre | Vendor SPIR, mapped to the owner's unit list |
| Lead time | Time from order to delivery | Vendor quotation |
| Storage requirements | Shelf life, temperature and humidity limits, preservation, and handling such as anti-static packaging for electronics | Vendor manual and preservation instructions |
| Owner stock number | The material number issued when the part is catalogued | CMMS material master |
| Source document | The SPIR number and revision the row came from | Supplier document register |
Owners often add a criticality field and a stocking decision. Both come from the owner's maintenance strategy and are filled in during the owner's review of the vendor's recommendation.
Descriptions usually follow a noun-first standard, such as KIT, PACKING, GLOBE VALVE, 2 IN, CLASS 300, so similar parts sort together in the catalogue. The unit of measure decides what one means. A packing set bought as one set and issued as single rings breaks the stock count unless the list states which unit the store holds.
From the instrument index and valve list to the material master
The spare parts list joins three registers. The instrument index and the valve list say which tags exist and what model each one is, and the CMMS material master holds one record per stocked part. The spare parts list links them, tag to part.
The model code on the datasheet makes that link dependable. Flow transmitters FT-101 and FT-102 with the same model code and options take the same electronics module, so the module is one material linked to both tags. A valve list that carries valve model, size, pressure rating, trim and actuator allows the same check on valves, so FCV-302 and TCV-303 share a packing set only when those columns match.
In SAP PM the link is usually an equipment bill of materials listing material numbers against the equipment record. In IBM Maximo the part is an item in the item master, and the asset's spare parts list names the items that fit it. Either way the equipment records come first, and the P&ID to CMMS article covers how tags become those records. ISO 14224 breaks equipment down through subunits and maintainable items to parts, the level a spare attaches at.
Pre-commissioning and commissioning draw on the commissioning spares around mechanical completion, and the unused ones pass to the owner's stores at handover where the contract says so.
Where spares records go wrong
A stock item linked to no tag looks the same in the catalogue as one linked to ten, so these gaps stay hidden until a part is needed. Three patterns recur.
One part number under many descriptions. The same packing set arrives on SPIRs from several orders as packing kit, gland packing set and repair kit. Each becomes its own stock item, so the store holds one part under several numbers and a planner searching one description misses the others. Part numbers written with and without dashes, or replaced by a superseding number, hide the duplicate from a text search. Merge on manufacturer and manufacturer part number before a stock number is issued.
Spares for removed equipment. A transmitter replaced by a different model, a valve taken out in a modification or a package decommissioned leaves its spares in stock with no installed tag. The part-to-tag link exposes them once the tag is marked removed on the instrument index or valve list. Check the list against the as-built registers, and keep removed tags with a removed status so their spares still trace back to them.
Missing interchangeability across identical items. Identical transmitters bought on three orders arrive with three SPIRs, each recording interchangeability only within its own order. The store then holds three sets of spares for one model, and when a transmitter fails its tag can show no spare while an identical module sits under another order. Grouping tags by model code across orders closes the gap.
Checks before the spares load
Run these on the draft list before it goes into the CMMS.
- Each row names a tag on the current instrument index or valve list, or carries a status that says why the tag is absent.
- Each manufacturer part number appears once, with one description and one unit of measure.
- Each group of tags sharing a model code carries one interchangeability group.
Spares attach to equipment records, so the load depends on a tag register that matches the plant. Tagsight builds the CMMS asset register from the plant's own P&IDs, with the equipment and instruments taken off the drawings and exported for IBM Maximo, SAP PM or Excel.