What this is
What is a spares criticality review?
What is a spares criticality review?
It is a periodic review that works through the parts fitted to critical and important assets and decides, part by part, whether each should be held on site, held by the supplier, shared across sites, or accepted as a risk. It weighs lead time and asset criticality against the cost of holding stock, and is built against ISO 55001 clause 8.1.
How is it different from an equipment FMEA?
An FMEA works out how an asset can fail and how likely each failure mode is to be detected. This review starts from that criticality output and asks a narrower question: if the failure happens, can the part actually be replaced quickly enough, and is holding stock for it worth the cost.
Why does lead time matter as much as criticality?
A critical asset with a same-day local supplier needs no stock at all, while an important asset with a single overseas source and a twelve-week lead time can justify holding stock even though it fails rarely. The review exists because criticality alone answers the wrong question.
Scope
When is a spares criticality review required?
This review is one step in the Reliability and Predictive Maintenance programme. Using it to record a single part's failure history, or to set an asset's overall maintenance strategy, produces records that are hard to report on later.
Use this template when
- The yearly review interval has come round, or a trigger event has flagged it early
- A new record is needed; each one gets its own ID in the form SCR3-2026-000
- You are running the Reliability and Predictive Maintenance programme and this review is one of its steps
- A linked record needs this one to exist: it links to Asset and Parts registers
- An FMEA has just re-rated an asset's criticality and the spares holding needs re-checking against it
Do not use it for
- Equipment FMEA, which works through how an asset could fail, what the effect would be and how likely it is to be detected, and feeds criticality into this review rather than duplicating it.
- Reliability Centred Maintenance Study, which decides the maintenance strategy for a failure mode, not whether a part for it should sit on a shelf.
- MTBF Review, which reviews failure frequency trends over a period, rather than a stocking decision on individual parts.
- Repeat Failure Review, which looks at why an asset keeps failing, not what it would cost to be ready for the next one.
- Anything outside KnowMaintain, which belongs in the workspace that owns that process.
Compliance mapping
Which ISO 55001 cl.8.1 requirements does this satisfy?
ISO 55001 clause 8.1 requires operational planning and control that manages risk to asset performance — this review is where that requirement becomes a specific stocking decision, part by part.
| Clause | Requirement | Where it lands |
|---|---|---|
| ISO 55001 cl.8.1 | Operational controls must be established to manage risks that could prevent an asset delivering its intended function. | Header |
| ISO 55001 cl.8.1 | Criticality and lead time must be assessed together for each part, not treated as independent factors. | Parts assessed |
| ISO 55001 cl.8.1 | The cost of not having a part available must be weighed against the cost of holding it before a stocking decision is made. | Parts assessed |
| ISO 55001 cl.8.1 | Obsolescence and shelf-life risk must be assessed alongside failure and usage history so stock does not simply age out unnoticed. | Parts assessed |
| ISO 55001 cl.8.1 | The failure-mode analysis that established criticality must be cross-referenced when it is available. | Related records |
| ISO 55001 cl.8.1 | The number of critical assets left without adequate spares must be reported as a distinct outcome of the review, not implied by the parts list. | Result |
| ISO 55001 cl.8.1 | Actions arising from the review must be assigned an owner and, where raised, a corrective action reference. | Result |
What it does not cover
- A part rated Critical asset criticality with Lead Time Weeks left blank, which removes the exact figure the stocking decision is supposed to turn on.
- A Stocking Decision of 'Accept the risk' with no entry in Cost Of Not Having It, which leaves the acceptance undefended if the part then fails.
- Single Source marked 'Yes' with Alternative Sourcing Possible also left blank, which skips the cheaper option — a supplier holding agreement — before defaulting to on-site stock.
- Critical Assets Without Spares reported as zero with no parts list to support it, which is a result nobody can check against the review that produced it.
- Action Required marked 'Yes' with no CAPA ID or Action Owner entered, which leaves a flagged gap with nobody accountable for closing it.
Global
Spares Criticality Review requirements by country
Spares holding is rarely mandated directly, but it sits underneath obligations that are — the review's stocking decisions are what keep those obligations achievable in practice.
ISO 55001, clause 8.1
Requires operational planning and control of the risks that threaten an asset's intended function, without prescribing how much spares stock that requires.
The standard sets the obligation to manage the risk; this review is the evidence that lead time and criticality were actually weighed, not just assumed adequate.
Provision and Use of Work Equipment Regulations 1998 (PUWER), reg. 5
Requires work equipment to be maintained in an efficient state, which in practice depends on being able to source the parts a maintenance regime calls for.
A PUWER maintenance duty that assumes parts availability is only as sound as the spares review behind it — an unstocked, long-lead-time part can turn a routine repair into an extended non-compliant outage.
OSHA 29 CFR 1910.119(j) — mechanical integrity
Process safety management facilities must maintain the mechanical integrity of covered equipment, including timely correction of deficiencies.
Where a covered process depends on a single-source, long-lead-time part, the mechanical integrity obligation to correct deficiencies 'in a safe and timely manner' is only achievable if this review has already secured that part's availability.
How to complete it
How to complete a spares criticality review, step by step
Entering the numbers is the easy part. These are the calls that decide whether the resulting stocking decisions actually hold up against the next failure.
Asset Criticality can be inherited from an old rating that no longer reflects how the asset is used. A part on a Critical asset that is now largely a standby unit needs a different stocking answer than one on a Critical asset running continuously.
A single-source part isn't automatically a stock-it decision if a supplier holding agreement is realistic — that alternative is often cheaper than carrying inventory, and skipping the check defaults every single-source part to on-site stock by habit.
This figure is lead time multiplied by the cost of downtime, and it is the number that actually justifies stock — a Recommended Minimum set without it is a guess dressed up as a decision.
A part flagged High on obsolescence but still stocked at its old Recommended Minimum is a decision quietly deferred, not made — the review needs to either commit to a last-buy or set a plan to requalify an alternative before the part disappears from the market.
What auditors find
Most common spares criticality review findings
Patterns worth checking before a spares review is treated as complete.
| Finding | Clause | What fixes it |
|---|---|---|
| Asset Criticality is Critical but Lead Time Weeks is left blank for the part fitted to it. | ISO 55001 cl.8.1 | Require a lead time entry whenever the fitted asset is rated Critical — it is the field the stocking decision actually depends on. |
| Stocking Decision is 'Accept the risk' with no figure in Cost Of Not Having It. | ISO 55001 cl.8.1 | Require the cost-of-absence figure before 'accept the risk' can be selected, so the acceptance is a calculated one. |
| Single Source is 'Yes' and Alternative Sourcing Possible is left blank. | ISO 55001 cl.8.1 | Force an Alternative Sourcing Possible answer whenever Single Source is Yes, before a hold-on-site decision defaults in. |
| Shelf Life Limited is marked 'Yes' but Recommended Maximum is not revisited from the prior review. | ISO 55001 cl.8.1 | Flag shelf-life-limited parts for a maximum-stock review each cycle, rather than carrying the same figure forward. |
| Critical Assets Without Spares is reported but does not match the count of Critical-rated parts with a Stocking Decision of 'Accept the risk'. | ISO 55001 cl.8.1 | Derive the Critical Assets Without Spares total directly from the parts list rather than entering it separately. |
| Action Required is 'Yes' with no CAPA ID or Action Owner recorded. | ISO 55001 cl.8.1 | Make CAPA ID and Action Owner mandatory together whenever Action Required is Yes, so a flagged gap has a named owner from the outset. |
Case in point
Case in point: the gearbox that was never rated worth stocking
A packing line gearbox was rated Important rather than Critical, because the line had a manual fallback. Its replacement had a single overseas source and a lead time of eleven weeks, but because the asset itself wasn't Critical, the part never surfaced in a prior spares review built around asset criticality alone.
When the gearbox failed, the manual fallback covered roughly a third of the line's output. Eleven weeks of reduced throughput cost several times what a single spare would have. The following review added Lead Time Weeks and Cost Of Not Having It as required fields for every Important-rated asset, not only Critical ones.
The template
The template, field by field
The form exactly as it installs. Every field, option, score and conditional rule is editable, and the links to other templates come with it.
4 sections
- Reference
- MNT-054
- Archetype
- Review
- Record ID
- SCR3-2026-000
- Scoring
- Stocking decision
- Direction
- n/a
- Singleton
- No
- Basis
- ISO 55001 cl.8.1
- Links
- Links Asset, Parts
- Tags
- Reliability, Parts
- Sections
- 4
- Fields
- 44
- Follow up fields
- 3
- Repeating sections
- 1
- Links out
- 4
Header
12 fieldsReview ID*
Auto sequence. Format SCR3-2026-000.
The record's own ID. Other templates point at this value.
Status*
Drives who this goes to next.
- Planned2 pts
- In progress2 pts
- Complete3 pts
- Deferred0 pts
- Open0 pts
- Closed3 pts
- Overdue0 pts
Date and Time*
Raised By*
Site*
Site ID*
Format SITE-000.
Links to FDN-001 Site ID
Area
The area within the site.
Exact Location
Drop a pin for anything hard to find.
Lead Time Times Criticality
The question is not what fails often, it is what would stop you for weeks if it failed and could not be replaced. Long lead time on a critical asset is where spares earn their keep.
Period Reviewed*
Reviewed By*
Scope*
Parts assessed
Repeats17 fieldsPart Description*
Part Number
Fitted To
Asset Criticality*
Lead Time Weeks*
Single Source*
- No3 pts
- Yes0 pts
Failure Rate History*
- Pass2 pts
- Partial1 pt
- Fail0 pts
- N/Aexcluded from denominator
Usage Last 24 Months
Current Stock Level
Unit Cost
Cost Of Not Having It
Lead time multiplied by the cost of downtime. This is the number that justifies the stock.
Shelf Life Limited
- No3 pts
- Yes1 pt
Stocking Decision*
Recommended Minimum
Recommended Maximum
Alternative Sourcing Possible
A supplier agreement to hold stock is often cheaper than holding it yourself.
- Yes3 pts
- No0 pts
Obsolescence Risk*
- None3 pts
- Emerging1 pt
- High0 pts
Related records
1 fieldFMEA ID
The failure modes that set the criticality.
Links to MNT-049 Assessment ID
Result
14 fieldsParts Reviewed*
Parts Added To Stock*
Parts Removed From Stock*
Critical Assets Without Spares*
Obsolete Parts Identified*
Stock Value Change
Action Required*
Raise the action record, then enter its reference here.
- No2 pts
- Yes0 pts
Priority
- High0 pts
- Medium1 pt
- Low3 pts
CAPA ID
Format CAPA-2026-00000.
Links to FDN-014 CAPA ID
Action Owner
Planner*
Signature*
Maintenance Manager*
Second Signature*
MNT-054 · record IDs look like SCR3-2026-000 · Links Asset, Parts
Open in KnowellaRun it with agents
From a document you fill in to a programme that runs itself
The form is the easy part. Keeping the stocking decisions current as lead times and suppliers shift is the work that actually slips.
Holds the spares review against the asset and parts registers, so criticality and lead time are checked together rather than from memory.
Tracks supplier lead time and single-source risk over time, so Lead Time Weeks reflects the current market, not last year's order.
Rolls Critical Assets Without Spares and Action Required flags into one operating view, so a gap raised in a review doesn't sit unassigned.
Coordinates the crew across these workspaces, surfaces overdue stocking actions, and holds every write for your approval before it touches a record.
This template lives in KnowMaintain — asset maintenance. Work orders, planned maintenance, calibration, reliability and shutdowns.
Meet KnowMaintain→Glossary
Spares Criticality Review definitions and key terms
- SCR3
- Spares Criticality Review — this template's own record type, the periodic assessment behind each stocking decision.
- Single source
- A part available from only one supplier, which removes the option of competitive lead time or price if that supplier is delayed.
- Lead time
- The time between placing an order for a part and having it available on site — the figure that, multiplied against downtime cost, justifies holding stock.
- Obsolescence risk
- The likelihood that a part will stop being manufactured or supported before the asset it fits is retired.
- CAPA
- Corrective and Preventive Action — the record raised when a review finds a gap, such as a critical asset left without adequate spares.
FAQ
Frequently asked questions about spares criticality review
Does every part fitted to an asset need to go through this review?+
No. The Scope field sets whether a given cycle covers a whole site, a single area, a single process, or all sites — most reviews focus on parts for Critical and Important assets, since Standard-rated assets rarely justify the effort.
What if a part's lead time changes between reviews?+
Lead Time Weeks is re-entered each cycle rather than carried forward, precisely because supplier lead times shift — a part that was a two-week order last year can become a twelve-week one without any change to the asset itself.
Who decides between holding stock and accepting the risk?+
The Stocking Decision field is set by the planner and procurement together, informed by the scored fields, but it is a judgement call — Recommended Minimum and Maximum only make sense once that decision is made, not before.
How does this review connect to an FMEA?+
Where an FMEA has been run on the asset, its ID is recorded in Related Records, since the failure modes it identified are what set the criticality this review starts from.
What happens to obsolete parts identified during the review?+
They are counted in the Result section as Obsolete Parts Identified, and where action is needed, a CAPA is raised — typically to qualify a replacement part or secure a last-time buy before the original goes out of production.
Does a completed review guarantee stock is correct until the next cycle?+
No. It is a point-in-time decision. A trigger event — a new FMEA rating, a supplier ceasing to stock a part, or a failure that exposes a gap — can and should prompt an earlier review of the affected parts.
Keep going
Related templates and programmes
Industries this is written for
Programmes this belongs to
Used together in Reliability and Predictive Maintenance
Root Cause Analysis
Finds out why something happened rather than who was involved
Equipment Failure Report
Records that an asset has failed and stopped or degraded production
Failure Mode Record
Records how an asset failed, using standard failure mode codes rather than free text
Repair Record
Records what was actually done to fix the asset, including parts replaced and settings changed
Temporary Repair Record
Records a repair that is not permanent, with an expiry date and a plan for the proper fix
Repeat Failure Review
Reviews an asset that has failed the same way more than once
More in Reliability
Equipment FMEA
Works through how an asset could fail, what the effect would be and how likely it is to be detected
Reliability Centred Maintenance Study
Decides the right maintenance strategy for each failure mode, from run to failure through to condition monitoring
MTBF Review
Reviews mean time between failures for an asset or asset class over a period
PM Optimization Review
Reviews whether preventive tasks are set at the right frequency, using actual failure and finding data
Root Cause Failure Analysis Trigger
Decides whether a failure warrants a full investigation, based on cost, safety and repeat history
Written and reviewed by
Siddarth Singh
Founder & Chief Executive Officer, Knowella
Certified Safety Professional and industrial and systems engineer with more than a decade inside food supply chain, freight and manufacturing operations. This page was written against the current text of the standards it cites, not against secondary summaries of them.
- Certified Safety Professional (CSP), Board of Certified Safety Professionals
- MBA, University of Chicago Booth School of Business
- MS and BS, The Ohio State University, Industrial and Systems Engineering
- Six Sigma Black Belt
Sources and last review. Reviewed 16 August 2026 against:
- ISO 55001, clause 8.1 — Operational planning and control
- Provision and Use of Work Equipment Regulations 1998, reg. 5 — Maintenance
- OSHA 29 CFR 1910.119(j) — Process safety management, mechanical integrity
- ISO 14224 — Reliability and maintenance data, equipment taxonomy
This page is general guidance, not legal advice. Confirm requirements with your jurisdiction’s regulator.