The question of spares is really a question of downtime. A vapor recovery unit that sits waiting for a gasket is not saving money on inventory; it is spending it on emissions, throughput and expedited freight. Yet a site that stocks everything carries dead capital and expiry dates instead. A good spare parts strategy sorts the list by consequence, not by price.
Sort parts by what happens without them
Three classes emerge from every parts list. Consumables: filters, seals and drain parts that wear on a predictable schedule and should be on site in the quantity the schedule implies. Single points of failure: the one sensor or board whose loss stops the unit, where holding one spare is cheap against days of downtime. And everything else: parts that fail rarely, can be sourced within a tolerable window, and belong in the supplier’s warehouse rather than the site’s shelf.
Let the lead times argue for themselves
The honest input to the decision is delivery time, and the honest output is a shelf that matches it. A part that arrives in two days does not need shelf space at a site with a unit that can idle two days without drama. A part with a twelve-week lead time at a remote site is a different conversation entirely. Distance, season and customs realities all push the same direction: the harder the delivery, the stronger the case for holding.
Storage conditions are part of the strategy too. Elastomer parts age on the shelf, electronics want stable conditions, and a spare that expires before it is used is not a spare. Rotating stock, recording receipt dates and storing parts as the manufacturer specifies turn the shelf from a gamble into an inventory.
Writing the list down and reviewing it
- Take the supplier’s recommended spares list as the starting point, not the answer;
- Classify every part: consumable, single point of failure, or sourced-on-demand;
- Adjust the classification with the site’s delivery realities and downtime tolerance;
- Record receipt dates and storage requirements for everything held;
- Review the holding after the first year of real failure history;
- Update the list whenever the unit, its duty or the site’s access changes.
Parts classes and where they belong
| Part class | Where to hold it | Why |
|---|---|---|
| Scheduled consumables | On site, sized to the schedule | They will be used; the only question is when |
| Single points of failure | On site, one each | Downtime cost dwarfs the part cost |
| Long-lead critical parts | On site at remote locations | Delivery time exceeds tolerable downtime |
| Rarely failing, quick to source | At the supplier | Holding them on site is dead capital |
| Expiring items | On site with rotation discipline | An expired spare is not a spare |
The first year teaches the most
No starting list is perfect, and it does not need to be. The first year of operation produces the data that no brochure can: what actually failed, how long delivery actually took, and which shelf items earned their place. Sites that close the loop, feeding real history back into the parts list, end up with holdings that look modest and perform disproportionately well.
Frequently asked questions
Should the supplier just ship a standard spares package?
A standard package is a fine starting list but a poor ending point. Delivery distance, site criticality and duty pattern vary too much for one package to fit all sites. Use it as the raw material for the classification exercise, not as the final answer.
How many consumables should be on the shelf?
Enough to cover the scheduled service interval plus one interval, so a delayed delivery never turns into a missed service. The number comes from the site’s own loading, which the first months of operation establish.
Who owns the spares inventory after handover?
Whoever already owns site maintenance stores, with the vapor recovery list reviewed as part of the normal inventory round. A parts list nobody reviews becomes a shelf of surprises exactly when it is needed.
Luoyang Wohong Petrochemical Equipment Co., Ltd. designs and manufactures vapor recovery units, membrane separation skids and condensers for fuel depots, terminals and retail sites. Contact us for duty assessment and equipment selection support.